objtool: Convert ANNOTATE_IGNORE_ALTERNATIVE to ANNOTATE

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Link: https://lore.kernel.org/r/20241128094311.465691316@infradead.org

diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
index dc03a647776d93f58058cd85752bba6e063f2ecf..595695f85f80462c18cb5a9158e31951d5c35721 100644 (file)
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -4,6 +4,7 @@
 
 #include <linux/types.h>
 #include <linux/stringify.h>
+#include <linux/objtool.h>
 #include <asm/asm.h>
 
 #define ALT_FLAGS_SHIFT                16
@@ -58,11 +59,7 @@
  * 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"
+#define ANNOTATE_IGNORE_ALTERNATIVE    ASM_ANNOTATE(ANNOTYPE_IGNORE_ALTS)
 
 /*
  * The patching flags are part of the upper bits of the @ft_flags parameter when
@@ -314,12 +311,7 @@ void nop_func(void);
  * 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
+#define ANNOTATE_IGNORE_ALTERNATIVE ANNOTATE type=ANNOTYPE_IGNORE_ALTS
 
 /*
  * Issue one struct alt_instr descriptor entry (need to put it into

diff --git a/include/linux/objtool_types.h b/include/linux/objtool_types.h
index 16236a56364b56d3bca5706ba6bd6bacce725d59..eab15dbe1cb724604a03ab068cd4b50a20267357 100644 (file)
--- a/include/linux/objtool_types.h
+++ b/include/linux/objtool_types.h
@@ -62,5 +62,6 @@ struct unwind_hint {
 #define ANNOTYPE_INSTR_BEGIN           3
 #define ANNOTYPE_INSTR_END             4
 #define ANNOTYPE_UNRET_BEGIN           5
+#define ANNOTYPE_IGNORE_ALTS           6
 
 #endif /* _LINUX_OBJTOOL_TYPES_H */

diff --git a/tools/include/linux/objtool_types.h b/tools/include/linux/objtool_types.h
index 16236a56364b56d3bca5706ba6bd6bacce725d59..eab15dbe1cb724604a03ab068cd4b50a20267357 100644 (file)
--- a/tools/include/linux/objtool_types.h
+++ b/tools/include/linux/objtool_types.h
@@ -62,5 +62,6 @@ struct unwind_hint {
 #define ANNOTYPE_INSTR_BEGIN           3
 #define ANNOTYPE_INSTR_END             4
 #define ANNOTYPE_UNRET_BEGIN           5
+#define ANNOTYPE_IGNORE_ALTS           6
 
 #endif /* _LINUX_OBJTOOL_TYPES_H */

diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 2a703748cad1f47289a28514da0fc975853fe48b..ba2cb9b6939991687d729f5584ae559309d3fce3 100644 (file)
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -1309,40 +1309,6 @@ static void add_uaccess_safe(struct objtool_file *file)
        }
 }
 
-/*
- * FIXME: For now, just ignore any alternatives which add retpolines.  This is
- * a temporary hack, as it doesn't allow ORC to unwind from inside a retpoline.
- * But it at least allows objtool to understand the control flow *around* the
- * retpoline.
- */
-static int add_ignore_alternatives(struct objtool_file *file)
-{
-       struct section *rsec;
-       struct reloc *reloc;
-       struct instruction *insn;
-
-       rsec = find_section_by_name(file->elf, ".rela.discard.ignore_alts");
-       if (!rsec)
-               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.ignore_alts entry");
-                       return -1;
-               }
-
-               insn->ignore_alts = true;
-       }
-
-       return 0;
-}
-
 /*
  * Symbols that replace INSN_CALL_DYNAMIC, every (tail) call to such a symbol
  * will be added to the .retpoline_sites section.
@@ -2414,6 +2380,15 @@ static int read_annotate(struct objtool_file *file, int (*func)(int type, struct
        return 0;
 }
 
+static int __annotate_ignore_alts(int type, struct instruction *insn)
+{
+       if (type != ANNOTYPE_IGNORE_ALTS)
+               return 0;
+
+       insn->ignore_alts = true;
+       return 0;
+}
+
 static int __annotate_noendbr(int type, struct instruction *insn)
 {
        if (type != ANNOTYPE_NOENDBR)
@@ -2626,7 +2601,7 @@ static int decode_sections(struct objtool_file *file)
        add_ignores(file);
        add_uaccess_safe(file);
 
-       ret = add_ignore_alternatives(file);
+       ret = read_annotate(file, __annotate_ignore_alts);
        if (ret)
                return ret;