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x86, vdso: Patch alternatives in the 32-bit VDSO

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We need the alternatives mechanism for rdtsc_barrier() to work.

Signed-off-by: Stefani Seibold <stefani@seibold.net>
Link: http://lkml.kernel.org/r/1395094933-14252-9-git-send-email-stefani@seibold.net
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
This commit is contained in:
Andy Lutomirski 2014-03-17 23:22:08 +01:00 committed by H. Peter Anvin
parent ef721987ae
commit b4b541a610
4 changed files with 26 additions and 15 deletions
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2
arch/x86/include/asm/vdso.h
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@ -28,4 +28,6 @@ extern const char vdso32_int80_start, vdso32_int80_end;
extern const char vdso32_syscall_start, vdso32_syscall_end;
extern const char vdso32_sysenter_start, vdso32_sysenter_end;
void __init patch_vdso32(void *vdso, size_t len);
#endif /* _ASM_X86_VDSO_H */

3
arch/x86/vdso/Makefile
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@ -21,7 +21,8 @@ vobjs-$(VDSOX32-y) += $(vobjx32s-compat)
vobj64s := $(filter-out $(vobjx32s-compat),$(vobjs-y))
# files to link into kernel
obj-$(VDSO64-y) += vma.o vdso.o
obj-y += vma.o
obj-$(VDSO64-y) += vdso.o
obj-$(VDSOX32-y) += vdsox32.o
obj-$(VDSO32-y) += vdso32.o vdso32-setup.o

23
arch/x86/vdso/vdso32-setup.c
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@ -112,24 +112,25 @@ void enable_sep_cpu(void)
int __init sysenter_setup(void)
{
void *syscall_page = (void *)get_zeroed_page(GFP_ATOMIC);
const void *vsyscall;
size_t vsyscall_len;
void *vdso_page = (void *)get_zeroed_page(GFP_ATOMIC);
const void *vdso;
size_t vdso_len;
vdso32_pages[0] = virt_to_page(syscall_page);
vdso32_pages[0] = virt_to_page(vdso_page);
if (vdso32_syscall()) {
vsyscall = &vdso32_syscall_start;
vsyscall_len = &vdso32_syscall_end - &vdso32_syscall_start;
vdso = &vdso32_syscall_start;
vdso_len = &vdso32_syscall_end - &vdso32_syscall_start;
} else if (vdso32_sysenter()){
vsyscall = &vdso32_sysenter_start;
vsyscall_len = &vdso32_sysenter_end - &vdso32_sysenter_start;
vdso = &vdso32_sysenter_start;
vdso_len = &vdso32_sysenter_end - &vdso32_sysenter_start;
} else {
vsyscall = &vdso32_int80_start;
vsyscall_len = &vdso32_int80_end - &vdso32_int80_start;
vdso = &vdso32_int80_start;
vdso_len = &vdso32_int80_end - &vdso32_int80_start;
}
memcpy(syscall_page, vsyscall, vsyscall_len);
memcpy(vdso_page, vdso, vdso_len);
patch_vdso32(vdso_page, vdso_len);
return 0;
}

13
arch/x86/vdso/vma.c
View File

@ -16,6 +16,7 @@
#include <asm/vdso.h>
#include <asm/page.h>
#if defined(CONFIG_X86_64)
unsigned int __read_mostly vdso_enabled = 1;
extern char vdso_start[], vdso_end[];
@ -28,8 +29,12 @@ static unsigned vdso_size;
extern char vdsox32_start[], vdsox32_end[];
extern struct page *vdsox32_pages[];
static unsigned vdsox32_size;
#endif
#endif
static void __init patch_vdsox32(void *vdso, size_t len)
#if defined(CONFIG_X86_32) || defined(CONFIG_X86_X32_ABI) || \
defined(CONFIG_COMPAT)
void __init patch_vdso32(void *vdso, size_t len)
{
Elf32_Ehdr *hdr = vdso;
Elf32_Shdr *sechdrs, *alt_sec = 0;
@ -52,7 +57,7 @@ static void __init patch_vdsox32(void *vdso, size_t len)
}
/* If we get here, it's probably a bug. */
pr_warning("patch_vdsox32: .altinstructions not found\n");
pr_warning("patch_vdso32: .altinstructions not found\n");
return; /* nothing to patch */
found:
@ -61,6 +66,7 @@ found:
}
#endif
#if defined(CONFIG_X86_64)
static void __init patch_vdso64(void *vdso, size_t len)
{
Elf64_Ehdr *hdr = vdso;
@ -104,7 +110,7 @@ static int __init init_vdso(void)
vdso_pages[i] = virt_to_page(vdso_start + i*PAGE_SIZE);
#ifdef CONFIG_X86_X32_ABI
patch_vdsox32(vdsox32_start, vdsox32_end - vdsox32_start);
patch_vdso32(vdsox32_start, vdsox32_end - vdsox32_start);
npages = (vdsox32_end - vdsox32_start + PAGE_SIZE - 1) / PAGE_SIZE;
vdsox32_size = npages << PAGE_SHIFT;
for (i = 0; i < npages; i++)
@ -204,3 +210,4 @@ static __init int vdso_setup(char *s)
return 0;
}
__setup("vdso=", vdso_setup);
#endif