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