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 df2aeb8..6ece2f1 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 v1.1 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 +++++++- 4 files changed, 161 insertions(+), 104 deletions(-) create mode 100644 arch/arm64/include/asm/arch_timer.h delete mode 100644 arch/arm64/include/asm/arm_generic.h (limited to 'arch/arm64') diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index f8f362a..2b6cef6 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 0000000..91e2a6a --- /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 6ece2f1..0000000 --- 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 3b4b725..b0ef18d 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; } -- cgit v1.1