Commit 96f3b16a authored by Josh Poimboeuf's avatar Josh Poimboeuf Committed by Peter Zijlstra
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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: default avatarArnd Bergmann <arnd@arndb.de>
Signed-off-by: default avatarJosh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/3f33dc720b83dc6d3a2b7094f75a5c90a0b1cbc5.1773708458.git.jpoimboe@kernel.org
parent 51a0b7c4

arch/x86/include/asm/orc_types.h

+1 −0
Original line number Diff line number Diff line
@@ -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

arch/x86/kernel/unwind_orc.c

+8 −0
Original line number Diff line number Diff line
@@ -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);

tools/arch/x86/include/asm/orc_types.h

+1 −0
Original line number Diff line number Diff line
@@ -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

tools/objtool/arch/x86/decode.c

+3 −0
Original line number Diff line number Diff line
@@ -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;

	}

tools/objtool/arch/x86/orc.c

+5 −0
Original line number Diff line number Diff line
@@ -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 "?";

	}