Commit f387d0e1 authored by Josh Poimboeuf's avatar Josh Poimboeuf Committed by Ingo Molnar
Browse files

x86/asm: Remove ANNOTATE_DATA_SPECIAL usage 



Instead of manually annotating each __ex_table entry, just make the
section mergeable and store the entry size in the ELF section header.

Either way works for objtool create_fake_symbols(), this way produces
cleaner code generation.

Signed-off-by: default avatarJosh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://patch.msgid.link/b858cb7891c1ba0080e22a9c32595e6c302435e2.1764694625.git.jpoimboe@kernel.org
parent a818f28f

arch/um/include/asm/Kbuild

+0 −1
Original line number Diff line number Diff line
@@ -5,7 +5,6 @@ generic-y += device.h 
generic-y += dma-mapping.h

generic-y += emergency-restart.h

generic-y += exec.h

generic-y += extable.h

generic-y += ftrace.h

generic-y += hw_irq.h

generic-y += irq_regs.h

arch/um/include/shared/common-offsets.h

+1 −0
Original line number Diff line number Diff line
@@ -20,3 +20,4 @@ DEFINE(UM_KERN_GDT_ENTRY_TLS_ENTRIES, GDT_ENTRY_TLS_ENTRIES); 
DEFINE(UM_SECCOMP_ARCH_NATIVE, SECCOMP_ARCH_NATIVE);



DEFINE(ALT_INSTR_SIZE, sizeof(struct alt_instr));

DEFINE(EXTABLE_SIZE,   sizeof(struct exception_table_entry));

arch/x86/include/asm/asm.h

+14 −11
Original line number Diff line number Diff line
@@ -126,15 +126,18 @@ static __always_inline __pure void *rip_rel_ptr(void *p) 


#ifdef __KERNEL__



#ifndef COMPILE_OFFSETS

#include <asm/asm-offsets.h>

#endif



# include <asm/extable_fixup_types.h>



/* Exception table entry */

#ifdef __ASSEMBLER__



# define _ASM_EXTABLE_TYPE(from, to, type)				\

	.pushsection "__ex_table","a" ;				\

	.pushsection "__ex_table", "aM", @progbits, EXTABLE_SIZE ;	\

	.balign 4 ;							\

	ANNOTATE_DATA_SPECIAL ;					\

	.long (from) - . ;						\

	.long (to) - . ;						\

	.long type ;							\
@@ -180,18 +183,18 @@ static __always_inline __pure void *rip_rel_ptr(void *p) 
	".purgem extable_type_reg\n"



# define _ASM_EXTABLE_TYPE(from, to, type)			\

	" .pushsection \"__ex_table\",\"a\"\n"			\

	" .pushsection __ex_table, \"aM\", @progbits, "		\

		       __stringify(EXTABLE_SIZE) "\n"		\

	" .balign 4\n"						\

	ANNOTATE_DATA_SPECIAL					\

	" .long (" #from ") - .\n"				\

	" .long (" #to ") - .\n"				\

	" .long " __stringify(type) " \n"			\

	" .popsection\n"



# define _ASM_EXTABLE_TYPE_REG(from, to, type, reg)				\

	" .pushsection \"__ex_table\",\"a\"\n"					\

	" .pushsection __ex_table, \"aM\", @progbits, "				\

		       __stringify(EXTABLE_SIZE) "\n"				\

	" .balign 4\n"								\

	ANNOTATE_DATA_SPECIAL							\

	" .long (" #from ") - .\n"						\

	" .long (" #to ") - .\n"						\

	DEFINE_EXTABLE_TYPE_REG							\

arch/x86/kernel/asm-offsets.c

+1 −0
Original line number Diff line number Diff line
@@ -126,4 +126,5 @@ static void __used common(void) 


	BLANK();

	DEFINE(ALT_INSTR_SIZE,	sizeof(struct alt_instr));

	DEFINE(EXTABLE_SIZE,	sizeof(struct exception_table_entry));

}

arch/x86/um/shared/sysdep/kernel-offsets.h

+2 −0
Original line number Diff line number Diff line 
/* SPDX-License-Identifier: GPL-2.0 */

#define COMPILE_OFFSETS

#include <linux/stddef.h>

#include <linux/sched.h>

#include <linux/elf.h>
@@ -7,6 +8,7 @@ 
#include <linux/audit.h>

#include <asm/mman.h>

#include <asm/seccomp.h>

#include <asm/extable.h>



/* workaround for a warning with -Wmissing-prototypes */

void foo(void);