Commit-ID: ff05ab2305aaeb21a3002ae95a17e176c198b71b
Gitweb: https://git.kernel.org/tip/ff05ab2305aaeb21a3002ae95a17e176c198b71b
Author: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
AuthorDate: Mon, 18 Mar 2019 14:33:07 +0100
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Wed, 3 Apr 2019 09:39:46 +0200
x86/nospec, objtool: Introduce ANNOTATE_IGNORE_ALTERNATIVE
To facillitate other usage of ignoring alternatives; rename
ANNOTATE_NOSPEC_IGNORE to ANNOTATE_IGNORE_ALTERNATIVE.
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
arch/x86/include/asm/alternative-asm.h | 11 +++++++++++
arch/x86/include/asm/alternative.h | 10 ++++++++++
arch/x86/include/asm/nospec-branch.h | 28 +++++++++-------------------
tools/objtool/check.c | 8 ++++----
4 files changed, 34 insertions(+), 23 deletions(-)
diff --git a/arch/x86/include/asm/alternative-asm.h b/arch/x86/include/asm/alternative-asm.h
index 31b627b43a8e..464034db299f 100644
--- a/arch/x86/include/asm/alternative-asm.h
+++ b/arch/x86/include/asm/alternative-asm.h
@@ -19,6 +19,17 @@
.endm
#endif
+/*
+ * objtool annotation to ignore the alternatives and only consider the original
+ * instruction(s).
+ */
+.macro ANNOTATE_IGNORE_ALTERNATIVE
+ .Lannotate_\@:
+ .pushsection .discard.ignore_alts
+ .long .Lannotate_\@ - .
+ .popsection
+.endm
+
/*
* Issue one struct alt_instr descriptor entry (need to put it into
* the section .altinstructions, see below). This entry contains
diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
index 4c74073a19cc..094fbc9c0b1c 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -45,6 +45,16 @@
#define LOCK_PREFIX ""
#endif
+/*
+ * objtool annotation to ignore the alternatives and only consider the original
+ * instruction(s).
+ */
+#define ANNOTATE_IGNORE_ALTERNATIVE \
+ "999:\n\t" \
+ ".pushsection .discard.ignore_alts\n\t" \
+ ".long 999b - .\n\t" \
+ ".popsection\n\t"
+
struct alt_instr {
s32 instr_offset; /* original instruction */
s32 repl_offset; /* offset to replacement instruction */
diff --git a/arch/x86/include/asm/nospec-branch.h b/arch/x86/include/asm/nospec-branch.h
index dad12b767ba0..daf25b60c9e3 100644
--- a/arch/x86/include/asm/nospec-branch.h
+++ b/arch/x86/include/asm/nospec-branch.h
@@ -10,6 +10,15 @@
#include <asm/cpufeatures.h>
#include <asm/msr-index.h>
+/*
+ * This should be used immediately before a retpoline alternative. It tells
+ * objtool where the retpolines are so that it can make sense of the control
+ * flow by just reading the original instruction(s) and ignoring the
+ * alternatives.
+ */
+#define ANNOTATE_NOSPEC_ALTERNATIVE \
+ ANNOTATE_IGNORE_ALTERNATIVE
+
/*
* Fill the CPU return stack buffer.
*
@@ -56,19 +65,6 @@
#ifdef __ASSEMBLY__
-/*
- * This should be used immediately before a retpoline alternative. It tells
- * objtool where the retpolines are so that it can make sense of the control
- * flow by just reading the original instruction(s) and ignoring the
- * alternatives.
- */
-.macro ANNOTATE_NOSPEC_ALTERNATIVE
- .Lannotate_\@:
- .pushsection .discard.nospec
- .long .Lannotate_\@ - .
- .popsection
-.endm
-
/*
* This should be used immediately before an indirect jump/call. It tells
* objtool the subsequent indirect jump/call is vouched safe for retpoline
@@ -152,12 +148,6 @@
#else /* __ASSEMBLY__ */
-#define ANNOTATE_NOSPEC_ALTERNATIVE \
- "999:\n\t" \
- ".pushsection .discard.nospec\n\t" \
- ".long 999b - .\n\t" \
- ".popsection\n\t"
-
#define ANNOTATE_RETPOLINE_SAFE \
"999:\n\t" \
".pushsection .discard.retpoline_safe\n\t" \
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 5dde107083c6..110ea3d84772 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -457,13 +457,13 @@ static void add_ignores(struct objtool_file *file)
* But it at least allows objtool to understand the control flow *around* the
* retpoline.
*/
-static int add_nospec_ignores(struct objtool_file *file)
+static int add_ignore_alternatives(struct objtool_file *file)
{
struct section *sec;
struct rela *rela;
struct instruction *insn;
- sec = find_section_by_name(file->elf, ".rela.discard.nospec");
+ sec = find_section_by_name(file->elf, ".rela.discard.ignore_alts");
if (!sec)
return 0;
@@ -475,7 +475,7 @@ static int add_nospec_ignores(struct objtool_file *file)
insn = find_insn(file, rela->sym->sec, rela->addend);
if (!insn) {
- WARN("bad .discard.nospec entry");
+ WARN("bad .discard.ignore_alts entry");
return -1;
}
@@ -1239,7 +1239,7 @@ static int decode_sections(struct objtool_file *file)
add_ignores(file);
- ret = add_nospec_ignores(file);
+ ret = add_ignore_alternatives(file);
if (ret)
return ret;
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