Messages in this thread Patch in this message | | | From | Jinyang He <> | Subject | [PATCH 2/6] LoongArch: Use correct sp value to get graph addr in unwinder guess | Date | Thu, 15 Dec 2022 12:01:37 +0800 |
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The stack frame when function_graph enable like follows,
--------- <- function sp_on_entry | | | FAKE_RA <- sp_on_entry - sizeof(pt_regs) + PT_R1 | --------- <- sp_on_entry - sizeof(pt_regs)
So if we want to get the &FAKE_RA we should get sp_on_entry first. In unwinder_prologue case, we can get the sp_on_entry as state->sp, because we try to calculate each CFA and the ra saved address. But in unwinder_guess case, we cannot get it because we do not try to calculate the CFA. Although LoongArch have not fixed frame, the $ra is saved at CFA - 8 in most cases, we can try guess, too. As we store the pc in state, we not need to dereference state->sp, too.
Signed-off-by: Jinyang He <hejinyang@loongson.cn> --- arch/loongarch/include/asm/ftrace.h | 2 -- arch/loongarch/include/asm/unwind.h | 9 +++++++++ arch/loongarch/kernel/unwind_guess.c | 12 ++++-------- arch/loongarch/kernel/unwind_prologue.c | 22 ++++++---------------- 4 files changed, 19 insertions(+), 26 deletions(-)
diff --git a/arch/loongarch/include/asm/ftrace.h b/arch/loongarch/include/asm/ftrace.h index 90f9d3399b2a..3418d32d4fc7 100644 --- a/arch/loongarch/include/asm/ftrace.h +++ b/arch/loongarch/include/asm/ftrace.h @@ -10,8 +10,6 @@ #define FTRACE_REGS_PLT_IDX 1 #define NR_FTRACE_PLTS 2 -#define GRAPH_FAKE_OFFSET (sizeof(struct pt_regs) - offsetof(struct pt_regs, regs[1])) - #ifdef CONFIG_FUNCTION_TRACER #define MCOUNT_INSN_SIZE 4 /* sizeof mcount call */ diff --git a/arch/loongarch/include/asm/unwind.h b/arch/loongarch/include/asm/unwind.h index f2b52b9ea93d..6ece48f0ff77 100644 --- a/arch/loongarch/include/asm/unwind.h +++ b/arch/loongarch/include/asm/unwind.h @@ -7,8 +7,10 @@ #ifndef _ASM_UNWIND_H #define _ASM_UNWIND_H +#include <linux/ftrace.h> #include <linux/sched.h> +#include <asm/ptrace.h> #include <asm/stacktrace.h> enum unwinder_type { @@ -40,4 +42,11 @@ static inline bool unwind_error(struct unwind_state *state) return state->error; } +#define GRAPH_FAKE_OFFSET (sizeof(struct pt_regs) - offsetof(struct pt_regs, regs[1])) +static inline unsigned long unwind_graph_addr(struct unwind_state *state, + unsigned long pc, unsigned long cfa) +{ + return ftrace_graph_ret_addr(state->task, &state->graph_idx, + pc, (unsigned long *)(cfa - GRAPH_FAKE_OFFSET)); +} #endif /* _ASM_UNWIND_H */ diff --git a/arch/loongarch/kernel/unwind_guess.c b/arch/loongarch/kernel/unwind_guess.c index e03864511582..8ce32c37c587 100644 --- a/arch/loongarch/kernel/unwind_guess.c +++ b/arch/loongarch/kernel/unwind_guess.c @@ -11,10 +11,7 @@ unsigned long unwind_get_return_address(struct unwind_state *state) { if (unwind_done(state)) return 0; - else if (state->first) - return state->pc; - - return *(unsigned long *)(state->sp); + return state->pc; } EXPORT_SYMBOL_GPL(unwind_get_return_address); @@ -36,7 +33,7 @@ void unwind_start(struct unwind_state *state, struct task_struct *task, state->task = task; state->first = true; - + state->pc = unwind_graph_addr(state, state->pc, state->sp); get_stack_info(state->sp, state->task, &state->stack_info); if (!unwind_done(state) && !__kernel_text_address(state->pc)) @@ -60,9 +57,8 @@ bool unwind_next_frame(struct unwind_state *state) state->sp < info->end; state->sp += sizeof(unsigned long)) { addr = *(unsigned long *)(state->sp); - state->pc = ftrace_graph_ret_addr(state->task, &state->graph_idx, - addr, (unsigned long *)(state->sp - GRAPH_FAKE_OFFSET)); - if (__kernel_text_address(addr)) + state->pc = unwind_graph_addr(state, addr, state->sp + 8); + if (__kernel_text_address(state->pc)) return true; } diff --git a/arch/loongarch/kernel/unwind_prologue.c b/arch/loongarch/kernel/unwind_prologue.c index 9d51ea37782e..35cab7f77c6b 100644 --- a/arch/loongarch/kernel/unwind_prologue.c +++ b/arch/loongarch/kernel/unwind_prologue.c @@ -21,16 +21,9 @@ static inline void unwind_state_fixup(struct unwind_state *state) unsigned long unwind_get_return_address(struct unwind_state *state) { - if (unwind_done(state)) return 0; - else if (state->type) - return state->pc; - else if (state->first) - return state->pc; - - return *(unsigned long *)(state->sp); - + return state->pc; } EXPORT_SYMBOL_GPL(unwind_get_return_address); @@ -43,9 +36,8 @@ static bool unwind_by_guess(struct unwind_state *state) state->sp < info->end; state->sp += sizeof(unsigned long)) { addr = *(unsigned long *)(state->sp); - state->pc = ftrace_graph_ret_addr(state->task, &state->graph_idx, - addr, (unsigned long *)(state->sp - GRAPH_FAKE_OFFSET)); - if (__kernel_text_address(addr)) + state->pc = unwind_graph_addr(state, addr, state->sp + 8); + if (__kernel_text_address(state->pc)) return true; } @@ -161,7 +153,7 @@ void unwind_start(struct unwind_state *state, struct task_struct *task, state->task = task; state->first = true; - + state->pc = unwind_graph_addr(state, state->pc, state->sp); get_stack_info(state->sp, state->task, &state->stack_info); if (!unwind_done(state) && !__kernel_text_address(state->pc)) @@ -188,8 +180,7 @@ bool unwind_next_frame(struct unwind_state *state) case UNWINDER_PROLOGUE: if (unwind_by_prologue(state)) { - state->pc = ftrace_graph_ret_addr(state->task, &state->graph_idx, - state->pc, (unsigned long *)(state->sp - GRAPH_FAKE_OFFSET)); + state->pc = unwind_graph_addr(state, state->pc, state->sp); return true; } @@ -204,8 +195,7 @@ bool unwind_next_frame(struct unwind_state *state) state->first = true; state->ra = regs->regs[1]; state->sp = regs->regs[3]; - state->pc = ftrace_graph_ret_addr(state->task, &state->graph_idx, - pc, (unsigned long *)(state->sp - GRAPH_FAKE_OFFSET)); + state->pc = pc; get_stack_info(state->sp, state->task, info); return true; -- 2.34.3
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