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140 lines
4.4 KiB
140 lines
4.4 KiB
/* 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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#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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#ifdef CONFIG_STACK_VALIDATION |
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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/stack-validation.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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#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 sp_reg:req sp_offset=0 type:req 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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.long \func - . |
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.popsection |
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.endm |
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#endif /* __ASSEMBLY__ */ |
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#else /* !CONFIG_STACK_VALIDATION */ |
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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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#else |
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#define ANNOTATE_INTRA_FUNCTION_CALL |
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.macro UNWIND_HINT sp_reg:req sp_offset=0 type:req 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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#endif |
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#endif /* CONFIG_STACK_VALIDATION */ |
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#endif /* _LINUX_OBJTOOL_H */
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