Re: [PATCH v7 04/25] arm64: Substitute gettimeofday with C implementation

Hi Marek,

On 6/28/19 2:09 PM, Marek Szyprowski wrote:

Dear All,

On 2019-06-21 11:52, Vincenzo Frascino wrote:

...

To take advantage of the commonly defined vdso interface for gettimeofday the architectural code requires an adaptation.

Re-implement the gettimeofday vdso in C in order to use lib/vdso.

With the new implementation arm64 gains support for CLOCK_BOOTTIME and CLOCK_TAI.

Cc: Catalin Marinas catalin.marinas@arm.com Cc: Will Deacon will.deacon@arm.com Signed-off-by: Vincenzo Frascino vincenzo.frascino@arm.com Tested-by: Shijith Thotton sthotton@marvell.com Tested-by: Andre Przywara andre.przywara@arm.com Signed-off-by: Catalin Marinas catalin.marinas@arm.com

This patch causes serious regression on Samsung Exynos5433 SoC based TM2(e) boards. The time in userspace is always set to begin of the epoch:

# date 062813152019 Fri Jun 28 13:15:00 UTC 2019 # date Thu Jan  1 00:00:00 UTC 1970 # date Thu Jan  1 00:00:00 UTC 1970

I've noticed that since the patch landed in Linux next-20190625 and bisect indeed pointed to this patch.

Thank you for reporting this, seems that the next that you posted is missing some fixes for arm64.

Could you please try the tree below?

git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git timers/vdso

Let us know if the functionality is restored. Otherwise the issue will require further investigation.

...

---

arch/arm64/Kconfig | 2 + arch/arm64/include/asm/vdso/gettimeofday.h | 86 ++++++ arch/arm64/include/asm/vdso/vsyscall.h | 53 ++++ arch/arm64/include/asm/vdso_datapage.h | 48 --- arch/arm64/kernel/asm-offsets.c | 33 +- arch/arm64/kernel/vdso.c | 51 +--- arch/arm64/kernel/vdso/Makefile | 34 ++- arch/arm64/kernel/vdso/gettimeofday.S | 334 --------------------- arch/arm64/kernel/vdso/vgettimeofday.c | 28 ++ 9 files changed, 223 insertions(+), 446 deletions(-) create mode 100644 arch/arm64/include/asm/vdso/gettimeofday.h create mode 100644 arch/arm64/include/asm/vdso/vsyscall.h delete mode 100644 arch/arm64/include/asm/vdso_datapage.h delete mode 100644 arch/arm64/kernel/vdso/gettimeofday.S create mode 100644 arch/arm64/kernel/vdso/vgettimeofday.c

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 697ea0510729..952c9f8cf3b8 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -107,6 +107,7 @@ config ARM64 select GENERIC_STRNCPY_FROM_USER select GENERIC_STRNLEN_USER select GENERIC_TIME_VSYSCALL

• select GENERIC_GETTIMEOFDAY select HANDLE_DOMAIN_IRQ select HARDIRQS_SW_RESEND select HAVE_PCI

@@ -160,6 +161,7 @@ config ARM64 select HAVE_SYSCALL_TRACEPOINTS select HAVE_KPROBES select HAVE_KRETPROBES

• select HAVE_GENERIC_VDSO select IOMMU_DMA if IOMMU_SUPPORT select IRQ_DOMAIN select IRQ_FORCED_THREADING

diff --git a/arch/arm64/include/asm/vdso/gettimeofday.h b/arch/arm64/include/asm/vdso/gettimeofday.h new file mode 100644 index 000000000000..bc3cb6738051 --- /dev/null +++ b/arch/arm64/include/asm/vdso/gettimeofday.h @@ -0,0 +1,86 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/*

• • Copyright (C) 2018 ARM Limited
• */

+#ifndef __ASM_VDSO_GETTIMEOFDAY_H +#define __ASM_VDSO_GETTIMEOFDAY_H

+#ifndef __ASSEMBLY__

+#include <asm/unistd.h> +#include <uapi/linux/time.h>

+#define VDSO_HAS_CLOCK_GETRES 1

+static __always_inline int gettimeofday_fallback(

• 			struct __kernel_old_timeval *_tv,
  

• 			struct timezone *_tz)
  

+{

• register struct timezone *tz asm("x1") = _tz;
• register struct __kernel_old_timeval *tv asm("x0") = _tv;
• register long ret asm ("x0");
• register long nr asm("x8") = __NR_gettimeofday;
• asm volatile(
• " svc #0\n"
• : "=r" (ret)
• : "r" (tv), "r" (tz), "r" (nr)
• : "memory");
• return ret;

+}

+static __always_inline long clock_gettime_fallback(

• 			clockid_t _clkid,
  

• 			struct __kernel_timespec *_ts)
  

+{

• register struct __kernel_timespec *ts asm("x1") = _ts;
• register clockid_t clkid asm("x0") = _clkid;
• register long ret asm ("x0");
• register long nr asm("x8") = __NR_clock_gettime;
• asm volatile(
• " svc #0\n"
• : "=r" (ret)
• : "r" (clkid), "r" (ts), "r" (nr)
• : "memory");
• return ret;

+}

+static __always_inline int clock_getres_fallback(

• 			clockid_t _clkid,
  

• 			struct __kernel_timespec *_ts)
  

+{

• register struct __kernel_timespec *ts asm("x1") = _ts;
• register clockid_t clkid asm("x0") = _clkid;
• register long ret asm ("x0");
• register long nr asm("x8") = __NR_clock_getres;
• asm volatile(
• " svc #0\n"
• : "=r" (ret)
• : "r" (clkid), "r" (ts), "r" (nr)
• : "memory");
• return ret;

+}

+static __always_inline u64 __arch_get_hw_counter(s32 clock_mode) +{

• u64 res;
• asm volatile("mrs %0, cntvct_el0" : "=r" (res) :: "memory");
• return res;

+}

+static __always_inline +const struct vdso_data *__arch_get_vdso_data(void) +{

• return _vdso_data;

+}

+#endif /* !__ASSEMBLY__ */

+#endif /* __ASM_VDSO_GETTIMEOFDAY_H */ diff --git a/arch/arm64/include/asm/vdso/vsyscall.h b/arch/arm64/include/asm/vdso/vsyscall.h new file mode 100644 index 000000000000..0c731bfc7c8c --- /dev/null +++ b/arch/arm64/include/asm/vdso/vsyscall.h @@ -0,0 +1,53 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __ASM_VDSO_VSYSCALL_H +#define __ASM_VDSO_VSYSCALL_H

+#ifndef __ASSEMBLY__

+#include <linux/timekeeper_internal.h> +#include <vdso/datapage.h>

+#define VDSO_PRECISION_MASK ~(0xFF00ULL<<48)

+extern struct vdso_data *vdso_data;

+/*

• • Update the vDSO data page to keep in sync with kernel timekeeping.
• */

+static __always_inline +struct vdso_data *__arm64_get_k_vdso_data(void) +{

• return vdso_data;

+} +#define __arch_get_k_vdso_data __arm64_get_k_vdso_data

+static __always_inline +int __arm64_get_clock_mode(struct timekeeper *tk) +{

• u32 use_syscall = !tk->tkr_mono.clock->archdata.vdso_direct;
• return use_syscall;

+} +#define __arch_get_clock_mode __arm64_get_clock_mode

+static __always_inline +int __arm64_use_vsyscall(struct vdso_data *vdata) +{

• return !vdata[CS_HRES_COARSE].clock_mode;

+} +#define __arch_use_vsyscall __arm64_use_vsyscall

+static __always_inline +void __arm64_update_vsyscall(struct vdso_data *vdata, struct timekeeper *tk) +{

• vdata[CS_HRES_COARSE].mask = VDSO_PRECISION_MASK;
• vdata[CS_RAW].mask = VDSO_PRECISION_MASK;

+} +#define __arch_update_vsyscall __arm64_update_vsyscall

+/* The asm-generic header needs to be included after the definitions above */ +#include <asm-generic/vdso/vsyscall.h>

+#endif /* !__ASSEMBLY__ */

+#endif /* __ASM_VDSO_VSYSCALL_H */ diff --git a/arch/arm64/include/asm/vdso_datapage.h b/arch/arm64/include/asm/vdso_datapage.h deleted file mode 100644 index f89263c8e11a..000000000000 --- a/arch/arm64/include/asm/vdso_datapage.h +++ /dev/null @@ -1,48 +0,0 @@ -/*

• • Copyright (C) 2012 ARM Limited
• • This program is free software; you can redistribute it and/or modify
• • it under the terms of the GNU General Public License version 2 as
• • published by the Free Software Foundation.
• • This program is distributed in the hope that it will be useful,
• • but WITHOUT ANY WARRANTY; without even the implied warranty of
• • MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
• • GNU General Public License for more details.
• • You should have received a copy of the GNU General Public License
• • along with this program. If not, see http://www.gnu.org/licenses/.
• */

-#ifndef __ASM_VDSO_DATAPAGE_H -#define __ASM_VDSO_DATAPAGE_H

-#ifdef __KERNEL__

-#ifndef __ASSEMBLY__

-struct vdso_data {

• __u64 cs_cycle_last; /* Timebase at clocksource init */
• __u64 raw_time_sec; /* Raw time */
• __u64 raw_time_nsec;
• __u64 xtime_clock_sec; /* Kernel time */
• __u64 xtime_clock_nsec;
• __u64 xtime_coarse_sec; /* Coarse time */
• __u64 xtime_coarse_nsec;
• __u64 wtm_clock_sec; /* Wall to monotonic time */
• __u64 wtm_clock_nsec;
• __u32 tb_seq_count; /* Timebase sequence counter */
• /* cs_* members must be adjacent and in this order (ldp accesses) */
• __u32 cs_mono_mult; /* NTP-adjusted clocksource multiplier */
• __u32 cs_shift; /* Clocksource shift (mono = raw) */
• __u32 cs_raw_mult; /* Raw clocksource multiplier */
• __u32 tz_minuteswest; /* Whacky timezone stuff */
• __u32 tz_dsttime;
• __u32 use_syscall;
• __u32 hrtimer_res;

-};

-#endif /* !__ASSEMBLY__ */

-#endif /* __KERNEL__ */

-#endif /* __ASM_VDSO_DATAPAGE_H */ diff --git a/arch/arm64/kernel/asm-offsets.c b/arch/arm64/kernel/asm-offsets.c index 947e39896e28..9e4b7ccbab2f 100644 --- a/arch/arm64/kernel/asm-offsets.c +++ b/arch/arm64/kernel/asm-offsets.c @@ -25,13 +25,13 @@ #include <linux/kvm_host.h> #include <linux/preempt.h> #include <linux/suspend.h> +#include <vdso/datapage.h> #include <asm/cpufeature.h> #include <asm/fixmap.h> #include <asm/thread_info.h> #include <asm/memory.h> #include <asm/smp_plat.h> #include <asm/suspend.h> -#include <asm/vdso_datapage.h> #include <linux/kbuild.h> #include <linux/arm-smccc.h> @@ -100,17 +100,28 @@ int main(void) DEFINE(CLOCK_COARSE_RES, LOW_RES_NSEC); DEFINE(NSEC_PER_SEC, NSEC_PER_SEC); BLANK();

• DEFINE(VDSO_CS_CYCLE_LAST, offsetof(struct vdso_data, cs_cycle_last));
• DEFINE(VDSO_RAW_TIME_SEC, offsetof(struct vdso_data, raw_time_sec));
• DEFINE(VDSO_XTIME_CLK_SEC, offsetof(struct vdso_data, xtime_clock_sec));
• DEFINE(VDSO_XTIME_CRS_SEC, offsetof(struct vdso_data, xtime_coarse_sec));
• DEFINE(VDSO_XTIME_CRS_NSEC, offsetof(struct vdso_data, xtime_coarse_nsec));
• DEFINE(VDSO_WTM_CLK_SEC, offsetof(struct vdso_data, wtm_clock_sec));
• DEFINE(VDSO_TB_SEQ_COUNT, offsetof(struct vdso_data, tb_seq_count));
• DEFINE(VDSO_CS_MONO_MULT, offsetof(struct vdso_data, cs_mono_mult));
• DEFINE(VDSO_CS_SHIFT, offsetof(struct vdso_data, cs_shift));

• DEFINE(VDSO_SEQ, offsetof(struct vdso_data, seq));
• DEFINE(VDSO_CLK_MODE, offsetof(struct vdso_data, clock_mode));
• DEFINE(VDSO_CYCLE_LAST, offsetof(struct vdso_data, cycle_last));
• DEFINE(VDSO_MASK, offsetof(struct vdso_data, mask));
• DEFINE(VDSO_MULT, offsetof(struct vdso_data, mult));
• DEFINE(VDSO_SHIFT, offsetof(struct vdso_data, shift));
• DEFINE(VDSO_REALTIME_SEC, offsetof(struct vdso_data, basetime[CLOCK_REALTIME].sec));
• DEFINE(VDSO_REALTIME_NSEC, offsetof(struct vdso_data, basetime[CLOCK_REALTIME].nsec));
• DEFINE(VDSO_MONO_SEC, offsetof(struct vdso_data, basetime[CLOCK_MONOTONIC].sec));
• DEFINE(VDSO_MONO_NSEC, offsetof(struct vdso_data, basetime[CLOCK_MONOTONIC].nsec));
• DEFINE(VDSO_MONO_RAW_SEC, offsetof(struct vdso_data, basetime[CLOCK_MONOTONIC_RAW].sec));
• DEFINE(VDSO_MONO_RAW_NSEC, offsetof(struct vdso_data, basetime[CLOCK_MONOTONIC_RAW].nsec));
• DEFINE(VDSO_BOOTTIME_SEC, offsetof(struct vdso_data, basetime[CLOCK_BOOTTIME].sec));
• DEFINE(VDSO_BOOTTIME_NSEC, offsetof(struct vdso_data, basetime[CLOCK_BOOTTIME].nsec));
• DEFINE(VDSO_TAI_SEC, offsetof(struct vdso_data, basetime[CLOCK_TAI].sec));
• DEFINE(VDSO_TAI_NSEC, offsetof(struct vdso_data, basetime[CLOCK_TAI].nsec));
• DEFINE(VDSO_RT_COARSE_SEC, offsetof(struct vdso_data, basetime[CLOCK_REALTIME_COARSE].sec));
• DEFINE(VDSO_RT_COARSE_NSEC, offsetof(struct vdso_data, basetime[CLOCK_REALTIME_COARSE].nsec));
• DEFINE(VDSO_MONO_COARSE_SEC, offsetof(struct vdso_data, basetime[CLOCK_MONOTONIC_COARSE].sec));
• DEFINE(VDSO_MONO_COARSE_NSEC, offsetof(struct vdso_data, basetime[CLOCK_MONOTONIC_COARSE].nsec)); DEFINE(VDSO_TZ_MINWEST, offsetof(struct vdso_data, tz_minuteswest));

• DEFINE(VDSO_USE_SYSCALL, offsetof(struct vdso_data, use_syscall));

• DEFINE(VDSO_TZ_DSTTIME, offsetof(struct vdso_data, tz_dsttime)); BLANK(); DEFINE(TVAL_TV_SEC, offsetof(struct timeval, tv_sec)); DEFINE(TSPEC_TV_SEC, offsetof(struct timespec, tv_sec));

diff --git a/arch/arm64/kernel/vdso.c b/arch/arm64/kernel/vdso.c index 8074cbd3a3a8..23c38303a52a 100644 --- a/arch/arm64/kernel/vdso.c +++ b/arch/arm64/kernel/vdso.c @@ -31,11 +31,13 @@ #include <linux/slab.h> #include <linux/timekeeper_internal.h> #include <linux/vmalloc.h> +#include <vdso/datapage.h> +#include <vdso/helpers.h> +#include <vdso/vsyscall.h> #include <asm/cacheflush.h> #include <asm/signal32.h> #include <asm/vdso.h> -#include <asm/vdso_datapage.h> extern char vdso_start[], vdso_end[]; static unsigned long vdso_pages __ro_after_init; @@ -44,10 +46,10 @@ static unsigned long vdso_pages __ro_after_init;

• The vDSO data page.

*/ static union {

• struct vdso_data data;

• struct vdso_data data[CS_BASES]; u8 page[PAGE_SIZE]; } vdso_data_store __page_aligned_data;

-struct vdso_data *vdso_data = &vdso_data_store.data; +struct vdso_data *vdso_data = vdso_data_store.data; #ifdef CONFIG_COMPAT /* @@ -280,46 +282,3 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, up_write(&mm->mmap_sem); return PTR_ERR(ret); }

-/*

• • Update the vDSO data page to keep in sync with kernel timekeeping.
• */

-void update_vsyscall(struct timekeeper *tk) -{

• u32 use_syscall = !tk->tkr_mono.clock->archdata.vdso_direct;
• ++vdso_data->tb_seq_count;
• smp_wmb();
• vdso_data->use_syscall = use_syscall;
• vdso_data->xtime_coarse_sec = tk->xtime_sec;
• vdso_data->xtime_coarse_nsec = tk->tkr_mono.xtime_nsec >>

• 					tk->tkr_mono.shift;
  

• vdso_data->wtm_clock_sec = tk->wall_to_monotonic.tv_sec;
• vdso_data->wtm_clock_nsec = tk->wall_to_monotonic.tv_nsec;
• /* Read without the seqlock held by clock_getres() */
• WRITE_ONCE(vdso_data->hrtimer_res, hrtimer_resolution);
• if (!use_syscall) {

• /* tkr_mono.cycle_last == tkr_raw.cycle_last */
  

• vdso_data->cs_cycle_last	= tk->tkr_mono.cycle_last;
  

• vdso_data->raw_time_sec         = tk->raw_sec;
  

• vdso_data->raw_time_nsec        = tk->tkr_raw.xtime_nsec;
  

• vdso_data->xtime_clock_sec	= tk->xtime_sec;
  

• vdso_data->xtime_clock_nsec	= tk->tkr_mono.xtime_nsec;
  

• vdso_data->cs_mono_mult		= tk->tkr_mono.mult;
  

• vdso_data->cs_raw_mult		= tk->tkr_raw.mult;
  

• /* tkr_mono.shift == tkr_raw.shift */
  

• vdso_data->cs_shift		= tk->tkr_mono.shift;
  

• }
• smp_wmb();
• ++vdso_data->tb_seq_count;

-}

-void update_vsyscall_tz(void) -{

• vdso_data->tz_minuteswest = sys_tz.tz_minuteswest;
• vdso_data->tz_dsttime = sys_tz.tz_dsttime;

-} diff --git a/arch/arm64/kernel/vdso/Makefile b/arch/arm64/kernel/vdso/Makefile index fa230ff09aa1..3acfc813e966 100644 --- a/arch/arm64/kernel/vdso/Makefile +++ b/arch/arm64/kernel/vdso/Makefile @@ -6,7 +6,12 @@ # Heavily based on the vDSO Makefiles for other archs. # -obj-vdso := gettimeofday.o note.o sigreturn.o +# Absolute relocation type $(ARCH_REL_TYPE_ABS) needs to be defined before +# the inclusion of generic Makefile. +ARCH_REL_TYPE_ABS := R_AARCH64_JUMP_SLOT|R_AARCH64_GLOB_DAT|R_AARCH64_ABS64 +include $(srctree)/lib/vdso/Makefile

+obj-vdso := vgettimeofday.o note.o sigreturn.o # Build rules targets := $(obj-vdso) vdso.so vdso.so.dbg @@ -15,6 +20,24 @@ obj-vdso := $(addprefix $(obj)/, $(obj-vdso)) ldflags-y := -shared -nostdlib -soname=linux-vdso.so.1 --hash-style=sysv \ --build-id -n -T +ccflags-y := -fno-common -fno-builtin -fno-stack-protector +ccflags-y += -DDISABLE_BRANCH_PROFILING

+VDSO_LDFLAGS := -Bsymbolic

+CFLAGS_REMOVE_vgettimeofday.o = $(CC_FLAGS_FTRACE) -Os +KBUILD_CFLAGS += $(DISABLE_LTO) +KASAN_SANITIZE := n +UBSAN_SANITIZE := n +OBJECT_FILES_NON_STANDARD := y +KCOV_INSTRUMENT := n

+ifeq ($(c-gettimeofday-y),) +CFLAGS_vgettimeofday.o = -O2 -mcmodel=tiny +else +CFLAGS_vgettimeofday.o = -O2 -mcmodel=tiny -include $(c-gettimeofday-y) +endif

• # Disable gcov profiling for VDSO code GCOV_PROFILE := n

@@ -28,6 +51,7 @@ $(obj)/vdso.o : $(obj)/vdso.so # Link rule for the .so file, .lds has to be first $(obj)/vdso.so.dbg: $(obj)/vdso.lds $(obj-vdso) FORCE $(call if_changed,ld)

• $(call if_changed,vdso_check)

# Strip rule for the .so file $(obj)/%.so: OBJCOPYFLAGS := -S @@ -42,13 +66,9 @@ quiet_cmd_vdsosym = VDSOSYM $@ include/generated/vdso-offsets.h: $(obj)/vdso.so.dbg FORCE $(call if_changed,vdsosym) -# Assembly rules for the .S files -$(obj-vdso): %.o: %.S FORCE

• $(call if_changed_dep,vdsoas)
• # Actual build commands

-quiet_cmd_vdsoas = VDSOA $@

•  cmd_vdsoas = $(CC) $(a_flags) -c -o $@ $<
  

+quiet_cmd_vdsocc = VDSOCC $@

•  cmd_vdsocc = $(CC) $(a_flags) $(c_flags) -c -o $@ $<
  

# Install commands for the unstripped file quiet_cmd_vdso_install = INSTALL $@ diff --git a/arch/arm64/kernel/vdso/gettimeofday.S b/arch/arm64/kernel/vdso/gettimeofday.S deleted file mode 100644 index 856fee6d3512..000000000000 --- a/arch/arm64/kernel/vdso/gettimeofday.S +++ /dev/null @@ -1,334 +0,0 @@ -/*

• • Userspace implementations of gettimeofday() and friends.
• • Copyright (C) 2012 ARM Limited
• • This program is free software; you can redistribute it and/or modify
• • it under the terms of the GNU General Public License version 2 as
• • published by the Free Software Foundation.
• • This program is distributed in the hope that it will be useful,
• • but WITHOUT ANY WARRANTY; without even the implied warranty of
• • MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
• • GNU General Public License for more details.
• • You should have received a copy of the GNU General Public License
• • along with this program. If not, see http://www.gnu.org/licenses/.
• • Author: Will Deacon will.deacon@arm.com
• */

-#include <linux/linkage.h> -#include <asm/asm-offsets.h> -#include <asm/unistd.h>

-#define NSEC_PER_SEC_LO16 0xca00 -#define NSEC_PER_SEC_HI16 0x3b9a

-vdso_data .req x6 -seqcnt .req w7 -w_tmp .req w8 -x_tmp .req x8

-/*

• • Conventions for macro arguments:
• • • An argument is write-only if its name starts with "res".
• • • All other arguments are read-only, unless otherwise specified.
• */
• .macro seqcnt_acquire

-9999: ldr seqcnt, [vdso_data, #VDSO_TB_SEQ_COUNT]

• tbnz seqcnt, #0, 9999b
• dmb ishld
• .endm
• .macro seqcnt_check fail
• dmb ishld
• ldr w_tmp, [vdso_data, #VDSO_TB_SEQ_COUNT]
• cmp w_tmp, seqcnt
• b.ne \fail
• .endm
• .macro syscall_check fail
• ldr w_tmp, [vdso_data, #VDSO_USE_SYSCALL]
• cbnz w_tmp, \fail
• .endm
• .macro get_nsec_per_sec res
• mov \res, #NSEC_PER_SEC_LO16
• movk \res, #NSEC_PER_SEC_HI16, lsl #16
• .endm
• /*

• * Returns the clock delta, in nanoseconds left-shifted by the clock
  

• * shift.
  

• */
  

• .macro get_clock_shifted_nsec res, cycle_last, mult
• /* Read the virtual counter. */
• isb
• mrs x_tmp, cntvct_el0
• /* Calculate cycle delta and convert to ns. */
• sub \res, x_tmp, \cycle_last
• /* We can only guarantee 56 bits of precision. */
• movn x_tmp, #0xff00, lsl #48
• and \res, x_tmp, \res
• mul \res, \res, \mult
• /*

• * Fake address dependency from the value computed from the counter
  

• * register to subsequent data page accesses so that the sequence
  

• * locking also orders the read of the counter.
  

• */
  

• and x_tmp, \res, xzr
• add vdso_data, vdso_data, x_tmp
• .endm
• /*

• * Returns in res_{sec,nsec} the REALTIME timespec, based on the
  

• * "wall time" (xtime) and the clock_mono delta.
  

• */
  

• .macro get_ts_realtime res_sec, res_nsec, \

• 	clock_nsec, xtime_sec, xtime_nsec, nsec_to_sec
  

• add \res_nsec, \clock_nsec, \xtime_nsec
• udiv x_tmp, \res_nsec, \nsec_to_sec
• add \res_sec, \xtime_sec, x_tmp
• msub \res_nsec, x_tmp, \nsec_to_sec, \res_nsec
• .endm
• /*

• * Returns in res_{sec,nsec} the timespec based on the clock_raw delta,
  

• * used for CLOCK_MONOTONIC_RAW.
  

• */
  

• .macro get_ts_clock_raw res_sec, res_nsec, clock_nsec, nsec_to_sec
• udiv \res_sec, \clock_nsec, \nsec_to_sec
• msub \res_nsec, \res_sec, \nsec_to_sec, \clock_nsec
• .endm
• /* sec and nsec are modified in place. */
• .macro add_ts sec, nsec, ts_sec, ts_nsec, nsec_to_sec
• /* Add timespec. */
• add \sec, \sec, \ts_sec
• add \nsec, \nsec, \ts_nsec
• /* Normalise the new timespec. */
• cmp \nsec, \nsec_to_sec
• b.lt 9999f
• sub \nsec, \nsec, \nsec_to_sec
• add \sec, \sec, #1

-9999:

• cmp \nsec, #0
• b.ge 9998f
• add \nsec, \nsec, \nsec_to_sec
• sub \sec, \sec, #1

-9998:

• .endm
• .macro clock_gettime_return, shift=0
• .if \shift == 1
• lsr x11, x11, x12
• .endif
• stp x10, x11, [x1, #TSPEC_TV_SEC]
• mov x0, xzr
• ret
• .endm
• .macro jump_slot jumptable, index, label
• .if (. - \jumptable) != 4 * (\index)
• .error "Jump slot index mismatch"
• .endif
• b \label
• .endm
• .text

-/* int __kernel_gettimeofday(struct timeval *tv, struct timezone *tz); */ -ENTRY(__kernel_gettimeofday)

• .cfi_startproc
• adr vdso_data, _vdso_data
• /* If tv is NULL, skip to the timezone code. */
• cbz x0, 2f
• /* Compute the time of day. */

-1: seqcnt_acquire

• syscall_check fail=4f
• ldr x10, [vdso_data, #VDSO_CS_CYCLE_LAST]
• /* w11 = cs_mono_mult, w12 = cs_shift */
• ldp w11, w12, [vdso_data, #VDSO_CS_MONO_MULT]
• ldp x13, x14, [vdso_data, #VDSO_XTIME_CLK_SEC]
• get_nsec_per_sec res=x9
• lsl x9, x9, x12
• get_clock_shifted_nsec res=x15, cycle_last=x10, mult=x11
• seqcnt_check fail=1b
• get_ts_realtime res_sec=x10, res_nsec=x11, \

• clock_nsec=x15, xtime_sec=x13, xtime_nsec=x14, nsec_to_sec=x9
  

• /* Convert ns to us. */
• mov x13, #1000
• lsl x13, x13, x12
• udiv x11, x11, x13
• stp x10, x11, [x0, #TVAL_TV_SEC]

-2:

• /* If tz is NULL, return 0. */
• cbz x1, 3f
• ldp w4, w5, [vdso_data, #VDSO_TZ_MINWEST]
• stp w4, w5, [x1, #TZ_MINWEST]

-3:

• mov x0, xzr
• ret

-4:

• /* Syscall fallback. */
• mov x8, #__NR_gettimeofday
• svc #0
• ret
• .cfi_endproc

-ENDPROC(__kernel_gettimeofday)

-#define JUMPSLOT_MAX CLOCK_MONOTONIC_COARSE

-/* int __kernel_clock_gettime(clockid_t clock_id, struct timespec *tp); */ -ENTRY(__kernel_clock_gettime)

• .cfi_startproc
• cmp w0, #JUMPSLOT_MAX
• b.hi syscall
• adr vdso_data, _vdso_data
• adr x_tmp, jumptable
• add x_tmp, x_tmp, w0, uxtw #2
• br x_tmp
• ALIGN

-jumptable:

• jump_slot jumptable, CLOCK_REALTIME, realtime
• jump_slot jumptable, CLOCK_MONOTONIC, monotonic
• b syscall
• b syscall
• jump_slot jumptable, CLOCK_MONOTONIC_RAW, monotonic_raw
• jump_slot jumptable, CLOCK_REALTIME_COARSE, realtime_coarse
• jump_slot jumptable, CLOCK_MONOTONIC_COARSE, monotonic_coarse
• .if (. - jumptable) != 4 * (JUMPSLOT_MAX + 1)
• .error "Wrong jumptable size"
• .endif
• ALIGN

-realtime:

• seqcnt_acquire
• syscall_check fail=syscall
• ldr x10, [vdso_data, #VDSO_CS_CYCLE_LAST]
• /* w11 = cs_mono_mult, w12 = cs_shift */
• ldp w11, w12, [vdso_data, #VDSO_CS_MONO_MULT]
• ldp x13, x14, [vdso_data, #VDSO_XTIME_CLK_SEC]
• /* All computations are done with left-shifted nsecs. */
• get_nsec_per_sec res=x9
• lsl x9, x9, x12
• get_clock_shifted_nsec res=x15, cycle_last=x10, mult=x11
• seqcnt_check fail=realtime
• get_ts_realtime res_sec=x10, res_nsec=x11, \

• clock_nsec=x15, xtime_sec=x13, xtime_nsec=x14, nsec_to_sec=x9
  

• clock_gettime_return, shift=1
• ALIGN

-monotonic:

• seqcnt_acquire
• syscall_check fail=syscall
• ldr x10, [vdso_data, #VDSO_CS_CYCLE_LAST]
• /* w11 = cs_mono_mult, w12 = cs_shift */
• ldp w11, w12, [vdso_data, #VDSO_CS_MONO_MULT]
• ldp x13, x14, [vdso_data, #VDSO_XTIME_CLK_SEC]
• ldp x3, x4, [vdso_data, #VDSO_WTM_CLK_SEC]
• /* All computations are done with left-shifted nsecs. */
• lsl x4, x4, x12
• get_nsec_per_sec res=x9
• lsl x9, x9, x12
• get_clock_shifted_nsec res=x15, cycle_last=x10, mult=x11
• seqcnt_check fail=monotonic
• get_ts_realtime res_sec=x10, res_nsec=x11, \

• clock_nsec=x15, xtime_sec=x13, xtime_nsec=x14, nsec_to_sec=x9
  

• add_ts sec=x10, nsec=x11, ts_sec=x3, ts_nsec=x4, nsec_to_sec=x9
• clock_gettime_return, shift=1
• ALIGN

-monotonic_raw:

• seqcnt_acquire
• syscall_check fail=syscall
• ldr x10, [vdso_data, #VDSO_CS_CYCLE_LAST]
• /* w11 = cs_raw_mult, w12 = cs_shift */
• ldp w12, w11, [vdso_data, #VDSO_CS_SHIFT]
• ldp x13, x14, [vdso_data, #VDSO_RAW_TIME_SEC]
• /* All computations are done with left-shifted nsecs. */
• get_nsec_per_sec res=x9
• lsl x9, x9, x12
• get_clock_shifted_nsec res=x15, cycle_last=x10, mult=x11
• seqcnt_check fail=monotonic_raw
• get_ts_clock_raw res_sec=x10, res_nsec=x11, \

• clock_nsec=x15, nsec_to_sec=x9
  

• add_ts sec=x10, nsec=x11, ts_sec=x13, ts_nsec=x14, nsec_to_sec=x9
• clock_gettime_return, shift=1
• ALIGN

-realtime_coarse:

• seqcnt_acquire
• ldp x10, x11, [vdso_data, #VDSO_XTIME_CRS_SEC]
• seqcnt_check fail=realtime_coarse
• clock_gettime_return
• ALIGN

-monotonic_coarse:

• seqcnt_acquire
• ldp x10, x11, [vdso_data, #VDSO_XTIME_CRS_SEC]
• ldp x13, x14, [vdso_data, #VDSO_WTM_CLK_SEC]
• seqcnt_check fail=monotonic_coarse
• /* Computations are done in (non-shifted) nsecs. */
• get_nsec_per_sec res=x9
• add_ts sec=x10, nsec=x11, ts_sec=x13, ts_nsec=x14, nsec_to_sec=x9
• clock_gettime_return
• ALIGN

-syscall: /* Syscall fallback. */

• mov x8, #__NR_clock_gettime
• svc #0
• ret
• .cfi_endproc

-ENDPROC(__kernel_clock_gettime)

-/* int __kernel_clock_getres(clockid_t clock_id, struct timespec *res); */ -ENTRY(__kernel_clock_getres)

• .cfi_startproc
• cmp w0, #CLOCK_REALTIME
• ccmp w0, #CLOCK_MONOTONIC, #0x4, ne
• ccmp w0, #CLOCK_MONOTONIC_RAW, #0x4, ne
• b.ne 1f
• adr vdso_data, _vdso_data
• ldr w2, [vdso_data, #CLOCK_REALTIME_RES]
• b 2f

-1:

• cmp w0, #CLOCK_REALTIME_COARSE
• ccmp w0, #CLOCK_MONOTONIC_COARSE, #0x4, ne
• b.ne 4f
• ldr x2, 5f

-2:

• cbz x1, 3f
• stp xzr, x2, [x1]

-3: /* res == NULL. */

• mov w0, wzr
• ret

-4: /* Syscall fallback. */

• mov x8, #__NR_clock_getres
• svc #0
• ret

-5:

• .quad CLOCK_COARSE_RES
• .cfi_endproc

-ENDPROC(__kernel_clock_getres) diff --git a/arch/arm64/kernel/vdso/vgettimeofday.c b/arch/arm64/kernel/vdso/vgettimeofday.c new file mode 100644 index 000000000000..3c58f19dbdf4 --- /dev/null +++ b/arch/arm64/kernel/vdso/vgettimeofday.c @@ -0,0 +1,28 @@ +// SPDX-License-Identifier: GPL-2.0 +/*

• • ARM64 userspace implementations of gettimeofday() and similar.
• • Copyright (C) 2018 ARM Limited
• */

+#include <linux/time.h> +#include <linux/types.h>

+int __kernel_clock_gettime(clockid_t clock,

• 	   struct __kernel_timespec *ts)
  

+{

• return __cvdso_clock_gettime(clock, ts);

+}

+int __kernel_gettimeofday(struct __kernel_old_timeval *tv,

• 	  struct timezone *tz)
  

+{

• return __cvdso_gettimeofday(tv, tz);

+}

+int __kernel_clock_getres(clockid_t clock_id,

• 	  struct __kernel_timespec *res)
  

+{

• return __cvdso_clock_getres(clock_id, res);

+}

Best regards