From 7c977393b8277ed319e92e4b598b26598c9d30c0 Mon Sep 17 00:00:00 2001 From: Josh Poimboeuf Date: Mon, 31 Mar 2025 21:26:43 -0700 Subject: [PATCH] objtool/loongarch: Add unwind hints in prepare_frametrace() If 'regs' points to a local stack variable, prepare_frametrace() stores all registers to the stack. This confuses objtool as it expects them to be restored from the stack later. The stores don't affect stack tracing, so use unwind hints to hide them from objtool. Fixes the following warnings: arch/loongarch/kernel/traps.o: warning: objtool: show_stack+0xe0: stack state mismatch: reg1[22]=-1+0 reg2[22]=-2-160 arch/loongarch/kernel/traps.o: warning: objtool: show_stack+0xe0: stack state mismatch: reg1[23]=-1+0 reg2[23]=-2-152 Fixes: cb8a2ef0848c ("LoongArch: Add ORC stack unwinder support") Reported-by: kernel test robot Tested-by: Tiezhu Yang Signed-off-by: Josh Poimboeuf Signed-off-by: Ingo Molnar Cc: Linus Torvalds Link: https://lore.kernel.org/r/270cadd8040dda74db2307f23497bb68e65db98d.1743481539.git.jpoimboe@kernel.org Closes: https://lore.kernel.org/oe-kbuild-all/202503280703.OARM8SrY-lkp@intel.com/ --- arch/loongarch/include/asm/stacktrace.h | 3 +++ arch/loongarch/include/asm/unwind_hints.h | 10 +++++++++- 2 files changed, 12 insertions(+), 1 deletion(-) diff --git a/arch/loongarch/include/asm/stacktrace.h b/arch/loongarch/include/asm/stacktrace.h index f23adb15f418..fc8b64773794 100644 --- a/arch/loongarch/include/asm/stacktrace.h +++ b/arch/loongarch/include/asm/stacktrace.h @@ -8,6 +8,7 @@ #include #include #include +#include #include enum stack_type { @@ -43,6 +44,7 @@ int get_stack_info(unsigned long stack, struct task_struct *task, struct stack_i static __always_inline void prepare_frametrace(struct pt_regs *regs) { __asm__ __volatile__( + UNWIND_HINT_SAVE /* Save $ra */ STORE_ONE_REG(1) /* Use $ra to save PC */ @@ -80,6 +82,7 @@ static __always_inline void prepare_frametrace(struct pt_regs *regs) STORE_ONE_REG(29) STORE_ONE_REG(30) STORE_ONE_REG(31) + UNWIND_HINT_RESTORE : "=m" (regs->csr_era) : "r" (regs->regs) : "memory"); diff --git a/arch/loongarch/include/asm/unwind_hints.h b/arch/loongarch/include/asm/unwind_hints.h index a01086ad9dde..2c68bc72736c 100644 --- a/arch/loongarch/include/asm/unwind_hints.h +++ b/arch/loongarch/include/asm/unwind_hints.h @@ -23,6 +23,14 @@ UNWIND_HINT sp_reg=ORC_REG_SP type=UNWIND_HINT_TYPE_CALL .endm -#endif /* __ASSEMBLY__ */ +#else /* !__ASSEMBLY__ */ + +#define UNWIND_HINT_SAVE \ + UNWIND_HINT(UNWIND_HINT_TYPE_SAVE, 0, 0, 0) + +#define UNWIND_HINT_RESTORE \ + UNWIND_HINT(UNWIND_HINT_TYPE_RESTORE, 0, 0, 0) + +#endif /* !__ASSEMBLY__ */ #endif /* _ASM_LOONGARCH_UNWIND_HINTS_H */