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b60e714dc3
If TIF_SYSCALL_TRACE or TIF_SINGLESTEP is set while inside a syscall,
the path back to user mode should get to syscall_trace_leave.
This does happen in most circumstances. The exception to this is on
the 64-bit syscall fastpath, when no such flag was set on syscall
entry and nothing else has punted it off the fastpath for exit. That
one exit fastpath fails to check for _TIF_WORK_SYSCALL_EXIT flags.
This makes the behavior inconsistent with what 32-bit tasks see and
what the native 32-bit kernel always does, and what 64-bit tasks see
in all cases where the iret path is taken anyhow.
Perhaps the only example that is affected is a ptrace stop inside
do_fork (for PTRACE_O_TRACE{CLONE,FORK,VFORK,VFORKDONE}). Other
syscalls with internal ptrace stop points (execve) already take the
iret exit path for unrelated reasons.
Test cases for both PTRACE_SYSCALL and PTRACE_SINGLESTEP variants are at:
http://sources.redhat.com/cgi-bin/cvsweb.cgi/~checkout~/tests/ptrace-tests/tests/syscall-from-clone.c?cvsroot=systemtap
http://sources.redhat.com/cgi-bin/cvsweb.cgi/~checkout~/tests/ptrace-tests/tests/step-from-clone.c?cvsroot=systemtap
There was no special benefit to the sysret path's special path to call
do_notify_resume, because it always takes the iret exit path at the end.
So this change just makes the sysret exit path join the iret exit path
for all the signals and ptrace cases. The fastpath still applies to
the plain syscall-audit and resched cases.
Signed-off-by: Roland McGrath <roland@redhat.com>
CC: Oleg Nesterov <oleg@redhat.com>
1589 lines
38 KiB
ArmAsm
1589 lines
38 KiB
ArmAsm
/*
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* linux/arch/x86_64/entry.S
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*
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* Copyright (C) 1991, 1992 Linus Torvalds
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* Copyright (C) 2000, 2001, 2002 Andi Kleen SuSE Labs
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* Copyright (C) 2000 Pavel Machek <pavel@suse.cz>
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*/
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/*
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* entry.S contains the system-call and fault low-level handling routines.
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*
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* NOTE: This code handles signal-recognition, which happens every time
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* after an interrupt and after each system call.
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*
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* Normal syscalls and interrupts don't save a full stack frame, this is
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* only done for syscall tracing, signals or fork/exec et.al.
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*
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* A note on terminology:
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* - top of stack: Architecture defined interrupt frame from SS to RIP
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* at the top of the kernel process stack.
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* - partial stack frame: partially saved registers upto R11.
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* - full stack frame: Like partial stack frame, but all register saved.
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*
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* Some macro usage:
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* - CFI macros are used to generate dwarf2 unwind information for better
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* backtraces. They don't change any code.
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* - SAVE_ALL/RESTORE_ALL - Save/restore all registers
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* - SAVE_ARGS/RESTORE_ARGS - Save/restore registers that C functions modify.
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* There are unfortunately lots of special cases where some registers
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* not touched. The macro is a big mess that should be cleaned up.
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* - SAVE_REST/RESTORE_REST - Handle the registers not saved by SAVE_ARGS.
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* Gives a full stack frame.
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* - ENTRY/END Define functions in the symbol table.
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* - FIXUP_TOP_OF_STACK/RESTORE_TOP_OF_STACK - Fix up the hardware stack
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* frame that is otherwise undefined after a SYSCALL
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* - TRACE_IRQ_* - Trace hard interrupt state for lock debugging.
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* - errorentry/paranoidentry/zeroentry - Define exception entry points.
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*/
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#include <linux/linkage.h>
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#include <asm/segment.h>
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#include <asm/cache.h>
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#include <asm/errno.h>
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#include <asm/dwarf2.h>
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#include <asm/calling.h>
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#include <asm/asm-offsets.h>
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#include <asm/msr.h>
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#include <asm/unistd.h>
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#include <asm/thread_info.h>
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#include <asm/hw_irq.h>
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#include <asm/page_types.h>
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#include <asm/irqflags.h>
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#include <asm/paravirt.h>
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#include <asm/ftrace.h>
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#include <asm/percpu.h>
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/* Avoid __ASSEMBLER__'ifying <linux/audit.h> just for this. */
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#include <linux/elf-em.h>
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#define AUDIT_ARCH_X86_64 (EM_X86_64|__AUDIT_ARCH_64BIT|__AUDIT_ARCH_LE)
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#define __AUDIT_ARCH_64BIT 0x80000000
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#define __AUDIT_ARCH_LE 0x40000000
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.code64
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#ifdef CONFIG_FUNCTION_TRACER
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#ifdef CONFIG_DYNAMIC_FTRACE
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ENTRY(mcount)
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retq
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END(mcount)
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ENTRY(ftrace_caller)
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cmpl $0, function_trace_stop
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jne ftrace_stub
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MCOUNT_SAVE_FRAME
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movq 0x38(%rsp), %rdi
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movq 8(%rbp), %rsi
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subq $MCOUNT_INSN_SIZE, %rdi
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GLOBAL(ftrace_call)
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call ftrace_stub
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MCOUNT_RESTORE_FRAME
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#ifdef CONFIG_FUNCTION_GRAPH_TRACER
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GLOBAL(ftrace_graph_call)
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jmp ftrace_stub
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#endif
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GLOBAL(ftrace_stub)
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retq
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END(ftrace_caller)
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#else /* ! CONFIG_DYNAMIC_FTRACE */
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ENTRY(mcount)
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cmpl $0, function_trace_stop
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jne ftrace_stub
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cmpq $ftrace_stub, ftrace_trace_function
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jnz trace
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#ifdef CONFIG_FUNCTION_GRAPH_TRACER
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cmpq $ftrace_stub, ftrace_graph_return
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jnz ftrace_graph_caller
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cmpq $ftrace_graph_entry_stub, ftrace_graph_entry
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jnz ftrace_graph_caller
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#endif
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GLOBAL(ftrace_stub)
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retq
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trace:
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MCOUNT_SAVE_FRAME
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movq 0x38(%rsp), %rdi
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movq 8(%rbp), %rsi
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subq $MCOUNT_INSN_SIZE, %rdi
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call *ftrace_trace_function
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MCOUNT_RESTORE_FRAME
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jmp ftrace_stub
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END(mcount)
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#endif /* CONFIG_DYNAMIC_FTRACE */
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#endif /* CONFIG_FUNCTION_TRACER */
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#ifdef CONFIG_FUNCTION_GRAPH_TRACER
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ENTRY(ftrace_graph_caller)
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cmpl $0, function_trace_stop
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jne ftrace_stub
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MCOUNT_SAVE_FRAME
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leaq 8(%rbp), %rdi
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movq 0x38(%rsp), %rsi
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movq (%rbp), %rdx
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subq $MCOUNT_INSN_SIZE, %rsi
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call prepare_ftrace_return
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MCOUNT_RESTORE_FRAME
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retq
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END(ftrace_graph_caller)
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GLOBAL(return_to_handler)
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subq $24, %rsp
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/* Save the return values */
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movq %rax, (%rsp)
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movq %rdx, 8(%rsp)
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movq %rbp, %rdi
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call ftrace_return_to_handler
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movq %rax, 16(%rsp)
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movq 8(%rsp), %rdx
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movq (%rsp), %rax
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addq $16, %rsp
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retq
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#endif
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#ifndef CONFIG_PREEMPT
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#define retint_kernel retint_restore_args
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#endif
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#ifdef CONFIG_PARAVIRT
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ENTRY(native_usergs_sysret64)
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swapgs
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sysretq
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ENDPROC(native_usergs_sysret64)
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#endif /* CONFIG_PARAVIRT */
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.macro TRACE_IRQS_IRETQ offset=ARGOFFSET
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#ifdef CONFIG_TRACE_IRQFLAGS
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bt $9,EFLAGS-\offset(%rsp) /* interrupts off? */
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jnc 1f
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TRACE_IRQS_ON
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1:
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#endif
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.endm
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/*
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* C code is not supposed to know about undefined top of stack. Every time
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* a C function with an pt_regs argument is called from the SYSCALL based
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* fast path FIXUP_TOP_OF_STACK is needed.
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* RESTORE_TOP_OF_STACK syncs the syscall state after any possible ptregs
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* manipulation.
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*/
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/* %rsp:at FRAMEEND */
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.macro FIXUP_TOP_OF_STACK tmp offset=0
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movq PER_CPU_VAR(old_rsp),\tmp
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movq \tmp,RSP+\offset(%rsp)
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movq $__USER_DS,SS+\offset(%rsp)
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movq $__USER_CS,CS+\offset(%rsp)
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movq $-1,RCX+\offset(%rsp)
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movq R11+\offset(%rsp),\tmp /* get eflags */
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movq \tmp,EFLAGS+\offset(%rsp)
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.endm
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.macro RESTORE_TOP_OF_STACK tmp offset=0
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movq RSP+\offset(%rsp),\tmp
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movq \tmp,PER_CPU_VAR(old_rsp)
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movq EFLAGS+\offset(%rsp),\tmp
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movq \tmp,R11+\offset(%rsp)
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.endm
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.macro FAKE_STACK_FRAME child_rip
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/* push in order ss, rsp, eflags, cs, rip */
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xorl %eax, %eax
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pushq $__KERNEL_DS /* ss */
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CFI_ADJUST_CFA_OFFSET 8
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/*CFI_REL_OFFSET ss,0*/
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pushq %rax /* rsp */
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CFI_ADJUST_CFA_OFFSET 8
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CFI_REL_OFFSET rsp,0
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pushq $X86_EFLAGS_IF /* eflags - interrupts on */
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CFI_ADJUST_CFA_OFFSET 8
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/*CFI_REL_OFFSET rflags,0*/
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pushq $__KERNEL_CS /* cs */
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CFI_ADJUST_CFA_OFFSET 8
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/*CFI_REL_OFFSET cs,0*/
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pushq \child_rip /* rip */
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CFI_ADJUST_CFA_OFFSET 8
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CFI_REL_OFFSET rip,0
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pushq %rax /* orig rax */
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CFI_ADJUST_CFA_OFFSET 8
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.endm
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.macro UNFAKE_STACK_FRAME
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addq $8*6, %rsp
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CFI_ADJUST_CFA_OFFSET -(6*8)
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.endm
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/*
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* initial frame state for interrupts (and exceptions without error code)
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*/
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.macro EMPTY_FRAME start=1 offset=0
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.if \start
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CFI_STARTPROC simple
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CFI_SIGNAL_FRAME
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CFI_DEF_CFA rsp,8+\offset
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.else
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CFI_DEF_CFA_OFFSET 8+\offset
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.endif
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.endm
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/*
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* initial frame state for interrupts (and exceptions without error code)
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*/
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.macro INTR_FRAME start=1 offset=0
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EMPTY_FRAME \start, SS+8+\offset-RIP
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/*CFI_REL_OFFSET ss, SS+\offset-RIP*/
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CFI_REL_OFFSET rsp, RSP+\offset-RIP
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/*CFI_REL_OFFSET rflags, EFLAGS+\offset-RIP*/
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/*CFI_REL_OFFSET cs, CS+\offset-RIP*/
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CFI_REL_OFFSET rip, RIP+\offset-RIP
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.endm
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/*
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* initial frame state for exceptions with error code (and interrupts
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* with vector already pushed)
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*/
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.macro XCPT_FRAME start=1 offset=0
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INTR_FRAME \start, RIP+\offset-ORIG_RAX
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/*CFI_REL_OFFSET orig_rax, ORIG_RAX-ORIG_RAX*/
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.endm
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/*
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* frame that enables calling into C.
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*/
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.macro PARTIAL_FRAME start=1 offset=0
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XCPT_FRAME \start, ORIG_RAX+\offset-ARGOFFSET
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CFI_REL_OFFSET rdi, RDI+\offset-ARGOFFSET
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CFI_REL_OFFSET rsi, RSI+\offset-ARGOFFSET
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CFI_REL_OFFSET rdx, RDX+\offset-ARGOFFSET
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CFI_REL_OFFSET rcx, RCX+\offset-ARGOFFSET
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CFI_REL_OFFSET rax, RAX+\offset-ARGOFFSET
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CFI_REL_OFFSET r8, R8+\offset-ARGOFFSET
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CFI_REL_OFFSET r9, R9+\offset-ARGOFFSET
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CFI_REL_OFFSET r10, R10+\offset-ARGOFFSET
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CFI_REL_OFFSET r11, R11+\offset-ARGOFFSET
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.endm
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/*
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* frame that enables passing a complete pt_regs to a C function.
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*/
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.macro DEFAULT_FRAME start=1 offset=0
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PARTIAL_FRAME \start, R11+\offset-R15
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CFI_REL_OFFSET rbx, RBX+\offset
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CFI_REL_OFFSET rbp, RBP+\offset
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CFI_REL_OFFSET r12, R12+\offset
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CFI_REL_OFFSET r13, R13+\offset
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CFI_REL_OFFSET r14, R14+\offset
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CFI_REL_OFFSET r15, R15+\offset
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.endm
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/* save partial stack frame */
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ENTRY(save_args)
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XCPT_FRAME
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cld
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movq_cfi rdi, RDI+16-ARGOFFSET
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movq_cfi rsi, RSI+16-ARGOFFSET
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movq_cfi rdx, RDX+16-ARGOFFSET
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movq_cfi rcx, RCX+16-ARGOFFSET
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movq_cfi rax, RAX+16-ARGOFFSET
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movq_cfi r8, R8+16-ARGOFFSET
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movq_cfi r9, R9+16-ARGOFFSET
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movq_cfi r10, R10+16-ARGOFFSET
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movq_cfi r11, R11+16-ARGOFFSET
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leaq -ARGOFFSET+16(%rsp),%rdi /* arg1 for handler */
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movq_cfi rbp, 8 /* push %rbp */
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leaq 8(%rsp), %rbp /* mov %rsp, %ebp */
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testl $3, CS(%rdi)
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je 1f
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SWAPGS
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/*
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* irq_count is used to check if a CPU is already on an interrupt stack
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* or not. While this is essentially redundant with preempt_count it is
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* a little cheaper to use a separate counter in the PDA (short of
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* moving irq_enter into assembly, which would be too much work)
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*/
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1: incl PER_CPU_VAR(irq_count)
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jne 2f
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popq_cfi %rax /* move return address... */
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mov PER_CPU_VAR(irq_stack_ptr),%rsp
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EMPTY_FRAME 0
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pushq_cfi %rbp /* backlink for unwinder */
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pushq_cfi %rax /* ... to the new stack */
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/*
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* We entered an interrupt context - irqs are off:
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*/
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2: TRACE_IRQS_OFF
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ret
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CFI_ENDPROC
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END(save_args)
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ENTRY(save_rest)
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PARTIAL_FRAME 1 REST_SKIP+8
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movq 5*8+16(%rsp), %r11 /* save return address */
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movq_cfi rbx, RBX+16
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movq_cfi rbp, RBP+16
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movq_cfi r12, R12+16
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movq_cfi r13, R13+16
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movq_cfi r14, R14+16
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movq_cfi r15, R15+16
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movq %r11, 8(%rsp) /* return address */
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FIXUP_TOP_OF_STACK %r11, 16
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ret
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CFI_ENDPROC
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END(save_rest)
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/* save complete stack frame */
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.pushsection .kprobes.text, "ax"
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ENTRY(save_paranoid)
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XCPT_FRAME 1 RDI+8
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cld
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movq_cfi rdi, RDI+8
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movq_cfi rsi, RSI+8
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movq_cfi rdx, RDX+8
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movq_cfi rcx, RCX+8
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movq_cfi rax, RAX+8
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movq_cfi r8, R8+8
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movq_cfi r9, R9+8
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movq_cfi r10, R10+8
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movq_cfi r11, R11+8
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movq_cfi rbx, RBX+8
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movq_cfi rbp, RBP+8
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movq_cfi r12, R12+8
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movq_cfi r13, R13+8
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movq_cfi r14, R14+8
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movq_cfi r15, R15+8
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movl $1,%ebx
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movl $MSR_GS_BASE,%ecx
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rdmsr
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testl %edx,%edx
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js 1f /* negative -> in kernel */
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SWAPGS
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xorl %ebx,%ebx
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1: ret
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CFI_ENDPROC
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END(save_paranoid)
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.popsection
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/*
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* A newly forked process directly context switches into this address.
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*
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* rdi: prev task we switched from
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*/
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ENTRY(ret_from_fork)
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DEFAULT_FRAME
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LOCK ; btr $TIF_FORK,TI_flags(%r8)
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push kernel_eflags(%rip)
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CFI_ADJUST_CFA_OFFSET 8
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popf # reset kernel eflags
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CFI_ADJUST_CFA_OFFSET -8
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call schedule_tail # rdi: 'prev' task parameter
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GET_THREAD_INFO(%rcx)
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RESTORE_REST
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testl $3, CS-ARGOFFSET(%rsp) # from kernel_thread?
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je int_ret_from_sys_call
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testl $_TIF_IA32, TI_flags(%rcx) # 32-bit compat task needs IRET
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jnz int_ret_from_sys_call
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RESTORE_TOP_OF_STACK %rdi, -ARGOFFSET
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jmp ret_from_sys_call # go to the SYSRET fastpath
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CFI_ENDPROC
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END(ret_from_fork)
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/*
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* System call entry. Upto 6 arguments in registers are supported.
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*
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* SYSCALL does not save anything on the stack and does not change the
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* stack pointer.
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*/
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/*
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* Register setup:
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* rax system call number
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* rdi arg0
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* rcx return address for syscall/sysret, C arg3
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* rsi arg1
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* rdx arg2
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* r10 arg3 (--> moved to rcx for C)
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* r8 arg4
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* r9 arg5
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* r11 eflags for syscall/sysret, temporary for C
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* r12-r15,rbp,rbx saved by C code, not touched.
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*
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* Interrupts are off on entry.
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* Only called from user space.
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*
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* XXX if we had a free scratch register we could save the RSP into the stack frame
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* and report it properly in ps. Unfortunately we haven't.
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*
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* When user can change the frames always force IRET. That is because
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* it deals with uncanonical addresses better. SYSRET has trouble
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* with them due to bugs in both AMD and Intel CPUs.
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*/
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ENTRY(system_call)
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CFI_STARTPROC simple
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CFI_SIGNAL_FRAME
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CFI_DEF_CFA rsp,KERNEL_STACK_OFFSET
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CFI_REGISTER rip,rcx
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/*CFI_REGISTER rflags,r11*/
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SWAPGS_UNSAFE_STACK
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/*
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* A hypervisor implementation might want to use a label
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* after the swapgs, so that it can do the swapgs
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* for the guest and jump here on syscall.
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*/
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ENTRY(system_call_after_swapgs)
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|
|
movq %rsp,PER_CPU_VAR(old_rsp)
|
|
movq PER_CPU_VAR(kernel_stack),%rsp
|
|
/*
|
|
* No need to follow this irqs off/on section - it's straight
|
|
* and short:
|
|
*/
|
|
ENABLE_INTERRUPTS(CLBR_NONE)
|
|
SAVE_ARGS 8,1
|
|
movq %rax,ORIG_RAX-ARGOFFSET(%rsp)
|
|
movq %rcx,RIP-ARGOFFSET(%rsp)
|
|
CFI_REL_OFFSET rip,RIP-ARGOFFSET
|
|
GET_THREAD_INFO(%rcx)
|
|
testl $_TIF_WORK_SYSCALL_ENTRY,TI_flags(%rcx)
|
|
jnz tracesys
|
|
system_call_fastpath:
|
|
cmpq $__NR_syscall_max,%rax
|
|
ja badsys
|
|
movq %r10,%rcx
|
|
call *sys_call_table(,%rax,8) # XXX: rip relative
|
|
movq %rax,RAX-ARGOFFSET(%rsp)
|
|
/*
|
|
* Syscall return path ending with SYSRET (fast path)
|
|
* Has incomplete stack frame and undefined top of stack.
|
|
*/
|
|
ret_from_sys_call:
|
|
movl $_TIF_ALLWORK_MASK,%edi
|
|
/* edi: flagmask */
|
|
sysret_check:
|
|
LOCKDEP_SYS_EXIT
|
|
GET_THREAD_INFO(%rcx)
|
|
DISABLE_INTERRUPTS(CLBR_NONE)
|
|
TRACE_IRQS_OFF
|
|
movl TI_flags(%rcx),%edx
|
|
andl %edi,%edx
|
|
jnz sysret_careful
|
|
CFI_REMEMBER_STATE
|
|
/*
|
|
* sysretq will re-enable interrupts:
|
|
*/
|
|
TRACE_IRQS_ON
|
|
movq RIP-ARGOFFSET(%rsp),%rcx
|
|
CFI_REGISTER rip,rcx
|
|
RESTORE_ARGS 0,-ARG_SKIP,1
|
|
/*CFI_REGISTER rflags,r11*/
|
|
movq PER_CPU_VAR(old_rsp), %rsp
|
|
USERGS_SYSRET64
|
|
|
|
CFI_RESTORE_STATE
|
|
/* Handle reschedules */
|
|
/* edx: work, edi: workmask */
|
|
sysret_careful:
|
|
bt $TIF_NEED_RESCHED,%edx
|
|
jnc sysret_signal
|
|
TRACE_IRQS_ON
|
|
ENABLE_INTERRUPTS(CLBR_NONE)
|
|
pushq %rdi
|
|
CFI_ADJUST_CFA_OFFSET 8
|
|
call schedule
|
|
popq %rdi
|
|
CFI_ADJUST_CFA_OFFSET -8
|
|
jmp sysret_check
|
|
|
|
/* Handle a signal */
|
|
sysret_signal:
|
|
TRACE_IRQS_ON
|
|
ENABLE_INTERRUPTS(CLBR_NONE)
|
|
#ifdef CONFIG_AUDITSYSCALL
|
|
bt $TIF_SYSCALL_AUDIT,%edx
|
|
jc sysret_audit
|
|
#endif
|
|
/*
|
|
* We have a signal, or exit tracing or single-step.
|
|
* These all wind up with the iret return path anyway,
|
|
* so just join that path right now.
|
|
*/
|
|
FIXUP_TOP_OF_STACK %r11, -ARGOFFSET
|
|
jmp int_check_syscall_exit_work
|
|
|
|
badsys:
|
|
movq $-ENOSYS,RAX-ARGOFFSET(%rsp)
|
|
jmp ret_from_sys_call
|
|
|
|
#ifdef CONFIG_AUDITSYSCALL
|
|
/*
|
|
* Fast path for syscall audit without full syscall trace.
|
|
* We just call audit_syscall_entry() directly, and then
|
|
* jump back to the normal fast path.
|
|
*/
|
|
auditsys:
|
|
movq %r10,%r9 /* 6th arg: 4th syscall arg */
|
|
movq %rdx,%r8 /* 5th arg: 3rd syscall arg */
|
|
movq %rsi,%rcx /* 4th arg: 2nd syscall arg */
|
|
movq %rdi,%rdx /* 3rd arg: 1st syscall arg */
|
|
movq %rax,%rsi /* 2nd arg: syscall number */
|
|
movl $AUDIT_ARCH_X86_64,%edi /* 1st arg: audit arch */
|
|
call audit_syscall_entry
|
|
LOAD_ARGS 0 /* reload call-clobbered registers */
|
|
jmp system_call_fastpath
|
|
|
|
/*
|
|
* Return fast path for syscall audit. Call audit_syscall_exit()
|
|
* directly and then jump back to the fast path with TIF_SYSCALL_AUDIT
|
|
* masked off.
|
|
*/
|
|
sysret_audit:
|
|
movq %rax,%rsi /* second arg, syscall return value */
|
|
cmpq $0,%rax /* is it < 0? */
|
|
setl %al /* 1 if so, 0 if not */
|
|
movzbl %al,%edi /* zero-extend that into %edi */
|
|
inc %edi /* first arg, 0->1(AUDITSC_SUCCESS), 1->2(AUDITSC_FAILURE) */
|
|
call audit_syscall_exit
|
|
movl $(_TIF_ALLWORK_MASK & ~_TIF_SYSCALL_AUDIT),%edi
|
|
jmp sysret_check
|
|
#endif /* CONFIG_AUDITSYSCALL */
|
|
|
|
/* Do syscall tracing */
|
|
tracesys:
|
|
#ifdef CONFIG_AUDITSYSCALL
|
|
testl $(_TIF_WORK_SYSCALL_ENTRY & ~_TIF_SYSCALL_AUDIT),TI_flags(%rcx)
|
|
jz auditsys
|
|
#endif
|
|
SAVE_REST
|
|
movq $-ENOSYS,RAX(%rsp) /* ptrace can change this for a bad syscall */
|
|
FIXUP_TOP_OF_STACK %rdi
|
|
movq %rsp,%rdi
|
|
call syscall_trace_enter
|
|
/*
|
|
* Reload arg registers from stack in case ptrace changed them.
|
|
* We don't reload %rax because syscall_trace_enter() returned
|
|
* the value it wants us to use in the table lookup.
|
|
*/
|
|
LOAD_ARGS ARGOFFSET, 1
|
|
RESTORE_REST
|
|
cmpq $__NR_syscall_max,%rax
|
|
ja int_ret_from_sys_call /* RAX(%rsp) set to -ENOSYS above */
|
|
movq %r10,%rcx /* fixup for C */
|
|
call *sys_call_table(,%rax,8)
|
|
movq %rax,RAX-ARGOFFSET(%rsp)
|
|
/* Use IRET because user could have changed frame */
|
|
|
|
/*
|
|
* Syscall return path ending with IRET.
|
|
* Has correct top of stack, but partial stack frame.
|
|
*/
|
|
GLOBAL(int_ret_from_sys_call)
|
|
DISABLE_INTERRUPTS(CLBR_NONE)
|
|
TRACE_IRQS_OFF
|
|
testl $3,CS-ARGOFFSET(%rsp)
|
|
je retint_restore_args
|
|
movl $_TIF_ALLWORK_MASK,%edi
|
|
/* edi: mask to check */
|
|
GLOBAL(int_with_check)
|
|
LOCKDEP_SYS_EXIT_IRQ
|
|
GET_THREAD_INFO(%rcx)
|
|
movl TI_flags(%rcx),%edx
|
|
andl %edi,%edx
|
|
jnz int_careful
|
|
andl $~TS_COMPAT,TI_status(%rcx)
|
|
jmp retint_swapgs
|
|
|
|
/* Either reschedule or signal or syscall exit tracking needed. */
|
|
/* First do a reschedule test. */
|
|
/* edx: work, edi: workmask */
|
|
int_careful:
|
|
bt $TIF_NEED_RESCHED,%edx
|
|
jnc int_very_careful
|
|
TRACE_IRQS_ON
|
|
ENABLE_INTERRUPTS(CLBR_NONE)
|
|
pushq %rdi
|
|
CFI_ADJUST_CFA_OFFSET 8
|
|
call schedule
|
|
popq %rdi
|
|
CFI_ADJUST_CFA_OFFSET -8
|
|
DISABLE_INTERRUPTS(CLBR_NONE)
|
|
TRACE_IRQS_OFF
|
|
jmp int_with_check
|
|
|
|
/* handle signals and tracing -- both require a full stack frame */
|
|
int_very_careful:
|
|
TRACE_IRQS_ON
|
|
ENABLE_INTERRUPTS(CLBR_NONE)
|
|
int_check_syscall_exit_work:
|
|
SAVE_REST
|
|
/* Check for syscall exit trace */
|
|
testl $_TIF_WORK_SYSCALL_EXIT,%edx
|
|
jz int_signal
|
|
pushq %rdi
|
|
CFI_ADJUST_CFA_OFFSET 8
|
|
leaq 8(%rsp),%rdi # &ptregs -> arg1
|
|
call syscall_trace_leave
|
|
popq %rdi
|
|
CFI_ADJUST_CFA_OFFSET -8
|
|
andl $~(_TIF_WORK_SYSCALL_EXIT|_TIF_SYSCALL_EMU),%edi
|
|
jmp int_restore_rest
|
|
|
|
int_signal:
|
|
testl $_TIF_DO_NOTIFY_MASK,%edx
|
|
jz 1f
|
|
movq %rsp,%rdi # &ptregs -> arg1
|
|
xorl %esi,%esi # oldset -> arg2
|
|
call do_notify_resume
|
|
1: movl $_TIF_WORK_MASK,%edi
|
|
int_restore_rest:
|
|
RESTORE_REST
|
|
DISABLE_INTERRUPTS(CLBR_NONE)
|
|
TRACE_IRQS_OFF
|
|
jmp int_with_check
|
|
CFI_ENDPROC
|
|
END(system_call)
|
|
|
|
/*
|
|
* Certain special system calls that need to save a complete full stack frame.
|
|
*/
|
|
.macro PTREGSCALL label,func,arg
|
|
ENTRY(\label)
|
|
PARTIAL_FRAME 1 8 /* offset 8: return address */
|
|
subq $REST_SKIP, %rsp
|
|
CFI_ADJUST_CFA_OFFSET REST_SKIP
|
|
call save_rest
|
|
DEFAULT_FRAME 0 8 /* offset 8: return address */
|
|
leaq 8(%rsp), \arg /* pt_regs pointer */
|
|
call \func
|
|
jmp ptregscall_common
|
|
CFI_ENDPROC
|
|
END(\label)
|
|
.endm
|
|
|
|
PTREGSCALL stub_clone, sys_clone, %r8
|
|
PTREGSCALL stub_fork, sys_fork, %rdi
|
|
PTREGSCALL stub_vfork, sys_vfork, %rdi
|
|
PTREGSCALL stub_sigaltstack, sys_sigaltstack, %rdx
|
|
PTREGSCALL stub_iopl, sys_iopl, %rsi
|
|
|
|
ENTRY(ptregscall_common)
|
|
DEFAULT_FRAME 1 8 /* offset 8: return address */
|
|
RESTORE_TOP_OF_STACK %r11, 8
|
|
movq_cfi_restore R15+8, r15
|
|
movq_cfi_restore R14+8, r14
|
|
movq_cfi_restore R13+8, r13
|
|
movq_cfi_restore R12+8, r12
|
|
movq_cfi_restore RBP+8, rbp
|
|
movq_cfi_restore RBX+8, rbx
|
|
ret $REST_SKIP /* pop extended registers */
|
|
CFI_ENDPROC
|
|
END(ptregscall_common)
|
|
|
|
ENTRY(stub_execve)
|
|
CFI_STARTPROC
|
|
popq %r11
|
|
CFI_ADJUST_CFA_OFFSET -8
|
|
CFI_REGISTER rip, r11
|
|
SAVE_REST
|
|
FIXUP_TOP_OF_STACK %r11
|
|
movq %rsp, %rcx
|
|
call sys_execve
|
|
RESTORE_TOP_OF_STACK %r11
|
|
movq %rax,RAX(%rsp)
|
|
RESTORE_REST
|
|
jmp int_ret_from_sys_call
|
|
CFI_ENDPROC
|
|
END(stub_execve)
|
|
|
|
/*
|
|
* sigreturn is special because it needs to restore all registers on return.
|
|
* This cannot be done with SYSRET, so use the IRET return path instead.
|
|
*/
|
|
ENTRY(stub_rt_sigreturn)
|
|
CFI_STARTPROC
|
|
addq $8, %rsp
|
|
CFI_ADJUST_CFA_OFFSET -8
|
|
SAVE_REST
|
|
movq %rsp,%rdi
|
|
FIXUP_TOP_OF_STACK %r11
|
|
call sys_rt_sigreturn
|
|
movq %rax,RAX(%rsp) # fixme, this could be done at the higher layer
|
|
RESTORE_REST
|
|
jmp int_ret_from_sys_call
|
|
CFI_ENDPROC
|
|
END(stub_rt_sigreturn)
|
|
|
|
/*
|
|
* Build the entry stubs and pointer table with some assembler magic.
|
|
* We pack 7 stubs into a single 32-byte chunk, which will fit in a
|
|
* single cache line on all modern x86 implementations.
|
|
*/
|
|
.section .init.rodata,"a"
|
|
ENTRY(interrupt)
|
|
.text
|
|
.p2align 5
|
|
.p2align CONFIG_X86_L1_CACHE_SHIFT
|
|
ENTRY(irq_entries_start)
|
|
INTR_FRAME
|
|
vector=FIRST_EXTERNAL_VECTOR
|
|
.rept (NR_VECTORS-FIRST_EXTERNAL_VECTOR+6)/7
|
|
.balign 32
|
|
.rept 7
|
|
.if vector < NR_VECTORS
|
|
.if vector <> FIRST_EXTERNAL_VECTOR
|
|
CFI_ADJUST_CFA_OFFSET -8
|
|
.endif
|
|
1: pushq $(~vector+0x80) /* Note: always in signed byte range */
|
|
CFI_ADJUST_CFA_OFFSET 8
|
|
.if ((vector-FIRST_EXTERNAL_VECTOR)%7) <> 6
|
|
jmp 2f
|
|
.endif
|
|
.previous
|
|
.quad 1b
|
|
.text
|
|
vector=vector+1
|
|
.endif
|
|
.endr
|
|
2: jmp common_interrupt
|
|
.endr
|
|
CFI_ENDPROC
|
|
END(irq_entries_start)
|
|
|
|
.previous
|
|
END(interrupt)
|
|
.previous
|
|
|
|
/*
|
|
* Interrupt entry/exit.
|
|
*
|
|
* Interrupt entry points save only callee clobbered registers in fast path.
|
|
*
|
|
* Entry runs with interrupts off.
|
|
*/
|
|
|
|
/* 0(%rsp): ~(interrupt number) */
|
|
.macro interrupt func
|
|
subq $10*8, %rsp
|
|
CFI_ADJUST_CFA_OFFSET 10*8
|
|
call save_args
|
|
PARTIAL_FRAME 0
|
|
call \func
|
|
.endm
|
|
|
|
/*
|
|
* The interrupt stubs push (~vector+0x80) onto the stack and
|
|
* then jump to common_interrupt.
|
|
*/
|
|
.p2align CONFIG_X86_L1_CACHE_SHIFT
|
|
common_interrupt:
|
|
XCPT_FRAME
|
|
addq $-0x80,(%rsp) /* Adjust vector to [-256,-1] range */
|
|
interrupt do_IRQ
|
|
/* 0(%rsp): old_rsp-ARGOFFSET */
|
|
ret_from_intr:
|
|
DISABLE_INTERRUPTS(CLBR_NONE)
|
|
TRACE_IRQS_OFF
|
|
decl PER_CPU_VAR(irq_count)
|
|
leaveq
|
|
CFI_DEF_CFA_REGISTER rsp
|
|
CFI_ADJUST_CFA_OFFSET -8
|
|
exit_intr:
|
|
GET_THREAD_INFO(%rcx)
|
|
testl $3,CS-ARGOFFSET(%rsp)
|
|
je retint_kernel
|
|
|
|
/* Interrupt came from user space */
|
|
/*
|
|
* Has a correct top of stack, but a partial stack frame
|
|
* %rcx: thread info. Interrupts off.
|
|
*/
|
|
retint_with_reschedule:
|
|
movl $_TIF_WORK_MASK,%edi
|
|
retint_check:
|
|
LOCKDEP_SYS_EXIT_IRQ
|
|
movl TI_flags(%rcx),%edx
|
|
andl %edi,%edx
|
|
CFI_REMEMBER_STATE
|
|
jnz retint_careful
|
|
|
|
retint_swapgs: /* return to user-space */
|
|
/*
|
|
* The iretq could re-enable interrupts:
|
|
*/
|
|
DISABLE_INTERRUPTS(CLBR_ANY)
|
|
TRACE_IRQS_IRETQ
|
|
SWAPGS
|
|
jmp restore_args
|
|
|
|
retint_restore_args: /* return to kernel space */
|
|
DISABLE_INTERRUPTS(CLBR_ANY)
|
|
/*
|
|
* The iretq could re-enable interrupts:
|
|
*/
|
|
TRACE_IRQS_IRETQ
|
|
restore_args:
|
|
RESTORE_ARGS 0,8,0
|
|
|
|
irq_return:
|
|
INTERRUPT_RETURN
|
|
|
|
.section __ex_table, "a"
|
|
.quad irq_return, bad_iret
|
|
.previous
|
|
|
|
#ifdef CONFIG_PARAVIRT
|
|
ENTRY(native_iret)
|
|
iretq
|
|
|
|
.section __ex_table,"a"
|
|
.quad native_iret, bad_iret
|
|
.previous
|
|
#endif
|
|
|
|
.section .fixup,"ax"
|
|
bad_iret:
|
|
/*
|
|
* The iret traps when the %cs or %ss being restored is bogus.
|
|
* We've lost the original trap vector and error code.
|
|
* #GPF is the most likely one to get for an invalid selector.
|
|
* So pretend we completed the iret and took the #GPF in user mode.
|
|
*
|
|
* We are now running with the kernel GS after exception recovery.
|
|
* But error_entry expects us to have user GS to match the user %cs,
|
|
* so swap back.
|
|
*/
|
|
pushq $0
|
|
|
|
SWAPGS
|
|
jmp general_protection
|
|
|
|
.previous
|
|
|
|
/* edi: workmask, edx: work */
|
|
retint_careful:
|
|
CFI_RESTORE_STATE
|
|
bt $TIF_NEED_RESCHED,%edx
|
|
jnc retint_signal
|
|
TRACE_IRQS_ON
|
|
ENABLE_INTERRUPTS(CLBR_NONE)
|
|
pushq %rdi
|
|
CFI_ADJUST_CFA_OFFSET 8
|
|
call schedule
|
|
popq %rdi
|
|
CFI_ADJUST_CFA_OFFSET -8
|
|
GET_THREAD_INFO(%rcx)
|
|
DISABLE_INTERRUPTS(CLBR_NONE)
|
|
TRACE_IRQS_OFF
|
|
jmp retint_check
|
|
|
|
retint_signal:
|
|
testl $_TIF_DO_NOTIFY_MASK,%edx
|
|
jz retint_swapgs
|
|
TRACE_IRQS_ON
|
|
ENABLE_INTERRUPTS(CLBR_NONE)
|
|
SAVE_REST
|
|
movq $-1,ORIG_RAX(%rsp)
|
|
xorl %esi,%esi # oldset
|
|
movq %rsp,%rdi # &pt_regs
|
|
call do_notify_resume
|
|
RESTORE_REST
|
|
DISABLE_INTERRUPTS(CLBR_NONE)
|
|
TRACE_IRQS_OFF
|
|
GET_THREAD_INFO(%rcx)
|
|
jmp retint_with_reschedule
|
|
|
|
#ifdef CONFIG_PREEMPT
|
|
/* Returning to kernel space. Check if we need preemption */
|
|
/* rcx: threadinfo. interrupts off. */
|
|
ENTRY(retint_kernel)
|
|
cmpl $0,TI_preempt_count(%rcx)
|
|
jnz retint_restore_args
|
|
bt $TIF_NEED_RESCHED,TI_flags(%rcx)
|
|
jnc retint_restore_args
|
|
bt $9,EFLAGS-ARGOFFSET(%rsp) /* interrupts off? */
|
|
jnc retint_restore_args
|
|
call preempt_schedule_irq
|
|
jmp exit_intr
|
|
#endif
|
|
|
|
CFI_ENDPROC
|
|
END(common_interrupt)
|
|
|
|
/*
|
|
* APIC interrupts.
|
|
*/
|
|
.macro apicinterrupt num sym do_sym
|
|
ENTRY(\sym)
|
|
INTR_FRAME
|
|
pushq $~(\num)
|
|
CFI_ADJUST_CFA_OFFSET 8
|
|
interrupt \do_sym
|
|
jmp ret_from_intr
|
|
CFI_ENDPROC
|
|
END(\sym)
|
|
.endm
|
|
|
|
#ifdef CONFIG_SMP
|
|
apicinterrupt IRQ_MOVE_CLEANUP_VECTOR \
|
|
irq_move_cleanup_interrupt smp_irq_move_cleanup_interrupt
|
|
apicinterrupt REBOOT_VECTOR \
|
|
reboot_interrupt smp_reboot_interrupt
|
|
#endif
|
|
|
|
#ifdef CONFIG_X86_UV
|
|
apicinterrupt UV_BAU_MESSAGE \
|
|
uv_bau_message_intr1 uv_bau_message_interrupt
|
|
#endif
|
|
apicinterrupt LOCAL_TIMER_VECTOR \
|
|
apic_timer_interrupt smp_apic_timer_interrupt
|
|
apicinterrupt GENERIC_INTERRUPT_VECTOR \
|
|
generic_interrupt smp_generic_interrupt
|
|
|
|
#ifdef CONFIG_SMP
|
|
apicinterrupt INVALIDATE_TLB_VECTOR_START+0 \
|
|
invalidate_interrupt0 smp_invalidate_interrupt
|
|
apicinterrupt INVALIDATE_TLB_VECTOR_START+1 \
|
|
invalidate_interrupt1 smp_invalidate_interrupt
|
|
apicinterrupt INVALIDATE_TLB_VECTOR_START+2 \
|
|
invalidate_interrupt2 smp_invalidate_interrupt
|
|
apicinterrupt INVALIDATE_TLB_VECTOR_START+3 \
|
|
invalidate_interrupt3 smp_invalidate_interrupt
|
|
apicinterrupt INVALIDATE_TLB_VECTOR_START+4 \
|
|
invalidate_interrupt4 smp_invalidate_interrupt
|
|
apicinterrupt INVALIDATE_TLB_VECTOR_START+5 \
|
|
invalidate_interrupt5 smp_invalidate_interrupt
|
|
apicinterrupt INVALIDATE_TLB_VECTOR_START+6 \
|
|
invalidate_interrupt6 smp_invalidate_interrupt
|
|
apicinterrupt INVALIDATE_TLB_VECTOR_START+7 \
|
|
invalidate_interrupt7 smp_invalidate_interrupt
|
|
#endif
|
|
|
|
apicinterrupt THRESHOLD_APIC_VECTOR \
|
|
threshold_interrupt smp_threshold_interrupt
|
|
apicinterrupt THERMAL_APIC_VECTOR \
|
|
thermal_interrupt smp_thermal_interrupt
|
|
|
|
#ifdef CONFIG_X86_MCE
|
|
apicinterrupt MCE_SELF_VECTOR \
|
|
mce_self_interrupt smp_mce_self_interrupt
|
|
#endif
|
|
|
|
#ifdef CONFIG_SMP
|
|
apicinterrupt CALL_FUNCTION_SINGLE_VECTOR \
|
|
call_function_single_interrupt smp_call_function_single_interrupt
|
|
apicinterrupt CALL_FUNCTION_VECTOR \
|
|
call_function_interrupt smp_call_function_interrupt
|
|
apicinterrupt RESCHEDULE_VECTOR \
|
|
reschedule_interrupt smp_reschedule_interrupt
|
|
#endif
|
|
|
|
apicinterrupt ERROR_APIC_VECTOR \
|
|
error_interrupt smp_error_interrupt
|
|
apicinterrupt SPURIOUS_APIC_VECTOR \
|
|
spurious_interrupt smp_spurious_interrupt
|
|
|
|
#ifdef CONFIG_PERF_EVENTS
|
|
apicinterrupt LOCAL_PENDING_VECTOR \
|
|
perf_pending_interrupt smp_perf_pending_interrupt
|
|
#endif
|
|
|
|
/*
|
|
* Exception entry points.
|
|
*/
|
|
.macro zeroentry sym do_sym
|
|
ENTRY(\sym)
|
|
INTR_FRAME
|
|
PARAVIRT_ADJUST_EXCEPTION_FRAME
|
|
pushq_cfi $-1 /* ORIG_RAX: no syscall to restart */
|
|
subq $15*8,%rsp
|
|
CFI_ADJUST_CFA_OFFSET 15*8
|
|
call error_entry
|
|
DEFAULT_FRAME 0
|
|
movq %rsp,%rdi /* pt_regs pointer */
|
|
xorl %esi,%esi /* no error code */
|
|
call \do_sym
|
|
jmp error_exit /* %ebx: no swapgs flag */
|
|
CFI_ENDPROC
|
|
END(\sym)
|
|
.endm
|
|
|
|
.macro paranoidzeroentry sym do_sym
|
|
ENTRY(\sym)
|
|
INTR_FRAME
|
|
PARAVIRT_ADJUST_EXCEPTION_FRAME
|
|
pushq $-1 /* ORIG_RAX: no syscall to restart */
|
|
CFI_ADJUST_CFA_OFFSET 8
|
|
subq $15*8, %rsp
|
|
call save_paranoid
|
|
TRACE_IRQS_OFF
|
|
movq %rsp,%rdi /* pt_regs pointer */
|
|
xorl %esi,%esi /* no error code */
|
|
call \do_sym
|
|
jmp paranoid_exit /* %ebx: no swapgs flag */
|
|
CFI_ENDPROC
|
|
END(\sym)
|
|
.endm
|
|
|
|
.macro paranoidzeroentry_ist sym do_sym ist
|
|
ENTRY(\sym)
|
|
INTR_FRAME
|
|
PARAVIRT_ADJUST_EXCEPTION_FRAME
|
|
pushq $-1 /* ORIG_RAX: no syscall to restart */
|
|
CFI_ADJUST_CFA_OFFSET 8
|
|
subq $15*8, %rsp
|
|
call save_paranoid
|
|
TRACE_IRQS_OFF
|
|
movq %rsp,%rdi /* pt_regs pointer */
|
|
xorl %esi,%esi /* no error code */
|
|
PER_CPU(init_tss, %rbp)
|
|
subq $EXCEPTION_STKSZ, TSS_ist + (\ist - 1) * 8(%rbp)
|
|
call \do_sym
|
|
addq $EXCEPTION_STKSZ, TSS_ist + (\ist - 1) * 8(%rbp)
|
|
jmp paranoid_exit /* %ebx: no swapgs flag */
|
|
CFI_ENDPROC
|
|
END(\sym)
|
|
.endm
|
|
|
|
.macro errorentry sym do_sym
|
|
ENTRY(\sym)
|
|
XCPT_FRAME
|
|
PARAVIRT_ADJUST_EXCEPTION_FRAME
|
|
subq $15*8,%rsp
|
|
CFI_ADJUST_CFA_OFFSET 15*8
|
|
call error_entry
|
|
DEFAULT_FRAME 0
|
|
movq %rsp,%rdi /* pt_regs pointer */
|
|
movq ORIG_RAX(%rsp),%rsi /* get error code */
|
|
movq $-1,ORIG_RAX(%rsp) /* no syscall to restart */
|
|
call \do_sym
|
|
jmp error_exit /* %ebx: no swapgs flag */
|
|
CFI_ENDPROC
|
|
END(\sym)
|
|
.endm
|
|
|
|
/* error code is on the stack already */
|
|
.macro paranoiderrorentry sym do_sym
|
|
ENTRY(\sym)
|
|
XCPT_FRAME
|
|
PARAVIRT_ADJUST_EXCEPTION_FRAME
|
|
subq $15*8,%rsp
|
|
CFI_ADJUST_CFA_OFFSET 15*8
|
|
call save_paranoid
|
|
DEFAULT_FRAME 0
|
|
TRACE_IRQS_OFF
|
|
movq %rsp,%rdi /* pt_regs pointer */
|
|
movq ORIG_RAX(%rsp),%rsi /* get error code */
|
|
movq $-1,ORIG_RAX(%rsp) /* no syscall to restart */
|
|
call \do_sym
|
|
jmp paranoid_exit /* %ebx: no swapgs flag */
|
|
CFI_ENDPROC
|
|
END(\sym)
|
|
.endm
|
|
|
|
zeroentry divide_error do_divide_error
|
|
zeroentry overflow do_overflow
|
|
zeroentry bounds do_bounds
|
|
zeroentry invalid_op do_invalid_op
|
|
zeroentry device_not_available do_device_not_available
|
|
paranoiderrorentry double_fault do_double_fault
|
|
zeroentry coprocessor_segment_overrun do_coprocessor_segment_overrun
|
|
errorentry invalid_TSS do_invalid_TSS
|
|
errorentry segment_not_present do_segment_not_present
|
|
zeroentry spurious_interrupt_bug do_spurious_interrupt_bug
|
|
zeroentry coprocessor_error do_coprocessor_error
|
|
errorentry alignment_check do_alignment_check
|
|
zeroentry simd_coprocessor_error do_simd_coprocessor_error
|
|
|
|
/* Reload gs selector with exception handling */
|
|
/* edi: new selector */
|
|
ENTRY(native_load_gs_index)
|
|
CFI_STARTPROC
|
|
pushf
|
|
CFI_ADJUST_CFA_OFFSET 8
|
|
DISABLE_INTERRUPTS(CLBR_ANY & ~CLBR_RDI)
|
|
SWAPGS
|
|
gs_change:
|
|
movl %edi,%gs
|
|
2: mfence /* workaround */
|
|
SWAPGS
|
|
popf
|
|
CFI_ADJUST_CFA_OFFSET -8
|
|
ret
|
|
CFI_ENDPROC
|
|
END(native_load_gs_index)
|
|
|
|
.section __ex_table,"a"
|
|
.align 8
|
|
.quad gs_change,bad_gs
|
|
.previous
|
|
.section .fixup,"ax"
|
|
/* running with kernelgs */
|
|
bad_gs:
|
|
SWAPGS /* switch back to user gs */
|
|
xorl %eax,%eax
|
|
movl %eax,%gs
|
|
jmp 2b
|
|
.previous
|
|
|
|
/*
|
|
* Create a kernel thread.
|
|
*
|
|
* C extern interface:
|
|
* extern long kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
|
|
*
|
|
* asm input arguments:
|
|
* rdi: fn, rsi: arg, rdx: flags
|
|
*/
|
|
ENTRY(kernel_thread)
|
|
CFI_STARTPROC
|
|
FAKE_STACK_FRAME $child_rip
|
|
SAVE_ALL
|
|
|
|
# rdi: flags, rsi: usp, rdx: will be &pt_regs
|
|
movq %rdx,%rdi
|
|
orq kernel_thread_flags(%rip),%rdi
|
|
movq $-1, %rsi
|
|
movq %rsp, %rdx
|
|
|
|
xorl %r8d,%r8d
|
|
xorl %r9d,%r9d
|
|
|
|
# clone now
|
|
call do_fork
|
|
movq %rax,RAX(%rsp)
|
|
xorl %edi,%edi
|
|
|
|
/*
|
|
* It isn't worth to check for reschedule here,
|
|
* so internally to the x86_64 port you can rely on kernel_thread()
|
|
* not to reschedule the child before returning, this avoids the need
|
|
* of hacks for example to fork off the per-CPU idle tasks.
|
|
* [Hopefully no generic code relies on the reschedule -AK]
|
|
*/
|
|
RESTORE_ALL
|
|
UNFAKE_STACK_FRAME
|
|
ret
|
|
CFI_ENDPROC
|
|
END(kernel_thread)
|
|
|
|
ENTRY(child_rip)
|
|
pushq $0 # fake return address
|
|
CFI_STARTPROC
|
|
/*
|
|
* Here we are in the child and the registers are set as they were
|
|
* at kernel_thread() invocation in the parent.
|
|
*/
|
|
movq %rdi, %rax
|
|
movq %rsi, %rdi
|
|
call *%rax
|
|
# exit
|
|
mov %eax, %edi
|
|
call do_exit
|
|
ud2 # padding for call trace
|
|
CFI_ENDPROC
|
|
END(child_rip)
|
|
|
|
/*
|
|
* execve(). This function needs to use IRET, not SYSRET, to set up all state properly.
|
|
*
|
|
* C extern interface:
|
|
* extern long execve(char *name, char **argv, char **envp)
|
|
*
|
|
* asm input arguments:
|
|
* rdi: name, rsi: argv, rdx: envp
|
|
*
|
|
* We want to fallback into:
|
|
* extern long sys_execve(char *name, char **argv,char **envp, struct pt_regs *regs)
|
|
*
|
|
* do_sys_execve asm fallback arguments:
|
|
* rdi: name, rsi: argv, rdx: envp, rcx: fake frame on the stack
|
|
*/
|
|
ENTRY(kernel_execve)
|
|
CFI_STARTPROC
|
|
FAKE_STACK_FRAME $0
|
|
SAVE_ALL
|
|
movq %rsp,%rcx
|
|
call sys_execve
|
|
movq %rax, RAX(%rsp)
|
|
RESTORE_REST
|
|
testq %rax,%rax
|
|
je int_ret_from_sys_call
|
|
RESTORE_ARGS
|
|
UNFAKE_STACK_FRAME
|
|
ret
|
|
CFI_ENDPROC
|
|
END(kernel_execve)
|
|
|
|
/* Call softirq on interrupt stack. Interrupts are off. */
|
|
ENTRY(call_softirq)
|
|
CFI_STARTPROC
|
|
push %rbp
|
|
CFI_ADJUST_CFA_OFFSET 8
|
|
CFI_REL_OFFSET rbp,0
|
|
mov %rsp,%rbp
|
|
CFI_DEF_CFA_REGISTER rbp
|
|
incl PER_CPU_VAR(irq_count)
|
|
cmove PER_CPU_VAR(irq_stack_ptr),%rsp
|
|
push %rbp # backlink for old unwinder
|
|
call __do_softirq
|
|
leaveq
|
|
CFI_DEF_CFA_REGISTER rsp
|
|
CFI_ADJUST_CFA_OFFSET -8
|
|
decl PER_CPU_VAR(irq_count)
|
|
ret
|
|
CFI_ENDPROC
|
|
END(call_softirq)
|
|
|
|
#ifdef CONFIG_XEN
|
|
zeroentry xen_hypervisor_callback xen_do_hypervisor_callback
|
|
|
|
/*
|
|
* A note on the "critical region" in our callback handler.
|
|
* We want to avoid stacking callback handlers due to events occurring
|
|
* during handling of the last event. To do this, we keep events disabled
|
|
* until we've done all processing. HOWEVER, we must enable events before
|
|
* popping the stack frame (can't be done atomically) and so it would still
|
|
* be possible to get enough handler activations to overflow the stack.
|
|
* Although unlikely, bugs of that kind are hard to track down, so we'd
|
|
* like to avoid the possibility.
|
|
* So, on entry to the handler we detect whether we interrupted an
|
|
* existing activation in its critical region -- if so, we pop the current
|
|
* activation and restart the handler using the previous one.
|
|
*/
|
|
ENTRY(xen_do_hypervisor_callback) # do_hypervisor_callback(struct *pt_regs)
|
|
CFI_STARTPROC
|
|
/*
|
|
* Since we don't modify %rdi, evtchn_do_upall(struct *pt_regs) will
|
|
* see the correct pointer to the pt_regs
|
|
*/
|
|
movq %rdi, %rsp # we don't return, adjust the stack frame
|
|
CFI_ENDPROC
|
|
DEFAULT_FRAME
|
|
11: incl PER_CPU_VAR(irq_count)
|
|
movq %rsp,%rbp
|
|
CFI_DEF_CFA_REGISTER rbp
|
|
cmovzq PER_CPU_VAR(irq_stack_ptr),%rsp
|
|
pushq %rbp # backlink for old unwinder
|
|
call xen_evtchn_do_upcall
|
|
popq %rsp
|
|
CFI_DEF_CFA_REGISTER rsp
|
|
decl PER_CPU_VAR(irq_count)
|
|
jmp error_exit
|
|
CFI_ENDPROC
|
|
END(do_hypervisor_callback)
|
|
|
|
/*
|
|
* Hypervisor uses this for application faults while it executes.
|
|
* We get here for two reasons:
|
|
* 1. Fault while reloading DS, ES, FS or GS
|
|
* 2. Fault while executing IRET
|
|
* Category 1 we do not need to fix up as Xen has already reloaded all segment
|
|
* registers that could be reloaded and zeroed the others.
|
|
* Category 2 we fix up by killing the current process. We cannot use the
|
|
* normal Linux return path in this case because if we use the IRET hypercall
|
|
* to pop the stack frame we end up in an infinite loop of failsafe callbacks.
|
|
* We distinguish between categories by comparing each saved segment register
|
|
* with its current contents: any discrepancy means we in category 1.
|
|
*/
|
|
ENTRY(xen_failsafe_callback)
|
|
INTR_FRAME 1 (6*8)
|
|
/*CFI_REL_OFFSET gs,GS*/
|
|
/*CFI_REL_OFFSET fs,FS*/
|
|
/*CFI_REL_OFFSET es,ES*/
|
|
/*CFI_REL_OFFSET ds,DS*/
|
|
CFI_REL_OFFSET r11,8
|
|
CFI_REL_OFFSET rcx,0
|
|
movw %ds,%cx
|
|
cmpw %cx,0x10(%rsp)
|
|
CFI_REMEMBER_STATE
|
|
jne 1f
|
|
movw %es,%cx
|
|
cmpw %cx,0x18(%rsp)
|
|
jne 1f
|
|
movw %fs,%cx
|
|
cmpw %cx,0x20(%rsp)
|
|
jne 1f
|
|
movw %gs,%cx
|
|
cmpw %cx,0x28(%rsp)
|
|
jne 1f
|
|
/* All segments match their saved values => Category 2 (Bad IRET). */
|
|
movq (%rsp),%rcx
|
|
CFI_RESTORE rcx
|
|
movq 8(%rsp),%r11
|
|
CFI_RESTORE r11
|
|
addq $0x30,%rsp
|
|
CFI_ADJUST_CFA_OFFSET -0x30
|
|
pushq_cfi $0 /* RIP */
|
|
pushq_cfi %r11
|
|
pushq_cfi %rcx
|
|
jmp general_protection
|
|
CFI_RESTORE_STATE
|
|
1: /* Segment mismatch => Category 1 (Bad segment). Retry the IRET. */
|
|
movq (%rsp),%rcx
|
|
CFI_RESTORE rcx
|
|
movq 8(%rsp),%r11
|
|
CFI_RESTORE r11
|
|
addq $0x30,%rsp
|
|
CFI_ADJUST_CFA_OFFSET -0x30
|
|
pushq_cfi $0
|
|
SAVE_ALL
|
|
jmp error_exit
|
|
CFI_ENDPROC
|
|
END(xen_failsafe_callback)
|
|
|
|
#endif /* CONFIG_XEN */
|
|
|
|
/*
|
|
* Some functions should be protected against kprobes
|
|
*/
|
|
.pushsection .kprobes.text, "ax"
|
|
|
|
paranoidzeroentry_ist debug do_debug DEBUG_STACK
|
|
paranoidzeroentry_ist int3 do_int3 DEBUG_STACK
|
|
paranoiderrorentry stack_segment do_stack_segment
|
|
#ifdef CONFIG_XEN
|
|
zeroentry xen_debug do_debug
|
|
zeroentry xen_int3 do_int3
|
|
errorentry xen_stack_segment do_stack_segment
|
|
#endif
|
|
errorentry general_protection do_general_protection
|
|
errorentry page_fault do_page_fault
|
|
#ifdef CONFIG_X86_MCE
|
|
paranoidzeroentry machine_check *machine_check_vector(%rip)
|
|
#endif
|
|
|
|
/*
|
|
* "Paranoid" exit path from exception stack.
|
|
* Paranoid because this is used by NMIs and cannot take
|
|
* any kernel state for granted.
|
|
* We don't do kernel preemption checks here, because only
|
|
* NMI should be common and it does not enable IRQs and
|
|
* cannot get reschedule ticks.
|
|
*
|
|
* "trace" is 0 for the NMI handler only, because irq-tracing
|
|
* is fundamentally NMI-unsafe. (we cannot change the soft and
|
|
* hard flags at once, atomically)
|
|
*/
|
|
|
|
/* ebx: no swapgs flag */
|
|
ENTRY(paranoid_exit)
|
|
INTR_FRAME
|
|
DISABLE_INTERRUPTS(CLBR_NONE)
|
|
TRACE_IRQS_OFF
|
|
testl %ebx,%ebx /* swapgs needed? */
|
|
jnz paranoid_restore
|
|
testl $3,CS(%rsp)
|
|
jnz paranoid_userspace
|
|
paranoid_swapgs:
|
|
TRACE_IRQS_IRETQ 0
|
|
SWAPGS_UNSAFE_STACK
|
|
RESTORE_ALL 8
|
|
jmp irq_return
|
|
paranoid_restore:
|
|
TRACE_IRQS_IRETQ 0
|
|
RESTORE_ALL 8
|
|
jmp irq_return
|
|
paranoid_userspace:
|
|
GET_THREAD_INFO(%rcx)
|
|
movl TI_flags(%rcx),%ebx
|
|
andl $_TIF_WORK_MASK,%ebx
|
|
jz paranoid_swapgs
|
|
movq %rsp,%rdi /* &pt_regs */
|
|
call sync_regs
|
|
movq %rax,%rsp /* switch stack for scheduling */
|
|
testl $_TIF_NEED_RESCHED,%ebx
|
|
jnz paranoid_schedule
|
|
movl %ebx,%edx /* arg3: thread flags */
|
|
TRACE_IRQS_ON
|
|
ENABLE_INTERRUPTS(CLBR_NONE)
|
|
xorl %esi,%esi /* arg2: oldset */
|
|
movq %rsp,%rdi /* arg1: &pt_regs */
|
|
call do_notify_resume
|
|
DISABLE_INTERRUPTS(CLBR_NONE)
|
|
TRACE_IRQS_OFF
|
|
jmp paranoid_userspace
|
|
paranoid_schedule:
|
|
TRACE_IRQS_ON
|
|
ENABLE_INTERRUPTS(CLBR_ANY)
|
|
call schedule
|
|
DISABLE_INTERRUPTS(CLBR_ANY)
|
|
TRACE_IRQS_OFF
|
|
jmp paranoid_userspace
|
|
CFI_ENDPROC
|
|
END(paranoid_exit)
|
|
|
|
/*
|
|
* Exception entry point. This expects an error code/orig_rax on the stack.
|
|
* returns in "no swapgs flag" in %ebx.
|
|
*/
|
|
ENTRY(error_entry)
|
|
XCPT_FRAME
|
|
CFI_ADJUST_CFA_OFFSET 15*8
|
|
/* oldrax contains error code */
|
|
cld
|
|
movq_cfi rdi, RDI+8
|
|
movq_cfi rsi, RSI+8
|
|
movq_cfi rdx, RDX+8
|
|
movq_cfi rcx, RCX+8
|
|
movq_cfi rax, RAX+8
|
|
movq_cfi r8, R8+8
|
|
movq_cfi r9, R9+8
|
|
movq_cfi r10, R10+8
|
|
movq_cfi r11, R11+8
|
|
movq_cfi rbx, RBX+8
|
|
movq_cfi rbp, RBP+8
|
|
movq_cfi r12, R12+8
|
|
movq_cfi r13, R13+8
|
|
movq_cfi r14, R14+8
|
|
movq_cfi r15, R15+8
|
|
xorl %ebx,%ebx
|
|
testl $3,CS+8(%rsp)
|
|
je error_kernelspace
|
|
error_swapgs:
|
|
SWAPGS
|
|
error_sti:
|
|
TRACE_IRQS_OFF
|
|
ret
|
|
CFI_ENDPROC
|
|
|
|
/*
|
|
* There are two places in the kernel that can potentially fault with
|
|
* usergs. Handle them here. The exception handlers after iret run with
|
|
* kernel gs again, so don't set the user space flag. B stepping K8s
|
|
* sometimes report an truncated RIP for IRET exceptions returning to
|
|
* compat mode. Check for these here too.
|
|
*/
|
|
error_kernelspace:
|
|
incl %ebx
|
|
leaq irq_return(%rip),%rcx
|
|
cmpq %rcx,RIP+8(%rsp)
|
|
je error_swapgs
|
|
movl %ecx,%ecx /* zero extend */
|
|
cmpq %rcx,RIP+8(%rsp)
|
|
je error_swapgs
|
|
cmpq $gs_change,RIP+8(%rsp)
|
|
je error_swapgs
|
|
jmp error_sti
|
|
END(error_entry)
|
|
|
|
|
|
/* ebx: no swapgs flag (1: don't need swapgs, 0: need it) */
|
|
ENTRY(error_exit)
|
|
DEFAULT_FRAME
|
|
movl %ebx,%eax
|
|
RESTORE_REST
|
|
DISABLE_INTERRUPTS(CLBR_NONE)
|
|
TRACE_IRQS_OFF
|
|
GET_THREAD_INFO(%rcx)
|
|
testl %eax,%eax
|
|
jne retint_kernel
|
|
LOCKDEP_SYS_EXIT_IRQ
|
|
movl TI_flags(%rcx),%edx
|
|
movl $_TIF_WORK_MASK,%edi
|
|
andl %edi,%edx
|
|
jnz retint_careful
|
|
jmp retint_swapgs
|
|
CFI_ENDPROC
|
|
END(error_exit)
|
|
|
|
|
|
/* runs on exception stack */
|
|
ENTRY(nmi)
|
|
INTR_FRAME
|
|
PARAVIRT_ADJUST_EXCEPTION_FRAME
|
|
pushq_cfi $-1
|
|
subq $15*8, %rsp
|
|
CFI_ADJUST_CFA_OFFSET 15*8
|
|
call save_paranoid
|
|
DEFAULT_FRAME 0
|
|
/* paranoidentry do_nmi, 0; without TRACE_IRQS_OFF */
|
|
movq %rsp,%rdi
|
|
movq $-1,%rsi
|
|
call do_nmi
|
|
#ifdef CONFIG_TRACE_IRQFLAGS
|
|
/* paranoidexit; without TRACE_IRQS_OFF */
|
|
/* ebx: no swapgs flag */
|
|
DISABLE_INTERRUPTS(CLBR_NONE)
|
|
testl %ebx,%ebx /* swapgs needed? */
|
|
jnz nmi_restore
|
|
testl $3,CS(%rsp)
|
|
jnz nmi_userspace
|
|
nmi_swapgs:
|
|
SWAPGS_UNSAFE_STACK
|
|
nmi_restore:
|
|
RESTORE_ALL 8
|
|
jmp irq_return
|
|
nmi_userspace:
|
|
GET_THREAD_INFO(%rcx)
|
|
movl TI_flags(%rcx),%ebx
|
|
andl $_TIF_WORK_MASK,%ebx
|
|
jz nmi_swapgs
|
|
movq %rsp,%rdi /* &pt_regs */
|
|
call sync_regs
|
|
movq %rax,%rsp /* switch stack for scheduling */
|
|
testl $_TIF_NEED_RESCHED,%ebx
|
|
jnz nmi_schedule
|
|
movl %ebx,%edx /* arg3: thread flags */
|
|
ENABLE_INTERRUPTS(CLBR_NONE)
|
|
xorl %esi,%esi /* arg2: oldset */
|
|
movq %rsp,%rdi /* arg1: &pt_regs */
|
|
call do_notify_resume
|
|
DISABLE_INTERRUPTS(CLBR_NONE)
|
|
jmp nmi_userspace
|
|
nmi_schedule:
|
|
ENABLE_INTERRUPTS(CLBR_ANY)
|
|
call schedule
|
|
DISABLE_INTERRUPTS(CLBR_ANY)
|
|
jmp nmi_userspace
|
|
CFI_ENDPROC
|
|
#else
|
|
jmp paranoid_exit
|
|
CFI_ENDPROC
|
|
#endif
|
|
END(nmi)
|
|
|
|
ENTRY(ignore_sysret)
|
|
CFI_STARTPROC
|
|
mov $-ENOSYS,%eax
|
|
sysret
|
|
CFI_ENDPROC
|
|
END(ignore_sysret)
|
|
|
|
/*
|
|
* End of kprobes section
|
|
*/
|
|
.popsection
|