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@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/arch/x86/include/asm/alternative-asm.h b/arch/x86/include/asm/alternative-asm.h
index 31b627b..464034d 100644 (file)
--- 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 4c74073..094fbc9 100644 (file)
--- 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 dad12b7..daf25b6 100644 (file)
--- 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 5dde107..110ea3d 100644 (file)
--- 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;