1*4882a593Smuzhiyun /* SPDX-License-Identifier: GPL-2.0 */ 2*4882a593Smuzhiyun #ifndef _LINUX_OBJTOOL_H 3*4882a593Smuzhiyun #define _LINUX_OBJTOOL_H 4*4882a593Smuzhiyun 5*4882a593Smuzhiyun #ifndef __ASSEMBLY__ 6*4882a593Smuzhiyun 7*4882a593Smuzhiyun #include <linux/types.h> 8*4882a593Smuzhiyun 9*4882a593Smuzhiyun /* 10*4882a593Smuzhiyun * This struct is used by asm and inline asm code to manually annotate the 11*4882a593Smuzhiyun * location of registers on the stack. 12*4882a593Smuzhiyun */ 13*4882a593Smuzhiyun struct unwind_hint { 14*4882a593Smuzhiyun u32 ip; 15*4882a593Smuzhiyun s16 sp_offset; 16*4882a593Smuzhiyun u8 sp_reg; 17*4882a593Smuzhiyun u8 type; 18*4882a593Smuzhiyun u8 end; 19*4882a593Smuzhiyun }; 20*4882a593Smuzhiyun #endif 21*4882a593Smuzhiyun 22*4882a593Smuzhiyun /* 23*4882a593Smuzhiyun * UNWIND_HINT_TYPE_CALL: Indicates that sp_reg+sp_offset resolves to PREV_SP 24*4882a593Smuzhiyun * (the caller's SP right before it made the call). Used for all callable 25*4882a593Smuzhiyun * functions, i.e. all C code and all callable asm functions. 26*4882a593Smuzhiyun * 27*4882a593Smuzhiyun * UNWIND_HINT_TYPE_REGS: Used in entry code to indicate that sp_reg+sp_offset 28*4882a593Smuzhiyun * points to a fully populated pt_regs from a syscall, interrupt, or exception. 29*4882a593Smuzhiyun * 30*4882a593Smuzhiyun * UNWIND_HINT_TYPE_REGS_PARTIAL: Used in entry code to indicate that 31*4882a593Smuzhiyun * sp_reg+sp_offset points to the iret return frame. 32*4882a593Smuzhiyun * 33*4882a593Smuzhiyun * UNWIND_HINT_FUNC: Generate the unwind metadata of a callable function. 34*4882a593Smuzhiyun * Useful for code which doesn't have an ELF function annotation. 35*4882a593Smuzhiyun * 36*4882a593Smuzhiyun * UNWIND_HINT_ENTRY: machine entry without stack, SYSCALL/SYSENTER etc. 37*4882a593Smuzhiyun */ 38*4882a593Smuzhiyun #define UNWIND_HINT_TYPE_CALL 0 39*4882a593Smuzhiyun #define UNWIND_HINT_TYPE_REGS 1 40*4882a593Smuzhiyun #define UNWIND_HINT_TYPE_REGS_PARTIAL 2 41*4882a593Smuzhiyun #define UNWIND_HINT_TYPE_FUNC 3 42*4882a593Smuzhiyun #define UNWIND_HINT_TYPE_ENTRY 4 43*4882a593Smuzhiyun #define UNWIND_HINT_TYPE_SAVE 5 44*4882a593Smuzhiyun #define UNWIND_HINT_TYPE_RESTORE 6 45*4882a593Smuzhiyun 46*4882a593Smuzhiyun #ifdef CONFIG_STACK_VALIDATION 47*4882a593Smuzhiyun 48*4882a593Smuzhiyun #ifndef __ASSEMBLY__ 49*4882a593Smuzhiyun 50*4882a593Smuzhiyun #define UNWIND_HINT(sp_reg, sp_offset, type, end) \ 51*4882a593Smuzhiyun "987: \n\t" \ 52*4882a593Smuzhiyun ".pushsection .discard.unwind_hints\n\t" \ 53*4882a593Smuzhiyun /* struct unwind_hint */ \ 54*4882a593Smuzhiyun ".long 987b - .\n\t" \ 55*4882a593Smuzhiyun ".short " __stringify(sp_offset) "\n\t" \ 56*4882a593Smuzhiyun ".byte " __stringify(sp_reg) "\n\t" \ 57*4882a593Smuzhiyun ".byte " __stringify(type) "\n\t" \ 58*4882a593Smuzhiyun ".byte " __stringify(end) "\n\t" \ 59*4882a593Smuzhiyun ".balign 4 \n\t" \ 60*4882a593Smuzhiyun ".popsection\n\t" 61*4882a593Smuzhiyun 62*4882a593Smuzhiyun /* 63*4882a593Smuzhiyun * This macro marks the given function's stack frame as "non-standard", which 64*4882a593Smuzhiyun * tells objtool to ignore the function when doing stack metadata validation. 65*4882a593Smuzhiyun * It should only be used in special cases where you're 100% sure it won't 66*4882a593Smuzhiyun * affect the reliability of frame pointers and kernel stack traces. 67*4882a593Smuzhiyun * 68*4882a593Smuzhiyun * For more information, see tools/objtool/Documentation/stack-validation.txt. 69*4882a593Smuzhiyun */ 70*4882a593Smuzhiyun #define STACK_FRAME_NON_STANDARD(func) \ 71*4882a593Smuzhiyun static void __used __section(".discard.func_stack_frame_non_standard") \ 72*4882a593Smuzhiyun *__func_stack_frame_non_standard_##func = func 73*4882a593Smuzhiyun 74*4882a593Smuzhiyun #else /* __ASSEMBLY__ */ 75*4882a593Smuzhiyun 76*4882a593Smuzhiyun /* 77*4882a593Smuzhiyun * This macro indicates that the following intra-function call is valid. 78*4882a593Smuzhiyun * Any non-annotated intra-function call will cause objtool to issue a warning. 79*4882a593Smuzhiyun */ 80*4882a593Smuzhiyun #define ANNOTATE_INTRA_FUNCTION_CALL \ 81*4882a593Smuzhiyun 999: \ 82*4882a593Smuzhiyun .pushsection .discard.intra_function_calls; \ 83*4882a593Smuzhiyun .long 999b; \ 84*4882a593Smuzhiyun .popsection; 85*4882a593Smuzhiyun 86*4882a593Smuzhiyun /* 87*4882a593Smuzhiyun * In asm, there are two kinds of code: normal C-type callable functions and 88*4882a593Smuzhiyun * the rest. The normal callable functions can be called by other code, and 89*4882a593Smuzhiyun * don't do anything unusual with the stack. Such normal callable functions 90*4882a593Smuzhiyun * are annotated with the ENTRY/ENDPROC macros. Most asm code falls in this 91*4882a593Smuzhiyun * category. In this case, no special debugging annotations are needed because 92*4882a593Smuzhiyun * objtool can automatically generate the ORC data for the ORC unwinder to read 93*4882a593Smuzhiyun * at runtime. 94*4882a593Smuzhiyun * 95*4882a593Smuzhiyun * Anything which doesn't fall into the above category, such as syscall and 96*4882a593Smuzhiyun * interrupt handlers, tends to not be called directly by other functions, and 97*4882a593Smuzhiyun * often does unusual non-C-function-type things with the stack pointer. Such 98*4882a593Smuzhiyun * code needs to be annotated such that objtool can understand it. The 99*4882a593Smuzhiyun * following CFI hint macros are for this type of code. 100*4882a593Smuzhiyun * 101*4882a593Smuzhiyun * These macros provide hints to objtool about the state of the stack at each 102*4882a593Smuzhiyun * instruction. Objtool starts from the hints and follows the code flow, 103*4882a593Smuzhiyun * making automatic CFI adjustments when it sees pushes and pops, filling out 104*4882a593Smuzhiyun * the debuginfo as necessary. It will also warn if it sees any 105*4882a593Smuzhiyun * inconsistencies. 106*4882a593Smuzhiyun */ 107*4882a593Smuzhiyun .macro UNWIND_HINT type:req sp_reg=0 sp_offset=0 end=0 108*4882a593Smuzhiyun .Lunwind_hint_ip_\@: 109*4882a593Smuzhiyun .pushsection .discard.unwind_hints 110*4882a593Smuzhiyun /* struct unwind_hint */ 111*4882a593Smuzhiyun .long .Lunwind_hint_ip_\@ - . 112*4882a593Smuzhiyun .short \sp_offset 113*4882a593Smuzhiyun .byte \sp_reg 114*4882a593Smuzhiyun .byte \type 115*4882a593Smuzhiyun .byte \end 116*4882a593Smuzhiyun .balign 4 117*4882a593Smuzhiyun .popsection 118*4882a593Smuzhiyun .endm 119*4882a593Smuzhiyun 120*4882a593Smuzhiyun #endif /* __ASSEMBLY__ */ 121*4882a593Smuzhiyun 122*4882a593Smuzhiyun #else /* !CONFIG_STACK_VALIDATION */ 123*4882a593Smuzhiyun 124*4882a593Smuzhiyun #ifndef __ASSEMBLY__ 125*4882a593Smuzhiyun 126*4882a593Smuzhiyun #define UNWIND_HINT(sp_reg, sp_offset, type, end) \ 127*4882a593Smuzhiyun "\n\t" 128*4882a593Smuzhiyun #define STACK_FRAME_NON_STANDARD(func) 129*4882a593Smuzhiyun #else 130*4882a593Smuzhiyun #define ANNOTATE_INTRA_FUNCTION_CALL 131*4882a593Smuzhiyun .macro UNWIND_HINT type:req sp_reg=0 sp_offset=0 end=0 132*4882a593Smuzhiyun .endm 133*4882a593Smuzhiyun #endif 134*4882a593Smuzhiyun 135*4882a593Smuzhiyun #endif /* CONFIG_STACK_VALIDATION */ 136*4882a593Smuzhiyun 137*4882a593Smuzhiyun #endif /* _LINUX_OBJTOOL_H */ 138