x86, vdso: Add 32 bit VDSO time support for 32 bit kernel
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
H. Peter Anvin
parent
b4b541a610
commit
7a59ed415f
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@ -2,6 +2,11 @@
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#define _ASM_X86_VDSO_H
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#if defined CONFIG_X86_32 || defined CONFIG_COMPAT
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#include <asm/vdso32.h>
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extern const char VDSO32_PRELINK[];
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/*
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* Given a pointer to the vDSO image, find the pointer to VDSO32_name
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* as that symbol is defined in the vDSO sources or linker script.
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@ -0,0 +1,11 @@
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#ifndef _ASM_X86_VDSO32_H
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#define _ASM_X86_VDSO32_H
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#define VDSO_BASE_PAGE 0
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#define VDSO_VVAR_PAGE 1
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#define VDSO_HPET_PAGE 2
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#define VDSO_PAGES 3
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#define VDSO_PREV_PAGES 2
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#define VDSO_OFFSET(x) ((x) * PAGE_SIZE)
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#endif
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@ -146,8 +146,16 @@ KBUILD_AFLAGS_32 := $(filter-out -m64,$(KBUILD_AFLAGS))
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$(vdso32-images:%=$(obj)/%.dbg): KBUILD_AFLAGS = $(KBUILD_AFLAGS_32)
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$(vdso32-images:%=$(obj)/%.dbg): asflags-$(CONFIG_X86_64) += -m32
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KBUILD_CFLAGS_32 := $(filter-out -m64,$(KBUILD_CFLAGS))
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KBUILD_CFLAGS_32 := $(filter-out -mcmodel=kernel,$(KBUILD_CFLAGS_32))
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KBUILD_CFLAGS_32 := $(filter-out -fno-pic,$(KBUILD_CFLAGS_32))
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KBUILD_CFLAGS_32 := $(filter-out -mfentry,$(KBUILD_CFLAGS_32))
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KBUILD_CFLAGS_32 += -m32 -msoft-float -mregparm=0 -fpic
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$(vdso32-images:%=$(obj)/%.dbg): KBUILD_CFLAGS = $(KBUILD_CFLAGS_32)
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$(vdso32-images:%=$(obj)/%.dbg): $(obj)/vdso32-%.so.dbg: FORCE \
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$(obj)/vdso32/vdso32.lds \
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$(obj)/vdso32/vclock_gettime.o \
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$(obj)/vdso32/note.o \
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$(obj)/vdso32/%.o
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$(call if_changed,vdso)
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@ -4,6 +4,9 @@
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*
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* Fast user context implementation of clock_gettime, gettimeofday, and time.
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*
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* 32 Bit compat layer by Stefani Seibold <stefani@seibold.net>
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* sponsored by Rohde & Schwarz GmbH & Co. KG Munich/Germany
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*
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* The code should have no internal unresolved relocations.
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* Check with readelf after changing.
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*/
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@ -12,13 +15,11 @@
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#define DISABLE_BRANCH_PROFILING
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#include <linux/kernel.h>
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#include <linux/posix-timers.h>
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#include <linux/time.h>
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#include <uapi/linux/time.h>
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#include <linux/string.h>
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#include <asm/vsyscall.h>
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#include <asm/fixmap.h>
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#include <asm/vgtod.h>
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#include <asm/timex.h>
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#include <asm/hpet.h>
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#include <asm/unistd.h>
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#include <asm/io.h>
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@ -26,6 +27,12 @@
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#define gtod (&VVAR(vsyscall_gtod_data))
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extern int __vdso_clock_gettime(clockid_t clock, struct timespec *ts);
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extern int __vdso_gettimeofday(struct timeval *tv, struct timezone *tz);
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extern time_t __vdso_time(time_t *t);
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#ifndef BUILD_VDSO32
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static notrace cycle_t vread_hpet(void)
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{
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return readl((const void __iomem *)fix_to_virt(VSYSCALL_HPET) + HPET_COUNTER);
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@ -118,6 +125,59 @@ static notrace cycle_t vread_pvclock(int *mode)
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}
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#endif
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#else
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extern u8 hpet_page
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__attribute__((visibility("hidden")));
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#ifdef CONFIG_HPET_TIMER
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static notrace cycle_t vread_hpet(void)
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{
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return readl((const void __iomem *)(&hpet_page + HPET_COUNTER));
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}
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#endif
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notrace static long vdso_fallback_gettime(long clock, struct timespec *ts)
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{
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long ret;
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asm(
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"mov %%ebx, %%edx \n"
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"mov %2, %%ebx \n"
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"call VDSO32_vsyscall \n"
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"mov %%edx, %%ebx \n"
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: "=a" (ret)
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: "0" (__NR_clock_gettime), "g" (clock), "c" (ts)
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: "memory", "edx");
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return ret;
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}
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notrace static long vdso_fallback_gtod(struct timeval *tv, struct timezone *tz)
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{
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long ret;
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asm(
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"mov %%ebx, %%edx \n"
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"mov %2, %%ebx \n"
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"call VDSO32_vsyscall \n"
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"mov %%edx, %%ebx \n"
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: "=a" (ret)
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: "0" (__NR_gettimeofday), "g" (tv), "c" (tz)
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: "memory", "edx");
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return ret;
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}
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#ifdef CONFIG_PARAVIRT_CLOCK
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static notrace cycle_t vread_pvclock(int *mode)
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{
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*mode = VCLOCK_NONE;
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return 0;
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}
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#endif
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#endif
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notrace static cycle_t vread_tsc(void)
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{
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cycle_t ret;
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@ -131,7 +191,7 @@ notrace static cycle_t vread_tsc(void)
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* but no one has ever seen it happen.
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*/
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rdtsc_barrier();
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ret = (cycle_t)vget_cycles();
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ret = (cycle_t)__native_read_tsc();
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last = gtod->clock.cycle_last;
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@ -152,12 +212,14 @@ notrace static cycle_t vread_tsc(void)
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notrace static inline u64 vgetsns(int *mode)
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{
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long v;
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u64 v;
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cycles_t cycles;
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if (gtod->clock.vclock_mode == VCLOCK_TSC)
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cycles = vread_tsc();
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#ifdef CONFIG_HPET_TIMER
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else if (gtod->clock.vclock_mode == VCLOCK_HPET)
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cycles = vread_hpet();
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#endif
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#ifdef CONFIG_PARAVIRT_CLOCK
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else if (gtod->clock.vclock_mode == VCLOCK_PVCLOCK)
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cycles = vread_pvclock(mode);
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@ -189,7 +251,7 @@ notrace static int __always_inline do_realtime(struct timespec *ts)
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return mode;
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}
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notrace static int do_monotonic(struct timespec *ts)
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notrace static int __always_inline do_monotonic(struct timespec *ts)
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{
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unsigned long seq;
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u64 ns;
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@ -284,7 +346,7 @@ int gettimeofday(struct timeval *, struct timezone *)
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*/
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notrace time_t __vdso_time(time_t *t)
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{
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/* This is atomic on x86_64 so we don't need any locks. */
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/* This is atomic on x86 so we don't need any locks. */
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time_t result = ACCESS_ONCE(gtod->wall_time_sec);
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if (t)
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@ -6,6 +6,24 @@
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SECTIONS
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{
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#ifdef BUILD_VDSO32
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#include <asm/vdso32.h>
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.hpet_sect : {
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hpet_page = . - VDSO_OFFSET(VDSO_HPET_PAGE);
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} :text :hpet_sect
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.vvar_sect : {
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vvar = . - VDSO_OFFSET(VDSO_VVAR_PAGE);
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/* Place all vvars at the offsets in asm/vvar.h. */
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#define EMIT_VVAR(name, offset) vvar_ ## name = vvar + offset;
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#define __VVAR_KERNEL_LDS
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#include <asm/vvar.h>
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#undef __VVAR_KERNEL_LDS
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#undef EMIT_VVAR
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} :text :vvar_sect
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#endif
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. = SIZEOF_HEADERS;
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.hash : { *(.hash) } :text
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@ -61,4 +79,8 @@ PHDRS
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dynamic PT_DYNAMIC FLAGS(4); /* PF_R */
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note PT_NOTE FLAGS(4); /* PF_R */
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eh_frame_hdr PT_GNU_EH_FRAME;
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#ifdef BUILD_VDSO32
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vvar_sect PT_NULL FLAGS(4); /* PF_R */
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hpet_sect PT_NULL FLAGS(4); /* PF_R */
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#endif
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}
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@ -25,6 +25,9 @@
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#include <asm/tlbflush.h>
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#include <asm/vdso.h>
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#include <asm/proto.h>
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#include <asm/fixmap.h>
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#include <asm/hpet.h>
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#include <asm/vvar.h>
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#ifdef CONFIG_COMPAT_VDSO
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#define VDSO_DEFAULT 0
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@ -141,6 +144,7 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
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struct mm_struct *mm = current->mm;
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unsigned long addr;
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int ret = 0;
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struct vm_area_struct *vma;
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#ifdef CONFIG_X86_X32_ABI
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if (test_thread_flag(TIF_X32))
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@ -163,14 +167,49 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
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/*
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* MAYWRITE to allow gdb to COW and set breakpoints
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*/
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ret = install_special_mapping(mm, addr, PAGE_SIZE,
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VM_READ|VM_EXEC|
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VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC,
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vdso32_pages);
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ret = install_special_mapping(mm,
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addr,
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VDSO_OFFSET(VDSO_PAGES - VDSO_PREV_PAGES),
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VM_READ|VM_EXEC|
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VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC,
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vdso32_pages);
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if (ret)
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goto up_fail;
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vma = _install_special_mapping(mm,
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addr - VDSO_OFFSET(VDSO_PREV_PAGES),
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VDSO_OFFSET(VDSO_PREV_PAGES),
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VM_READ,
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NULL);
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if (IS_ERR(vma)) {
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ret = PTR_ERR(vma);
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goto up_fail;
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}
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ret = remap_pfn_range(vma,
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addr - VDSO_OFFSET(VDSO_VVAR_PAGE),
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__pa_symbol(&__vvar_page) >> PAGE_SHIFT,
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PAGE_SIZE,
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PAGE_READONLY);
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if (ret)
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goto up_fail;
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#ifdef CONFIG_HPET_TIMER
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if (hpet_address) {
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ret = io_remap_pfn_range(vma,
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addr - VDSO_OFFSET(VDSO_HPET_PAGE),
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hpet_address >> PAGE_SHIFT,
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PAGE_SIZE,
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pgprot_noncached(PAGE_READONLY));
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if (ret)
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goto up_fail;
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}
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#endif
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current_thread_info()->sysenter_return =
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VDSO32_SYMBOL(addr, SYSENTER_RETURN);
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@ -0,0 +1,9 @@
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#define BUILD_VDSO32
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#ifndef CONFIG_CC_OPTIMIZE_FOR_SIZE
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#undef CONFIG_OPTIMIZE_INLINING
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#endif
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#undef CONFIG_X86_PPRO_FENCE
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#include "../vclock_gettime.c"
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@ -8,6 +8,11 @@
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* values visible using the asm-x86/vdso.h macros from the kernel proper.
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*/
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#include <asm/page.h>
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#define BUILD_VDSO32
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#define VDSO_PRELINK 0
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#include "../vdso-layout.lds.S"
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/* The ELF entry point can be used to set the AT_SYSINFO value. */
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@ -23,6 +28,9 @@ VERSION
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__kernel_vsyscall;
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__kernel_sigreturn;
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__kernel_rt_sigreturn;
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__vdso_clock_gettime;
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__vdso_gettimeofday;
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__vdso_time;
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local: *;
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};
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}
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@ -33,3 +41,6 @@ VERSION
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VDSO32_vsyscall = __kernel_vsyscall;
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VDSO32_sigreturn = __kernel_sigreturn;
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VDSO32_rt_sigreturn = __kernel_rt_sigreturn;
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VDSO32_clock_gettime = clock_gettime;
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VDSO32_gettimeofday = gettimeofday;
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VDSO32_time = time;
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