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x86/vdso: Get pvclock data from the vvar VMA instead of the fixmap

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Signed-off-by: Andy Lutomirski <luto@kernel.org>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Cc: Andy Lutomirski <luto@amacapital.net>
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>
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/9d37826fdc7e2d2809efe31d5345f97186859284.1449702533.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Andy Lutomirski 2015-12-10 19:20:20 -08:00 committed by Ingo Molnar
parent 6b078f5de7
commit dac16fba6f
7 changed files with 41 additions and 13 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

20
arch/x86/entry/vdso/vclock_gettime.c
View File

@ -36,6 +36,11 @@ static notrace cycle_t vread_hpet(void)
}
#endif
#ifdef CONFIG_PARAVIRT_CLOCK
extern u8 pvclock_page
__attribute__((visibility("hidden")));
#endif
#ifndef BUILD_VDSO32
#include <linux/kernel.h>
@ -62,23 +67,14 @@ notrace static long vdso_fallback_gtod(struct timeval *tv, struct timezone *tz)
#ifdef CONFIG_PARAVIRT_CLOCK
static notrace const struct pvclock_vsyscall_time_info *get_pvti(int cpu)
static notrace const struct pvclock_vsyscall_time_info *get_pvti0(void)
{
const struct pvclock_vsyscall_time_info *pvti_base;
int idx = cpu / (PAGE_SIZE/PVTI_SIZE);
int offset = cpu % (PAGE_SIZE/PVTI_SIZE);
BUG_ON(PVCLOCK_FIXMAP_BEGIN + idx > PVCLOCK_FIXMAP_END);
pvti_base = (struct pvclock_vsyscall_time_info *)
__fix_to_virt(PVCLOCK_FIXMAP_BEGIN+idx);
return &pvti_base[offset];
return (const struct pvclock_vsyscall_time_info *)&pvclock_page;
}
static notrace cycle_t vread_pvclock(int *mode)
{
const struct pvclock_vcpu_time_info *pvti = &get_pvti(0)->pvti;
const struct pvclock_vcpu_time_info *pvti = &get_pvti0()->pvti;
cycle_t ret;
u64 tsc, pvti_tsc;
u64 last, delta, pvti_system_time;

3
arch/x86/entry/vdso/vdso-layout.lds.S
View File

@ -25,7 +25,7 @@ SECTIONS
* segment.
*/
vvar_start = . - 2 * PAGE_SIZE;
vvar_start = . - 3 * PAGE_SIZE;
vvar_page = vvar_start;
/* Place all vvars at the offsets in asm/vvar.h. */
@ -36,6 +36,7 @@ SECTIONS
#undef EMIT_VVAR
hpet_page = vvar_start + PAGE_SIZE;
pvclock_page = vvar_start + 2 * PAGE_SIZE;
. = SIZEOF_HEADERS;

3
arch/x86/entry/vdso/vdso2c.c
View File

@ -73,6 +73,7 @@ enum {
sym_vvar_start,
sym_vvar_page,
sym_hpet_page,
sym_pvclock_page,
sym_VDSO_FAKE_SECTION_TABLE_START,
sym_VDSO_FAKE_SECTION_TABLE_END,
};
@ -80,6 +81,7 @@ enum {
const int special_pages[] = {
sym_vvar_page,
sym_hpet_page,
sym_pvclock_page,
};
struct vdso_sym {
@ -91,6 +93,7 @@ struct vdso_sym required_syms[] = {
[sym_vvar_start] = {"vvar_start", true},
[sym_vvar_page] = {"vvar_page", true},
[sym_hpet_page] = {"hpet_page", true},
[sym_pvclock_page] = {"pvclock_page", true},
[sym_VDSO_FAKE_SECTION_TABLE_START] = {
"VDSO_FAKE_SECTION_TABLE_START", false
},

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

@ -100,6 +100,7 @@ static int map_vdso(const struct vdso_image *image, bool calculate_addr)
.name = "[vvar]",
.pages = no_pages,
};
struct pvclock_vsyscall_time_info *pvti;
if (calculate_addr) {
addr = vdso_addr(current->mm->start_stack,
@ -169,6 +170,18 @@ static int map_vdso(const struct vdso_image *image, bool calculate_addr)
}
#endif
pvti = pvclock_pvti_cpu0_va();
if (pvti && image->sym_pvclock_page) {
ret = remap_pfn_range(vma,
text_start + image->sym_pvclock_page,
__pa(pvti) >> PAGE_SHIFT,
PAGE_SIZE,
PAGE_READONLY);
if (ret)
goto up_fail;
}
up_fail:
if (ret)
current->mm->context.vdso = NULL;

9
arch/x86/include/asm/pvclock.h
View File

@ -4,6 +4,15 @@
#include <linux/clocksource.h>
#include <asm/pvclock-abi.h>
#ifdef CONFIG_PARAVIRT_CLOCK
extern struct pvclock_vsyscall_time_info *pvclock_pvti_cpu0_va(void);
#else
static inline struct pvclock_vsyscall_time_info *pvclock_pvti_cpu0_va(void)
{
return NULL;
}
#endif
/* some helper functions for xen and kvm pv clock sources */
cycle_t pvclock_clocksource_read(struct pvclock_vcpu_time_info *src);
u8 pvclock_read_flags(struct pvclock_vcpu_time_info *src);

1
arch/x86/include/asm/vdso.h
View File

@ -22,6 +22,7 @@ struct vdso_image {
long sym_vvar_page;
long sym_hpet_page;
long sym_pvclock_page;
long sym_VDSO32_NOTE_MASK;
long sym___kernel_sigreturn;
long sym___kernel_rt_sigreturn;

5
arch/x86/kernel/kvmclock.c
View File

@ -45,6 +45,11 @@ early_param("no-kvmclock", parse_no_kvmclock);
static struct pvclock_vsyscall_time_info *hv_clock;
static struct pvclock_wall_clock wall_clock;
struct pvclock_vsyscall_time_info *pvclock_pvti_cpu0_va(void)
{
return hv_clock;
}
/*
* The wallclock is the time of day when we booted. Since then, some time may
* have elapsed since the hypervisor wrote the data. So we try to account for