From ee819aedf34a8f35cd54ee3967c7beb4d1d4a635 Mon Sep 17 00:00:00 2001 From: Julien Thierry Date: Fri, 4 Sep 2020 16:30:27 +0100 Subject: [PATCH] objtool: Make unwind hint definitions available to other architectures Unwind hints are useful to provide objtool with information about stack states in non-standard functions/code. While the type of information being provided might be very arch specific, the mechanism to provide the information can be useful for other architectures. Move the relevant unwint hint definitions for all architectures to see. [ jpoimboe: REGS_IRET -> REGS_PARTIAL ] Signed-off-by: Julien Thierry Signed-off-by: Josh Poimboeuf --- arch/x86/include/asm/orc_types.h | 34 ------- arch/x86/include/asm/unwind_hints.h | 56 +++-------- arch/x86/kernel/unwind_orc.c | 11 ++- include/linux/objtool.h | 88 +++++++++++++++++ tools/arch/x86/include/asm/orc_types.h | 34 ------- tools/include/linux/objtool.h | 129 +++++++++++++++++++++++++ tools/objtool/check.c | 4 +- tools/objtool/orc_dump.c | 9 +- tools/objtool/orc_gen.c | 5 +- tools/objtool/sync-check.sh | 4 +- 10 files changed, 249 insertions(+), 125 deletions(-) create mode 100644 tools/include/linux/objtool.h diff --git a/arch/x86/include/asm/orc_types.h b/arch/x86/include/asm/orc_types.h index d25534940bde..fdbffec4cfde 100644 --- a/arch/x86/include/asm/orc_types.h +++ b/arch/x86/include/asm/orc_types.h @@ -39,27 +39,6 @@ #define ORC_REG_SP_INDIRECT 9 #define ORC_REG_MAX 15 -/* - * ORC_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. - * - * ORC_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. - * - * ORC_TYPE_REGS_IRET: Used in entry code to indicate that sp_reg+sp_offset - * points to the iret return frame. - * - * The UNWIND_HINT macros are used only for the unwind_hint struct. They - * aren't used in struct orc_entry due to size and complexity constraints. - * Objtool converts them to real types when it converts the hints to orc - * entries. - */ -#define ORC_TYPE_CALL 0 -#define ORC_TYPE_REGS 1 -#define ORC_TYPE_REGS_IRET 2 -#define UNWIND_HINT_TYPE_RET_OFFSET 3 - #ifndef __ASSEMBLY__ /* * This struct is more or less a vastly simplified version of the DWARF Call @@ -78,19 +57,6 @@ struct orc_entry { unsigned end:1; } __packed; -/* - * This struct is used by asm and inline asm code to manually annotate the - * location of registers on the stack for the ORC unwinder. - * - * Type can be either ORC_TYPE_* or UNWIND_HINT_TYPE_*. - */ -struct unwind_hint { - u32 ip; - s16 sp_offset; - u8 sp_reg; - u8 type; - u8 end; -}; #endif /* __ASSEMBLY__ */ #endif /* _ORC_TYPES_H */ diff --git a/arch/x86/include/asm/unwind_hints.h b/arch/x86/include/asm/unwind_hints.h index 7d903fdb3f43..664d4610d700 100644 --- a/arch/x86/include/asm/unwind_hints.h +++ b/arch/x86/include/asm/unwind_hints.h @@ -1,51 +1,17 @@ #ifndef _ASM_X86_UNWIND_HINTS_H #define _ASM_X86_UNWIND_HINTS_H +#include + #include "orc_types.h" #ifdef __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 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 sp_reg=ORC_REG_SP sp_offset=0 type=ORC_TYPE_CALL end=0 -#ifdef CONFIG_STACK_VALIDATION -.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 -#endif -.endm - .macro UNWIND_HINT_EMPTY - UNWIND_HINT sp_reg=ORC_REG_UNDEFINED end=1 + UNWIND_HINT sp_reg=ORC_REG_UNDEFINED type=UNWIND_HINT_TYPE_CALL end=1 .endm -.macro UNWIND_HINT_REGS base=%rsp offset=0 indirect=0 extra=1 iret=0 +.macro UNWIND_HINT_REGS base=%rsp offset=0 indirect=0 extra=1 partial=0 .if \base == %rsp .if \indirect .set sp_reg, ORC_REG_SP_INDIRECT @@ -66,24 +32,24 @@ .set sp_offset, \offset - .if \iret - .set type, ORC_TYPE_REGS_IRET + .if \partial + .set type, UNWIND_HINT_TYPE_REGS_PARTIAL .elseif \extra == 0 - .set type, ORC_TYPE_REGS_IRET + .set type, UNWIND_HINT_TYPE_REGS_PARTIAL .set sp_offset, \offset + (16*8) .else - .set type, ORC_TYPE_REGS + .set type, UNWIND_HINT_TYPE_REGS .endif UNWIND_HINT sp_reg=sp_reg sp_offset=sp_offset type=type .endm .macro UNWIND_HINT_IRET_REGS base=%rsp offset=0 - UNWIND_HINT_REGS base=\base offset=\offset iret=1 + UNWIND_HINT_REGS base=\base offset=\offset partial=1 .endm .macro UNWIND_HINT_FUNC sp_offset=8 - UNWIND_HINT sp_offset=\sp_offset + UNWIND_HINT sp_reg=ORC_REG_SP sp_offset=\sp_offset type=UNWIND_HINT_TYPE_CALL .endm /* @@ -92,7 +58,7 @@ * initial_func_cfi. */ .macro UNWIND_HINT_RET_OFFSET sp_offset=8 - UNWIND_HINT type=UNWIND_HINT_TYPE_RET_OFFSET sp_offset=\sp_offset + UNWIND_HINT sp_reg=ORC_REG_SP type=UNWIND_HINT_TYPE_RET_OFFSET sp_offset=\sp_offset .endm #endif /* __ASSEMBLY__ */ diff --git a/arch/x86/kernel/unwind_orc.c b/arch/x86/kernel/unwind_orc.c index ec88bbe08a32..6a339ce328e0 100644 --- a/arch/x86/kernel/unwind_orc.c +++ b/arch/x86/kernel/unwind_orc.c @@ -1,4 +1,5 @@ // SPDX-License-Identifier: GPL-2.0-only +#include #include #include #include @@ -127,12 +128,12 @@ static struct orc_entry null_orc_entry = { .sp_offset = sizeof(long), .sp_reg = ORC_REG_SP, .bp_reg = ORC_REG_UNDEFINED, - .type = ORC_TYPE_CALL + .type = UNWIND_HINT_TYPE_CALL }; /* Fake frame pointer entry -- used as a fallback for generated code */ static struct orc_entry orc_fp_entry = { - .type = ORC_TYPE_CALL, + .type = UNWIND_HINT_TYPE_CALL, .sp_reg = ORC_REG_BP, .sp_offset = 16, .bp_reg = ORC_REG_PREV_SP, @@ -531,7 +532,7 @@ bool unwind_next_frame(struct unwind_state *state) /* Find IP, SP and possibly regs: */ switch (orc->type) { - case ORC_TYPE_CALL: + case UNWIND_HINT_TYPE_CALL: ip_p = sp - sizeof(long); if (!deref_stack_reg(state, ip_p, &state->ip)) @@ -546,7 +547,7 @@ bool unwind_next_frame(struct unwind_state *state) state->signal = false; break; - case ORC_TYPE_REGS: + case UNWIND_HINT_TYPE_REGS: if (!deref_stack_regs(state, sp, &state->ip, &state->sp)) { orc_warn_current("can't access registers at %pB\n", (void *)orig_ip); @@ -559,7 +560,7 @@ bool unwind_next_frame(struct unwind_state *state) state->signal = true; break; - case ORC_TYPE_REGS_IRET: + case UNWIND_HINT_TYPE_REGS_PARTIAL: if (!deref_stack_iret_regs(state, sp, &state->ip, &state->sp)) { orc_warn_current("can't access iret registers at %pB\n", (void *)orig_ip); diff --git a/include/linux/objtool.h b/include/linux/objtool.h index 15e9997a9fb4..ab82c793c897 100644 --- a/include/linux/objtool.h +++ b/include/linux/objtool.h @@ -2,9 +2,55 @@ #ifndef _LINUX_OBJTOOL_H #define _LINUX_OBJTOOL_H +#ifndef __ASSEMBLY__ + +#include + +/* + * 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. + */ +#define UNWIND_HINT_TYPE_CALL 0 +#define UNWIND_HINT_TYPE_REGS 1 +#define UNWIND_HINT_TYPE_REGS_PARTIAL 2 +#define UNWIND_HINT_TYPE_RET_OFFSET 3 + #ifdef CONFIG_STACK_VALIDATION #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. @@ -29,12 +75,54 @@ .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 sp_reg:req sp_offset=0 type:req 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 + #endif /* __ASSEMBLY__ */ #else /* !CONFIG_STACK_VALIDATION */ +#ifndef __ASSEMBLY__ + +#define UNWIND_HINT(sp_reg, sp_offset, type, end) \ + "\n\t" #define STACK_FRAME_NON_STANDARD(func) +#else #define ANNOTATE_INTRA_FUNCTION_CALL +.macro UNWIND_HINT sp_reg:req sp_offset=0 type:req end=0 +.endm +#endif #endif /* CONFIG_STACK_VALIDATION */ diff --git a/tools/arch/x86/include/asm/orc_types.h b/tools/arch/x86/include/asm/orc_types.h index d25534940bde..fdbffec4cfde 100644 --- a/tools/arch/x86/include/asm/orc_types.h +++ b/tools/arch/x86/include/asm/orc_types.h @@ -39,27 +39,6 @@ #define ORC_REG_SP_INDIRECT 9 #define ORC_REG_MAX 15 -/* - * ORC_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. - * - * ORC_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. - * - * ORC_TYPE_REGS_IRET: Used in entry code to indicate that sp_reg+sp_offset - * points to the iret return frame. - * - * The UNWIND_HINT macros are used only for the unwind_hint struct. They - * aren't used in struct orc_entry due to size and complexity constraints. - * Objtool converts them to real types when it converts the hints to orc - * entries. - */ -#define ORC_TYPE_CALL 0 -#define ORC_TYPE_REGS 1 -#define ORC_TYPE_REGS_IRET 2 -#define UNWIND_HINT_TYPE_RET_OFFSET 3 - #ifndef __ASSEMBLY__ /* * This struct is more or less a vastly simplified version of the DWARF Call @@ -78,19 +57,6 @@ struct orc_entry { unsigned end:1; } __packed; -/* - * This struct is used by asm and inline asm code to manually annotate the - * location of registers on the stack for the ORC unwinder. - * - * Type can be either ORC_TYPE_* or UNWIND_HINT_TYPE_*. - */ -struct unwind_hint { - u32 ip; - s16 sp_offset; - u8 sp_reg; - u8 type; - u8 end; -}; #endif /* __ASSEMBLY__ */ #endif /* _ORC_TYPES_H */ diff --git a/tools/include/linux/objtool.h b/tools/include/linux/objtool.h new file mode 100644 index 000000000000..ab82c793c897 --- /dev/null +++ b/tools/include/linux/objtool.h @@ -0,0 +1,129 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _LINUX_OBJTOOL_H +#define _LINUX_OBJTOOL_H + +#ifndef __ASSEMBLY__ + +#include + +/* + * 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. + */ +#define UNWIND_HINT_TYPE_CALL 0 +#define UNWIND_HINT_TYPE_REGS 1 +#define UNWIND_HINT_TYPE_REGS_PARTIAL 2 +#define UNWIND_HINT_TYPE_RET_OFFSET 3 + +#ifdef CONFIG_STACK_VALIDATION + +#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/stack-validation.txt. + */ +#define STACK_FRAME_NON_STANDARD(func) \ + static void __used __section(.discard.func_stack_frame_non_standard) \ + *__func_stack_frame_non_standard_##func = func + +#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 sp_reg:req sp_offset=0 type:req 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 + +#endif /* __ASSEMBLY__ */ + +#else /* !CONFIG_STACK_VALIDATION */ + +#ifndef __ASSEMBLY__ + +#define UNWIND_HINT(sp_reg, sp_offset, type, end) \ + "\n\t" +#define STACK_FRAME_NON_STANDARD(func) +#else +#define ANNOTATE_INTRA_FUNCTION_CALL +.macro UNWIND_HINT sp_reg:req sp_offset=0 type:req end=0 +.endm +#endif + +#endif /* CONFIG_STACK_VALIDATION */ + +#endif /* _LINUX_OBJTOOL_H */ diff --git a/tools/objtool/check.c b/tools/objtool/check.c index a94ad88d036c..95c6e0d31c0a 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -14,6 +14,7 @@ #include "warn.h" #include "arch_elf.h" +#include #include #include #include @@ -1805,7 +1806,8 @@ static int update_cfi_state(struct instruction *insn, struct cfi_state *cfi, return 0; } - if (cfi->type == ORC_TYPE_REGS || cfi->type == ORC_TYPE_REGS_IRET) + if (cfi->type == UNWIND_HINT_TYPE_REGS || + cfi->type == UNWIND_HINT_TYPE_REGS_PARTIAL) return update_cfi_state_regs(insn, cfi, op); switch (op->dest.type) { diff --git a/tools/objtool/orc_dump.c b/tools/objtool/orc_dump.c index fca46e006fc2..5e6a95368d35 100644 --- a/tools/objtool/orc_dump.c +++ b/tools/objtool/orc_dump.c @@ -4,6 +4,7 @@ */ #include +#include #include #include "objtool.h" #include "warn.h" @@ -37,12 +38,12 @@ static const char *reg_name(unsigned int reg) static const char *orc_type_name(unsigned int type) { switch (type) { - case ORC_TYPE_CALL: + case UNWIND_HINT_TYPE_CALL: return "call"; - case ORC_TYPE_REGS: + case UNWIND_HINT_TYPE_REGS: return "regs"; - case ORC_TYPE_REGS_IRET: - return "iret"; + case UNWIND_HINT_TYPE_REGS_PARTIAL: + return "regs (partial)"; default: return "?"; } diff --git a/tools/objtool/orc_gen.c b/tools/objtool/orc_gen.c index 22fe4398197f..235663b96adc 100644 --- a/tools/objtool/orc_gen.c +++ b/tools/objtool/orc_gen.c @@ -6,6 +6,9 @@ #include #include +#include +#include + #include "check.h" #include "warn.h" @@ -146,7 +149,7 @@ int create_orc_sections(struct objtool_file *file) struct orc_entry empty = { .sp_reg = ORC_REG_UNDEFINED, .bp_reg = ORC_REG_UNDEFINED, - .type = ORC_TYPE_CALL, + .type = UNWIND_HINT_TYPE_CALL, }; sec = find_section_by_name(file->elf, ".orc_unwind"); diff --git a/tools/objtool/sync-check.sh b/tools/objtool/sync-check.sh index cea1c12607b9..606a4b5e929f 100755 --- a/tools/objtool/sync-check.sh +++ b/tools/objtool/sync-check.sh @@ -6,8 +6,10 @@ if [ -z "$SRCARCH" ]; then exit 1 fi +FILES="include/linux/objtool.h" + if [ "$SRCARCH" = "x86" ]; then -FILES=" +FILES="$FILES arch/x86/include/asm/inat_types.h arch/x86/include/asm/orc_types.h arch/x86/include/asm/emulate_prefix.h