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authorVincenzo Frascino <vincenzo.frascino@arm.com>2019-06-21 10:52:49 +0100
committerThomas Gleixner <tglx@linutronix.de>2019-06-22 21:21:10 +0200
commit7ac8707479886c75f353bfb6a8273f423cfccb23 (patch)
treef4ec20e1087fa08a0df1ed49ecf109ba0b864a37 /arch/x86/entry/vdso
parentbfe801ebe84f42b4666d3f0adde90f504d56e35b (diff)
downloadlinux-7ac8707479886c75f353bfb6a8273f423cfccb23.tar.bz2
x86/vdso: Switch to generic vDSO implementation
The x86 vDSO library requires some adaptations to take advantage of the newly introduced generic vDSO library. Introduce the following changes: - Modification of vdso.c to be compliant with the common vdso datapage - Use of lib/vdso for gettimeofday [ tglx: Massaged changelog and cleaned up the function signature formatting ] Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: linux-arch@vger.kernel.org Cc: linux-arm-kernel@lists.infradead.org Cc: linux-mips@vger.kernel.org Cc: linux-kselftest@vger.kernel.org Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Russell King <linux@armlinux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Burton <paul.burton@mips.com> Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: Mark Salyzyn <salyzyn@android.com> Cc: Peter Collingbourne <pcc@google.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Dmitry Safonov <0x7f454c46@gmail.com> Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk> Cc: Huw Davies <huw@codeweavers.com> Cc: Shijith Thotton <sthotton@marvell.com> Cc: Andre Przywara <andre.przywara@arm.com> Link: https://lkml.kernel.org/r/20190621095252.32307-23-vincenzo.frascino@arm.com
Diffstat (limited to 'arch/x86/entry/vdso')
-rw-r--r--arch/x86/entry/vdso/Makefile9
-rw-r--r--arch/x86/entry/vdso/vclock_gettime.c245
-rw-r--r--arch/x86/entry/vdso/vdsox32.lds.S1
3 files changed, 37 insertions, 218 deletions
diff --git a/arch/x86/entry/vdso/Makefile b/arch/x86/entry/vdso/Makefile
index 42fe42e82baf..39106111be86 100644
--- a/arch/x86/entry/vdso/Makefile
+++ b/arch/x86/entry/vdso/Makefile
@@ -3,6 +3,12 @@
# Building vDSO images for x86.
#
+# Absolute relocation type $(ARCH_REL_TYPE_ABS) needs to be defined before
+# the inclusion of generic Makefile.
+ARCH_REL_TYPE_ABS := R_X86_64_JUMP_SLOT|R_X86_64_GLOB_DAT|R_X86_64_RELATIVE|
+ARCH_REL_TYPE_ABS += R_386_GLOB_DAT|R_386_JMP_SLOT|R_386_RELATIVE
+include $(srctree)/lib/vdso/Makefile
+
KBUILD_CFLAGS += $(DISABLE_LTO)
KASAN_SANITIZE := n
UBSAN_SANITIZE := n
@@ -51,6 +57,7 @@ VDSO_LDFLAGS_vdso.lds = -m elf_x86_64 -soname linux-vdso.so.1 --no-undefined \
$(obj)/vdso64.so.dbg: $(obj)/vdso.lds $(vobjs) FORCE
$(call if_changed,vdso)
+ $(call if_changed,vdso_check)
HOST_EXTRACFLAGS += -I$(srctree)/tools/include -I$(srctree)/include/uapi -I$(srctree)/arch/$(SUBARCH)/include/uapi
hostprogs-y += vdso2c
@@ -121,6 +128,7 @@ $(obj)/%.so: $(obj)/%.so.dbg FORCE
$(obj)/vdsox32.so.dbg: $(obj)/vdsox32.lds $(vobjx32s) FORCE
$(call if_changed,vdso)
+ $(call if_changed,vdso_check)
CPPFLAGS_vdso32.lds = $(CPPFLAGS_vdso.lds)
VDSO_LDFLAGS_vdso32.lds = -m elf_i386 -soname linux-gate.so.1
@@ -160,6 +168,7 @@ $(obj)/vdso32.so.dbg: FORCE \
$(obj)/vdso32/system_call.o \
$(obj)/vdso32/sigreturn.o
$(call if_changed,vdso)
+ $(call if_changed,vdso_check)
#
# The DSO images are built using a special linker script.
diff --git a/arch/x86/entry/vdso/vclock_gettime.c b/arch/x86/entry/vdso/vclock_gettime.c
index 4aed41f638bb..f01a3f0787ca 100644
--- a/arch/x86/entry/vdso/vclock_gettime.c
+++ b/arch/x86/entry/vdso/vclock_gettime.c
@@ -1,251 +1,60 @@
// SPDX-License-Identifier: GPL-2.0-only
/*
- * Copyright 2006 Andi Kleen, SUSE Labs.
- *
* Fast user context implementation of clock_gettime, gettimeofday, and time.
*
+ * Copyright 2006 Andi Kleen, SUSE Labs.
+ * Copyright 2019 ARM Limited
+ *
* 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.
*/
-
-#include <uapi/linux/time.h>
-#include <asm/vgtod.h>
-#include <asm/vvar.h>
-#include <asm/unistd.h>
-#include <asm/msr.h>
-#include <asm/pvclock.h>
-#include <asm/mshyperv.h>
-#include <linux/math64.h>
#include <linux/time.h>
#include <linux/kernel.h>
+#include <linux/types.h>
-#define gtod (&VVAR(vsyscall_gtod_data))
+#include "../../../../lib/vdso/gettimeofday.c"
-extern int __vdso_clock_gettime(clockid_t clock, struct timespec *ts);
-extern int __vdso_gettimeofday(struct timeval *tv, struct timezone *tz);
+extern int __vdso_gettimeofday(struct __kernel_old_timeval *tv, struct timezone *tz);
extern time_t __vdso_time(time_t *t);
-#ifdef CONFIG_PARAVIRT_CLOCK
-extern u8 pvclock_page[PAGE_SIZE]
- __attribute__((visibility("hidden")));
-#endif
-
-#ifdef CONFIG_HYPERV_TSCPAGE
-extern u8 hvclock_page[PAGE_SIZE]
- __attribute__((visibility("hidden")));
-#endif
-
-#ifndef BUILD_VDSO32
-
-notrace static long vdso_fallback_gettime(long clock, struct timespec *ts)
-{
- long ret;
- asm ("syscall" : "=a" (ret), "=m" (*ts) :
- "0" (__NR_clock_gettime), "D" (clock), "S" (ts) :
- "rcx", "r11");
- return ret;
-}
-
-#else
-
-notrace static long vdso_fallback_gettime(long clock, struct timespec *ts)
+int __vdso_gettimeofday(struct __kernel_old_timeval *tv, struct timezone *tz)
{
- long ret;
-
- asm (
- "mov %%ebx, %%edx \n"
- "mov %[clock], %%ebx \n"
- "call __kernel_vsyscall \n"
- "mov %%edx, %%ebx \n"
- : "=a" (ret), "=m" (*ts)
- : "0" (__NR_clock_gettime), [clock] "g" (clock), "c" (ts)
- : "edx");
- return ret;
+ return __cvdso_gettimeofday(tv, tz);
}
-#endif
-
-#ifdef CONFIG_PARAVIRT_CLOCK
-static notrace const struct pvclock_vsyscall_time_info *get_pvti0(void)
-{
- return (const struct pvclock_vsyscall_time_info *)&pvclock_page;
-}
+int gettimeofday(struct __kernel_old_timeval *, struct timezone *)
+ __attribute__((weak, alias("__vdso_gettimeofday")));
-static notrace u64 vread_pvclock(void)
+time_t __vdso_time(time_t *t)
{
- const struct pvclock_vcpu_time_info *pvti = &get_pvti0()->pvti;
- u32 version;
- u64 ret;
-
- /*
- * Note: The kernel and hypervisor must guarantee that cpu ID
- * number maps 1:1 to per-CPU pvclock time info.
- *
- * Because the hypervisor is entirely unaware of guest userspace
- * preemption, it cannot guarantee that per-CPU pvclock time
- * info is updated if the underlying CPU changes or that that
- * version is increased whenever underlying CPU changes.
- *
- * On KVM, we are guaranteed that pvti updates for any vCPU are
- * atomic as seen by *all* vCPUs. This is an even stronger
- * guarantee than we get with a normal seqlock.
- *
- * On Xen, we don't appear to have that guarantee, but Xen still
- * supplies a valid seqlock using the version field.
- *
- * We only do pvclock vdso timing at all if
- * PVCLOCK_TSC_STABLE_BIT is set, and we interpret that bit to
- * mean that all vCPUs have matching pvti and that the TSC is
- * synced, so we can just look at vCPU 0's pvti.
- */
-
- do {
- version = pvclock_read_begin(pvti);
-
- if (unlikely(!(pvti->flags & PVCLOCK_TSC_STABLE_BIT)))
- return U64_MAX;
-
- ret = __pvclock_read_cycles(pvti, rdtsc_ordered());
- } while (pvclock_read_retry(pvti, version));
-
- return ret;
+ return __cvdso_time(t);
}
-#endif
-#ifdef CONFIG_HYPERV_TSCPAGE
-static notrace u64 vread_hvclock(void)
-{
- const struct ms_hyperv_tsc_page *tsc_pg =
- (const struct ms_hyperv_tsc_page *)&hvclock_page;
- return hv_read_tsc_page(tsc_pg);
-}
-#endif
+time_t time(time_t *t) __attribute__((weak, alias("__vdso_time")));
-notrace static inline u64 vgetcyc(int mode)
-{
- if (mode == VCLOCK_TSC)
- return (u64)rdtsc_ordered();
- /*
- * For any memory-mapped vclock type, we need to make sure that gcc
- * doesn't cleverly hoist a load before the mode check. Otherwise we
- * might end up touching the memory-mapped page even if the vclock in
- * question isn't enabled, which will segfault. Hence the barriers.
- */
-#ifdef CONFIG_PARAVIRT_CLOCK
- if (mode == VCLOCK_PVCLOCK) {
- barrier();
- return vread_pvclock();
- }
-#endif
-#ifdef CONFIG_HYPERV_TSCPAGE
- if (mode == VCLOCK_HVCLOCK) {
- barrier();
- return vread_hvclock();
- }
-#endif
- return U64_MAX;
-}
+#if defined(CONFIG_X86_64) && !defined(BUILD_VDSO32_64)
+/* both 64-bit and x32 use these */
+extern int __vdso_clock_gettime(clockid_t clock, struct __kernel_timespec *ts);
-notrace static int do_hres(clockid_t clk, struct timespec *ts)
+int __vdso_clock_gettime(clockid_t clock, struct __kernel_timespec *ts)
{
- struct vgtod_ts *base = &gtod->basetime[clk];
- u64 cycles, last, sec, ns;
- unsigned int seq;
-
- do {
- seq = gtod_read_begin(gtod);
- cycles = vgetcyc(gtod->vclock_mode);
- ns = base->nsec;
- last = gtod->cycle_last;
- if (unlikely((s64)cycles < 0))
- return vdso_fallback_gettime(clk, ts);
- if (cycles > last)
- ns += (cycles - last) * gtod->mult;
- ns >>= gtod->shift;
- sec = base->sec;
- } while (unlikely(gtod_read_retry(gtod, seq)));
-
- /*
- * Do this outside the loop: a race inside the loop could result
- * in __iter_div_u64_rem() being extremely slow.
- */
- ts->tv_sec = sec + __iter_div_u64_rem(ns, NSEC_PER_SEC, &ns);
- ts->tv_nsec = ns;
-
- return 0;
+ return __cvdso_clock_gettime(clock, ts);
}
-notrace static void do_coarse(clockid_t clk, struct timespec *ts)
-{
- struct vgtod_ts *base = &gtod->basetime[clk];
- unsigned int seq;
+int clock_gettime(clockid_t, struct __kernel_timespec *)
+ __attribute__((weak, alias("__vdso_clock_gettime")));
- do {
- seq = gtod_read_begin(gtod);
- ts->tv_sec = base->sec;
- ts->tv_nsec = base->nsec;
- } while (unlikely(gtod_read_retry(gtod, seq)));
-}
+#else
+/* i386 only */
+extern int __vdso_clock_gettime(clockid_t clock, struct old_timespec32 *ts);
-notrace int __vdso_clock_gettime(clockid_t clock, struct timespec *ts)
+int __vdso_clock_gettime(clockid_t clock, struct old_timespec32 *ts)
{
- unsigned int msk;
-
- /* Sort out negative (CPU/FD) and invalid clocks */
- if (unlikely((unsigned int) clock >= MAX_CLOCKS))
- return vdso_fallback_gettime(clock, ts);
-
- /*
- * Convert the clockid to a bitmask and use it to check which
- * clocks are handled in the VDSO directly.
- */
- msk = 1U << clock;
- if (likely(msk & VGTOD_HRES)) {
- return do_hres(clock, ts);
- } else if (msk & VGTOD_COARSE) {
- do_coarse(clock, ts);
- return 0;
- }
- return vdso_fallback_gettime(clock, ts);
+ return __cvdso_clock_gettime32(clock, ts);
}
-int clock_gettime(clockid_t, struct timespec *)
+int clock_gettime(clockid_t, struct old_timespec32 *)
__attribute__((weak, alias("__vdso_clock_gettime")));
-notrace int __vdso_gettimeofday(struct timeval *tv, struct timezone *tz)
-{
- if (likely(tv != NULL)) {
- struct timespec *ts = (struct timespec *) tv;
-
- do_hres(CLOCK_REALTIME, ts);
- tv->tv_usec /= 1000;
- }
- if (unlikely(tz != NULL)) {
- tz->tz_minuteswest = gtod->tz_minuteswest;
- tz->tz_dsttime = gtod->tz_dsttime;
- }
-
- return 0;
-}
-int gettimeofday(struct timeval *, struct timezone *)
- __attribute__((weak, alias("__vdso_gettimeofday")));
-
-/*
- * This will break when the xtime seconds get inaccurate, but that is
- * unlikely
- */
-notrace time_t __vdso_time(time_t *t)
-{
- /* This is atomic on x86 so we don't need any locks. */
- time_t result = READ_ONCE(gtod->basetime[CLOCK_REALTIME].sec);
-
- if (t)
- *t = result;
- return result;
-}
-time_t time(time_t *t)
- __attribute__((weak, alias("__vdso_time")));
+#endif
diff --git a/arch/x86/entry/vdso/vdsox32.lds.S b/arch/x86/entry/vdso/vdsox32.lds.S
index 05cd1c5c4a15..16a8050a4fb6 100644
--- a/arch/x86/entry/vdso/vdsox32.lds.S
+++ b/arch/x86/entry/vdso/vdsox32.lds.S
@@ -21,6 +21,7 @@ VERSION {
__vdso_gettimeofday;
__vdso_getcpu;
__vdso_time;
+ __vdso_clock_getres;
local: *;
};
}