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Subject[PATCH] csky: Bugfix add zero_fp fixup perf backtrace panic
Date
From: Guo Ren <ren_guo@c-sky.com>

We need set fp zero to let backtrace know the end. The patch fixup perf
callchain panic problem, because backtrace didn't know what is the end
of fp.

Signed-off-by: Guo Ren <ren_guo@c-sky.com>
Reported-by: Mao Han <han_mao@c-sky.com>
---
arch/csky/kernel/entry.S | 50 +++++++++++++++++++++++++++-------------------
arch/csky/kernel/process.c | 2 +-
2 files changed, 31 insertions(+), 21 deletions(-)

diff --git a/arch/csky/kernel/entry.S b/arch/csky/kernel/entry.S
index a7e84cc..564dab2 100644
--- a/arch/csky/kernel/entry.S
+++ b/arch/csky/kernel/entry.S
@@ -17,6 +17,12 @@
#define PTE_INDX_SHIFT 10
#define _PGDIR_SHIFT 22

+.macro zero_fp
+#ifdef CONFIG_STACKTRACE
+ movi r8, 0
+#endif
+.endm
+
.macro tlbop_begin name, val0, val1, val2
ENTRY(csky_\name)
mtcr a3, ss2
@@ -96,6 +102,7 @@ ENTRY(csky_\name)
SAVE_ALL 0
.endm
.macro tlbop_end is_write
+ zero_fp
RD_MEH a2
psrset ee, ie
mov a0, sp
@@ -120,6 +127,7 @@ tlbop_end 1

ENTRY(csky_systemcall)
SAVE_ALL TRAP0_SIZE
+ zero_fp

psrset ee, ie

@@ -136,9 +144,9 @@ ENTRY(csky_systemcall)
mov r9, sp
bmaski r10, THREAD_SHIFT
andn r9, r10
- ldw r8, (r9, TINFO_FLAGS)
- ANDI_R3 r8, (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_TRACEPOINT | _TIF_SYSCALL_AUDIT)
- cmpnei r8, 0
+ ldw r12, (r9, TINFO_FLAGS)
+ ANDI_R3 r12, (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_TRACEPOINT | _TIF_SYSCALL_AUDIT)
+ cmpnei r12, 0
bt csky_syscall_trace
#if defined(__CSKYABIV2__)
subi sp, 8
@@ -180,7 +188,7 @@ csky_syscall_trace:

ENTRY(ret_from_kernel_thread)
jbsr schedule_tail
- mov a0, r8
+ mov a0, r10
jsr r9
jbsr ret_from_exception

@@ -189,9 +197,9 @@ ENTRY(ret_from_fork)
mov r9, sp
bmaski r10, THREAD_SHIFT
andn r9, r10
- ldw r8, (r9, TINFO_FLAGS)
- ANDI_R3 r8, (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_TRACEPOINT | _TIF_SYSCALL_AUDIT)
- cmpnei r8, 0
+ ldw r12, (r9, TINFO_FLAGS)
+ ANDI_R3 r12, (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_TRACEPOINT | _TIF_SYSCALL_AUDIT)
+ cmpnei r12, 0
bf ret_from_exception
mov a0, sp /* sp = pt_regs pointer */
jbsr syscall_trace_exit
@@ -209,9 +217,9 @@ ret_from_exception:
bmaski r10, THREAD_SHIFT
andn r9, r10

- ldw r8, (r9, TINFO_FLAGS)
- andi r8, (_TIF_SIGPENDING | _TIF_NOTIFY_RESUME | _TIF_NEED_RESCHED)
- cmpnei r8, 0
+ ldw r12, (r9, TINFO_FLAGS)
+ andi r12, (_TIF_SIGPENDING | _TIF_NOTIFY_RESUME | _TIF_NEED_RESCHED)
+ cmpnei r12, 0
bt exit_work
1:
RESTORE_ALL
@@ -220,11 +228,11 @@ exit_work:
lrw syscallid, ret_from_exception
mov lr, syscallid

- btsti r8, TIF_NEED_RESCHED
+ btsti r12, TIF_NEED_RESCHED
bt work_resched

mov a0, sp
- mov a1, r8
+ mov a1, r12
jmpi do_notify_resume

work_resched:
@@ -232,6 +240,7 @@ work_resched:

ENTRY(csky_trap)
SAVE_ALL 0
+ zero_fp
psrset ee
mov a0, sp /* Push Stack pointer arg */
jbsr trap_c /* Call C-level trap handler */
@@ -265,6 +274,7 @@ ENTRY(csky_get_tls)

ENTRY(csky_irq)
SAVE_ALL 0
+ zero_fp
psrset ee

#ifdef CONFIG_PREEMPT
@@ -276,21 +286,21 @@ ENTRY(csky_irq)
* Get task_struct->stack.preempt_count for current,
* and increase 1.
*/
- ldw r8, (r9, TINFO_PREEMPT)
- addi r8, 1
- stw r8, (r9, TINFO_PREEMPT)
+ ldw r12, (r9, TINFO_PREEMPT)
+ addi r12, 1
+ stw r12, (r9, TINFO_PREEMPT)
#endif

mov a0, sp
jbsr csky_do_IRQ

#ifdef CONFIG_PREEMPT
- subi r8, 1
- stw r8, (r9, TINFO_PREEMPT)
- cmpnei r8, 0
+ subi r12, 1
+ stw r12, (r9, TINFO_PREEMPT)
+ cmpnei r12, 0
bt 2f
- ldw r8, (r9, TINFO_FLAGS)
- btsti r8, TIF_NEED_RESCHED
+ ldw r12, (r9, TINFO_FLAGS)
+ btsti r12, TIF_NEED_RESCHED
bf 2f
1:
jbsr preempt_schedule_irq /* irq en/disable is done inside */
diff --git a/arch/csky/kernel/process.c b/arch/csky/kernel/process.c
index e555740..f320d92 100644
--- a/arch/csky/kernel/process.c
+++ b/arch/csky/kernel/process.c
@@ -55,7 +55,7 @@ int copy_thread(unsigned long clone_flags,
if (unlikely(p->flags & PF_KTHREAD)) {
memset(childregs, 0, sizeof(struct pt_regs));
childstack->r15 = (unsigned long) ret_from_kernel_thread;
- childstack->r8 = kthread_arg;
+ childstack->r10 = kthread_arg;
childstack->r9 = usp;
childregs->sr = mfcr("psr");
} else {
--
2.7.4
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