[PATCH v2] bug: Use normal relative pointers in 'struct bug_entry'
From: Josh Poimboeuf <jpoimboe@kernel.org>
Date: 2022-05-12 13:57:14
Also in:
linux-arm-kernel, linux-riscv, linux-s390, lkml
Subsystem:
arm64 port (aarch64 architecture), library code, linux for powerpc (32-bit and 64-bit), risc-v architecture, s390 architecture, the rest, x86 architecture (32-bit and 64-bit) · Maintainers:
Catalin Marinas, Will Deacon, Andrew Morton, Madhavan Srinivasan, Paul Walmsley, Palmer Dabbelt, Albert Ou, Heiko Carstens, Vasily Gorbik, Alexander Gordeev, Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen
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. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Sven Schnelle <svens@linux.ibm.com> # s390 Reviewed-by: Mark Rutland <mark.rutland@arm.com> Tested-by: Mark Rutland <mark.rutland@arm.com> [arm64] Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc) Acked-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> --- v2: - fix ppc64le C macros (and actually test them) 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 aaf0cb0db4ae..a3ec87d198ac 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
--
2.34.1