Messages in this thread Patch in this message | | | From | Tiezhu Yang <> | Subject | [PATCH] LoongArch: Define the symbol fault as a local label in fpu.S | Date | Wed, 30 Aug 2023 10:47:07 +0800 |
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The initial aim is to silence the following objtool warnings:
arch/loongarch/kernel/fpu.o: warning: objtool: _save_fp_context() falls through to next function fault() arch/loongarch/kernel/fpu.o: warning: objtool: _restore_fp_context() falls through to next function fault() arch/loongarch/kernel/fpu.o: warning: objtool: _save_lsx_context() falls through to next function fault() arch/loongarch/kernel/fpu.o: warning: objtool: _restore_lsx_context() falls through to next function fault() arch/loongarch/kernel/fpu.o: warning: objtool: _save_lasx_context() falls through to next function fault() arch/loongarch/kernel/fpu.o: warning: objtool: _restore_lasx_context() falls through to next function fault()
Currently, SYM_FUNC_END() defines the symbol fault as SYM_T_FUNC which is STT_FUNC, the objtool warnings are generated through the following code:
tools/objtool/include/objtool/check.h static inline struct symbol *insn_func(struct instruction *insn) { struct symbol *sym = insn->sym;
if (sym && sym->type != STT_FUNC) sym = NULL;
return sym; }
tools/objtool/check.c static int validate_branch(struct objtool_file *file, struct symbol *func, struct instruction *insn, struct insn_state state) { ... if (func && insn_func(insn) && func != insn_func(insn)->pfunc) { ... WARN("%s() falls through to next function %s()", func->name, insn_func(insn)->name); return 1; } ... }
We can see that the fixup can be a local label in the following code:
arch/loongarch/include/asm/asm-extable.h .pushsection __ex_table, "a"; \ .balign 4; \ .long ((insn) - .); \ .long ((fixup) - .); \ .short (type); \ .short (data); \ .popsection;
.macro _asm_extable, insn, fixup __ASM_EXTABLE_RAW(\insn, \fixup, EX_TYPE_FIXUP, 0) .endm
Like arch/loongarch/lib/*.S, just define the symbol fault as a local label in fpu.S.
Before:
$ readelf -s arch/loongarch/kernel/fpu.o | awk -F: /fault/'{print $2}' 000000000000053c 8 FUNC GLOBAL DEFAULT 1 fault
After:
$ readelf -s arch/loongarch/kernel/fpu.o | awk -F: /fault/'{print $2}' 000000000000053c 0 NOTYPE LOCAL DEFAULT 1 .L_fixup_fpu_fault
Co-developed-by: Youling Tang <tangyouling@loongson.cn> Signed-off-by: Youling Tang <tangyouling@loongson.cn> Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn> ---
There is a same issue in lbt.S, Huacai suggested to squash the changes in the original patch: "LoongArch: Add Loongson Binary Translation (LBT) extension support"
arch/loongarch/kernel/fpu.S | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/arch/loongarch/kernel/fpu.S b/arch/loongarch/kernel/fpu.S index b4032de..3177725 100644 --- a/arch/loongarch/kernel/fpu.S +++ b/arch/loongarch/kernel/fpu.S @@ -22,7 +22,7 @@ .macro EX insn, reg, src, offs .ex\@: \insn \reg, \src, \offs - _asm_extable .ex\@, fault + _asm_extable .ex\@, .L_fixup_fpu_fault .endm .macro sc_save_fp base @@ -521,7 +521,6 @@ SYM_FUNC_START(_restore_lasx_context) jr ra SYM_FUNC_END(_restore_lasx_context) -SYM_FUNC_START(fault) +.L_fixup_fpu_fault: li.w a0, -EFAULT # failure jr ra -SYM_FUNC_END(fault) -- 2.1.0
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