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x86, vdso: Add 32 bit VDSO time support for 32 bit kernel

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This patch add the time support for 32 bit a VDSO to a 32 bit kernel.

For 32 bit programs running on a 32 bit kernel, the same mechanism is
used as for 64 bit programs running on a 64 bit kernel.

Reviewed-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Stefani Seibold <stefani@seibold.net>
Link: http://lkml.kernel.org/r/1395094933-14252-10-git-send-email-stefani@seibold.net
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
This commit is contained in:
Stefani Seibold 2014-03-17 23:22:09 +01:00 committed by H. Peter Anvin
parent b4b541a610
commit 7a59ed415f
8 changed files with 178 additions and 11 deletions
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5
arch/x86/include/asm/vdso.h
View File

@ -2,6 +2,11 @@
#define _ASM_X86_VDSO_H
#if defined CONFIG_X86_32 || defined CONFIG_COMPAT
#include <asm/vdso32.h>
extern const char VDSO32_PRELINK[];
/*
* Given a pointer to the vDSO image, find the pointer to VDSO32_name
* as that symbol is defined in the vDSO sources or linker script.

11
arch/x86/include/asm/vdso32.h Normal file
View File

@ -0,0 +1,11 @@
#ifndef _ASM_X86_VDSO32_H
#define _ASM_X86_VDSO32_H
#define VDSO_BASE_PAGE 0
#define VDSO_VVAR_PAGE 1
#define VDSO_HPET_PAGE 2
#define VDSO_PAGES 3
#define VDSO_PREV_PAGES 2
#define VDSO_OFFSET(x) ((x) * PAGE_SIZE)
#endif

8
arch/x86/vdso/Makefile
View File

@ -146,8 +146,16 @@ KBUILD_AFLAGS_32 := $(filter-out -m64,$(KBUILD_AFLAGS))
$(vdso32-images:%=$(obj)/%.dbg): KBUILD_AFLAGS = $(KBUILD_AFLAGS_32)
$(vdso32-images:%=$(obj)/%.dbg): asflags-$(CONFIG_X86_64) += -m32
KBUILD_CFLAGS_32 := $(filter-out -m64,$(KBUILD_CFLAGS))
KBUILD_CFLAGS_32 := $(filter-out -mcmodel=kernel,$(KBUILD_CFLAGS_32))
KBUILD_CFLAGS_32 := $(filter-out -fno-pic,$(KBUILD_CFLAGS_32))
KBUILD_CFLAGS_32 := $(filter-out -mfentry,$(KBUILD_CFLAGS_32))
KBUILD_CFLAGS_32 += -m32 -msoft-float -mregparm=0 -fpic
$(vdso32-images:%=$(obj)/%.dbg): KBUILD_CFLAGS = $(KBUILD_CFLAGS_32)
$(vdso32-images:%=$(obj)/%.dbg): $(obj)/vdso32-%.so.dbg: FORCE \
$(obj)/vdso32/vdso32.lds \
$(obj)/vdso32/vclock_gettime.o \
$(obj)/vdso32/note.o \
$(obj)/vdso32/%.o
$(call if_changed,vdso)

76
arch/x86/vdso/vclock_gettime.c
View File

@ -4,6 +4,9 @@
*
* Fast user context implementation of clock_gettime, gettimeofday, and time.
*
* 32 Bit compat layer by Stefani Seibold <stefani@seibold.net>
* sponsored by Rohde & Schwarz GmbH & Co. KG Munich/Germany
*
* The code should have no internal unresolved relocations.
* Check with readelf after changing.
*/
@ -12,13 +15,11 @@
#define DISABLE_BRANCH_PROFILING
#include <linux/kernel.h>
#include <linux/posix-timers.h>
#include <linux/time.h>
#include <uapi/linux/time.h>
#include <linux/string.h>
#include <asm/vsyscall.h>
#include <asm/fixmap.h>
#include <asm/vgtod.h>
#include <asm/timex.h>
#include <asm/hpet.h>
#include <asm/unistd.h>
#include <asm/io.h>
@ -26,6 +27,12 @@
#define gtod (&VVAR(vsyscall_gtod_data))
extern int __vdso_clock_gettime(clockid_t clock, struct timespec *ts);
extern int __vdso_gettimeofday(struct timeval *tv, struct timezone *tz);
extern time_t __vdso_time(time_t *t);
#ifndef BUILD_VDSO32
static notrace cycle_t vread_hpet(void)
{
return readl((const void __iomem *)fix_to_virt(VSYSCALL_HPET) + HPET_COUNTER);
@ -118,6 +125,59 @@ static notrace cycle_t vread_pvclock(int *mode)
}
#endif
#else
extern u8 hpet_page
__attribute__((visibility("hidden")));
#ifdef CONFIG_HPET_TIMER
static notrace cycle_t vread_hpet(void)
{
return readl((const void __iomem *)(&hpet_page + HPET_COUNTER));
}
#endif
notrace static long vdso_fallback_gettime(long clock, struct timespec *ts)
{
long ret;
asm(
"mov %%ebx, %%edx \n"
"mov %2, %%ebx \n"
"call VDSO32_vsyscall \n"
"mov %%edx, %%ebx \n"
: "=a" (ret)
: "0" (__NR_clock_gettime), "g" (clock), "c" (ts)
: "memory", "edx");
return ret;
}
notrace static long vdso_fallback_gtod(struct timeval *tv, struct timezone *tz)
{
long ret;
asm(
"mov %%ebx, %%edx \n"
"mov %2, %%ebx \n"
"call VDSO32_vsyscall \n"
"mov %%edx, %%ebx \n"
: "=a" (ret)
: "0" (__NR_gettimeofday), "g" (tv), "c" (tz)
: "memory", "edx");
return ret;
}
#ifdef CONFIG_PARAVIRT_CLOCK
static notrace cycle_t vread_pvclock(int *mode)
{
*mode = VCLOCK_NONE;
return 0;
}
#endif
#endif
notrace static cycle_t vread_tsc(void)
{
cycle_t ret;
@ -131,7 +191,7 @@ notrace static cycle_t vread_tsc(void)
* but no one has ever seen it happen.
*/
rdtsc_barrier();
ret = (cycle_t)vget_cycles();
ret = (cycle_t)__native_read_tsc();
last = gtod->clock.cycle_last;
@ -152,12 +212,14 @@ notrace static cycle_t vread_tsc(void)
notrace static inline u64 vgetsns(int *mode)
{
long v;
u64 v;
cycles_t cycles;
if (gtod->clock.vclock_mode == VCLOCK_TSC)
cycles = vread_tsc();
#ifdef CONFIG_HPET_TIMER
else if (gtod->clock.vclock_mode == VCLOCK_HPET)
cycles = vread_hpet();
#endif
#ifdef CONFIG_PARAVIRT_CLOCK
else if (gtod->clock.vclock_mode == VCLOCK_PVCLOCK)
cycles = vread_pvclock(mode);
@ -189,7 +251,7 @@ notrace static int __always_inline do_realtime(struct timespec *ts)
return mode;
}
notrace static int do_monotonic(struct timespec *ts)
notrace static int __always_inline do_monotonic(struct timespec *ts)
{
unsigned long seq;
u64 ns;
@ -284,7 +346,7 @@ int gettimeofday(struct timeval *, struct timezone *)
*/
notrace time_t __vdso_time(time_t *t)
{
/* This is atomic on x86_64 so we don't need any locks. */
/* This is atomic on x86 so we don't need any locks. */
time_t result = ACCESS_ONCE(gtod->wall_time_sec);
if (t)

22
arch/x86/vdso/vdso-layout.lds.S
View File

@ -6,6 +6,24 @@
SECTIONS
{
#ifdef BUILD_VDSO32
#include <asm/vdso32.h>
.hpet_sect : {
hpet_page = . - VDSO_OFFSET(VDSO_HPET_PAGE);
} :text :hpet_sect
.vvar_sect : {
vvar = . - VDSO_OFFSET(VDSO_VVAR_PAGE);
/* Place all vvars at the offsets in asm/vvar.h. */
#define EMIT_VVAR(name, offset) vvar_ ## name = vvar + offset;
#define __VVAR_KERNEL_LDS
#include <asm/vvar.h>
#undef __VVAR_KERNEL_LDS
#undef EMIT_VVAR
} :text :vvar_sect
#endif
. = SIZEOF_HEADERS;
.hash : { *(.hash) } :text
@ -61,4 +79,8 @@ PHDRS
dynamic PT_DYNAMIC FLAGS(4); /* PF_R */
note PT_NOTE FLAGS(4); /* PF_R */
eh_frame_hdr PT_GNU_EH_FRAME;
#ifdef BUILD_VDSO32
vvar_sect PT_NULL FLAGS(4); /* PF_R */
hpet_sect PT_NULL FLAGS(4); /* PF_R */
#endif
}

47
arch/x86/vdso/vdso32-setup.c
View File

@ -25,6 +25,9 @@
#include <asm/tlbflush.h>
#include <asm/vdso.h>
#include <asm/proto.h>
#include <asm/fixmap.h>
#include <asm/hpet.h>
#include <asm/vvar.h>
#ifdef CONFIG_COMPAT_VDSO
#define VDSO_DEFAULT 0
@ -141,6 +144,7 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
struct mm_struct *mm = current->mm;
unsigned long addr;
int ret = 0;
struct vm_area_struct *vma;
#ifdef CONFIG_X86_X32_ABI
if (test_thread_flag(TIF_X32))
@ -163,14 +167,49 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
/*
* MAYWRITE to allow gdb to COW and set breakpoints
*/
ret = install_special_mapping(mm, addr, PAGE_SIZE,
VM_READ|VM_EXEC|
VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC,
vdso32_pages);
ret = install_special_mapping(mm,
addr,
VDSO_OFFSET(VDSO_PAGES - VDSO_PREV_PAGES),
VM_READ|VM_EXEC|
VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC,
vdso32_pages);
if (ret)
goto up_fail;
vma = _install_special_mapping(mm,
addr - VDSO_OFFSET(VDSO_PREV_PAGES),
VDSO_OFFSET(VDSO_PREV_PAGES),
VM_READ,
NULL);
if (IS_ERR(vma)) {
ret = PTR_ERR(vma);
goto up_fail;
}
ret = remap_pfn_range(vma,
addr - VDSO_OFFSET(VDSO_VVAR_PAGE),
__pa_symbol(&__vvar_page) >> PAGE_SHIFT,
PAGE_SIZE,
PAGE_READONLY);
if (ret)
goto up_fail;
#ifdef CONFIG_HPET_TIMER
if (hpet_address) {
ret = io_remap_pfn_range(vma,
addr - VDSO_OFFSET(VDSO_HPET_PAGE),
hpet_address >> PAGE_SHIFT,
PAGE_SIZE,
pgprot_noncached(PAGE_READONLY));
if (ret)
goto up_fail;
}
#endif
current_thread_info()->sysenter_return =
VDSO32_SYMBOL(addr, SYSENTER_RETURN);

9
arch/x86/vdso/vdso32/vclock_gettime.c Normal file
View File

@ -0,0 +1,9 @@
#define BUILD_VDSO32
#ifndef CONFIG_CC_OPTIMIZE_FOR_SIZE
#undef CONFIG_OPTIMIZE_INLINING
#endif
#undef CONFIG_X86_PPRO_FENCE
#include "../vclock_gettime.c"

11
arch/x86/vdso/vdso32/vdso32.lds.S
View File

@ -8,6 +8,11 @@
* values visible using the asm-x86/vdso.h macros from the kernel proper.
*/
#include <asm/page.h>
#define BUILD_VDSO32
#define VDSO_PRELINK 0
#include "../vdso-layout.lds.S"
/* The ELF entry point can be used to set the AT_SYSINFO value. */
@ -23,6 +28,9 @@ VERSION
__kernel_vsyscall;
__kernel_sigreturn;
__kernel_rt_sigreturn;
__vdso_clock_gettime;
__vdso_gettimeofday;
__vdso_time;
local: *;
};
}
@ -33,3 +41,6 @@ VERSION
VDSO32_vsyscall = __kernel_vsyscall;
VDSO32_sigreturn = __kernel_sigreturn;
VDSO32_rt_sigreturn = __kernel_rt_sigreturn;
VDSO32_clock_gettime = clock_gettime;
VDSO32_gettimeofday = gettimeofday;
VDSO32_time = time;