| /* 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 */ |