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x86/vdso/32: Assemble sigreturn.S separately 

sigreturn.S was historically included by the various
__kernel_vsyscall implementations due to assumptions about all the
32-bit vDSO images having the sigreturn symbols at the same address.

Those assumptions were removed in v3.16, and as of v4.4, there is only
a single 32-bit vDSO left.

Simplify the build process by assembling sigreturn.S into a normal
object file.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/d7b6dfde3c7397aa26977320da90448363b5a7e9.1465505753.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Andy Lutomirski 2016-06-09 13:57:04 -07:00 committed by Ingo Molnar
parent 99158f10e9
commit f0702555b1
3 changed files with 4 additions and 16 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
arch/x86/entry/vdso/Makefile
View File

@ -134,7 +134,7 @@ VDSO_LDFLAGS_vdso32.lds = -m32 -Wl,-m,elf_i386 -Wl,-soname=linux-gate.so.1
override obj-dirs = $(dir $(obj)) $(obj)/vdso32/
targets += vdso32/vdso32.lds
targets += vdso32/note.o vdso32/vclock_gettime.o vdso32/system_call.o
targets += vdso32/note.o vdso32/system_call.o vdso32/sigreturn.o
targets += vdso32/vclock_gettime.o
KBUILD_AFLAGS_32 := $(filter-out -m64,$(KBUILD_AFLAGS)) -DBUILD_VDSO
@ -156,7 +156,8 @@ $(obj)/vdso32.so.dbg: FORCE \
$(obj)/vdso32/vdso32.lds \
$(obj)/vdso32/vclock_gettime.o \
$(obj)/vdso32/note.o \
$(obj)/vdso32/system_call.o
$(obj)/vdso32/system_call.o \
$(obj)/vdso32/sigreturn.o
$(call if_changed,vdso)
#

8
arch/x86/entry/vdso/vdso32/sigreturn.S
View File

@ -1,11 +1,3 @@
/*
* Common code for the sigreturn entry points in vDSO images.
* So far this code is the same for both int80 and sysenter versions.
* This file is #include'd by int80.S et al to define them first thing.
* The kernel assumes that the addresses of these routines are constant
* for all vDSO implementations.
*/
#include <linux/linkage.h>
#include <asm/unistd_32.h>
#include <asm/asm-offsets.h>

7
arch/x86/entry/vdso/vdso32/system_call.S
View File

@ -2,16 +2,11 @@
* AT_SYSINFO entry point
*/
#include <linux/linkage.h>
#include <asm/dwarf2.h>
#include <asm/cpufeatures.h>
#include <asm/alternative-asm.h>
/*
* First get the common code for the sigreturn entry points.
* This must come first.
*/
#include "sigreturn.S"
.text
.globl __kernel_vsyscall
.type __kernel_vsyscall,@function