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objtool: Collect more annotations in objtool.h
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Suggested-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Link: https://lore.kernel.org/r/20241128094311.786598147@infradead.org
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Peter Zijlstra committed Dec 2, 2024
1 parent a8a330d commit bb81700
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Showing 4 changed files with 55 additions and 50 deletions.
12 changes: 0 additions & 12 deletions arch/x86/include/asm/alternative.h
Original file line number Diff line number Diff line change
Expand Up @@ -55,12 +55,6 @@
#define LOCK_PREFIX ""
#endif

/*
* objtool annotation to ignore the alternatives and only consider the original
* instruction(s).
*/
#define ANNOTATE_IGNORE_ALTERNATIVE ASM_ANNOTATE(ANNOTYPE_IGNORE_ALTS)

/*
* The patching flags are part of the upper bits of the @ft_flags parameter when
* specifying them. The split is currently like this:
Expand Down Expand Up @@ -307,12 +301,6 @@ void nop_func(void);
.endm
#endif

/*
* objtool annotation to ignore the alternatives and only consider the original
* instruction(s).
*/
#define ANNOTATE_IGNORE_ALTERNATIVE ANNOTATE type=ANNOTYPE_IGNORE_ALTS

/*
* Issue one struct alt_instr descriptor entry (need to put it into
* the section .altinstructions, see below). This entry contains
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9 changes: 0 additions & 9 deletions arch/x86/include/asm/nospec-branch.h
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Expand Up @@ -179,13 +179,6 @@

#ifdef __ASSEMBLY__

/*
* This should be used immediately before an indirect jump/call. It tells
* objtool the subsequent indirect jump/call is vouched safe for retpoline
* builds.
*/
#define ANNOTATE_RETPOLINE_SAFE ANNOTATE type=ANNOTYPE_RETPOLINE_SAFE

/*
* (ab)use RETPOLINE_SAFE on RET to annotate away 'bare' RET instructions
* vs RETBleed validation.
Expand Down Expand Up @@ -345,8 +338,6 @@

#else /* __ASSEMBLY__ */

#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[];
extern retpoline_thunk_t __x86_indirect_call_thunk_array[];
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4 changes: 2 additions & 2 deletions include/linux/instrumentation.h
Original file line number Diff line number Diff line change
Expand Up @@ -10,7 +10,7 @@
/* Begin/end of an instrumentation safe region */
#define __instrumentation_begin(c) ({ \
asm volatile(__stringify(c) ": nop\n\t" \
__ASM_ANNOTATE(__ASM_BREF(c), ANNOTYPE_INSTR_BEGIN)\
ANNOTATE_INSTR_BEGIN(__ASM_BREF(c)) \
: : "i" (c)); \
})
#define instrumentation_begin() __instrumentation_begin(__COUNTER__)
Expand Down Expand Up @@ -48,7 +48,7 @@
*/
#define __instrumentation_end(c) ({ \
asm volatile(__stringify(c) ": nop\n\t" \
__ASM_ANNOTATE(__ASM_BREF(c), ANNOTYPE_INSTR_END) \
ANNOTATE_INSTR_END(__ASM_BREF(c)) \
: : "i" (c)); \
})
#define instrumentation_end() __instrumentation_end(__COUNTER__)
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80 changes: 53 additions & 27 deletions include/linux/objtool.h
Original file line number Diff line number Diff line change
Expand Up @@ -63,8 +63,6 @@
"911:\n\t" \
__ASM_ANNOTATE(911b, type)

#define ANNOTATE_NOENDBR ASM_ANNOTATE(ANNOTYPE_NOENDBR)

#else /* __ASSEMBLY__ */

/*
Expand Down Expand Up @@ -113,19 +111,6 @@
#endif
.endm

/*
* Use objtool to validate the entry requirement that all code paths do
* VALIDATE_UNRET_END before RET.
*
* NOTE: The macro must be used at the beginning of a global symbol, otherwise
* it will be ignored.
*/
#if defined(CONFIG_NOINSTR_VALIDATION) && \
(defined(CONFIG_MITIGATION_UNRET_ENTRY) || defined(CONFIG_MITIGATION_SRSO))
#define VALIDATE_UNRET_BEGIN ANNOTATE type=ANNOTYPE_UNRET_BEGIN
#else
#define VALIDATE_UNRET_BEGIN
#endif

.macro REACHABLE
.Lhere_\@:
Expand All @@ -142,14 +127,6 @@
.popsection
.endm

#define ANNOTATE_NOENDBR ANNOTATE type=ANNOTYPE_NOENDBR

/*
* This macro indicates that the following intra-function call is valid.
* Any non-annotated intra-function call will cause objtool to issue a warning.
*/
#define ANNOTATE_INTRA_FUNCTION_CALL ANNOTATE type=ANNOTYPE_INTRA_FUNCTION_CALL

#endif /* __ASSEMBLY__ */

#else /* !CONFIG_OBJTOOL */
Expand All @@ -161,16 +138,12 @@
#define STACK_FRAME_NON_STANDARD_FP(func)
#define __ASM_ANNOTATE(label, type)
#define ASM_ANNOTATE(type)
#define ANNOTATE_NOENDBR
#define ASM_REACHABLE
#else
#define ANNOTATE_INTRA_FUNCTION_CALL
.macro UNWIND_HINT type:req sp_reg=0 sp_offset=0 signal=0
.endm
.macro STACK_FRAME_NON_STANDARD func:req
.endm
.macro ANNOTATE_NOENDBR
.endm
.macro REACHABLE
.endm
.macro ANNOTATE type:req
Expand All @@ -179,4 +152,57 @@

#endif /* CONFIG_OBJTOOL */

#ifndef __ASSEMBLY__
/*
* Annotate away the various 'relocation to !ENDBR` complaints; knowing that
* these relocations will never be used for indirect calls.
*/
#define ANNOTATE_NOENDBR ASM_ANNOTATE(ANNOTYPE_NOENDBR)
/*
* This should be used immediately before an indirect jump/call. It tells
* objtool the subsequent indirect jump/call is vouched safe for retpoline
* builds.
*/
#define ANNOTATE_RETPOLINE_SAFE ASM_ANNOTATE(ANNOTYPE_RETPOLINE_SAFE)
/*
* See linux/instrumentation.h
*/
#define ANNOTATE_INSTR_BEGIN(label) __ASM_ANNOTATE(label, ANNOTYPE_INSTR_BEGIN)
#define ANNOTATE_INSTR_END(label) __ASM_ANNOTATE(label, ANNOTYPE_INSTR_END)
/*
* objtool annotation to ignore the alternatives and only consider the original
* instruction(s).
*/
#define ANNOTATE_IGNORE_ALTERNATIVE ASM_ANNOTATE(ANNOTYPE_IGNORE_ALTS)
/*
* This macro indicates that the following intra-function call is valid.
* Any non-annotated intra-function call will cause objtool to issue a warning.
*/
#define ANNOTATE_INTRA_FUNCTION_CALL ASM_ANNOTATE(ANNOTYPE_INTRA_FUNCTION_CALL)
/*
* Use objtool to validate the entry requirement that all code paths do
* VALIDATE_UNRET_END before RET.
*
* NOTE: The macro must be used at the beginning of a global symbol, otherwise
* it will be ignored.
*/
#define ANNOTATE_UNRET_BEGIN ASM_ANNOTATE(ANNOTYPE_UNRET_BEGIN)

#else
#define ANNOTATE_NOENDBR ANNOTATE type=ANNOTYPE_NOENDBR
#define ANNOTATE_RETPOLINE_SAFE ANNOTATE type=ANNOTYPE_RETPOLINE_SAFE
/* ANNOTATE_INSTR_BEGIN ANNOTATE type=ANNOTYPE_INSTR_BEGIN */
/* ANNOTATE_INSTR_END ANNOTATE type=ANNOTYPE_INSTR_END */
#define ANNOTATE_IGNORE_ALTERNATIVE ANNOTATE type=ANNOTYPE_IGNORE_ALTS
#define ANNOTATE_INTRA_FUNCTION_CALL ANNOTATE type=ANNOTYPE_INTRA_FUNCTION_CALL
#define ANNOTATE_UNRET_BEGIN ANNOTATE type=ANNOTYPE_UNRET_BEGIN
#endif

#if defined(CONFIG_NOINSTR_VALIDATION) && \
(defined(CONFIG_MITIGATION_UNRET_ENTRY) || defined(CONFIG_MITIGATION_SRSO))
#define VALIDATE_UNRET_BEGIN ANNOTATE_UNRET_BEGIN
#else
#define VALIDATE_UNRET_BEGIN
#endif

#endif /* _LINUX_OBJTOOL_H */

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