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linux/arch/microblaze/kernel/entry-nommu.S
Al Viro e9f9252667 microblaze: fix handling of multiple pending signals 
We need to keep building sigframes until no pending signals remain.
Wrap do_notify_resume() calls into loops; do _not_ allow syscall
restart logics to trigger after the first iteration.

Incidentally, comments about pending signals that should (somehow)
be in r18 are pure BS.  Doesn't work that way and cannot work that
way, sorry...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2013-02-03 18:16:02 -05:00

623 lines
15 KiB
ArmAsm
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/*
* Copyright (C) 2007-2009 Michal Simek <monstr@monstr.eu>
* Copyright (C) 2007-2009 PetaLogix
* Copyright (C) 2006 Atmark Techno, Inc.
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*/
#include <linux/linkage.h>
#include <asm/thread_info.h>
#include <linux/errno.h>
#include <asm/entry.h>
#include <asm/asm-offsets.h>
#include <asm/registers.h>
#include <asm/unistd.h>
#include <asm/percpu.h>
#include <asm/signal.h>
#if CONFIG_XILINX_MICROBLAZE0_USE_MSR_INSTR
.macro disable_irq
msrclr r0, MSR_IE
.endm
.macro enable_irq
msrset r0, MSR_IE
.endm
.macro clear_bip
msrclr r0, MSR_BIP
.endm
#else
.macro disable_irq
mfs r11, rmsr
andi r11, r11, ~MSR_IE
mts rmsr, r11
.endm
.macro enable_irq
mfs r11, rmsr
ori r11, r11, MSR_IE
mts rmsr, r11
.endm
.macro clear_bip
mfs r11, rmsr
andi r11, r11, ~MSR_BIP
mts rmsr, r11
.endm
#endif
ENTRY(_interrupt)
swi r1, r0, PER_CPU(ENTRY_SP) /* save the current sp */
swi r11, r0, PER_CPU(R11_SAVE) /* temporarily save r11 */
lwi r11, r0, PER_CPU(KM) /* load mode indicator */
beqid r11, 1f
nop
brid 2f /* jump over */
addik r1, r1, (-PT_SIZE) /* room for pt_regs (delay slot) */
1: /* switch to kernel stack */
lwi r1, r0, PER_CPU(CURRENT_SAVE) /* get the saved current */
lwi r1, r1, TS_THREAD_INFO /* get the thread info */
/* calculate kernel stack pointer */
addik r1, r1, THREAD_SIZE - PT_SIZE
2:
swi r11, r1, PT_MODE /* store the mode */
lwi r11, r0, PER_CPU(R11_SAVE) /* reload r11 */
swi r2, r1, PT_R2
swi r3, r1, PT_R3
swi r4, r1, PT_R4
swi r5, r1, PT_R5
swi r6, r1, PT_R6
swi r7, r1, PT_R7
swi r8, r1, PT_R8
swi r9, r1, PT_R9
swi r10, r1, PT_R10
swi r11, r1, PT_R11
swi r12, r1, PT_R12
swi r13, r1, PT_R13
swi r14, r1, PT_R14
swi r14, r1, PT_PC
swi r15, r1, PT_R15
swi r16, r1, PT_R16
swi r17, r1, PT_R17
swi r18, r1, PT_R18
swi r19, r1, PT_R19
swi r20, r1, PT_R20
swi r21, r1, PT_R21
swi r22, r1, PT_R22
swi r23, r1, PT_R23
swi r24, r1, PT_R24
swi r25, r1, PT_R25
swi r26, r1, PT_R26
swi r27, r1, PT_R27
swi r28, r1, PT_R28
swi r29, r1, PT_R29
swi r30, r1, PT_R30
swi r31, r1, PT_R31
/* special purpose registers */
mfs r11, rmsr
swi r11, r1, PT_MSR
mfs r11, rear
swi r11, r1, PT_EAR
mfs r11, resr
swi r11, r1, PT_ESR
mfs r11, rfsr
swi r11, r1, PT_FSR
/* reload original stack pointer and save it */
lwi r11, r0, PER_CPU(ENTRY_SP)
swi r11, r1, PT_R1
/* update mode indicator we are in kernel mode */
addik r11, r0, 1
swi r11, r0, PER_CPU(KM)
/* restore r31 */
lwi r31, r0, PER_CPU(CURRENT_SAVE)
/* prepare the link register, the argument and jump */
addik r15, r0, ret_from_intr - 8
addk r6, r0, r15
braid do_IRQ
add r5, r0, r1
ret_from_intr:
lwi r11, r1, PT_MODE
bneid r11, no_intr_resched
3:
lwi r6, r31, TS_THREAD_INFO /* get thread info */
lwi r19, r6, TI_FLAGS /* get flags in thread info */
/* do an extra work if any bits are set */
andi r11, r19, _TIF_NEED_RESCHED
beqi r11, 1f
bralid r15, schedule
nop
bri 3b
1: andi r11, r19, _TIF_SIGPENDING | _TIF_NOTIFY_RESUME
beqid r11, no_intr_resched
addk r5, r1, r0
bralid r15, do_notify_resume
addk r6, r0, r0
bri 3b
no_intr_resched:
/* Disable interrupts, we are now committed to the state restore */
disable_irq
/* save mode indicator */
lwi r11, r1, PT_MODE
swi r11, r0, PER_CPU(KM)
/* save r31 */
swi r31, r0, PER_CPU(CURRENT_SAVE)
restore_context:
/* special purpose registers */
lwi r11, r1, PT_FSR
mts rfsr, r11
lwi r11, r1, PT_ESR
mts resr, r11
lwi r11, r1, PT_EAR
mts rear, r11
lwi r11, r1, PT_MSR
mts rmsr, r11
lwi r31, r1, PT_R31
lwi r30, r1, PT_R30
lwi r29, r1, PT_R29
lwi r28, r1, PT_R28
lwi r27, r1, PT_R27
lwi r26, r1, PT_R26
lwi r25, r1, PT_R25
lwi r24, r1, PT_R24
lwi r23, r1, PT_R23
lwi r22, r1, PT_R22
lwi r21, r1, PT_R21
lwi r20, r1, PT_R20
lwi r19, r1, PT_R19
lwi r18, r1, PT_R18
lwi r17, r1, PT_R17
lwi r16, r1, PT_R16
lwi r15, r1, PT_R15
lwi r14, r1, PT_PC
lwi r13, r1, PT_R13
lwi r12, r1, PT_R12
lwi r11, r1, PT_R11
lwi r10, r1, PT_R10
lwi r9, r1, PT_R9
lwi r8, r1, PT_R8
lwi r7, r1, PT_R7
lwi r6, r1, PT_R6
lwi r5, r1, PT_R5
lwi r4, r1, PT_R4
lwi r3, r1, PT_R3
lwi r2, r1, PT_R2
lwi r1, r1, PT_R1
rtid r14, 0
nop
ENTRY(_reset)
brai 0;
ENTRY(_user_exception)
swi r1, r0, PER_CPU(ENTRY_SP) /* save the current sp */
swi r11, r0, PER_CPU(R11_SAVE) /* temporarily save r11 */
lwi r11, r0, PER_CPU(KM) /* load mode indicator */
beqid r11, 1f /* Already in kernel mode? */
nop
brid 2f /* jump over */
addik r1, r1, (-PT_SIZE) /* Room for pt_regs (delay slot) */
1: /* Switch to kernel stack */
lwi r1, r0, PER_CPU(CURRENT_SAVE) /* get the saved current */
lwi r1, r1, TS_THREAD_INFO /* get the thread info */
/* calculate kernel stack pointer */
addik r1, r1, THREAD_SIZE - PT_SIZE
2:
swi r11, r1, PT_MODE /* store the mode */
lwi r11, r0, PER_CPU(R11_SAVE) /* reload r11 */
/* save them on stack */
swi r2, r1, PT_R2
swi r3, r1, PT_R3 /* r3: _always_ in clobber list; see unistd.h */
swi r4, r1, PT_R4 /* r4: _always_ in clobber list; see unistd.h */
swi r5, r1, PT_R5
swi r6, r1, PT_R6
swi r7, r1, PT_R7
swi r8, r1, PT_R8
swi r9, r1, PT_R9
swi r10, r1, PT_R10
swi r11, r1, PT_R11
/* r12: _always_ in clobber list; see unistd.h */
swi r12, r1, PT_R12
swi r13, r1, PT_R13
/* r14: _always_ in clobber list; see unistd.h */
swi r14, r1, PT_R14
/* but we want to return to the next inst. */
addik r14, r14, 0x4
swi r14, r1, PT_PC /* increment by 4 and store in pc */
swi r15, r1, PT_R15
swi r16, r1, PT_R16
swi r17, r1, PT_R17
swi r18, r1, PT_R18
swi r19, r1, PT_R19
swi r20, r1, PT_R20
swi r21, r1, PT_R21
swi r22, r1, PT_R22
swi r23, r1, PT_R23
swi r24, r1, PT_R24
swi r25, r1, PT_R25
swi r26, r1, PT_R26
swi r27, r1, PT_R27
swi r28, r1, PT_R28
swi r29, r1, PT_R29
swi r30, r1, PT_R30
swi r31, r1, PT_R31
disable_irq
nop /* make sure IE bit is in effect */
clear_bip /* once IE is in effect it is safe to clear BIP */
nop
/* special purpose registers */
mfs r11, rmsr
swi r11, r1, PT_MSR
mfs r11, rear
swi r11, r1, PT_EAR
mfs r11, resr
swi r11, r1, PT_ESR
mfs r11, rfsr
swi r11, r1, PT_FSR
/* reload original stack pointer and save it */
lwi r11, r0, PER_CPU(ENTRY_SP)
swi r11, r1, PT_R1
/* update mode indicator we are in kernel mode */
addik r11, r0, 1
swi r11, r0, PER_CPU(KM)
/* restore r31 */
lwi r31, r0, PER_CPU(CURRENT_SAVE)
/* re-enable interrupts now we are in kernel mode */
enable_irq
/* See if the system call number is valid. */
addi r11, r12, -__NR_syscalls
bgei r11, 1f /* return to user if not valid */
/* Figure out which function to use for this system call. */
/* Note Microblaze barrel shift is optional, so don't rely on it */
add r12, r12, r12 /* convert num -> ptr */
addik r30, r0, 1 /* restarts allowed */
add r12, r12, r12
lwi r12, r12, sys_call_table /* Get function pointer */
addik r15, r0, ret_to_user-8 /* set return address */
bra r12 /* Make the system call. */
bri 0 /* won't reach here */
1:
brid ret_to_user /* jump to syscall epilogue */
addi r3, r0, -ENOSYS /* set errno in delay slot */
/*
* Debug traps are like a system call, but entered via brki r14, 0x60
* All we need to do is send the SIGTRAP signal to current, ptrace and
* do_notify_resume will handle the rest
*/
ENTRY(_debug_exception)
swi r1, r0, PER_CPU(ENTRY_SP) /* save the current sp */
lwi r1, r0, PER_CPU(CURRENT_SAVE) /* get the saved current */
lwi r1, r1, TS_THREAD_INFO /* get the thread info */
addik r1, r1, THREAD_SIZE - PT_SIZE /* get the kernel stack */
swi r11, r0, PER_CPU(R11_SAVE) /* temporarily save r11 */
lwi r11, r0, PER_CPU(KM) /* load mode indicator */
//save_context:
swi r11, r1, PT_MODE /* store the mode */
lwi r11, r0, PER_CPU(R11_SAVE) /* reload r11 */
/* save them on stack */
swi r2, r1, PT_R2
swi r3, r1, PT_R3 /* r3: _always_ in clobber list; see unistd.h */
swi r4, r1, PT_R4 /* r4: _always_ in clobber list; see unistd.h */
swi r5, r1, PT_R5
swi r6, r1, PT_R6
swi r7, r1, PT_R7
swi r8, r1, PT_R8
swi r9, r1, PT_R9
swi r10, r1, PT_R10
swi r11, r1, PT_R11
/* r12: _always_ in clobber list; see unistd.h */
swi r12, r1, PT_R12
swi r13, r1, PT_R13
/* r14: _always_ in clobber list; see unistd.h */
swi r14, r1, PT_R14
swi r14, r1, PT_PC /* Will return to interrupted instruction */
swi r15, r1, PT_R15
swi r16, r1, PT_R16
swi r17, r1, PT_R17
swi r18, r1, PT_R18
swi r19, r1, PT_R19
swi r20, r1, PT_R20
swi r21, r1, PT_R21
swi r22, r1, PT_R22
swi r23, r1, PT_R23
swi r24, r1, PT_R24
swi r25, r1, PT_R25
swi r26, r1, PT_R26
swi r27, r1, PT_R27
swi r28, r1, PT_R28
swi r29, r1, PT_R29
swi r30, r1, PT_R30
swi r31, r1, PT_R31
disable_irq
nop /* make sure IE bit is in effect */
clear_bip /* once IE is in effect it is safe to clear BIP */
nop
/* special purpose registers */
mfs r11, rmsr
swi r11, r1, PT_MSR
mfs r11, rear
swi r11, r1, PT_EAR
mfs r11, resr
swi r11, r1, PT_ESR
mfs r11, rfsr
swi r11, r1, PT_FSR
/* reload original stack pointer and save it */
lwi r11, r0, PER_CPU(ENTRY_SP)
swi r11, r1, PT_R1
/* update mode indicator we are in kernel mode */
addik r11, r0, 1
swi r11, r0, PER_CPU(KM)
/* restore r31 */
lwi r31, r0, PER_CPU(CURRENT_SAVE)
/* re-enable interrupts now we are in kernel mode */
enable_irq
addi r5, r0, SIGTRAP /* sending the trap signal */
add r6, r0, r31 /* to current */
bralid r15, send_sig
add r7, r0, r0 /* 3rd param zero */
addik r30, r0, 1 /* restarts allowed ??? */
/* Restore r3/r4 to work around how ret_to_user works */
lwi r3, r1, PT_R3
lwi r4, r1, PT_R4
bri ret_to_user
ENTRY(_break)
bri 0
/* struct task_struct *_switch_to(struct thread_info *prev,
struct thread_info *next); */
ENTRY(_switch_to)
/* prepare return value */
addk r3, r0, r31
/* save registers in cpu_context */
/* use r11 and r12, volatile registers, as temp register */
addik r11, r5, TI_CPU_CONTEXT
swi r1, r11, CC_R1
swi r2, r11, CC_R2
/* skip volatile registers.
* they are saved on stack when we jumped to _switch_to() */
/* dedicated registers */
swi r13, r11, CC_R13
swi r14, r11, CC_R14
swi r15, r11, CC_R15
swi r16, r11, CC_R16
swi r17, r11, CC_R17
swi r18, r11, CC_R18
/* save non-volatile registers */
swi r19, r11, CC_R19
swi r20, r11, CC_R20
swi r21, r11, CC_R21
swi r22, r11, CC_R22
swi r23, r11, CC_R23
swi r24, r11, CC_R24
swi r25, r11, CC_R25
swi r26, r11, CC_R26
swi r27, r11, CC_R27
swi r28, r11, CC_R28
swi r29, r11, CC_R29
swi r30, r11, CC_R30
/* special purpose registers */
mfs r12, rmsr
swi r12, r11, CC_MSR
mfs r12, rear
swi r12, r11, CC_EAR
mfs r12, resr
swi r12, r11, CC_ESR
mfs r12, rfsr
swi r12, r11, CC_FSR
/* update r31, the current */
lwi r31, r6, TI_TASK
swi r31, r0, PER_CPU(CURRENT_SAVE)
/* get new process' cpu context and restore */
addik r11, r6, TI_CPU_CONTEXT
/* special purpose registers */
lwi r12, r11, CC_FSR
mts rfsr, r12
lwi r12, r11, CC_ESR
mts resr, r12
lwi r12, r11, CC_EAR
mts rear, r12
lwi r12, r11, CC_MSR
mts rmsr, r12
/* non-volatile registers */
lwi r30, r11, CC_R30
lwi r29, r11, CC_R29
lwi r28, r11, CC_R28
lwi r27, r11, CC_R27
lwi r26, r11, CC_R26
lwi r25, r11, CC_R25
lwi r24, r11, CC_R24
lwi r23, r11, CC_R23
lwi r22, r11, CC_R22
lwi r21, r11, CC_R21
lwi r20, r11, CC_R20
lwi r19, r11, CC_R19
/* dedicated registers */
lwi r18, r11, CC_R18
lwi r17, r11, CC_R17
lwi r16, r11, CC_R16
lwi r15, r11, CC_R15
lwi r14, r11, CC_R14
lwi r13, r11, CC_R13
/* skip volatile registers */
lwi r2, r11, CC_R2
lwi r1, r11, CC_R1
rtsd r15, 8
nop
ENTRY(ret_from_fork)
addk r5, r0, r3
brlid r15, schedule_tail
nop
swi r31, r1, PT_R31 /* save r31 in user context. */
/* will soon be restored to r31 in ret_to_user */
addk r3, r0, r0
brid ret_to_user
nop
ENTRY(ret_from_kernel_thread)
brlid r15, schedule_tail
addk r5, r0, r3
brald r15, r20
addk r5, r0, r19
brid ret_to_user
addk r3, r0, r0
work_pending:
lwi r11, r1, PT_MODE
bneid r11, 2f
3:
enable_irq
andi r11, r19, _TIF_NEED_RESCHED
beqi r11, 1f
bralid r15, schedule
nop
bri 4f
1: andi r11, r19, _TIF_SIGPENDING | _TIF_NOTIFY_RESUME
beqi r11, no_work_pending
addk r5, r30, r0
bralid r15, do_notify_resume
addik r6, r0, 1
addk r30, r0, r0 /* no restarts from now on */
4:
disable_irq
lwi r6, r31, TS_THREAD_INFO /* get thread info */
lwi r19, r6, TI_FLAGS /* get flags in thread info */
bri 3b
ENTRY(ret_to_user)
disable_irq
swi r4, r1, PT_R4 /* return val */
swi r3, r1, PT_R3 /* return val */
lwi r6, r31, TS_THREAD_INFO /* get thread info */
lwi r19, r6, TI_FLAGS /* get flags in thread info */
bnei r19, work_pending /* do an extra work if any bits are set */
no_work_pending:
disable_irq
2:
/* save r31 */
swi r31, r0, PER_CPU(CURRENT_SAVE)
/* save mode indicator */
lwi r18, r1, PT_MODE
swi r18, r0, PER_CPU(KM)
//restore_context:
/* special purpose registers */
lwi r18, r1, PT_FSR
mts rfsr, r18
lwi r18, r1, PT_ESR
mts resr, r18
lwi r18, r1, PT_EAR
mts rear, r18
lwi r18, r1, PT_MSR
mts rmsr, r18
lwi r31, r1, PT_R31
lwi r30, r1, PT_R30
lwi r29, r1, PT_R29
lwi r28, r1, PT_R28
lwi r27, r1, PT_R27
lwi r26, r1, PT_R26
lwi r25, r1, PT_R25
lwi r24, r1, PT_R24
lwi r23, r1, PT_R23
lwi r22, r1, PT_R22
lwi r21, r1, PT_R21
lwi r20, r1, PT_R20
lwi r19, r1, PT_R19
lwi r18, r1, PT_R18
lwi r17, r1, PT_R17
lwi r16, r1, PT_R16
lwi r15, r1, PT_R15
lwi r14, r1, PT_PC
lwi r13, r1, PT_R13
lwi r12, r1, PT_R12
lwi r11, r1, PT_R11
lwi r10, r1, PT_R10
lwi r9, r1, PT_R9
lwi r8, r1, PT_R8
lwi r7, r1, PT_R7
lwi r6, r1, PT_R6
lwi r5, r1, PT_R5
lwi r4, r1, PT_R4 /* return val */
lwi r3, r1, PT_R3 /* return val */
lwi r2, r1, PT_R2
lwi r1, r1, PT_R1
rtid r14, 0
nop
sys_rt_sigreturn_wrapper:
addk r30, r0, r0 /* no restarts for this one */
brid sys_rt_sigreturn
addk r5, r1, r0
/* Interrupt vector table */
.section .init.ivt, "ax"
.org 0x0
brai _reset
brai _user_exception
brai _interrupt
brai _break
brai _hw_exception_handler
.org 0x60
brai _debug_exception
.section .rodata,"a"
#include "syscall_table.S"
syscall_table_size=(.-sys_call_table)
type_SYSCALL:
.ascii "SYSCALL\0"
type_IRQ:
.ascii "IRQ\0"
type_IRQ_PREEMPT:
.ascii "IRQ (PREEMPTED)\0"
type_SYSCALL_PREEMPT:
.ascii " SYSCALL (PREEMPTED)\0"
/*
* Trap decoding for stack unwinder
* Tuples are (start addr, end addr, string)
* If return address lies on [start addr, end addr],
* unwinder displays 'string'
*/
.align 4
.global microblaze_trap_handlers
microblaze_trap_handlers:
/* Exact matches come first */
.word ret_to_user ; .word ret_to_user ; .word type_SYSCALL
.word ret_from_intr; .word ret_from_intr ; .word type_IRQ
/* Fuzzy matches go here */
.word ret_from_intr; .word no_intr_resched; .word type_IRQ_PREEMPT
.word work_pending ; .word no_work_pending; .word type_SYSCALL_PREEMPT
/* End of table */
.word 0 ; .word 0 ; .word 0
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