From: Josh Poimboeuf jpoimboe@kernel.org
commit 8faea26e611189e933ea2281975ff4dc7c1106b6 upstream.
Commit
c536ed2fffd5 ("objtool: Remove SAVE/RESTORE hints")
removed the save/restore unwind hints because they were no longer needed. Now they're going to be needed again so re-add them.
Signed-off-by: Josh Poimboeuf jpoimboe@kernel.org Signed-off-by: Peter Zijlstra (Intel) peterz@infradead.org Signed-off-by: Borislav Petkov bp@suse.de Signed-off-by: Thadeu Lima de Souza Cascardo cascardo@canonical.com Signed-off-by: Ben Hutchings ben@decadent.org.uk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/x86/include/asm/unwind_hints.h | 12 +++++++++- include/linux/objtool.h | 6 +++-- tools/include/linux/objtool.h | 6 +++-- tools/objtool/check.c | 40 ++++++++++++++++++++++++++++++++++++ tools/objtool/check.h | 1 5 files changed, 59 insertions(+), 6 deletions(-)
--- a/arch/x86/include/asm/unwind_hints.h +++ b/arch/x86/include/asm/unwind_hints.h @@ -8,11 +8,11 @@ #ifdef __ASSEMBLY__
.macro UNWIND_HINT_EMPTY - UNWIND_HINT sp_reg=ORC_REG_UNDEFINED type=UNWIND_HINT_TYPE_CALL end=1 + UNWIND_HINT type=UNWIND_HINT_TYPE_CALL end=1 .endm
.macro UNWIND_HINT_ENTRY - UNWIND_HINT sp_reg=ORC_REG_UNDEFINED type=UNWIND_HINT_TYPE_ENTRY end=1 + UNWIND_HINT type=UNWIND_HINT_TYPE_ENTRY end=1 .endm
.macro UNWIND_HINT_REGS base=%rsp offset=0 indirect=0 extra=1 partial=0 @@ -56,6 +56,14 @@ UNWIND_HINT sp_reg=ORC_REG_SP sp_offset=8 type=UNWIND_HINT_TYPE_FUNC .endm
+.macro UNWIND_HINT_SAVE + UNWIND_HINT type=UNWIND_HINT_TYPE_SAVE +.endm + +.macro UNWIND_HINT_RESTORE + UNWIND_HINT type=UNWIND_HINT_TYPE_RESTORE +.endm + #endif /* __ASSEMBLY__ */
#endif /* _ASM_X86_UNWIND_HINTS_H */ --- a/include/linux/objtool.h +++ b/include/linux/objtool.h @@ -40,6 +40,8 @@ struct unwind_hint { #define UNWIND_HINT_TYPE_REGS_PARTIAL 2 #define UNWIND_HINT_TYPE_FUNC 3 #define UNWIND_HINT_TYPE_ENTRY 4 +#define UNWIND_HINT_TYPE_SAVE 5 +#define UNWIND_HINT_TYPE_RESTORE 6
#ifdef CONFIG_STACK_VALIDATION
@@ -102,7 +104,7 @@ struct unwind_hint { * the debuginfo as necessary. It will also warn if it sees any * inconsistencies. */ -.macro UNWIND_HINT sp_reg:req sp_offset=0 type:req end=0 +.macro UNWIND_HINT type:req sp_reg=0 sp_offset=0 end=0 .Lunwind_hint_ip_@: .pushsection .discard.unwind_hints /* struct unwind_hint */ @@ -126,7 +128,7 @@ struct unwind_hint { #define STACK_FRAME_NON_STANDARD(func) #else #define ANNOTATE_INTRA_FUNCTION_CALL -.macro UNWIND_HINT sp_reg:req sp_offset=0 type:req end=0 +.macro UNWIND_HINT type:req sp_reg=0 sp_offset=0 end=0 .endm #endif
--- a/tools/include/linux/objtool.h +++ b/tools/include/linux/objtool.h @@ -40,6 +40,8 @@ struct unwind_hint { #define UNWIND_HINT_TYPE_REGS_PARTIAL 2 #define UNWIND_HINT_TYPE_FUNC 3 #define UNWIND_HINT_TYPE_ENTRY 4 +#define UNWIND_HINT_TYPE_SAVE 5 +#define UNWIND_HINT_TYPE_RESTORE 6
#ifdef CONFIG_STACK_VALIDATION
@@ -102,7 +104,7 @@ struct unwind_hint { * the debuginfo as necessary. It will also warn if it sees any * inconsistencies. */ -.macro UNWIND_HINT sp_reg:req sp_offset=0 type:req end=0 +.macro UNWIND_HINT type:req sp_reg=0 sp_offset=0 end=0 .Lunwind_hint_ip_@: .pushsection .discard.unwind_hints /* struct unwind_hint */ @@ -126,7 +128,7 @@ struct unwind_hint { #define STACK_FRAME_NON_STANDARD(func) #else #define ANNOTATE_INTRA_FUNCTION_CALL -.macro UNWIND_HINT sp_reg:req sp_offset=0 type:req end=0 +.macro UNWIND_HINT type:req sp_reg=0 sp_offset=0 end=0 .endm #endif
--- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -1752,6 +1752,17 @@ static int read_unwind_hints(struct objt
insn->hint = true;
+ if (hint->type == UNWIND_HINT_TYPE_SAVE) { + insn->hint = false; + insn->save = true; + continue; + } + + if (hint->type == UNWIND_HINT_TYPE_RESTORE) { + insn->restore = true; + continue; + } + if (hint->type == UNWIND_HINT_TYPE_REGS_PARTIAL) { struct symbol *sym = find_symbol_by_offset(insn->sec, insn->offset);
@@ -2847,6 +2858,35 @@ static int validate_branch(struct objtoo state.instr += insn->instr;
if (insn->hint) { + if (insn->restore) { + struct instruction *save_insn, *i; + + i = insn; + save_insn = NULL; + + sym_for_each_insn_continue_reverse(file, func, i) { + if (i->save) { + save_insn = i; + break; + } + } + + if (!save_insn) { + WARN_FUNC("no corresponding CFI save for CFI restore", + sec, insn->offset); + return 1; + } + + if (!save_insn->visited) { + WARN_FUNC("objtool isn't smart enough to handle this CFI save/restore combo", + sec, insn->offset); + return 1; + } + + insn->cfi = save_insn->cfi; + nr_cfi_reused++; + } + state.cfi = *insn->cfi; } else { /* XXX track if we actually changed state.cfi */ --- a/tools/objtool/check.h +++ b/tools/objtool/check.h @@ -47,6 +47,7 @@ struct instruction { unsigned long immediate; bool dead_end, ignore, ignore_alts; bool hint; + bool save, restore; bool retpoline_safe; bool entry; s8 instr;