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Diffstat (limited to 'include/linux/objtool.h')
| -rw-r--r-- | include/linux/objtool.h | 130 |
1 files changed, 130 insertions, 0 deletions
diff --git a/include/linux/objtool.h b/include/linux/objtool.h new file mode 100644 index 000000000000..9a00e701454c --- /dev/null +++ b/include/linux/objtool.h @@ -0,0 +1,130 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _LINUX_OBJTOOL_H +#define _LINUX_OBJTOOL_H + +#include <linux/objtool_types.h> +#include <linux/annotate.h> + +#ifdef CONFIG_OBJTOOL + +#ifndef __ASSEMBLY__ + +#define UNWIND_HINT(type, sp_reg, sp_offset, signal) \ + "987: \n\t" \ + ".pushsection .discard.unwind_hints\n\t" \ + ANNOTATE_DATA_SPECIAL "\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(signal) "\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 ASM_REACHABLE \ + "998:\n\t" \ + ".pushsection .discard.reachable\n\t" \ + ".long 998b\n\t" \ + ".popsection\n\t" + +#define __ASM_BREF(label) label ## b + +#else /* __ASSEMBLY__ */ + +/* + * 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 SYM_FUNC_{START,END}. 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 signal=0 +.Lhere_\@: + .pushsection .discard.unwind_hints + ANNOTATE_DATA_SPECIAL + /* struct unwind_hint */ + .long .Lhere_\@ - . + .short \sp_offset + .byte \sp_reg + .byte \type + .byte \signal + .balign 4 + .popsection +.endm + +.macro STACK_FRAME_NON_STANDARD func:req + .pushsection .discard.func_stack_frame_non_standard, "aw" + .quad \func + .popsection +.endm + +.macro STACK_FRAME_NON_STANDARD_FP func:req +#ifdef CONFIG_FRAME_POINTER + STACK_FRAME_NON_STANDARD \func +#endif +.endm + +#endif /* __ASSEMBLY__ */ + +#else /* !CONFIG_OBJTOOL */ + +#ifndef __ASSEMBLY__ + +#define UNWIND_HINT(type, sp_reg, sp_offset, signal) "\n\t" +#define STACK_FRAME_NON_STANDARD(func) +#define STACK_FRAME_NON_STANDARD_FP(func) +#else +.macro UNWIND_HINT type:req sp_reg=0 sp_offset=0 signal=0 +.endm +.macro STACK_FRAME_NON_STANDARD func:req +.endm +#endif + +#endif /* CONFIG_OBJTOOL */ + +#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 */ |