From f2e600c149fda3453344f89c7e9353fe278ebd32 Mon Sep 17 00:00:00 2001 From: Christoffer Dall Date: Wed, 18 Oct 2017 13:06:25 +0200 Subject: [PATCH] arm64: Implement arch_counter_get_cntpct to read the physical counter As we are about to use the physical counter on arm64 systems that have KVM support, implement arch_counter_get_cntpct() and the associated errata workaround functionality for stable timer reads. Cc: Will Deacon Cc: Mark Rutland Acked-by: Catalin Marinas Acked-by: Marc Zyngier Signed-off-by: Christoffer Dall --- arch/arm64/include/asm/arch_timer.h | 8 +++----- drivers/clocksource/arm_arch_timer.c | 23 +++++++++++++++++++++++ 2 files changed, 26 insertions(+), 5 deletions(-) --- a/arch/arm64/include/asm/arch_timer.h +++ b/arch/arm64/include/asm/arch_timer.h @@ -52,6 +52,7 @@ struct arch_timer_erratum_workaround { const char *desc; u32 (*read_cntp_tval_el0)(void); u32 (*read_cntv_tval_el0)(void); + u64 (*read_cntpct_el0)(void); u64 (*read_cntvct_el0)(void); int (*set_next_event_phys)(unsigned long, struct clock_event_device *); int (*set_next_event_virt)(unsigned long, struct clock_event_device *); @@ -148,11 +149,8 @@ static inline void arch_timer_set_cntkct static inline u64 arch_counter_get_cntpct(void) { - /* - * AArch64 kernel and user space mandate the use of CNTVCT. - */ - BUG(); - return 0; + isb(); + return arch_timer_reg_read_stable(cntpct_el0); } static inline u64 arch_counter_get_cntvct(void) --- a/drivers/clocksource/arm_arch_timer.c +++ b/drivers/clocksource/arm_arch_timer.c @@ -217,6 +217,11 @@ static u32 notrace fsl_a008585_read_cntv return __fsl_a008585_read_reg(cntv_tval_el0); } +static u64 notrace fsl_a008585_read_cntpct_el0(void) +{ + return __fsl_a008585_read_reg(cntpct_el0); +} + static u64 notrace fsl_a008585_read_cntvct_el0(void) { return __fsl_a008585_read_reg(cntvct_el0); @@ -258,6 +263,11 @@ static u32 notrace hisi_161010101_read_c return __hisi_161010101_read_reg(cntv_tval_el0); } +static u64 notrace hisi_161010101_read_cntpct_el0(void) +{ + return __hisi_161010101_read_reg(cntpct_el0); +} + static u64 notrace hisi_161010101_read_cntvct_el0(void) { return __hisi_161010101_read_reg(cntvct_el0); @@ -288,6 +298,15 @@ static struct ate_acpi_oem_info hisi_161 #endif #ifdef CONFIG_ARM64_ERRATUM_858921 +static u64 notrace arm64_858921_read_cntpct_el0(void) +{ + u64 old, new; + + old = read_sysreg(cntpct_el0); + new = read_sysreg(cntpct_el0); + return (((old ^ new) >> 32) & 1) ? old : new; +} + static u64 notrace arm64_858921_read_cntvct_el0(void) { u64 old, new; @@ -346,6 +365,7 @@ static const struct arch_timer_erratum_w .desc = "Freescale erratum a005858", .read_cntp_tval_el0 = fsl_a008585_read_cntp_tval_el0, .read_cntv_tval_el0 = fsl_a008585_read_cntv_tval_el0, + .read_cntpct_el0 = fsl_a008585_read_cntpct_el0, .read_cntvct_el0 = fsl_a008585_read_cntvct_el0, .set_next_event_phys = erratum_set_next_event_tval_phys, .set_next_event_virt = erratum_set_next_event_tval_virt, @@ -358,6 +378,7 @@ static const struct arch_timer_erratum_w .desc = "HiSilicon erratum 161010101", .read_cntp_tval_el0 = hisi_161010101_read_cntp_tval_el0, .read_cntv_tval_el0 = hisi_161010101_read_cntv_tval_el0, + .read_cntpct_el0 = hisi_161010101_read_cntpct_el0, .read_cntvct_el0 = hisi_161010101_read_cntvct_el0, .set_next_event_phys = erratum_set_next_event_tval_phys, .set_next_event_virt = erratum_set_next_event_tval_virt, @@ -368,6 +389,7 @@ static const struct arch_timer_erratum_w .desc = "HiSilicon erratum 161010101", .read_cntp_tval_el0 = hisi_161010101_read_cntp_tval_el0, .read_cntv_tval_el0 = hisi_161010101_read_cntv_tval_el0, + .read_cntpct_el0 = hisi_161010101_read_cntpct_el0, .read_cntvct_el0 = hisi_161010101_read_cntvct_el0, .set_next_event_phys = erratum_set_next_event_tval_phys, .set_next_event_virt = erratum_set_next_event_tval_virt, @@ -378,6 +400,7 @@ static const struct arch_timer_erratum_w .match_type = ate_match_local_cap_id, .id = (void *)ARM64_WORKAROUND_858921, .desc = "ARM erratum 858921", + .read_cntpct_el0 = arm64_858921_read_cntpct_el0, .read_cntvct_el0 = arm64_858921_read_cntvct_el0, }, #endif