x86,objtool: Separate unret validation from unwind hints

The ENTRY unwind hint type is serving double duty as both an empty
unwind hint and an unret validation annotation.

Unret validation is unrelated to unwinding. Separate it out into its own
annotation.

Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/ff7448d492ea21b86d8a90264b105fbd0d751077.1677683419.git.jpoimboe@kernel.org

4 files changed, 18 insertions, 17 deletions

diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index eccc3431e515..5b93eb7db0ab 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -388,9 +388,9 @@ SYM_CODE_START(\asmsym)
 
 	.if \vector == X86_TRAP_BP
 		/* #BP advances %rip to the next instruction */
-		UNWIND_HINT_IRET_REGS offset=\has_error_code*8 signal=0
+		UNWIND_HINT_IRET_ENTRY offset=\has_error_code*8 signal=0
 	.else
-		UNWIND_HINT_IRET_REGS offset=\has_error_code*8
+		UNWIND_HINT_IRET_ENTRY offset=\has_error_code*8
 	.endif
 
 	ENDBR
@@ -461,7 +461,7 @@ SYM_CODE_END(\asmsym)
  */
 .macro idtentry_mce_db vector asmsym cfunc
 SYM_CODE_START(\asmsym)
-	UNWIND_HINT_IRET_REGS
+	UNWIND_HINT_IRET_ENTRY
 	ENDBR
 	ASM_CLAC
 	cld
@@ -518,7 +518,7 @@ SYM_CODE_END(\asmsym)
  */
 .macro idtentry_vc vector asmsym cfunc
 SYM_CODE_START(\asmsym)
-	UNWIND_HINT_IRET_REGS
+	UNWIND_HINT_IRET_ENTRY
 	ENDBR
 	ASM_CLAC
 	cld
@@ -582,7 +582,7 @@ SYM_CODE_END(\asmsym)
  */
 .macro idtentry_df vector asmsym cfunc
 SYM_CODE_START(\asmsym)
-	UNWIND_HINT_IRET_REGS offset=8
+	UNWIND_HINT_IRET_ENTRY offset=8
 	ENDBR
 	ASM_CLAC
 	cld
@@ -1107,7 +1107,7 @@ SYM_CODE_START(error_entry)
 	FENCE_SWAPGS_KERNEL_ENTRY
 	CALL_DEPTH_ACCOUNT
 	leaq	8(%rsp), %rax			/* return pt_regs pointer */
-	ANNOTATE_UNRET_END
+	VALIDATE_UNRET_END
 	RET
 
 .Lbstep_iret:
@@ -1153,7 +1153,7 @@ SYM_CODE_END(error_return)
  *	      when PAGE_TABLE_ISOLATION is in use.  Do not clobber.
  */
 SYM_CODE_START(asm_exc_nmi)
-	UNWIND_HINT_IRET_REGS
+	UNWIND_HINT_IRET_ENTRY
 	ENDBR
 
 	/*
diff --git a/arch/x86/include/asm/nospec-branch.h b/arch/x86/include/asm/nospec-branch.h
index 78ed1546b775..edb2b0cb8efe 100644
--- a/arch/x86/include/asm/nospec-branch.h
+++ b/arch/x86/include/asm/nospec-branch.h
@@ -210,8 +210,8 @@
  * Abuse ANNOTATE_RETPOLINE_SAFE on a NOP to indicate UNRET_END, should
  * eventually turn into it's own annotation.
  */
-.macro ANNOTATE_UNRET_END
-#ifdef CONFIG_DEBUG_ENTRY
+.macro VALIDATE_UNRET_END
+#if defined(CONFIG_NOINSTR_VALIDATION) && defined(CONFIG_CPU_UNRET_ENTRY)
 	ANNOTATE_RETPOLINE_SAFE
 	nop
 #endif
@@ -286,7 +286,7 @@
 .macro UNTRAIN_RET
 #if defined(CONFIG_CPU_UNRET_ENTRY) || defined(CONFIG_CPU_IBPB_ENTRY) || \
 	defined(CONFIG_CALL_DEPTH_TRACKING)
-	ANNOTATE_UNRET_END
+	VALIDATE_UNRET_END
 	ALTERNATIVE_3 "",						\
 		      CALL_ZEN_UNTRAIN_RET, X86_FEATURE_UNRET,		\
 		      "call entry_ibpb", X86_FEATURE_ENTRY_IBPB,	\
@@ -297,7 +297,7 @@
 .macro UNTRAIN_RET_FROM_CALL
 #if defined(CONFIG_CPU_UNRET_ENTRY) || defined(CONFIG_CPU_IBPB_ENTRY) || \
 	defined(CONFIG_CALL_DEPTH_TRACKING)
-	ANNOTATE_UNRET_END
+	VALIDATE_UNRET_END
 	ALTERNATIVE_3 "",						\
 		      CALL_ZEN_UNTRAIN_RET, X86_FEATURE_UNRET,		\
 		      "call entry_ibpb", X86_FEATURE_ENTRY_IBPB,	\
diff --git a/arch/x86/include/asm/unwind_hints.h b/arch/x86/include/asm/unwind_hints.h
index 97b392217c0f..4c0f28d665eb 100644
--- a/arch/x86/include/asm/unwind_hints.h
+++ b/arch/x86/include/asm/unwind_hints.h
@@ -12,7 +12,8 @@
 .endm
 
 .macro UNWIND_HINT_ENTRY
-	UNWIND_HINT type=UNWIND_HINT_TYPE_ENTRY end=1
+	VALIDATE_UNRET_BEGIN
+	UNWIND_HINT_EMPTY
 .endm
 
 .macro UNWIND_HINT_REGS base=%rsp offset=0 indirect=0 extra=1 partial=0 signal=1
@@ -52,6 +53,11 @@
 	UNWIND_HINT_REGS base=\base offset=\offset partial=1 signal=\signal
 .endm
 
+.macro UNWIND_HINT_IRET_ENTRY base=%rsp offset=0 signal=1
+	VALIDATE_UNRET_BEGIN
+	UNWIND_HINT_IRET_REGS base=\base offset=\offset signal=\signal
+.endm
+
 .macro UNWIND_HINT_FUNC
 	UNWIND_HINT sp_reg=ORC_REG_SP sp_offset=8 type=UNWIND_HINT_TYPE_FUNC
 .endm
diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S
index 222efd4a09bc..ee3ed15ee1f8 100644
--- a/arch/x86/kernel/head_64.S
+++ b/arch/x86/kernel/head_64.S
@@ -390,8 +390,6 @@ SYM_CODE_START_NOALIGN(vc_boot_ghcb)
 	UNWIND_HINT_IRET_REGS offset=8
 	ENDBR
 
-	ANNOTATE_UNRET_END
-
 	/* Build pt_regs */
 	PUSH_AND_CLEAR_REGS
 
@@ -451,7 +449,6 @@ SYM_CODE_END(early_idt_handler_array)
 
 SYM_CODE_START_LOCAL(early_idt_handler_common)
 	UNWIND_HINT_IRET_REGS offset=16
-	ANNOTATE_UNRET_END
 	/*
 	 * The stack is the hardware frame, an error code or zero, and the
 	 * vector number.
@@ -501,8 +498,6 @@ SYM_CODE_START_NOALIGN(vc_no_ghcb)
 	UNWIND_HINT_IRET_REGS offset=8
 	ENDBR
 
-	ANNOTATE_UNRET_END
-
 	/* Build pt_regs */
 	PUSH_AND_CLEAR_REGS