From: Josh Poimboeuf Date: Tue, 17 Mar 2026 00:47:56 +0000 (-0700) Subject: objtool: Support Clang RAX DRAP sequence X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=96f3b16a9de552538b810f773645d43f3b661b50;p=thirdparty%2Fkernel%2Flinux.git objtool: Support Clang RAX DRAP sequence Recent Clang can use RAX as a temporary register for the DRAP stack alignment sequence. Add support for that. Fixes the following warning: vmlinux.o: error: objtool: vmw_host_printf+0xd: unknown CFA base reg 0 Closes: https://lore.kernel.org/cefefdd1-7b82-406d-8ff4-e4b167e45ee6@app.fastmail.com Reported-by: Arnd Bergmann Signed-off-by: Josh Poimboeuf Signed-off-by: Peter Zijlstra (Intel) Link: https://patch.msgid.link/3f33dc720b83dc6d3a2b7094f75a5c90a0b1cbc5.1773708458.git.jpoimboe@kernel.org --- diff --git a/arch/x86/include/asm/orc_types.h b/arch/x86/include/asm/orc_types.h index e0125afa53fb9..b3cc7970fa548 100644 --- a/arch/x86/include/asm/orc_types.h +++ b/arch/x86/include/asm/orc_types.h @@ -37,6 +37,7 @@ #define ORC_REG_R13 7 #define ORC_REG_BP_INDIRECT 8 #define ORC_REG_SP_INDIRECT 9 +#define ORC_REG_AX 10 #define ORC_REG_MAX 15 #define ORC_TYPE_UNDEFINED 0 diff --git a/arch/x86/kernel/unwind_orc.c b/arch/x86/kernel/unwind_orc.c index f610fde2d5c4b..32f7e918d3d9f 100644 --- a/arch/x86/kernel/unwind_orc.c +++ b/arch/x86/kernel/unwind_orc.c @@ -578,6 +578,14 @@ bool unwind_next_frame(struct unwind_state *state) } break; + case ORC_REG_AX: + if (!get_reg(state, offsetof(struct pt_regs, ax), &sp)) { + orc_warn_current("missing AX value at %pB\n", + (void *)state->ip); + goto err; + } + break; + default: orc_warn("unknown SP base reg %d at %pB\n", orc->sp_reg, (void *)state->ip); diff --git a/tools/arch/x86/include/asm/orc_types.h b/tools/arch/x86/include/asm/orc_types.h index e0125afa53fb9..b3cc7970fa548 100644 --- a/tools/arch/x86/include/asm/orc_types.h +++ b/tools/arch/x86/include/asm/orc_types.h @@ -37,6 +37,7 @@ #define ORC_REG_R13 7 #define ORC_REG_BP_INDIRECT 8 #define ORC_REG_SP_INDIRECT 9 +#define ORC_REG_AX 10 #define ORC_REG_MAX 15 #define ORC_TYPE_UNDEFINED 0 diff --git a/tools/objtool/arch/x86/decode.c b/tools/objtool/arch/x86/decode.c index 73bfea220d1bf..c3a10f3c72d99 100644 --- a/tools/objtool/arch/x86/decode.c +++ b/tools/objtool/arch/x86/decode.c @@ -912,6 +912,9 @@ int arch_decode_hint_reg(u8 sp_reg, int *base) case ORC_REG_DX: *base = CFI_DX; break; + case ORC_REG_AX: + *base = CFI_AX; + break; default: return -1; } diff --git a/tools/objtool/arch/x86/orc.c b/tools/objtool/arch/x86/orc.c index 735e150ca6b73..5494bb450ab55 100644 --- a/tools/objtool/arch/x86/orc.c +++ b/tools/objtool/arch/x86/orc.c @@ -70,6 +70,9 @@ int init_orc_entry(struct orc_entry *orc, struct cfi_state *cfi, struct instruct case CFI_DX: orc->sp_reg = ORC_REG_DX; break; + case CFI_AX: + orc->sp_reg = ORC_REG_AX; + break; default: ERROR_INSN(insn, "unknown CFA base reg %d", cfi->cfa.base); return -1; @@ -138,6 +141,8 @@ static const char *reg_name(unsigned int reg) return "bp(ind)"; case ORC_REG_SP_INDIRECT: return "sp(ind)"; + case ORC_REG_AX: + return "ax"; default: return "?"; }