From 2d7c11bfc91637e5f9bc5f8c9a82aaffcc0e97aa Mon Sep 17 00:00:00 2001 From: Catalin Marinas Date: Wed, 11 Feb 2009 13:07:53 +0100 Subject: [PATCH] [ARM] 5382/1: unwind: Reorganise the stacktrace support This patch changes the walk_stacktrace and its callers for easier integration of stack unwinding. The arch/arm/kernel/stacktrace.h file is also moved to arch/arm/include/asm/stacktrace.h. Signed-off-by: Catalin Marinas Signed-off-by: Russell King --- arch/arm/include/asm/stacktrace.h | 15 +++++ arch/arm/include/asm/thread_info.h | 2 + arch/arm/kernel/process.c | 21 ++++--- arch/arm/kernel/stacktrace.c | 88 ++++++++++++++++++++---------- arch/arm/kernel/stacktrace.h | 9 --- arch/arm/kernel/time.c | 21 +++++-- arch/arm/oprofile/backtrace.c | 14 +++-- 7 files changed, 110 insertions(+), 60 deletions(-) create mode 100644 arch/arm/include/asm/stacktrace.h delete mode 100644 arch/arm/kernel/stacktrace.h diff --git a/arch/arm/include/asm/stacktrace.h b/arch/arm/include/asm/stacktrace.h new file mode 100644 index 000000000000..4d0a16441b29 --- /dev/null +++ b/arch/arm/include/asm/stacktrace.h @@ -0,0 +1,15 @@ +#ifndef __ASM_STACKTRACE_H +#define __ASM_STACKTRACE_H + +struct stackframe { + unsigned long fp; + unsigned long sp; + unsigned long lr; + unsigned long pc; +}; + +extern int unwind_frame(struct stackframe *frame); +extern void walk_stackframe(struct stackframe *frame, + int (*fn)(struct stackframe *, void *), void *data); + +#endif /* __ASM_STACKTRACE_H */ diff --git a/arch/arm/include/asm/thread_info.h b/arch/arm/include/asm/thread_info.h index b9dc8a842573..4f8848260ee2 100644 --- a/arch/arm/include/asm/thread_info.h +++ b/arch/arm/include/asm/thread_info.h @@ -99,6 +99,8 @@ static inline struct thread_info *current_thread_info(void) #define thread_saved_pc(tsk) \ ((unsigned long)(task_thread_info(tsk)->cpu_context.pc)) +#define thread_saved_sp(tsk) \ + ((unsigned long)(task_thread_info(tsk)->cpu_context.sp)) #define thread_saved_fp(tsk) \ ((unsigned long)(task_thread_info(tsk)->cpu_context.fp)) diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c index d3ea6fa89521..af377c73d90b 100644 --- a/arch/arm/kernel/process.c +++ b/arch/arm/kernel/process.c @@ -34,6 +34,7 @@ #include #include #include +#include #include static const char *processor_modes[] = { @@ -372,23 +373,21 @@ EXPORT_SYMBOL(kernel_thread); unsigned long get_wchan(struct task_struct *p) { - unsigned long fp, lr; - unsigned long stack_start, stack_end; + struct stackframe frame; int count = 0; if (!p || p == current || p->state == TASK_RUNNING) return 0; - stack_start = (unsigned long)end_of_stack(p); - stack_end = (unsigned long)task_stack_page(p) + THREAD_SIZE; - - fp = thread_saved_fp(p); + frame.fp = thread_saved_fp(p); + frame.sp = thread_saved_sp(p); + frame.lr = 0; /* recovered from the stack */ + frame.pc = thread_saved_pc(p); do { - if (fp < stack_start || fp > stack_end) + int ret = unwind_frame(&frame); + if (ret < 0) return 0; - lr = ((unsigned long *)fp)[-1]; - if (!in_sched_functions(lr)) - return lr; - fp = *(unsigned long *) (fp - 12); + if (!in_sched_functions(frame.pc)) + return frame.pc; } while (count ++ < 16); return 0; } diff --git a/arch/arm/kernel/stacktrace.c b/arch/arm/kernel/stacktrace.c index fc650f64df43..9f444e5cc165 100644 --- a/arch/arm/kernel/stacktrace.c +++ b/arch/arm/kernel/stacktrace.c @@ -2,35 +2,60 @@ #include #include -#include "stacktrace.h" - -int walk_stackframe(unsigned long fp, unsigned long low, unsigned long high, - int (*fn)(struct stackframe *, void *), void *data) +#include + +#if defined(CONFIG_FRAME_POINTER) && !defined(CONFIG_ARM_UNWIND) +/* + * Unwind the current stack frame and store the new register values in the + * structure passed as argument. Unwinding is equivalent to a function return, + * hence the new PC value rather than LR should be used for backtrace. + * + * With framepointer enabled, a simple function prologue looks like this: + * mov ip, sp + * stmdb sp!, {fp, ip, lr, pc} + * sub fp, ip, #4 + * + * A simple function epilogue looks like this: + * ldm sp, {fp, sp, pc} + * + * Note that with framepointer enabled, even the leaf functions have the same + * prologue and epilogue, therefore we can ignore the LR value in this case. + */ +int unwind_frame(struct stackframe *frame) { - struct stackframe *frame; - - do { - /* - * Check current frame pointer is within bounds - */ - if (fp < (low + 12) || fp + 4 >= high) - break; + unsigned long high, low; + unsigned long fp = frame->fp; - frame = (struct stackframe *)(fp - 12); + /* only go to a higher address on the stack */ + low = frame->sp; + high = ALIGN(low, THREAD_SIZE) + THREAD_SIZE; - if (fn(frame, data)) - break; + /* check current frame pointer is within bounds */ + if (fp < (low + 12) || fp + 4 >= high) + return -EINVAL; - /* - * Update the low bound - the next frame must always - * be at a higher address than the current frame. - */ - low = fp + 4; - fp = frame->fp; - } while (fp); + /* restore the registers from the stack frame */ + frame->fp = *(unsigned long *)(fp - 12); + frame->sp = *(unsigned long *)(fp - 8); + frame->pc = *(unsigned long *)(fp - 4); return 0; } +#endif + +void walk_stackframe(struct stackframe *frame, + int (*fn)(struct stackframe *, void *), void *data) +{ + while (1) { + int ret; + + if (fn(frame, data)) + break; + ret = unwind_frame(frame); + if (ret < 0) + break; + } +} EXPORT_SYMBOL(walk_stackframe); #ifdef CONFIG_STACKTRACE @@ -44,7 +69,7 @@ static int save_trace(struct stackframe *frame, void *d) { struct stack_trace_data *data = d; struct stack_trace *trace = data->trace; - unsigned long addr = frame->lr; + unsigned long addr = frame->pc; if (data->no_sched_functions && in_sched_functions(addr)) return 0; @@ -61,11 +86,10 @@ static int save_trace(struct stackframe *frame, void *d) void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace) { struct stack_trace_data data; - unsigned long fp, base; + struct stackframe frame; data.trace = trace; data.skip = trace->skip; - base = (unsigned long)task_stack_page(tsk); if (tsk != current) { #ifdef CONFIG_SMP @@ -76,14 +100,22 @@ void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace) BUG(); #else data.no_sched_functions = 1; - fp = thread_saved_fp(tsk); + frame.fp = thread_saved_fp(tsk); + frame.sp = thread_saved_sp(tsk); + frame.lr = 0; /* recovered from the stack */ + frame.pc = thread_saved_pc(tsk); #endif } else { + register unsigned long current_sp asm ("sp"); + data.no_sched_functions = 0; - asm("mov %0, fp" : "=r" (fp)); + frame.fp = (unsigned long)__builtin_frame_address(0); + frame.sp = current_sp; + frame.lr = (unsigned long)__builtin_return_address(0); + frame.pc = (unsigned long)save_stack_trace_tsk; } - walk_stackframe(fp, base, base + THREAD_SIZE, save_trace, &data); + walk_stackframe(&frame, save_trace, &data); if (trace->nr_entries < trace->max_entries) trace->entries[trace->nr_entries++] = ULONG_MAX; } diff --git a/arch/arm/kernel/stacktrace.h b/arch/arm/kernel/stacktrace.h deleted file mode 100644 index e9fd20cb5662..000000000000 --- a/arch/arm/kernel/stacktrace.h +++ /dev/null @@ -1,9 +0,0 @@ -struct stackframe { - unsigned long fp; - unsigned long sp; - unsigned long lr; - unsigned long pc; -}; - -int walk_stackframe(unsigned long fp, unsigned long low, unsigned long high, - int (*fn)(struct stackframe *, void *), void *data); diff --git a/arch/arm/kernel/time.c b/arch/arm/kernel/time.c index c68b44aa88d2..4cdc4a0bd02d 100644 --- a/arch/arm/kernel/time.c +++ b/arch/arm/kernel/time.c @@ -33,6 +33,7 @@ #include #include +#include #include /* @@ -55,14 +56,22 @@ EXPORT_SYMBOL(rtc_lock); #ifdef CONFIG_SMP unsigned long profile_pc(struct pt_regs *regs) { - unsigned long fp, pc = instruction_pointer(regs); + struct stackframe frame; - if (in_lock_functions(pc)) { - fp = regs->ARM_fp; - pc = ((unsigned long *)fp)[-1]; - } + if (!in_lock_functions(regs->ARM_pc)) + return regs->ARM_pc; + + frame.fp = regs->ARM_fp; + frame.sp = regs->ARM_sp; + frame.lr = regs->ARM_lr; + frame.pc = regs->ARM_pc; + do { + int ret = unwind_frame(&frame); + if (ret < 0) + return 0; + } while (in_lock_functions(frame.pc)); - return pc; + return frame.pc; } EXPORT_SYMBOL(profile_pc); #endif diff --git a/arch/arm/oprofile/backtrace.c b/arch/arm/oprofile/backtrace.c index cefc21c2eee4..d805a52b5032 100644 --- a/arch/arm/oprofile/backtrace.c +++ b/arch/arm/oprofile/backtrace.c @@ -18,15 +18,14 @@ #include #include #include - -#include "../kernel/stacktrace.h" +#include static int report_trace(struct stackframe *frame, void *d) { unsigned int *depth = d; if (*depth) { - oprofile_add_trace(frame->lr); + oprofile_add_trace(frame->pc); (*depth)--; } @@ -70,9 +69,12 @@ void arm_backtrace(struct pt_regs * const regs, unsigned int depth) struct frame_tail *tail = ((struct frame_tail *) regs->ARM_fp) - 1; if (!user_mode(regs)) { - unsigned long base = ((unsigned long)regs) & ~(THREAD_SIZE - 1); - walk_stackframe(regs->ARM_fp, base, base + THREAD_SIZE, - report_trace, &depth); + struct stackframe frame; + frame.fp = regs->ARM_fp; + frame.sp = regs->ARM_sp; + frame.lr = regs->ARM_lr; + frame.pc = regs->ARM_pc; + walk_stackframe(&frame, report_trace, &depth); return; } -- 2.34.1