diff options
| author | Clément Léger <cleger@rivosinc.com> | 2024-12-09 16:57:12 +0100 |
|---|---|---|
| committer | Palmer Dabbelt <palmer@rivosinc.com> | 2025-01-08 19:45:49 +0100 |
| commit | 51356ce60e5915a6bd812873186ed54e45c2699d (patch) | |
| tree | a9405cbfbe628c7ae7df9e668748d1e303e2ff79 /arch | |
| parent | riscv: mm: Fix the out of bound issue of vmemmap address (diff) | |
| download | linux-51356ce60e5915a6bd812873186ed54e45c2699d.tar.xz linux-51356ce60e5915a6bd812873186ed54e45c2699d.zip | |
riscv: stacktrace: fix backtracing through exceptions
Prior to commit 5d5fc33ce58e ("riscv: Improve exception and system call
latency"), backtrace through exception worked since ra was filled with
ret_from_exception symbol address and the stacktrace code checked 'pc' to
be equal to that symbol. Now that handle_exception uses regular 'call'
instructions, this isn't working anymore and backtrace stops at
handle_exception(). Since there are multiple call site to C code in the
exception handling path, rather than checking multiple potential return
addresses, add a new symbol at the end of exception handling and check pc
to be in that range.
Fixes: 5d5fc33ce58e ("riscv: Improve exception and system call latency")
Signed-off-by: Clément Léger <cleger@rivosinc.com>
Tested-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Link: https://lore.kernel.org/r/20241209155714.1239665-1-cleger@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/riscv/kernel/entry.S | 1 | ||||
| -rw-r--r-- | arch/riscv/kernel/stacktrace.c | 4 |
2 files changed, 4 insertions, 1 deletions
diff --git a/arch/riscv/kernel/entry.S b/arch/riscv/kernel/entry.S index c200d329d4bd..7a6c48e6d211 100644 --- a/arch/riscv/kernel/entry.S +++ b/arch/riscv/kernel/entry.S @@ -278,6 +278,7 @@ SYM_CODE_START_NOALIGN(ret_from_exception) #else sret #endif +SYM_INNER_LABEL(ret_from_exception_end, SYM_L_GLOBAL) SYM_CODE_END(ret_from_exception) ASM_NOKPROBE(ret_from_exception) diff --git a/arch/riscv/kernel/stacktrace.c b/arch/riscv/kernel/stacktrace.c index 153a2db4c5fa..d4355c770c36 100644 --- a/arch/riscv/kernel/stacktrace.c +++ b/arch/riscv/kernel/stacktrace.c @@ -17,6 +17,7 @@ #ifdef CONFIG_FRAME_POINTER extern asmlinkage void handle_exception(void); +extern unsigned long ret_from_exception_end; static inline int fp_is_valid(unsigned long fp, unsigned long sp) { @@ -71,7 +72,8 @@ void notrace walk_stackframe(struct task_struct *task, struct pt_regs *regs, fp = frame->fp; pc = ftrace_graph_ret_addr(current, &graph_idx, frame->ra, &frame->ra); - if (pc == (unsigned long)handle_exception) { + if (pc >= (unsigned long)handle_exception && + pc < (unsigned long)&ret_from_exception_end) { if (unlikely(!__kernel_text_address(pc) || !fn(arg, pc))) break; |