198 lines
5.6 KiB
C
198 lines
5.6 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _LINUX_OBJTOOL_H
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#define _LINUX_OBJTOOL_H
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#ifndef __ASSEMBLY__
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#include <linux/types.h>
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/*
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* This struct is used by asm and inline asm code to manually annotate the
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* location of registers on the stack.
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*/
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struct unwind_hint {
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u32 ip;
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s16 sp_offset;
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u8 sp_reg;
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u8 type;
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u8 end;
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};
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#endif
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/*
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* UNWIND_HINT_TYPE_CALL: Indicates that sp_reg+sp_offset resolves to PREV_SP
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* (the caller's SP right before it made the call). Used for all callable
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* functions, i.e. all C code and all callable asm functions.
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*
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* UNWIND_HINT_TYPE_REGS: Used in entry code to indicate that sp_reg+sp_offset
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* points to a fully populated pt_regs from a syscall, interrupt, or exception.
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*
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* UNWIND_HINT_TYPE_REGS_PARTIAL: Used in entry code to indicate that
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* sp_reg+sp_offset points to the iret return frame.
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*
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* UNWIND_HINT_FUNC: Generate the unwind metadata of a callable function.
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* Useful for code which doesn't have an ELF function annotation.
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*
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* UNWIND_HINT_ENTRY: machine entry without stack, SYSCALL/SYSENTER etc.
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*/
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#define UNWIND_HINT_TYPE_CALL 0
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#define UNWIND_HINT_TYPE_REGS 1
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#define UNWIND_HINT_TYPE_REGS_PARTIAL 2
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#define UNWIND_HINT_TYPE_FUNC 3
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#define UNWIND_HINT_TYPE_ENTRY 4
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#define UNWIND_HINT_TYPE_SAVE 5
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#define UNWIND_HINT_TYPE_RESTORE 6
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#ifdef CONFIG_OBJTOOL
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#include <asm/asm.h>
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#ifndef __ASSEMBLY__
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#define UNWIND_HINT(sp_reg, sp_offset, type, end) \
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"987: \n\t" \
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".pushsection .discard.unwind_hints\n\t" \
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/* struct unwind_hint */ \
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".long 987b - .\n\t" \
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".short " __stringify(sp_offset) "\n\t" \
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".byte " __stringify(sp_reg) "\n\t" \
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".byte " __stringify(type) "\n\t" \
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".byte " __stringify(end) "\n\t" \
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".balign 4 \n\t" \
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".popsection\n\t"
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/*
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* This macro marks the given function's stack frame as "non-standard", which
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* tells objtool to ignore the function when doing stack metadata validation.
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* It should only be used in special cases where you're 100% sure it won't
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* affect the reliability of frame pointers and kernel stack traces.
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*
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* For more information, see tools/objtool/Documentation/objtool.txt.
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*/
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#define STACK_FRAME_NON_STANDARD(func) \
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static void __used __section(".discard.func_stack_frame_non_standard") \
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*__func_stack_frame_non_standard_##func = func
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/*
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* STACK_FRAME_NON_STANDARD_FP() is a frame-pointer-specific function ignore
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* for the case where a function is intentionally missing frame pointer setup,
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* but otherwise needs objtool/ORC coverage when frame pointers are disabled.
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*/
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#ifdef CONFIG_FRAME_POINTER
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#define STACK_FRAME_NON_STANDARD_FP(func) STACK_FRAME_NON_STANDARD(func)
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#else
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#define STACK_FRAME_NON_STANDARD_FP(func)
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#endif
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#define ANNOTATE_NOENDBR \
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"986: \n\t" \
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".pushsection .discard.noendbr\n\t" \
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_ASM_PTR " 986b\n\t" \
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".popsection\n\t"
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#define ASM_REACHABLE \
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"998:\n\t" \
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".pushsection .discard.reachable\n\t" \
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".long 998b - .\n\t" \
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".popsection\n\t"
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#else /* __ASSEMBLY__ */
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/*
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* This macro indicates that the following intra-function call is valid.
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* Any non-annotated intra-function call will cause objtool to issue a warning.
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*/
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#define ANNOTATE_INTRA_FUNCTION_CALL \
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999: \
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.pushsection .discard.intra_function_calls; \
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.long 999b; \
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.popsection;
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/*
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* In asm, there are two kinds of code: normal C-type callable functions and
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* the rest. The normal callable functions can be called by other code, and
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* don't do anything unusual with the stack. Such normal callable functions
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* are annotated with the ENTRY/ENDPROC macros. Most asm code falls in this
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* category. In this case, no special debugging annotations are needed because
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* objtool can automatically generate the ORC data for the ORC unwinder to read
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* at runtime.
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*
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* Anything which doesn't fall into the above category, such as syscall and
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* interrupt handlers, tends to not be called directly by other functions, and
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* often does unusual non-C-function-type things with the stack pointer. Such
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* code needs to be annotated such that objtool can understand it. The
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* following CFI hint macros are for this type of code.
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*
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* These macros provide hints to objtool about the state of the stack at each
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* instruction. Objtool starts from the hints and follows the code flow,
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* making automatic CFI adjustments when it sees pushes and pops, filling out
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* the debuginfo as necessary. It will also warn if it sees any
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* inconsistencies.
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*/
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.macro UNWIND_HINT type:req sp_reg=0 sp_offset=0 end=0
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.Lunwind_hint_ip_\@:
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.pushsection .discard.unwind_hints
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/* struct unwind_hint */
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.long .Lunwind_hint_ip_\@ - .
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.short \sp_offset
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.byte \sp_reg
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.byte \type
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.byte \end
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.balign 4
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.popsection
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.endm
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.macro STACK_FRAME_NON_STANDARD func:req
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.pushsection .discard.func_stack_frame_non_standard, "aw"
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_ASM_PTR \func
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.popsection
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.endm
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.macro STACK_FRAME_NON_STANDARD_FP func:req
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#ifdef CONFIG_FRAME_POINTER
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STACK_FRAME_NON_STANDARD \func
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#endif
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.endm
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.macro ANNOTATE_NOENDBR
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.Lhere_\@:
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.pushsection .discard.noendbr
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.quad .Lhere_\@
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.popsection
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.endm
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.macro REACHABLE
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.Lhere_\@:
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.pushsection .discard.reachable
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.long .Lhere_\@ - .
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.popsection
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.endm
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#endif /* __ASSEMBLY__ */
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#else /* !CONFIG_OBJTOOL */
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#ifndef __ASSEMBLY__
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#define UNWIND_HINT(sp_reg, sp_offset, type, end) \
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"\n\t"
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#define STACK_FRAME_NON_STANDARD(func)
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#define STACK_FRAME_NON_STANDARD_FP(func)
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#define ANNOTATE_NOENDBR
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#define ASM_REACHABLE
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#else
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#define ANNOTATE_INTRA_FUNCTION_CALL
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.macro UNWIND_HINT type:req sp_reg=0 sp_offset=0 end=0
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.endm
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.macro STACK_FRAME_NON_STANDARD func:req
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.endm
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.macro ANNOTATE_NOENDBR
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.endm
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.macro REACHABLE
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.endm
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#endif
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#endif /* CONFIG_OBJTOOL */
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#endif /* _LINUX_OBJTOOL_H */
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