From f7515d9fe8fc4b80754cd4d98a5fcaee84adeebb Mon Sep 17 00:00:00 2001 From: Josh Poimboeuf Date: Wed, 1 Mar 2023 07:13:07 -0800 Subject: objtool: Add objtool_types.h Reduce the amount of header sync churn by splitting the shared objtool.h types into a new file. Signed-off-by: Josh Poimboeuf Signed-off-by: Peter Zijlstra (Intel) Acked-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/r/dec622720851210ceafa12d4f4c5f9e73c832152.1677683419.git.jpoimboe@kernel.org --- include/linux/objtool.h | 42 +----------------------------------------- 1 file changed, 1 insertion(+), 41 deletions(-) (limited to 'include/linux/objtool.h') diff --git a/include/linux/objtool.h b/include/linux/objtool.h index 9ac3df3fccf0..8375792acfc0 100644 --- a/include/linux/objtool.h +++ b/include/linux/objtool.h @@ -2,47 +2,7 @@ #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 signal; - 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 +#include #ifdef CONFIG_OBJTOOL -- cgit v1.2.3 From 1c0c1faf5692c18c127d044ecc0cc92c7bab3477 Mon Sep 17 00:00:00 2001 From: Josh Poimboeuf Date: Wed, 1 Mar 2023 07:13:08 -0800 Subject: objtool: Use relative pointers for annotations They produce the needed relocations while using half the space. Signed-off-by: Josh Poimboeuf Signed-off-by: Peter Zijlstra (Intel) Acked-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/r/bed05c64e28200220c9b1754a2f3ce71f73076ea.1677683419.git.jpoimboe@kernel.org --- include/linux/objtool.h | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) (limited to 'include/linux/objtool.h') diff --git a/include/linux/objtool.h b/include/linux/objtool.h index 8375792acfc0..2b0258d273fc 100644 --- a/include/linux/objtool.h +++ b/include/linux/objtool.h @@ -49,7 +49,7 @@ #define ANNOTATE_NOENDBR \ "986: \n\t" \ ".pushsection .discard.noendbr\n\t" \ - _ASM_PTR " 986b\n\t" \ + ".long 986b - .\n\t" \ ".popsection\n\t" #define ASM_REACHABLE \ @@ -67,7 +67,7 @@ #define ANNOTATE_INTRA_FUNCTION_CALL \ 999: \ .pushsection .discard.intra_function_calls; \ - .long 999b; \ + .long 999b - .; \ .popsection; /* @@ -92,10 +92,10 @@ * inconsistencies. */ .macro UNWIND_HINT type:req sp_reg=0 sp_offset=0 signal=0 end=0 -.Lunwind_hint_ip_\@: +.Lhere_\@: .pushsection .discard.unwind_hints /* struct unwind_hint */ - .long .Lunwind_hint_ip_\@ - . + .long .Lhere_\@ - . .short \sp_offset .byte \sp_reg .byte \type @@ -107,7 +107,7 @@ .macro STACK_FRAME_NON_STANDARD func:req .pushsection .discard.func_stack_frame_non_standard, "aw" - _ASM_PTR \func + .long \func - . .popsection .endm @@ -120,7 +120,7 @@ .macro ANNOTATE_NOENDBR .Lhere_\@: .pushsection .discard.noendbr - .quad .Lhere_\@ + .long .Lhere_\@ - . .popsection .endm -- cgit v1.2.3 From d88ebba45dfe67114a6ac8c6514f2c65b6ed64c7 Mon Sep 17 00:00:00 2001 From: Josh Poimboeuf Date: Wed, 1 Mar 2023 07:13:09 -0800 Subject: objtool: Change UNWIND_HINT() argument order The most important argument is 'type', make that one first. Signed-off-by: Josh Poimboeuf Signed-off-by: Peter Zijlstra (Intel) Acked-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/r/d994f8c29376c5618c75698df28fc03b52d3a868.1677683419.git.jpoimboe@kernel.org --- include/linux/objtool.h | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) (limited to 'include/linux/objtool.h') diff --git a/include/linux/objtool.h b/include/linux/objtool.h index 2b0258d273fc..725d7f0b6748 100644 --- a/include/linux/objtool.h +++ b/include/linux/objtool.h @@ -10,7 +10,7 @@ #ifndef __ASSEMBLY__ -#define UNWIND_HINT(sp_reg, sp_offset, type, signal, end) \ +#define UNWIND_HINT(type, sp_reg, sp_offset, signal, end) \ "987: \n\t" \ ".pushsection .discard.unwind_hints\n\t" \ /* struct unwind_hint */ \ @@ -137,8 +137,7 @@ #ifndef __ASSEMBLY__ -#define UNWIND_HINT(sp_reg, sp_offset, type, signal, end) \ - "\n\t" +#define UNWIND_HINT(type, sp_reg, sp_offset, signal, end) "\n\t" #define STACK_FRAME_NON_STANDARD(func) #define STACK_FRAME_NON_STANDARD_FP(func) #define ANNOTATE_NOENDBR -- cgit v1.2.3 From 4708ea14bef314fc901857eefd65678236a9f2d9 Mon Sep 17 00:00:00 2001 From: Josh Poimboeuf Date: Wed, 1 Mar 2023 07:13:11 -0800 Subject: x86,objtool: Separate unret validation from unwind hints The ENTRY unwind hint type is serving double duty as both an empty unwind hint and an unret validation annotation. Unret validation is unrelated to unwinding. Separate it out into its own annotation. Signed-off-by: Josh Poimboeuf Signed-off-by: Peter Zijlstra (Intel) Acked-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/r/ff7448d492ea21b86d8a90264b105fbd0d751077.1677683419.git.jpoimboe@kernel.org --- include/linux/objtool.h | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) (limited to 'include/linux/objtool.h') diff --git a/include/linux/objtool.h b/include/linux/objtool.h index 725d7f0b6748..5aa475118820 100644 --- a/include/linux/objtool.h +++ b/include/linux/objtool.h @@ -124,6 +124,22 @@ .popsection .endm +/* + * Use objtool to validate the entry requirement that all code paths do + * VALIDATE_UNRET_END before RET. + * + * NOTE: The macro must be used at the beginning of a global symbol, otherwise + * it will be ignored. + */ +.macro VALIDATE_UNRET_BEGIN +#if defined(CONFIG_NOINSTR_VALIDATION) && defined(CONFIG_CPU_UNRET_ENTRY) +.Lhere_\@: + .pushsection .discard.validate_unret + .long .Lhere_\@ - . + .popsection +#endif +.endm + .macro REACHABLE .Lhere_\@: .pushsection .discard.reachable -- cgit v1.2.3 From fb799447ae2974a07907906dff5bd4b9e47b7123 Mon Sep 17 00:00:00 2001 From: Josh Poimboeuf Date: Wed, 1 Mar 2023 07:13:12 -0800 Subject: x86,objtool: Split UNWIND_HINT_EMPTY in two Mark reported that the ORC unwinder incorrectly marks an unwind as reliable when the unwind terminates prematurely in the dark corners of return_to_handler() due to lack of information about the next frame. The problem is UNWIND_HINT_EMPTY is used in two different situations: 1) The end of the kernel stack unwind before hitting user entry, boot code, or fork entry 2) A blind spot in ORC coverage where the unwinder has to bail due to lack of information about the next frame The ORC unwinder has no way to tell the difference between the two. When it encounters an undefined stack state with 'end=1', it blindly marks the stack reliable, which can break the livepatch consistency model. Fix it by splitting UNWIND_HINT_EMPTY into UNWIND_HINT_UNDEFINED and UNWIND_HINT_END_OF_STACK. Reported-by: Mark Rutland Signed-off-by: Josh Poimboeuf Signed-off-by: Peter Zijlstra (Intel) Acked-by: Steven Rostedt (Google) Acked-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/r/fd6212c8b450d3564b855e1cb48404d6277b4d9f.1677683419.git.jpoimboe@kernel.org --- include/linux/objtool.h | 10 ++++------ 1 file changed, 4 insertions(+), 6 deletions(-) (limited to 'include/linux/objtool.h') diff --git a/include/linux/objtool.h b/include/linux/objtool.h index 5aa475118820..03f82c2c2ebf 100644 --- a/include/linux/objtool.h +++ b/include/linux/objtool.h @@ -10,7 +10,7 @@ #ifndef __ASSEMBLY__ -#define UNWIND_HINT(type, sp_reg, sp_offset, signal, end) \ +#define UNWIND_HINT(type, sp_reg, sp_offset, signal) \ "987: \n\t" \ ".pushsection .discard.unwind_hints\n\t" \ /* struct unwind_hint */ \ @@ -19,7 +19,6 @@ ".byte " __stringify(sp_reg) "\n\t" \ ".byte " __stringify(type) "\n\t" \ ".byte " __stringify(signal) "\n\t" \ - ".byte " __stringify(end) "\n\t" \ ".balign 4 \n\t" \ ".popsection\n\t" @@ -91,7 +90,7 @@ * 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 end=0 +.macro UNWIND_HINT type:req sp_reg=0 sp_offset=0 signal=0 .Lhere_\@: .pushsection .discard.unwind_hints /* struct unwind_hint */ @@ -100,7 +99,6 @@ .byte \sp_reg .byte \type .byte \signal - .byte \end .balign 4 .popsection .endm @@ -153,14 +151,14 @@ #ifndef __ASSEMBLY__ -#define UNWIND_HINT(type, sp_reg, sp_offset, signal, end) "\n\t" +#define UNWIND_HINT(type, sp_reg, sp_offset, signal) "\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 signal=0 end=0 +.macro UNWIND_HINT type:req sp_reg=0 sp_offset=0 signal=0 .endm .macro STACK_FRAME_NON_STANDARD func:req .endm -- cgit v1.2.3