From 69505e3d9a39a988aaed9b58aa6b3482238f6516 Mon Sep 17 00:00:00 2001 From: Josh Poimboeuf Date: Thu, 12 May 2022 06:56:23 -0700 Subject: [PATCH] bug: Use normal relative pointers in 'struct bug_entry' With CONFIG_GENERIC_BUG_RELATIVE_POINTERS, the addr/file relative pointers are calculated weirdly: based on the beginning of the bug_entry struct address, rather than their respective pointer addresses. Make the relative pointers less surprising to both humans and tools by calculating them the normal way. Signed-off-by: Josh Poimboeuf Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Mark Rutland Acked-by: Peter Zijlstra (Intel) Acked-by: Sven Schnelle # s390 Acked-by: Michael Ellerman (powerpc) Acked-by: Catalin Marinas Tested-by: Mark Rutland [arm64] Link: https://lkml.kernel.org/r/f0e05be797a16f4fc2401eeb88c8450dcbe61df6.1652362951.git.jpoimboe@kernel.org --- arch/arm64/include/asm/asm-bug.h | 4 ++-- arch/powerpc/include/asm/bug.h | 14 ++++++++------ arch/riscv/include/asm/bug.h | 4 ++-- arch/s390/include/asm/bug.h | 5 +++-- arch/x86/include/asm/bug.h | 2 +- lib/bug.c | 15 +++++++-------- 6 files changed, 23 insertions(+), 21 deletions(-) diff --git a/arch/arm64/include/asm/asm-bug.h b/arch/arm64/include/asm/asm-bug.h index 03f52f84a4f3..c762038ba400 100644 --- a/arch/arm64/include/asm/asm-bug.h +++ b/arch/arm64/include/asm/asm-bug.h @@ -14,7 +14,7 @@ 14472: .string file; \ .popsection; \ \ - .long 14472b - 14470b; \ + .long 14472b - .; \ .short line; #else #define _BUGVERBOSE_LOCATION(file, line) @@ -25,7 +25,7 @@ #define __BUG_ENTRY(flags) \ .pushsection __bug_table,"aw"; \ .align 2; \ - 14470: .long 14471f - 14470b; \ + 14470: .long 14471f - .; \ _BUGVERBOSE_LOCATION(__FILE__, __LINE__) \ .short flags; \ .popsection; \ diff --git a/arch/powerpc/include/asm/bug.h b/arch/powerpc/include/asm/bug.h index ecbae1832de3..61a4736355c2 100644 --- a/arch/powerpc/include/asm/bug.h +++ b/arch/powerpc/include/asm/bug.h @@ -13,7 +13,8 @@ #ifdef CONFIG_DEBUG_BUGVERBOSE .macro __EMIT_BUG_ENTRY addr,file,line,flags .section __bug_table,"aw" -5001: .4byte \addr - 5001b, 5002f - 5001b +5001: .4byte \addr - . + .4byte 5002f - . .short \line, \flags .org 5001b+BUG_ENTRY_SIZE .previous @@ -24,7 +25,7 @@ #else .macro __EMIT_BUG_ENTRY addr,file,line,flags .section __bug_table,"aw" -5001: .4byte \addr - 5001b +5001: .4byte \addr - . .short \flags .org 5001b+BUG_ENTRY_SIZE .previous @@ -49,15 +50,16 @@ #ifdef CONFIG_DEBUG_BUGVERBOSE #define _EMIT_BUG_ENTRY \ ".section __bug_table,\"aw\"\n" \ - "2:\t.4byte 1b - 2b, %0 - 2b\n" \ - "\t.short %1, %2\n" \ + "2: .4byte 1b - .\n" \ + " .4byte %0 - .\n" \ + " .short %1, %2\n" \ ".org 2b+%3\n" \ ".previous\n" #else #define _EMIT_BUG_ENTRY \ ".section __bug_table,\"aw\"\n" \ - "2:\t.4byte 1b - 2b\n" \ - "\t.short %2\n" \ + "2: .4byte 1b - .\n" \ + " .short %2\n" \ ".org 2b+%3\n" \ ".previous\n" #endif diff --git a/arch/riscv/include/asm/bug.h b/arch/riscv/include/asm/bug.h index d3804a2f9aad..1aaea81fb141 100644 --- a/arch/riscv/include/asm/bug.h +++ b/arch/riscv/include/asm/bug.h @@ -30,8 +30,8 @@ typedef u32 bug_insn_t; #ifdef CONFIG_GENERIC_BUG_RELATIVE_POINTERS -#define __BUG_ENTRY_ADDR RISCV_INT " 1b - 2b" -#define __BUG_ENTRY_FILE RISCV_INT " %0 - 2b" +#define __BUG_ENTRY_ADDR RISCV_INT " 1b - ." +#define __BUG_ENTRY_FILE RISCV_INT " %0 - ." #else #define __BUG_ENTRY_ADDR RISCV_PTR " 1b" #define __BUG_ENTRY_FILE RISCV_PTR " %0" diff --git a/arch/s390/include/asm/bug.h b/arch/s390/include/asm/bug.h index 0b25f28351ed..aebe1e22c7be 100644 --- a/arch/s390/include/asm/bug.h +++ b/arch/s390/include/asm/bug.h @@ -15,7 +15,8 @@ "1: .asciz \""__FILE__"\"\n" \ ".previous\n" \ ".section __bug_table,\"awM\",@progbits,%2\n" \ - "2: .long 0b-2b,1b-2b\n" \ + "2: .long 0b-.\n" \ + " .long 1b-.\n" \ " .short %0,%1\n" \ " .org 2b+%2\n" \ ".previous\n" \ @@ -30,7 +31,7 @@ asm_inline volatile( \ "0: mc 0,0\n" \ ".section __bug_table,\"awM\",@progbits,%1\n" \ - "1: .long 0b-1b\n" \ + "1: .long 0b-.\n" \ " .short %0\n" \ " .org 1b+%1\n" \ ".previous\n" \ diff --git a/arch/x86/include/asm/bug.h b/arch/x86/include/asm/bug.h index 4d20a293c6fd..76fbe24cccf9 100644 --- a/arch/x86/include/asm/bug.h +++ b/arch/x86/include/asm/bug.h @@ -18,7 +18,7 @@ #ifdef CONFIG_X86_32 # define __BUG_REL(val) ".long " __stringify(val) #else -# define __BUG_REL(val) ".long " __stringify(val) " - 2b" +# define __BUG_REL(val) ".long " __stringify(val) " - ." #endif #ifdef CONFIG_DEBUG_BUGVERBOSE diff --git a/lib/bug.c b/lib/bug.c index 45a0584f6541..c223a2575b72 100644 --- a/lib/bug.c +++ b/lib/bug.c @@ -6,8 +6,7 @@ CONFIG_BUG - emit BUG traps. Nothing happens without this. CONFIG_GENERIC_BUG - enable this code. - CONFIG_GENERIC_BUG_RELATIVE_POINTERS - use 32-bit pointers relative to - the containing struct bug_entry for bug_addr and file. + CONFIG_GENERIC_BUG_RELATIVE_POINTERS - use 32-bit relative pointers for bug_addr and file CONFIG_DEBUG_BUGVERBOSE - emit full file+line information for each BUG CONFIG_BUG and CONFIG_DEBUG_BUGVERBOSE are potentially user-settable @@ -53,10 +52,10 @@ extern struct bug_entry __start___bug_table[], __stop___bug_table[]; static inline unsigned long bug_addr(const struct bug_entry *bug) { -#ifndef CONFIG_GENERIC_BUG_RELATIVE_POINTERS - return bug->bug_addr; +#ifdef CONFIG_GENERIC_BUG_RELATIVE_POINTERS + return (unsigned long)&bug->bug_addr_disp + bug->bug_addr_disp; #else - return (unsigned long)bug + bug->bug_addr_disp; + return bug->bug_addr; #endif } @@ -131,10 +130,10 @@ void bug_get_file_line(struct bug_entry *bug, const char **file, unsigned int *line) { #ifdef CONFIG_DEBUG_BUGVERBOSE -#ifndef CONFIG_GENERIC_BUG_RELATIVE_POINTERS - *file = bug->file; +#ifdef CONFIG_GENERIC_BUG_RELATIVE_POINTERS + *file = (const char *)&bug->file_disp + bug->file_disp; #else - *file = (const char *)bug + bug->file_disp; + *file = bug->file; #endif *line = bug->line; #else