From e8de3486a4b06389d4f996eb2dda678a39f20115 Mon Sep 17 00:00:00 2001 From: James Hogan Date: Fri, 5 Oct 2012 17:01:38 +0100 Subject: [PATCH] metag: Stack unwinding Add stack unwinding support for metag. Signed-off-by: James Hogan --- arch/metag/include/asm/stacktrace.h | 20 +++ arch/metag/kernel/stacktrace.c | 187 ++++++++++++++++++++++++++++ 2 files changed, 207 insertions(+) create mode 100644 arch/metag/include/asm/stacktrace.h create mode 100644 arch/metag/kernel/stacktrace.c diff --git a/arch/metag/include/asm/stacktrace.h b/arch/metag/include/asm/stacktrace.h new file mode 100644 index 000000000000..2830a0fe7ac9 --- /dev/null +++ b/arch/metag/include/asm/stacktrace.h @@ -0,0 +1,20 @@ +#ifndef __ASM_STACKTRACE_H +#define __ASM_STACKTRACE_H + +struct stackframe { + unsigned long fp; + unsigned long sp; + unsigned long lr; + unsigned long pc; +}; + +struct metag_frame { + unsigned long fp; + unsigned long lr; +}; + +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/metag/kernel/stacktrace.c b/arch/metag/kernel/stacktrace.c new file mode 100644 index 000000000000..5510361d5bea --- /dev/null +++ b/arch/metag/kernel/stacktrace.c @@ -0,0 +1,187 @@ +#include +#include +#include + +#include + +#if defined(CONFIG_FRAME_POINTER) + +#ifdef CONFIG_KALLSYMS +#include +#include + +static unsigned long tbi_boing_addr; +static unsigned long tbi_boing_size; + +static void tbi_boing_init(void) +{ + /* We need to know where TBIBoingVec is and it's size */ + unsigned long size; + unsigned long offset; + char modname[MODULE_NAME_LEN]; + char name[KSYM_NAME_LEN]; + tbi_boing_addr = kallsyms_lookup_name("___TBIBoingVec"); + if (!tbi_boing_addr) + tbi_boing_addr = 1; + else if (!lookup_symbol_attrs(tbi_boing_addr, &size, + &offset, modname, name)) + tbi_boing_size = size; +} +#endif + +#define ALIGN_DOWN(addr, size) ((addr)&(~((size)-1))) + +/* + * 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. + */ +int notrace unwind_frame(struct stackframe *frame) +{ + struct metag_frame *fp = (struct metag_frame *)frame->fp; + unsigned long lr; + unsigned long fpnew; + + if (frame->fp & 0x7) + return -EINVAL; + + fpnew = fp->fp; + lr = fp->lr - 4; + +#ifdef CONFIG_KALLSYMS + /* If we've reached TBIBoingVec then we're at an interrupt + * entry point or a syscall entry point. The frame pointer + * points to a pt_regs which can be used to continue tracing on + * the other side of the boing. + */ + if (!tbi_boing_addr) + tbi_boing_init(); + if (tbi_boing_size && lr >= tbi_boing_addr && + lr < tbi_boing_addr + tbi_boing_size) { + struct pt_regs *regs = (struct pt_regs *)fpnew; + if (user_mode(regs)) + return -EINVAL; + fpnew = regs->ctx.AX[1].U0; + lr = regs->ctx.DX[4].U1; + } +#endif + + /* stack grows up, so frame pointers must decrease */ + if (fpnew < (ALIGN_DOWN((unsigned long)fp, THREAD_SIZE) + + sizeof(struct thread_info)) || fpnew >= (unsigned long)fp) + return -EINVAL; + + /* restore the registers from the stack frame */ + frame->fp = fpnew; + frame->pc = lr; + + return 0; +} +#else +int notrace unwind_frame(struct stackframe *frame) +{ + struct metag_frame *sp = (struct metag_frame *)frame->sp; + + if (frame->sp & 0x7) + return -EINVAL; + + while (!kstack_end(sp)) { + unsigned long addr = sp->lr - 4; + sp--; + + if (__kernel_text_address(addr)) { + frame->sp = (unsigned long)sp; + frame->pc = addr; + return 0; + } + } + return -EINVAL; +} +#endif + +void notrace 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 +struct stack_trace_data { + struct stack_trace *trace; + unsigned int no_sched_functions; + unsigned int skip; +}; + +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->pc; + + if (data->no_sched_functions && in_sched_functions(addr)) + return 0; + if (data->skip) { + data->skip--; + return 0; + } + + trace->entries[trace->nr_entries++] = addr; + + return trace->nr_entries >= trace->max_entries; +} + +void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace) +{ + struct stack_trace_data data; + struct stackframe frame; + + data.trace = trace; + data.skip = trace->skip; + + if (tsk != current) { +#ifdef CONFIG_SMP + /* + * What guarantees do we have here that 'tsk' is not + * running on another CPU? For now, ignore it as we + * can't guarantee we won't explode. + */ + if (trace->nr_entries < trace->max_entries) + trace->entries[trace->nr_entries++] = ULONG_MAX; + return; +#else + data.no_sched_functions = 1; + 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 ("A0StP"); + + data.no_sched_functions = 0; + 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(&frame, save_trace, &data); + if (trace->nr_entries < trace->max_entries) + trace->entries[trace->nr_entries++] = ULONG_MAX; +} + +void save_stack_trace(struct stack_trace *trace) +{ + save_stack_trace_tsk(current, trace); +} +EXPORT_SYMBOL_GPL(save_stack_trace); +#endif -- 2.20.1