From 1dac0dd71cdda2bd7395dd47a6b617ed296d4901 Mon Sep 17 00:00:00 2001 From: Mark Rutland Date: Tue, 15 Jan 2013 11:12:29 +0000 Subject: arm64: arm_generic: prevent reading stale time Currently arch_counter_get_cnt{p,v}ct can be speculated, allowing for stale time values to be read. This could be problematic for the delay loop and other sensitive functions, as the time delta could jump around unexpectedly. This patch adds isbs to arch_counter_get_cnt{p,v}ct, preventing this possibility. Signed-off-by: Mark Rutland Acked-by: Catalin Marinas --- arch/arm64/include/asm/arm_generic.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'arch/arm64') diff --git a/arch/arm64/include/asm/arm_generic.h b/arch/arm64/include/asm/arm_generic.h index df2aeb82f74e..6ece2f107fa0 100644 --- a/arch/arm64/include/asm/arm_generic.h +++ b/arch/arm64/include/asm/arm_generic.h @@ -83,6 +83,7 @@ static inline cycle_t arch_counter_get_cntpct(void) { cycle_t cval; + isb(); asm volatile("mrs %0, cntpct_el0" : "=r" (cval)); return cval; @@ -92,6 +93,7 @@ static inline cycle_t arch_counter_get_cntvct(void) { cycle_t cval; + isb(); asm volatile("mrs %0, cntvct_el0" : "=r" (cval)); return cval; -- cgit v1.2.3 From 1aee5d7a8120cbe3eca9180ef9276d75a4f51dd2 Mon Sep 17 00:00:00 2001 From: Mark Rutland Date: Tue, 20 Nov 2012 10:06:00 +0000 Subject: arm64: move from arm_generic to arm_arch_timer The arch_timer driver supports a superset of the functionality of the arm_generic driver, and is not tied to a particular arch. This patch moves arm64 to use the arch_timer driver, gaining additional functionality in doing so, and removes the (now unused) arm_generic driver. Timer-related hooks specific to arm64 are moved into arch/arm64/kernel/time.c. Signed-off-by: Mark Rutland Acked-by: Catalin Marinas Acked-by: Marc Zyngier Acked-by: Santosh Shilimkar --- arch/arm64/Kconfig | 1 + arch/arm64/include/asm/arch_timer.h | 133 ++++++++++++++++++++ arch/arm64/include/asm/arm_generic.h | 102 --------------- arch/arm64/kernel/time.c | 29 ++++- drivers/clocksource/Kconfig | 5 - drivers/clocksource/Makefile | 1 - drivers/clocksource/arm_arch_timer.c | 1 + drivers/clocksource/arm_generic.c | 232 ----------------------------------- include/clocksource/arm_generic.h | 21 ---- 9 files changed, 162 insertions(+), 363 deletions(-) create mode 100644 arch/arm64/include/asm/arch_timer.h delete mode 100644 arch/arm64/include/asm/arm_generic.h delete mode 100644 drivers/clocksource/arm_generic.c delete mode 100644 include/clocksource/arm_generic.h (limited to 'arch/arm64') diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index f8f362aafee9..2b6cef6ad17f 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -3,6 +3,7 @@ config ARM64 select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE select ARCH_WANT_COMPAT_IPC_PARSE_VERSION select ARM_AMBA + select ARM_ARCH_TIMER select CLONE_BACKWARDS select COMMON_CLK select GENERIC_CLOCKEVENTS diff --git a/arch/arm64/include/asm/arch_timer.h b/arch/arm64/include/asm/arch_timer.h new file mode 100644 index 000000000000..91e2a6a6fcd4 --- /dev/null +++ b/arch/arm64/include/asm/arch_timer.h @@ -0,0 +1,133 @@ +/* + * arch/arm64/include/asm/arch_timer.h + * + * Copyright (C) 2012 ARM Ltd. + * Author: Marc Zyngier + * + * 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 . + */ +#ifndef __ASM_ARCH_TIMER_H +#define __ASM_ARCH_TIMER_H + +#include + +#include +#include + +#include + +static inline void arch_timer_reg_write(int access, int reg, u32 val) +{ + if (access == ARCH_TIMER_PHYS_ACCESS) { + switch (reg) { + case ARCH_TIMER_REG_CTRL: + asm volatile("msr cntp_ctl_el0, %0" : : "r" (val)); + break; + case ARCH_TIMER_REG_TVAL: + asm volatile("msr cntp_tval_el0, %0" : : "r" (val)); + break; + default: + BUILD_BUG(); + } + } else if (access == ARCH_TIMER_VIRT_ACCESS) { + switch (reg) { + case ARCH_TIMER_REG_CTRL: + asm volatile("msr cntv_ctl_el0, %0" : : "r" (val)); + break; + case ARCH_TIMER_REG_TVAL: + asm volatile("msr cntv_tval_el0, %0" : : "r" (val)); + break; + default: + BUILD_BUG(); + } + } else { + BUILD_BUG(); + } + + isb(); +} + +static inline u32 arch_timer_reg_read(int access, int reg) +{ + u32 val; + + if (access == ARCH_TIMER_PHYS_ACCESS) { + switch (reg) { + case ARCH_TIMER_REG_CTRL: + asm volatile("mrs %0, cntp_ctl_el0" : "=r" (val)); + break; + case ARCH_TIMER_REG_TVAL: + asm volatile("mrs %0, cntp_tval_el0" : "=r" (val)); + break; + default: + BUILD_BUG(); + } + } else if (access == ARCH_TIMER_VIRT_ACCESS) { + switch (reg) { + case ARCH_TIMER_REG_CTRL: + asm volatile("mrs %0, cntv_ctl_el0" : "=r" (val)); + break; + case ARCH_TIMER_REG_TVAL: + asm volatile("mrs %0, cntv_tval_el0" : "=r" (val)); + break; + default: + BUILD_BUG(); + } + } else { + BUILD_BUG(); + } + + return val; +} + +static inline u32 arch_timer_get_cntfrq(void) +{ + u32 val; + asm volatile("mrs %0, cntfrq_el0" : "=r" (val)); + return val; +} + +static inline void __cpuinit arch_counter_set_user_access(void) +{ + u32 cntkctl; + + /* Disable user access to the timers and the physical counter. */ + asm volatile("mrs %0, cntkctl_el1" : "=r" (cntkctl)); + cntkctl &= ~((3 << 8) | (1 << 0)); + + /* Enable user access to the virtual counter and frequency. */ + cntkctl |= (1 << 1); + asm volatile("msr cntkctl_el1, %0" : : "r" (cntkctl)); +} + +static inline u64 arch_counter_get_cntpct(void) +{ + u64 cval; + + isb(); + asm volatile("mrs %0, cntpct_el0" : "=r" (cval)); + + return cval; +} + +static inline u64 arch_counter_get_cntvct(void) +{ + u64 cval; + + isb(); + asm volatile("mrs %0, cntvct_el0" : "=r" (cval)); + + return cval; +} + +#endif diff --git a/arch/arm64/include/asm/arm_generic.h b/arch/arm64/include/asm/arm_generic.h deleted file mode 100644 index 6ece2f107fa0..000000000000 --- a/arch/arm64/include/asm/arm_generic.h +++ /dev/null @@ -1,102 +0,0 @@ -/* - * arch/arm64/include/asm/arm_generic.h - * - * Copyright (C) 2012 ARM Ltd. - * Author: Marc Zyngier - * - * 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 . - */ -#ifndef __ASM_ARM_GENERIC_H -#define __ASM_ARM_GENERIC_H - -#include - -#define ARCH_TIMER_CTRL_ENABLE (1 << 0) -#define ARCH_TIMER_CTRL_IMASK (1 << 1) -#define ARCH_TIMER_CTRL_ISTATUS (1 << 2) - -#define ARCH_TIMER_REG_CTRL 0 -#define ARCH_TIMER_REG_FREQ 1 -#define ARCH_TIMER_REG_TVAL 2 - -static inline void arch_timer_reg_write(int reg, u32 val) -{ - switch (reg) { - case ARCH_TIMER_REG_CTRL: - asm volatile("msr cntp_ctl_el0, %0" : : "r" (val)); - break; - case ARCH_TIMER_REG_TVAL: - asm volatile("msr cntp_tval_el0, %0" : : "r" (val)); - break; - default: - BUILD_BUG(); - } - - isb(); -} - -static inline u32 arch_timer_reg_read(int reg) -{ - u32 val; - - switch (reg) { - case ARCH_TIMER_REG_CTRL: - asm volatile("mrs %0, cntp_ctl_el0" : "=r" (val)); - break; - case ARCH_TIMER_REG_FREQ: - asm volatile("mrs %0, cntfrq_el0" : "=r" (val)); - break; - case ARCH_TIMER_REG_TVAL: - asm volatile("mrs %0, cntp_tval_el0" : "=r" (val)); - break; - default: - BUILD_BUG(); - } - - return val; -} - -static inline void __cpuinit arch_counter_enable_user_access(void) -{ - u32 cntkctl; - - /* Disable user access to the timers and the physical counter. */ - asm volatile("mrs %0, cntkctl_el1" : "=r" (cntkctl)); - cntkctl &= ~((3 << 8) | (1 << 0)); - - /* Enable user access to the virtual counter and frequency. */ - cntkctl |= (1 << 1); - asm volatile("msr cntkctl_el1, %0" : : "r" (cntkctl)); -} - -static inline cycle_t arch_counter_get_cntpct(void) -{ - cycle_t cval; - - isb(); - asm volatile("mrs %0, cntpct_el0" : "=r" (cval)); - - return cval; -} - -static inline cycle_t arch_counter_get_cntvct(void) -{ - cycle_t cval; - - isb(); - asm volatile("mrs %0, cntvct_el0" : "=r" (cval)); - - return cval; -} - -#endif diff --git a/arch/arm64/kernel/time.c b/arch/arm64/kernel/time.c index 3b4b7258f492..b0ef18d14c3b 100644 --- a/arch/arm64/kernel/time.c +++ b/arch/arm64/kernel/time.c @@ -31,8 +31,9 @@ #include #include #include +#include -#include +#include #include #include @@ -59,7 +60,31 @@ unsigned long profile_pc(struct pt_regs *regs) EXPORT_SYMBOL(profile_pc); #endif +static u64 sched_clock_mult __read_mostly; + +unsigned long long notrace sched_clock(void) +{ + return arch_timer_read_counter() * sched_clock_mult; +} + +int read_current_timer(unsigned long *timer_value) +{ + *timer_value = arch_timer_read_counter(); + return 0; +} + void __init time_init(void) { - arm_generic_timer_init(); + u32 arch_timer_rate; + + if (arch_timer_init()) + panic("Unable to initialise architected timer.\n"); + + arch_timer_rate = arch_timer_get_rate(); + + /* Cache the sched_clock multiplier to save a divide in the hot path. */ + sched_clock_mult = NSEC_PER_SEC / arch_timer_rate; + + /* Calibrate the delay loop directly */ + lpj_fine = arch_timer_rate / HZ; } diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig index dbb085ac64d4..64798424b6cb 100644 --- a/drivers/clocksource/Kconfig +++ b/drivers/clocksource/Kconfig @@ -54,10 +54,5 @@ config CLKSRC_DBX500_PRCMU_SCHED_CLOCK help Use the always on PRCMU Timer as sched_clock -config CLKSRC_ARM_GENERIC - def_bool y if ARM64 - help - This option enables support for the ARM generic timer. - config ARM_ARCH_TIMER bool diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile index 32f858c8eecc..e69511c4c66e 100644 --- a/drivers/clocksource/Makefile +++ b/drivers/clocksource/Makefile @@ -17,5 +17,4 @@ obj-$(CONFIG_ARMADA_370_XP_TIMER) += time-armada-370-xp.o obj-$(CONFIG_ARCH_BCM2835) += bcm2835_timer.o obj-$(CONFIG_SUNXI_TIMER) += sunxi_timer.o -obj-$(CONFIG_CLKSRC_ARM_GENERIC) += arm_generic.o obj-$(CONFIG_ARM_ARCH_TIMER) += arm_arch_timer.o diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c index 3e4739df0e82..ec30a7331587 100644 --- a/drivers/clocksource/arm_arch_timer.c +++ b/drivers/clocksource/arm_arch_timer.c @@ -338,6 +338,7 @@ out: static const struct of_device_id arch_timer_of_match[] __initconst = { { .compatible = "arm,armv7-timer", }, + { .compatible = "arm,armv8-timer", }, {}, }; diff --git a/drivers/clocksource/arm_generic.c b/drivers/clocksource/arm_generic.c deleted file mode 100644 index 8ae1a61523ff..000000000000 --- a/drivers/clocksource/arm_generic.c +++ /dev/null @@ -1,232 +0,0 @@ -/* - * Generic timers support - * - * Copyright (C) 2012 ARM Ltd. - * Author: Marc Zyngier - * - * 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 . - */ - -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include - -#include - -#include - -static u32 arch_timer_rate; -static u64 sched_clock_mult __read_mostly; -static DEFINE_PER_CPU(struct clock_event_device, arch_timer_evt); -static int arch_timer_ppi; - -static irqreturn_t arch_timer_handle_irq(int irq, void *dev_id) -{ - struct clock_event_device *evt = dev_id; - unsigned long ctrl; - - ctrl = arch_timer_reg_read(ARCH_TIMER_REG_CTRL); - if (ctrl & ARCH_TIMER_CTRL_ISTATUS) { - ctrl |= ARCH_TIMER_CTRL_IMASK; - arch_timer_reg_write(ARCH_TIMER_REG_CTRL, ctrl); - evt->event_handler(evt); - return IRQ_HANDLED; - } - - return IRQ_NONE; -} - -static void arch_timer_stop(void) -{ - unsigned long ctrl; - - ctrl = arch_timer_reg_read(ARCH_TIMER_REG_CTRL); - ctrl &= ~ARCH_TIMER_CTRL_ENABLE; - arch_timer_reg_write(ARCH_TIMER_REG_CTRL, ctrl); -} - -static void arch_timer_set_mode(enum clock_event_mode mode, - struct clock_event_device *clk) -{ - switch (mode) { - case CLOCK_EVT_MODE_UNUSED: - case CLOCK_EVT_MODE_SHUTDOWN: - arch_timer_stop(); - break; - default: - break; - } -} - -static int arch_timer_set_next_event(unsigned long evt, - struct clock_event_device *unused) -{ - unsigned long ctrl; - - ctrl = arch_timer_reg_read(ARCH_TIMER_REG_CTRL); - ctrl |= ARCH_TIMER_CTRL_ENABLE; - ctrl &= ~ARCH_TIMER_CTRL_IMASK; - - arch_timer_reg_write(ARCH_TIMER_REG_TVAL, evt); - arch_timer_reg_write(ARCH_TIMER_REG_CTRL, ctrl); - - return 0; -} - -static void __cpuinit arch_timer_setup(struct clock_event_device *clk) -{ - /* Let's make sure the timer is off before doing anything else */ - arch_timer_stop(); - - clk->features = CLOCK_EVT_FEAT_ONESHOT | CLOCK_EVT_FEAT_C3STOP; - clk->name = "arch_sys_timer"; - clk->rating = 400; - clk->set_mode = arch_timer_set_mode; - clk->set_next_event = arch_timer_set_next_event; - clk->irq = arch_timer_ppi; - clk->cpumask = cpumask_of(smp_processor_id()); - - clockevents_config_and_register(clk, arch_timer_rate, - 0xf, 0x7fffffff); - - enable_percpu_irq(clk->irq, 0); - - /* Ensure the virtual counter is visible to userspace for the vDSO. */ - arch_counter_enable_user_access(); -} - -static void __init arch_timer_calibrate(void) -{ - if (arch_timer_rate == 0) { - arch_timer_reg_write(ARCH_TIMER_REG_CTRL, 0); - arch_timer_rate = arch_timer_reg_read(ARCH_TIMER_REG_FREQ); - - /* Check the timer frequency. */ - if (arch_timer_rate == 0) - panic("Architected timer frequency is set to zero.\n" - "You must set this in your .dts file\n"); - } - - /* Cache the sched_clock multiplier to save a divide in the hot path. */ - - sched_clock_mult = DIV_ROUND_CLOSEST(NSEC_PER_SEC, arch_timer_rate); - - pr_info("Architected local timer running at %u.%02uMHz.\n", - arch_timer_rate / 1000000, (arch_timer_rate / 10000) % 100); -} - -static cycle_t arch_counter_read(struct clocksource *cs) -{ - return arch_counter_get_cntpct(); -} - -static struct clocksource clocksource_counter = { - .name = "arch_sys_counter", - .rating = 400, - .read = arch_counter_read, - .mask = CLOCKSOURCE_MASK(56), - .flags = (CLOCK_SOURCE_IS_CONTINUOUS | CLOCK_SOURCE_VALID_FOR_HRES), -}; - -int read_current_timer(unsigned long *timer_value) -{ - *timer_value = arch_counter_get_cntpct(); - return 0; -} - -unsigned long long notrace sched_clock(void) -{ - return arch_counter_get_cntvct() * sched_clock_mult; -} - -static int __cpuinit arch_timer_cpu_notify(struct notifier_block *self, - unsigned long action, void *hcpu) -{ - int cpu = (long)hcpu; - struct clock_event_device *clk = per_cpu_ptr(&arch_timer_evt, cpu); - - switch(action) { - case CPU_STARTING: - case CPU_STARTING_FROZEN: - arch_timer_setup(clk); - break; - - case CPU_DYING: - case CPU_DYING_FROZEN: - pr_debug("arch_timer_teardown disable IRQ%d cpu #%d\n", - clk->irq, cpu); - disable_percpu_irq(clk->irq); - arch_timer_set_mode(CLOCK_EVT_MODE_UNUSED, clk); - break; - } - - return NOTIFY_OK; -} - -static struct notifier_block __cpuinitdata arch_timer_cpu_nb = { - .notifier_call = arch_timer_cpu_notify, -}; - -static const struct of_device_id arch_timer_of_match[] __initconst = { - { .compatible = "arm,armv8-timer" }, - {}, -}; - -int __init arm_generic_timer_init(void) -{ - struct device_node *np; - int err; - u32 freq; - - np = of_find_matching_node(NULL, arch_timer_of_match); - if (!np) { - pr_err("arch_timer: can't find DT node\n"); - return -ENODEV; - } - - /* Try to determine the frequency from the device tree or CNTFRQ */ - if (!of_property_read_u32(np, "clock-frequency", &freq)) - arch_timer_rate = freq; - arch_timer_calibrate(); - - arch_timer_ppi = irq_of_parse_and_map(np, 0); - pr_info("arch_timer: found %s irq %d\n", np->name, arch_timer_ppi); - - err = request_percpu_irq(arch_timer_ppi, arch_timer_handle_irq, - np->name, &arch_timer_evt); - if (err) { - pr_err("arch_timer: can't register interrupt %d (%d)\n", - arch_timer_ppi, err); - return err; - } - - clocksource_register_hz(&clocksource_counter, arch_timer_rate); - - /* Calibrate the delay loop directly */ - lpj_fine = DIV_ROUND_CLOSEST(arch_timer_rate, HZ); - - /* Immediately configure the timer on the boot CPU */ - arch_timer_setup(this_cpu_ptr(&arch_timer_evt)); - - register_cpu_notifier(&arch_timer_cpu_nb); - - return 0; -} diff --git a/include/clocksource/arm_generic.h b/include/clocksource/arm_generic.h deleted file mode 100644 index 5b41b0d27f0f..000000000000 --- a/include/clocksource/arm_generic.h +++ /dev/null @@ -1,21 +0,0 @@ -/* - * Copyright (C) 2012 ARM Ltd. - * - * 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 . - */ -#ifndef __CLKSOURCE_ARM_GENERIC_H -#define __CLKSOURCE_ARM_GENERIC_H - -extern int arm_generic_timer_init(void); - -#endif -- cgit v1.2.3