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From: Peter Zijlstra <peterz@infradead.org>
To: Sean Christopherson <seanjc@google.com>,
	Paolo Bonzini <pbonzini@redhat.com>,
	Josh Poimboeuf <jpoimboe@redhat.com>,
	Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org, peterz@infradead.org,
	x86@kernel.org, kvm@vger.kernel.org
Subject: [PATCH 03/11] objtool: Convert ANNOTATE_RETPOLINE_SAFE to ANNOTATE
Date: Mon, 04 Dec 2023 10:37:05 +0100	[thread overview]
Message-ID: <20231204093731.574465649@infradead.org> (raw)
In-Reply-To: 20231204093702.989848513@infradead.org


Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
 arch/x86/include/asm/nospec-branch.h |   13 +-------
 include/linux/objtool_types.h        |    1 
 tools/include/linux/objtool_types.h  |    1 
 tools/objtool/check.c                |   52 ++++++++++++-----------------------
 4 files changed, 22 insertions(+), 45 deletions(-)

--- a/arch/x86/include/asm/nospec-branch.h
+++ b/arch/x86/include/asm/nospec-branch.h
@@ -193,12 +193,7 @@
  * objtool the subsequent indirect jump/call is vouched safe for retpoline
  * builds.
  */
-.macro ANNOTATE_RETPOLINE_SAFE
-.Lhere_\@:
-	.pushsection .discard.retpoline_safe
-	.long .Lhere_\@
-	.popsection
-.endm
+#define ANNOTATE_RETPOLINE_SAFE	ANNOTATE type=ANNOTYPE_RETPOLINE_SAFE
 
 /*
  * (ab)use RETPOLINE_SAFE on RET to annotate away 'bare' RET instructions
@@ -317,11 +312,7 @@
 
 #else /* __ASSEMBLY__ */
 
-#define ANNOTATE_RETPOLINE_SAFE					\
-	"999:\n\t"						\
-	".pushsection .discard.retpoline_safe\n\t"		\
-	".long 999b\n\t"					\
-	".popsection\n\t"
+#define ANNOTATE_RETPOLINE_SAFE ASM_ANNOTATE(ANNOTYPE_RETPOLINE_SAFE)
 
 typedef u8 retpoline_thunk_t[RETPOLINE_THUNK_SIZE];
 extern retpoline_thunk_t __x86_indirect_thunk_array[];
--- a/include/linux/objtool_types.h
+++ b/include/linux/objtool_types.h
@@ -58,5 +58,6 @@ struct unwind_hint {
  * Annotate types
  */
 #define ANNOTYPE_NOENDBR		1
+#define ANNOTYPE_RETPOLINE_SAFE		2
 
 #endif /* _LINUX_OBJTOOL_TYPES_H */
--- a/tools/include/linux/objtool_types.h
+++ b/tools/include/linux/objtool_types.h
@@ -58,5 +58,6 @@ struct unwind_hint {
  * Annotate types
  */
 #define ANNOTYPE_NOENDBR		1
+#define ANNOTYPE_RETPOLINE_SAFE		2
 
 #endif /* _LINUX_OBJTOOL_TYPES_H */
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -2308,12 +2308,12 @@ static int read_unwind_hints(struct objt
 	return 0;
 }
 
-static int read_annotate(struct objtool_file *file, void (*func)(int type, struct instruction *insn))
+static int read_annotate(struct objtool_file *file, int (*func)(int type, struct instruction *insn))
 {
 	struct section *rsec, *sec;
 	struct instruction *insn;
 	struct reloc *reloc;
-	int type;
+	int type, ret;
 
 	rsec = find_section_by_name(file->elf, ".rela.discard.annotate");
 	if (!rsec)
@@ -2333,53 +2333,37 @@ static int read_annotate(struct objtool_
 
 		type = *(u32 *)(sec->data->d_buf + (reloc_idx(reloc) * sec->sh.sh_entsize) + 4);
 
-		func(type, insn);
+		ret = func(type, insn);
+		if (ret < 0)
+			return ret;
 	}
 
 	return 0;
 }
 
-static void __annotate_noendbr(int type, struct instruction *insn)
+static int __annotate_noendbr(int type, struct instruction *insn)
 {
 	if (type != ANNOTYPE_NOENDBR)
-		return;
+		return 0;
 
 	insn->noendbr = 1;
+	return 0;
 }
 
-static int read_retpoline_hints(struct objtool_file *file)
+static int __annotate_retpoline_safe(int type, struct instruction *insn)
 {
-	struct section *rsec;
-	struct instruction *insn;
-	struct reloc *reloc;
-
-	rsec = find_section_by_name(file->elf, ".rela.discard.retpoline_safe");
-	if (!rsec)
+	if (type != ANNOTYPE_RETPOLINE_SAFE)
 		return 0;
 
-	for_each_reloc(rsec, reloc) {
-		if (reloc->sym->type != STT_SECTION) {
-			WARN("unexpected relocation symbol type in %s", rsec->name);
-			return -1;
-		}
-
-		insn = find_insn(file, reloc->sym->sec, reloc_addend(reloc));
-		if (!insn) {
-			WARN("bad .discard.retpoline_safe entry");
-			return -1;
-		}
-
-		if (insn->type != INSN_JUMP_DYNAMIC &&
-		    insn->type != INSN_CALL_DYNAMIC &&
-		    insn->type != INSN_RETURN &&
-		    insn->type != INSN_NOP) {
-			WARN_INSN(insn, "retpoline_safe hint not an indirect jump/call/ret/nop");
-			return -1;
-		}
-
-		insn->retpoline_safe = true;
+	if (insn->type != INSN_JUMP_DYNAMIC &&
+	    insn->type != INSN_CALL_DYNAMIC &&
+	    insn->type != INSN_RETURN &&
+	    insn->type != INSN_NOP) {
+		WARN_INSN(insn, "retpoline_safe hint not an indirect jump/call/ret/nop");
+		return -1;
 	}
 
+	insn->retpoline_safe = true;
 	return 0;
 }
 
@@ -2666,7 +2650,7 @@ static int decode_sections(struct objtoo
 	if (ret)
 		return ret;
 
-	ret = read_retpoline_hints(file);
+	ret = read_annotate(file, __annotate_retpoline_safe);
 	if (ret)
 		return ret;
 



  parent reply	other threads:[~2023-12-04  9:40 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-12-04  9:37 [PATCH 00/11] x86/kvm/emulate: Avoid RET for FASTOPs Peter Zijlstra
2023-12-04  9:37 ` [PATCH 01/11] objtool: Generic annotation infrastructure Peter Zijlstra
2023-12-04  9:37 ` [PATCH 02/11] objtool: Convert ANNOTATE_NOENDBR to ANNOTATE Peter Zijlstra
2023-12-04  9:37 ` Peter Zijlstra [this message]
2023-12-06 23:31   ` [PATCH 03/11] objtool: Convert ANNOTATE_RETPOLINE_SAFE " Sean Christopherson
2023-12-04  9:37 ` [PATCH 04/11] objtool: Convert instrumentation_{begin,end}() " Peter Zijlstra
2023-12-04  9:37 ` [PATCH 05/11] objtool: Convert VALIDATE_UNRET_BEGIN " Peter Zijlstra
2023-12-04  9:37 ` [PATCH 06/11] objtool: Convert ANNOTATE_IGNORE_ALTERNATIVE " Peter Zijlstra
2023-12-04  9:37 ` [PATCH 07/11] objtool: Convert ANNOTATE_INTRA_FUNCTION_CALLS " Peter Zijlstra
2023-12-04  9:37 ` [PATCH 08/11] objtool: Collapse annotate sequences Peter Zijlstra
2023-12-04  9:37 ` [PATCH 09/11] x86/kvm/emulate: Implement test_cc() in C Peter Zijlstra
2023-12-04  9:37 ` [PATCH 10/11] x86/nospec: JMP_NOSPEC Peter Zijlstra
2023-12-04  9:37 ` [PATCH 11/11] x86/kvm/emulate: Avoid RET for fastops Peter Zijlstra

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