This patch uses walk_stackframe(), instead of slurping stack contents as orignal check_stack() does, to identify each stack frame. return_to_handler() is handled in a special way because it is not a function, but invoked via function graph tracer by faking a saved lr register on stack.
Signed-off-by: AKASHI Takahiro <[email protected]> --- arch/arm64/include/asm/ftrace.h | 2 ++ arch/arm64/kernel/ftrace.c | 37 +++++++++++++++++++++++++ arch/arm64/kernel/stacktrace.c | 58 +++++++++++++++++++++++++++++++++++++-- 3 files changed, 95 insertions(+), 2 deletions(-) diff --git a/arch/arm64/include/asm/ftrace.h b/arch/arm64/include/asm/ftrace.h index 2b43e20..b7d597c 100644 --- a/arch/arm64/include/asm/ftrace.h +++ b/arch/arm64/include/asm/ftrace.h @@ -29,6 +29,8 @@ struct dyn_arch_ftrace { extern unsigned long ftrace_graph_call; +extern void return_to_handler(void); + static inline unsigned long ftrace_call_adjust(unsigned long addr) { /* diff --git a/arch/arm64/kernel/ftrace.c b/arch/arm64/kernel/ftrace.c index c851be7..d812870 100644 --- a/arch/arm64/kernel/ftrace.c +++ b/arch/arm64/kernel/ftrace.c @@ -176,3 +176,40 @@ int ftrace_disable_ftrace_graph_caller(void) } #endif /* CONFIG_DYNAMIC_FTRACE */ #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ + +#ifdef CONFIG_STACK_TRACER +#define stack_top(fp) (((fp) & ~(THREAD_SIZE-1)) + THREAD_SIZE) +#define stack_index(fp) (stack_top((fp)) - (fp)) + +extern struct stack_trace max_stack_trace; +extern void save_stack_trace_index(struct stack_trace *trace); + +void arch_check_stack(unsigned long ip, unsigned long *stack, + unsigned long *max_size, int *tracer_size) +{ + int i, j; + + max_stack_trace.skip = 0; + save_stack_trace_index(&max_stack_trace); + max_stack_trace.nr_entries--; /* for '-1' entry */ + + /* Skip over the overhead of the stack tracer itself */ + for (i = 0; i < max_stack_trace.nr_entries; i++) { + if ((max_stack_trace.entries[i] + FTRACE_STACK_FRAME_OFFSET) + == ip) + break; + } + + if (unlikely(!*tracer_size)) { + *tracer_size = stack_index((unsigned long)stack) + - max_stack_trace.index[i]; + *max_size -= *tracer_size; + } + + max_stack_trace.nr_entries -= i; + for (j = 0; j < max_stack_trace.nr_entries; j++) { + max_stack_trace.index[j] = max_stack_trace.index[j + i]; + max_stack_trace.entries[j] = max_stack_trace.entries[j + i]; + } +} +#endif /* CONFIG_STACK_TRACER */ diff --git a/arch/arm64/kernel/stacktrace.c b/arch/arm64/kernel/stacktrace.c index bc0689a..496ab0f 100644 --- a/arch/arm64/kernel/stacktrace.c +++ b/arch/arm64/kernel/stacktrace.c @@ -17,12 +17,15 @@ */ #include <linux/kernel.h> #include <linux/export.h> +#include <linux/ftrace.h> #include <linux/sched.h> #include <linux/stacktrace.h> #include <asm/insn.h> #include <asm/stacktrace.h> +#define S_FRAME_SIZE sizeof(struct pt_regs) /* asm-offsets.h */ + /* * AArch64 PCS assigns the frame pointer to x29. * @@ -78,9 +81,29 @@ struct stack_trace_data { struct stack_trace *trace; unsigned int no_sched_functions; unsigned int skip; +#ifdef CONFIG_STACK_TRACER + int ftracer; + int ret_stack_index; +#endif }; -static int save_trace(struct stackframe *frame, void *d) +#ifdef CONFIG_STACK_TRACER +static void notrace arm64_stack_index(struct stackframe *frame, + struct stack_trace_data *data) +{ + struct stack_trace *trace = data->trace; + unsigned long top; + unsigned int x = trace->nr_entries; + + top = (frame->fp & ~(THREAD_SIZE-1)) + THREAD_SIZE; + trace->index[x] = top - frame->fp; + /* should not go beyond this frame */ + if (trace->index[x] == THREAD_SIZE) + trace->index[x] = 0; +} +#endif /* CONFIG_STACK_TRACER */ + +static int notrace save_trace(struct stackframe *frame, void *d) { struct stack_trace_data *data = d; struct stack_trace *trace = data->trace; @@ -93,7 +116,13 @@ static int save_trace(struct stackframe *frame, void *d) return 0; } - trace->entries[trace->nr_entries++] = addr; + trace->entries[trace->nr_entries] = addr; +#ifdef CONFIG_STACK_TRACER + if (data->ftracer) { + arm64_stack_index(frame, data); + } +#endif + trace->nr_entries++; return trace->nr_entries >= trace->max_entries; } @@ -105,6 +134,9 @@ void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace) data.trace = trace; data.skip = trace->skip; +#ifdef CONFIG_STACK_TRACER + data.ftracer = 0; +#endif if (tsk != current) { data.no_sched_functions = 1; @@ -128,4 +160,26 @@ void save_stack_trace(struct stack_trace *trace) save_stack_trace_tsk(current, trace); } EXPORT_SYMBOL_GPL(save_stack_trace); + +#ifdef CONFIG_STACK_TRACER +void notrace save_stack_trace_index(struct stack_trace *trace) +{ + struct stack_trace_data data; + struct stackframe frame; + + data.trace = trace; + data.skip = trace->skip; + data.ftracer = 1; + data.ret_stack_index = current->curr_ret_stack; + + data.no_sched_functions = 0; + frame.fp = (unsigned long)__builtin_frame_address(0); + frame.sp = current_stack_pointer; + frame.pc = (unsigned long)save_stack_trace_index; + + walk_stackframe(&frame, save_trace, &data); + if (trace->nr_entries < trace->max_entries) + trace->entries[trace->nr_entries++] = ULONG_MAX; +} +#endif /* CONFIG_STACK_TRACER */ #endif -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
