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linux/arch/microblaze/kernel/entry-nommu.S
Steven J. Magnani ce3266c047 microblaze: Add stack unwinder 
Implement intelligent backtracing by searching for stack frame creation,
and emitting only return addresses. Use print_hex_dump() to display the
entire binary kernel stack.

Limitation: MMU kernels are not currently able to trace beyond a system trap
(interrupt, syscall, etc.). It is the intent of this patch to provide
infrastructure that can be extended to add this capability later.

Changes from V1:
* Removed checks in find_frame_creation() that prevented location of the frame
  creation instruction in heavily optimized code
* Various formatting/commenting/file location tweaks per review comments
* Dropped Kconfig option to enable STACKTRACE as something logically separate

Signed-off-by: Steven J. Magnani <steve@digidescorp.com>
2010-08-04 10:22:35 +02:00

619 lines
14 KiB
ArmAsm
Raw Blame History

/*
* 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 */
la 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
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
1: andi r11, r19, _TIF_SIGPENDING
beqid r11, no_intr_resched
addk r5, r1, r0
addk r7, r0, r0
bralid r15, do_signal
addk r6, r0, r0
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 */
add r12, r12, r12
lwi r12, r12, sys_call_table /* Get function pointer */
la 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_signal
* 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 */
/* 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
addk r6, r0, r1
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
work_pending:
enable_irq
andi r11, r19, _TIF_NEED_RESCHED
beqi r11, 1f
bralid r15, schedule
nop
1: andi r11, r19, _TIF_SIGPENDING
beqi r11, no_work_pending
addk r5, r1, r0
addik r7, r0, 1
bralid r15, do_signal
addk r6, r0, r0
bri no_work_pending
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
/* 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_vfork:
brid microblaze_vfork
addk r5, r1, r0
sys_clone:
brid microblaze_clone
addk r7, r1, r0
sys_execve:
brid microblaze_execve
addk r8, r1, r0
sys_rt_sigreturn_wrapper:
brid sys_rt_sigreturn
addk r5, r1, r0
sys_rt_sigsuspend_wrapper:
brid sys_rt_sigsuspend
addk r7, 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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