forked from Minki/linux
56e62a7370
This patch converts s390 to use the generic entry infrastructure from
kernel/entry/*.
There are a few special things on s390:
- PIF_PER_TRAP is moved to TIF_PER_TRAP as the generic code doesn't
know about our PIF flags in exit_to_user_mode_loop().
- The old code had several ways to restart syscalls:
a) PIF_SYSCALL_RESTART, which was only set during execve to force a
restart after upgrading a process (usually qemu-kvm) to pgste page
table extensions.
b) PIF_SYSCALL, which is set by do_signal() to indicate that the
current syscall should be restarted. This is changed so that
do_signal() now also uses PIF_SYSCALL_RESTART. Continuing to use
PIF_SYSCALL doesn't work with the generic code, and changing it
to PIF_SYSCALL_RESTART makes PIF_SYSCALL and PIF_SYSCALL_RESTART
more unique.
- On s390 calling sys_sigreturn or sys_rt_sigreturn is implemented by
executing a svc instruction on the process stack which causes a fault.
While handling that fault the fault code sets PIF_SYSCALL to hand over
processing to the syscall code on exit to usermode.
The patch introduces PIF_SYSCALL_RET_SET, which is set if ptrace sets
a return value for a syscall. The s390x ptrace ABI uses r2 both for the
syscall number and return value, so ptrace cannot set the syscall number +
return value at the same time. The flag makes handling that a bit easier.
do_syscall() will just skip executing the syscall if PIF_SYSCALL_RET_SET
is set.
CONFIG_DEBUG_ASCE was removd in favour of the generic CONFIG_DEBUG_ENTRY.
CR1/7/13 will be checked both on kernel entry and exit to contain the
correct asces.
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
108 lines
2.4 KiB
C
108 lines
2.4 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* Access to user system call parameters and results
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*
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* Copyright IBM Corp. 2008
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* Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com)
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*/
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#ifndef _ASM_SYSCALL_H
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#define _ASM_SYSCALL_H 1
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#include <uapi/linux/audit.h>
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#include <linux/sched.h>
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#include <linux/err.h>
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#include <asm/ptrace.h>
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extern const sys_call_ptr_t sys_call_table[];
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extern const sys_call_ptr_t sys_call_table_emu[];
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static inline long syscall_get_nr(struct task_struct *task,
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struct pt_regs *regs)
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{
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return test_pt_regs_flag(regs, PIF_SYSCALL) ?
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(regs->int_code & 0xffff) : -1;
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}
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static inline void syscall_rollback(struct task_struct *task,
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struct pt_regs *regs)
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{
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regs->gprs[2] = regs->orig_gpr2;
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}
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static inline long syscall_get_error(struct task_struct *task,
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struct pt_regs *regs)
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{
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unsigned long error = regs->gprs[2];
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#ifdef CONFIG_COMPAT
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if (test_tsk_thread_flag(task, TIF_31BIT)) {
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/*
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* Sign-extend the value so (int)-EFOO becomes (long)-EFOO
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* and will match correctly in comparisons.
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*/
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error = (long)(int)error;
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}
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#endif
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return IS_ERR_VALUE(error) ? error : 0;
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}
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static inline long syscall_get_return_value(struct task_struct *task,
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struct pt_regs *regs)
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{
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return regs->gprs[2];
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}
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static inline void syscall_set_return_value(struct task_struct *task,
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struct pt_regs *regs,
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int error, long val)
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{
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set_pt_regs_flag(regs, PIF_SYSCALL_RET_SET);
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regs->gprs[2] = error ? error : val;
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}
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static inline void syscall_get_arguments(struct task_struct *task,
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struct pt_regs *regs,
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unsigned long *args)
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{
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unsigned long mask = -1UL;
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unsigned int n = 6;
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#ifdef CONFIG_COMPAT
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if (test_tsk_thread_flag(task, TIF_31BIT))
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mask = 0xffffffff;
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#endif
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while (n-- > 0)
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if (n > 0)
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args[n] = regs->gprs[2 + n] & mask;
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args[0] = regs->orig_gpr2 & mask;
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}
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static inline void syscall_set_arguments(struct task_struct *task,
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struct pt_regs *regs,
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const unsigned long *args)
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{
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unsigned int n = 6;
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while (n-- > 0)
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if (n > 0)
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regs->gprs[2 + n] = args[n];
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regs->orig_gpr2 = args[0];
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}
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static inline int syscall_get_arch(struct task_struct *task)
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{
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#ifdef CONFIG_COMPAT
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if (test_tsk_thread_flag(task, TIF_31BIT))
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return AUDIT_ARCH_S390;
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#endif
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return AUDIT_ARCH_S390X;
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}
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static inline bool arch_syscall_is_vdso_sigreturn(struct pt_regs *regs)
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{
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return false;
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}
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#endif /* _ASM_SYSCALL_H */
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