The arm vDSO library requires some adaptations to use to take advantage of the newly introduced generic vDSO library.
Introduce the following changes: - Modification vdso.c to be compliant with the common vdso datapage - Use of lib/vdso for gettimeofday - Implementation of elf note
Cc: Russell King linux@armlinux.org.uk Signed-off-by: Vincenzo Frascino vincenzo.frascino@arm.com --- arch/arm/Kconfig | 3 + arch/arm/include/asm/vdso/gettimeofday.h | 74 +++++++ arch/arm/include/asm/vdso/vsyscall.h | 71 +++++++ arch/arm/include/asm/vdso_datapage.h | 29 +-- arch/arm/kernel/vdso.c | 87 +------- arch/arm/vdso/Makefile | 13 +- arch/arm/vdso/note.c | 15 ++ arch/arm/vdso/vgettimeofday.c | 256 +---------------------- 8 files changed, 192 insertions(+), 356 deletions(-) create mode 100644 arch/arm/include/asm/vdso/gettimeofday.h create mode 100644 arch/arm/include/asm/vdso/vsyscall.h create mode 100644 arch/arm/vdso/note.c
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index 8869742a85df..a238fc34e478 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -53,6 +53,8 @@ config ARM select GENERIC_SMP_IDLE_THREAD select GENERIC_STRNCPY_FROM_USER select GENERIC_STRNLEN_USER + select GENERIC_GETTIMEOFDAY + select GENERIC_VDSO_32 select HANDLE_DOMAIN_IRQ select HARDIRQS_SW_RESEND select HAVE_ARCH_AUDITSYSCALL if AEABI && !OABI_COMPAT @@ -101,6 +103,7 @@ config ARM select HAVE_SYSCALL_TRACEPOINTS select HAVE_UID16 select HAVE_VIRT_CPU_ACCOUNTING_GEN + select HAVE_GENERIC_VDSO if AEABI select IRQ_FORCED_THREADING select MODULES_USE_ELF_REL select NEED_DMA_MAP_STATE diff --git a/arch/arm/include/asm/vdso/gettimeofday.h b/arch/arm/include/asm/vdso/gettimeofday.h new file mode 100644 index 000000000000..30ce4e87dffc --- /dev/null +++ b/arch/arm/include/asm/vdso/gettimeofday.h @@ -0,0 +1,74 @@ +/* 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/barrier.h> +#include <asm/cp15.h> +#include <asm/unistd.h> +#include <uapi/linux/time.h> + +extern struct vdso_data *__get_datapage(void); + +static __always_inline int gettimeofday_fallback( + struct __kernel_old_timeval *_tv, + struct timezone *_tz) +{ + register struct timezone *tz asm("r1") = _tz; + register struct __kernel_old_timeval *tv asm("r0") = _tv; + register long ret asm ("r0"); + register long nr asm("r7") = __NR_gettimeofday; + + asm volatile( + " swi #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("r1") = _ts; + register clockid_t clkid asm("r0") = _clkid; + register long ret asm ("r0"); + register long nr asm("r7") = __NR_clock_gettime64; + + asm volatile( + " swi #0\n" + : "=r" (ret) + : "r" (clkid), "r" (ts), "r" (nr) + : "memory"); + + return ret; +} + +static __always_inline u64 __arch_get_hw_counter(int clock_mode) +{ +#ifdef CONFIG_ARM_ARCH_TIMER + u64 cycle_now; + + isb(); + cycle_now = read_sysreg(CNTVCT); + + return cycle_now; +#else + return -EINVAL; /* use fallback */ +#endif +} + +static __always_inline const struct vdso_data *__arch_get_vdso_data(void) +{ + return __get_datapage(); +} + +#endif /* !__ASSEMBLY__ */ + +#endif /* __ASM_VDSO_GETTIMEOFDAY_H */ diff --git a/arch/arm/include/asm/vdso/vsyscall.h b/arch/arm/include/asm/vdso/vsyscall.h new file mode 100644 index 000000000000..c4166f317071 --- /dev/null +++ b/arch/arm/include/asm/vdso/vsyscall.h @@ -0,0 +1,71 @@ +/* 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> +#include <asm/cacheflush.h> + +extern struct vdso_data *vdso_data; +extern bool cntvct_ok; + +static __always_inline +bool tk_is_cntvct(const struct timekeeper *tk) +{ + if (!IS_ENABLED(CONFIG_ARM_ARCH_TIMER)) + return false; + + if (!tk->tkr_mono.clock->archdata.vdso_direct) + return false; + + return true; +} + +/* + * Update the vDSO data page to keep in sync with kernel timekeeping. + */ +static __always_inline +struct vdso_data *__arm_get_k_vdso_data(void) +{ + return vdso_data; +} +#define __arch_get_k_vdso_data __arm_get_k_vdso_data + +static __always_inline +int __arm_update_vdso_data(void) +{ + return !cntvct_ok; +} +#define __arch_update_vdso_data __arm_update_vdso_data + +static __always_inline +int __arm_get_clock_mode(struct timekeeper *tk) +{ + u32 __tk_is_cntvct = tk_is_cntvct(tk); + + return __tk_is_cntvct; +} +#define __arch_get_clock_mode __arm_get_clock_mode + +static __always_inline +int __arm_use_vsyscall(struct vdso_data *vdata) +{ + return vdata[CS_HRES_COARSE].clock_mode; +} +#define __arch_use_vsyscall __arm_use_vsyscall + +static __always_inline +void __arm_sync_vdso_data(struct vdso_data *vdata) +{ + flush_dcache_page(virt_to_page(vdata)); +} +#define __arch_sync_vdso_data __arm_sync_vdso_data + +/* 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/arm/include/asm/vdso_datapage.h b/arch/arm/include/asm/vdso_datapage.h index 9be259442fca..bfdbbd2b5fe7 100644 --- a/arch/arm/include/asm/vdso_datapage.h +++ b/arch/arm/include/asm/vdso_datapage.h @@ -22,35 +22,12 @@
#ifndef __ASSEMBLY__
+#include <vdso/datapage.h> #include <asm/page.h>
-/* Try to be cache-friendly on systems that don't implement the - * generic timer: fit the unconditionally updated fields in the first - * 32 bytes. - */ -struct vdso_data { - u32 seq_count; /* sequence count - odd during updates */ - u16 tk_is_cntvct; /* fall back to syscall if false */ - u16 cs_shift; /* clocksource shift */ - u32 xtime_coarse_sec; /* coarse time */ - u32 xtime_coarse_nsec; - - u32 wtm_clock_sec; /* wall to monotonic offset */ - u32 wtm_clock_nsec; - u32 xtime_clock_sec; /* CLOCK_REALTIME - seconds */ - u32 cs_mult; /* clocksource multiplier */ - - u64 cs_cycle_last; /* last cycle value */ - u64 cs_mask; /* clocksource mask */ - - u64 xtime_clock_snsec; /* CLOCK_REALTIME sub-ns base */ - u32 tz_minuteswest; /* timezone info for gettimeofday(2) */ - u32 tz_dsttime; -}; - union vdso_data_store { - struct vdso_data data; - u8 page[PAGE_SIZE]; + struct vdso_data data[CS_BASES]; + u8 page[PAGE_SIZE]; };
#endif /* !__ASSEMBLY__ */ diff --git a/arch/arm/kernel/vdso.c b/arch/arm/kernel/vdso.c index f4dd7f9663c1..9a9cea8b333d 100644 --- a/arch/arm/kernel/vdso.c +++ b/arch/arm/kernel/vdso.c @@ -34,6 +34,8 @@ #include <asm/vdso.h> #include <asm/vdso_datapage.h> #include <clocksource/arm_arch_timer.h> +#include <vdso/helpers.h> +#include <vdso/vsyscall.h>
#define MAX_SYMNAME 64
@@ -48,7 +50,7 @@ unsigned int vdso_total_pages __ro_after_init; * The VDSO data page. */ static union vdso_data_store vdso_data_store __page_aligned_data; -static struct vdso_data *vdso_data = &vdso_data_store.data; +struct vdso_data *vdso_data = vdso_data_store.data;
static struct page *vdso_data_page __ro_after_init; static const struct vm_special_mapping vdso_data_mapping = { @@ -88,7 +90,7 @@ struct elfinfo { /* Cached result of boot-time check for whether the arch timer exists, * and if so, whether the virtual counter is useable. */ -static bool cntvct_ok __ro_after_init; +bool cntvct_ok __ro_after_init;
static bool __init cntvct_functional(void) { @@ -274,84 +276,3 @@ void arm_install_vdso(struct mm_struct *mm, unsigned long addr) mm->context.vdso = addr; }
-static void vdso_write_begin(struct vdso_data *vdata) -{ - ++vdso_data->seq_count; - smp_wmb(); /* Pairs with smp_rmb in vdso_read_retry */ -} - -static void vdso_write_end(struct vdso_data *vdata) -{ - smp_wmb(); /* Pairs with smp_rmb in vdso_read_begin */ - ++vdso_data->seq_count; -} - -static bool tk_is_cntvct(const struct timekeeper *tk) -{ - if (!IS_ENABLED(CONFIG_ARM_ARCH_TIMER)) - return false; - - if (!tk->tkr_mono.clock->archdata.vdso_direct) - return false; - - return true; -} - -/** - * update_vsyscall - update the vdso data page - * - * Increment the sequence counter, making it odd, indicating to - * userspace that an update is in progress. Update the fields used - * for coarse clocks and, if the architected system timer is in use, - * the fields used for high precision clocks. Increment the sequence - * counter again, making it even, indicating to userspace that the - * update is finished. - * - * Userspace is expected to sample seq_count before reading any other - * fields from the data page. If seq_count is odd, userspace is - * expected to wait until it becomes even. After copying data from - * the page, userspace must sample seq_count again; if it has changed - * from its previous value, userspace must retry the whole sequence. - * - * Calls to update_vsyscall are serialized by the timekeeping core. - */ -void update_vsyscall(struct timekeeper *tk) -{ - struct timespec64 *wtm = &tk->wall_to_monotonic; - - if (!cntvct_ok) { - /* The entry points have been zeroed, so there is no - * point in updating the data page. - */ - return; - } - - vdso_write_begin(vdso_data); - - vdso_data->tk_is_cntvct = tk_is_cntvct(tk); - vdso_data->xtime_coarse_sec = tk->xtime_sec; - vdso_data->xtime_coarse_nsec = (u32)(tk->tkr_mono.xtime_nsec >> - tk->tkr_mono.shift); - vdso_data->wtm_clock_sec = wtm->tv_sec; - vdso_data->wtm_clock_nsec = wtm->tv_nsec; - - if (vdso_data->tk_is_cntvct) { - vdso_data->cs_cycle_last = tk->tkr_mono.cycle_last; - vdso_data->xtime_clock_sec = tk->xtime_sec; - vdso_data->xtime_clock_snsec = tk->tkr_mono.xtime_nsec; - vdso_data->cs_mult = tk->tkr_mono.mult; - vdso_data->cs_shift = tk->tkr_mono.shift; - vdso_data->cs_mask = tk->tkr_mono.mask; - } - - vdso_write_end(vdso_data); - - flush_dcache_page(virt_to_page(vdso_data)); -} - -void update_vsyscall_tz(void) -{ - vdso_data->tz_minuteswest = sys_tz.tz_minuteswest; - vdso_data->tz_dsttime = sys_tz.tz_dsttime; - flush_dcache_page(virt_to_page(vdso_data)); -} diff --git a/arch/arm/vdso/Makefile b/arch/arm/vdso/Makefile index fadf554d9391..0c8a819ef4f1 100644 --- a/arch/arm/vdso/Makefile +++ b/arch/arm/vdso/Makefile @@ -1,7 +1,13 @@ # SPDX-License-Identifier: GPL-2.0 + +# Absolute relocation type $(ARCH_REL_TYPE_ABS) needs to be defined before +# the inclusion of generic Makefile. +ARCH_REL_TYPE_ABS := R_ARM_JUMP_SLOT|R_ARM_GLOB_DAT|R_ARM_ABS32 +include $(srctree)/lib/vdso/Makefile + hostprogs-y := vdsomunge
-obj-vdso := vgettimeofday.o datapage.o +obj-vdso := vgettimeofday.o datapage.o note.o
# Build rules targets := $(obj-vdso) vdso.so vdso.so.dbg vdso.so.raw vdso.lds @@ -25,7 +31,11 @@ CFLAGS_REMOVE_vdso.o = -pg
# Force -O2 to avoid libgcc dependencies CFLAGS_REMOVE_vgettimeofday.o = -pg -Os +ifeq ($(c-gettimeofday-y),) CFLAGS_vgettimeofday.o = -O2 +else +CFLAGS_vgettimeofday.o = -O2 -include $(c-gettimeofday-y) +endif
# Disable gcov profiling for VDSO code GCOV_PROFILE := n @@ -39,6 +49,7 @@ $(obj)/vdso.o : $(obj)/vdso.so # Link rule for the .so file $(obj)/vdso.so.raw: $(obj)/vdso.lds $(obj-vdso) FORCE $(call if_changed,ld) + $(call if_changed,vdso_check)
$(obj)/vdso.so.dbg: $(obj)/vdso.so.raw $(obj)/vdsomunge FORCE $(call if_changed,vdsomunge) diff --git a/arch/arm/vdso/note.c b/arch/arm/vdso/note.c new file mode 100644 index 000000000000..eff5bf9efb8b --- /dev/null +++ b/arch/arm/vdso/note.c @@ -0,0 +1,15 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2012-2018 ARM Limited + * + * This supplies .note.* sections to go into the PT_NOTE inside the vDSO text. + * Here we can supply some information useful to userland. + */ + +#include <linux/uts.h> +#include <linux/version.h> +#include <linux/elfnote.h> +#include <linux/build-salt.h> + +ELFNOTE32("Linux", 0, LINUX_VERSION_CODE); +BUILD_SALT; diff --git a/arch/arm/vdso/vgettimeofday.c b/arch/arm/vdso/vgettimeofday.c index 7bdbf5d5c47d..fea6b3c89f43 100644 --- a/arch/arm/vdso/vgettimeofday.c +++ b/arch/arm/vdso/vgettimeofday.c @@ -1,5 +1,8 @@ /* + * ARM userspace implementations of gettimeofday() and similar. + * * Copyright 2015 Mentor Graphics Corporation. + * Copyright (C) 2018 ARM Limited * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License @@ -14,258 +17,19 @@ * You should have received a copy of the GNU General Public License * along with this program. If not, see http://www.gnu.org/licenses/. */ - -#include <linux/compiler.h> -#include <linux/hrtimer.h> #include <linux/time.h> -#include <asm/barrier.h> -#include <asm/bug.h> -#include <asm/cp15.h> -#include <asm/page.h> -#include <asm/unistd.h> -#include <asm/vdso_datapage.h> - -#ifndef CONFIG_AEABI -#error This code depends on AEABI system call conventions -#endif - -extern struct vdso_data *__get_datapage(void); - -static notrace u32 __vdso_read_begin(const struct vdso_data *vdata) -{ - u32 seq; -repeat: - seq = READ_ONCE(vdata->seq_count); - if (seq & 1) { - cpu_relax(); - goto repeat; - } - return seq; -} - -static notrace u32 vdso_read_begin(const struct vdso_data *vdata) -{ - u32 seq; - - seq = __vdso_read_begin(vdata); - - smp_rmb(); /* Pairs with smp_wmb in vdso_write_end */ - return seq; -} - -static notrace int vdso_read_retry(const struct vdso_data *vdata, u32 start) -{ - smp_rmb(); /* Pairs with smp_wmb in vdso_write_begin */ - return vdata->seq_count != start; -} - -static notrace long clock_gettime_fallback(clockid_t _clkid, - struct timespec *_ts) -{ - register struct timespec *ts asm("r1") = _ts; - register clockid_t clkid asm("r0") = _clkid; - register long ret asm ("r0"); - register long nr asm("r7") = __NR_clock_gettime; - - asm volatile( - " swi #0\n" - : "=r" (ret) - : "r" (clkid), "r" (ts), "r" (nr) - : "memory"); - - return ret; -} - -static notrace int do_realtime_coarse(struct timespec *ts, - struct vdso_data *vdata) -{ - u32 seq; - - do { - seq = vdso_read_begin(vdata); - - ts->tv_sec = vdata->xtime_coarse_sec; - ts->tv_nsec = vdata->xtime_coarse_nsec; - - } while (vdso_read_retry(vdata, seq)); - - return 0; -} - -static notrace int do_monotonic_coarse(struct timespec *ts, - struct vdso_data *vdata) -{ - struct timespec tomono; - u32 seq; - - do { - seq = vdso_read_begin(vdata); - - ts->tv_sec = vdata->xtime_coarse_sec; - ts->tv_nsec = vdata->xtime_coarse_nsec; - - tomono.tv_sec = vdata->wtm_clock_sec; - tomono.tv_nsec = vdata->wtm_clock_nsec; - - } while (vdso_read_retry(vdata, seq)); - - ts->tv_sec += tomono.tv_sec; - timespec_add_ns(ts, tomono.tv_nsec); - - return 0; -} - -#ifdef CONFIG_ARM_ARCH_TIMER - -static notrace u64 get_ns(struct vdso_data *vdata) -{ - u64 cycle_delta; - u64 cycle_now; - u64 nsec; - - isb(); - cycle_now = read_sysreg(CNTVCT); - - cycle_delta = (cycle_now - vdata->cs_cycle_last) & vdata->cs_mask; - - nsec = (cycle_delta * vdata->cs_mult) + vdata->xtime_clock_snsec; - nsec >>= vdata->cs_shift; +#include <linux/types.h>
- return nsec; -} - -static notrace int do_realtime(struct timespec *ts, struct vdso_data *vdata) -{ - u64 nsecs; - u32 seq; - - do { - seq = vdso_read_begin(vdata); - - if (!vdata->tk_is_cntvct) - return -1; - - ts->tv_sec = vdata->xtime_clock_sec; - nsecs = get_ns(vdata); - - } while (vdso_read_retry(vdata, seq)); - - ts->tv_nsec = 0; - timespec_add_ns(ts, nsecs); - - return 0; -} - -static notrace int do_monotonic(struct timespec *ts, struct vdso_data *vdata) -{ - struct timespec tomono; - u64 nsecs; - u32 seq; - - do { - seq = vdso_read_begin(vdata); - - if (!vdata->tk_is_cntvct) - return -1; - - ts->tv_sec = vdata->xtime_clock_sec; - nsecs = get_ns(vdata); - - tomono.tv_sec = vdata->wtm_clock_sec; - tomono.tv_nsec = vdata->wtm_clock_nsec; - - } while (vdso_read_retry(vdata, seq)); - - ts->tv_sec += tomono.tv_sec; - ts->tv_nsec = 0; - timespec_add_ns(ts, nsecs + tomono.tv_nsec); - - return 0; -} - -#else /* CONFIG_ARM_ARCH_TIMER */ - -static notrace int do_realtime(struct timespec *ts, struct vdso_data *vdata) -{ - return -1; -} - -static notrace int do_monotonic(struct timespec *ts, struct vdso_data *vdata) +int __vdso_clock_gettime(clockid_t clock, + struct old_timespec32 *ts) { - return -1; + return __cvdso_clock_gettime32(clock, ts); }
-#endif /* CONFIG_ARM_ARCH_TIMER */ - -notrace int __vdso_clock_gettime(clockid_t clkid, struct timespec *ts) +int __vdso_gettimeofday(struct __kernel_old_timeval *tv, + struct timezone *tz) { - struct vdso_data *vdata; - int ret = -1; - - vdata = __get_datapage(); - - switch (clkid) { - case CLOCK_REALTIME_COARSE: - ret = do_realtime_coarse(ts, vdata); - break; - case CLOCK_MONOTONIC_COARSE: - ret = do_monotonic_coarse(ts, vdata); - break; - case CLOCK_REALTIME: - ret = do_realtime(ts, vdata); - break; - case CLOCK_MONOTONIC: - ret = do_monotonic(ts, vdata); - break; - default: - break; - } - - if (ret) - ret = clock_gettime_fallback(clkid, ts); - - return ret; -} - -static notrace long gettimeofday_fallback(struct timeval *_tv, - struct timezone *_tz) -{ - register struct timezone *tz asm("r1") = _tz; - register struct timeval *tv asm("r0") = _tv; - register long ret asm ("r0"); - register long nr asm("r7") = __NR_gettimeofday; - - asm volatile( - " swi #0\n" - : "=r" (ret) - : "r" (tv), "r" (tz), "r" (nr) - : "memory"); - - return ret; -} - -notrace int __vdso_gettimeofday(struct timeval *tv, struct timezone *tz) -{ - struct timespec ts; - struct vdso_data *vdata; - int ret; - - vdata = __get_datapage(); - - ret = do_realtime(&ts, vdata); - if (ret) - return gettimeofday_fallback(tv, tz); - - if (tv) { - tv->tv_sec = ts.tv_sec; - tv->tv_usec = ts.tv_nsec / 1000; - } - if (tz) { - tz->tz_minuteswest = vdata->tz_minuteswest; - tz->tz_dsttime = vdata->tz_dsttime; - } - - return ret; + return __cvdso_gettimeofday(tv, tz); }
/* Avoid unresolved references emitted by GCC */