From: Daniel Lezcano <daniel.lezcano@linaro.org>
To: tglx@linutronix.de
Cc: linux-kernel@vger.kernel.org, Marc Zyngier <marc.zyngier@arm.com>,
Mark Rutland <mark.rutland@arm.com>,
linux-arm-kernel@lists.infradead.org (moderated list:ARM
ARCHITECTED TIMER DRIVER)
Subject: [PATCH 15/29] arm64: arch_timer: Enable CNTVCT_EL0 trap if workaround is enabled
Date: Sun, 16 Apr 2017 22:27:05 +0200 [thread overview]
Message-ID: <1492374441-23336-15-git-send-email-daniel.lezcano@linaro.org> (raw)
In-Reply-To: <1492374441-23336-1-git-send-email-daniel.lezcano@linaro.org>
From: Marc Zyngier <marc.zyngier@arm.com>
Userspace being allowed to use read CNTVCT_EL0 anytime (and not
only in the VDSO), we need to enable trapping whenever a cntvct
workaround is enabled on a given CPU.
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
drivers/clocksource/arm_arch_timer.c | 45 +++++++++++++++++++++++++-----------
1 file changed, 32 insertions(+), 13 deletions(-)
diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c
index 5c114da..f8adea2 100644
--- a/drivers/clocksource/arm_arch_timer.c
+++ b/drivers/clocksource/arm_arch_timer.c
@@ -83,6 +83,7 @@ static enum ppi_nr arch_timer_uses_ppi = VIRT_PPI;
static bool arch_timer_c3stop;
static bool arch_timer_mem_use_virtual;
static bool arch_counter_suspend_stop;
+static bool vdso_default = true;
static bool evtstrm_enable = IS_ENABLED(CONFIG_ARM_ARCH_TIMER_EVTSTREAM);
@@ -383,6 +384,17 @@ void arch_timer_enable_workaround(const struct arch_timer_erratum_workaround *wa
}
static_branch_enable(&arch_timer_read_ool_enabled);
+
+ /*
+ * Don't use the vdso fastpath if errata require using the
+ * out-of-line counter accessor. We may change our mind pretty
+ * late in the game (with a per-CPU erratum, for example), so
+ * change both the default value and the vdso itself.
+ */
+ if (wa->read_cntvct_el0) {
+ clocksource_counter.archdata.vdso_direct = false;
+ vdso_default = false;
+ }
}
static void arch_timer_check_ool_workaround(enum arch_timer_erratum_match_type type,
@@ -443,11 +455,19 @@ static void arch_timer_check_ool_workaround(enum arch_timer_erratum_match_type t
__val; \
})
+static bool arch_timer_this_cpu_has_cntvct_wa(void)
+{
+ const struct arch_timer_erratum_workaround *wa;
+
+ wa = __this_cpu_read(timer_unstable_counter_workaround);
+ return wa && wa->read_cntvct_el0;
+}
#else
#define arch_timer_check_ool_workaround(t,a) do { } while(0)
#define erratum_set_next_event_tval_virt(...) ({BUG(); 0;})
#define erratum_set_next_event_tval_phys(...) ({BUG(); 0;})
#define erratum_handler(fn, r, ...) ({false;})
+#define arch_timer_this_cpu_has_cntvct_wa() ({false;})
#endif /* CONFIG_ARM_ARCH_TIMER_OOL_WORKAROUND */
static __always_inline irqreturn_t timer_handler(const int access,
@@ -660,15 +680,23 @@ static void arch_counter_set_user_access(void)
{
u32 cntkctl = arch_timer_get_cntkctl();
- /* Disable user access to the timers and the physical counter */
+ /* Disable user access to the timers and both counters */
/* Also disable virtual event stream */
cntkctl &= ~(ARCH_TIMER_USR_PT_ACCESS_EN
| ARCH_TIMER_USR_VT_ACCESS_EN
+ | ARCH_TIMER_USR_VCT_ACCESS_EN
| ARCH_TIMER_VIRT_EVT_EN
| ARCH_TIMER_USR_PCT_ACCESS_EN);
- /* Enable user access to the virtual counter */
- cntkctl |= ARCH_TIMER_USR_VCT_ACCESS_EN;
+ /*
+ * Enable user access to the virtual counter if it doesn't
+ * need to be workaround. The vdso may have been already
+ * disabled though.
+ */
+ if (arch_timer_this_cpu_has_cntvct_wa())
+ pr_info("CPU%d: Trapping CNTVCT access\n", smp_processor_id());
+ else
+ cntkctl |= ARCH_TIMER_USR_VCT_ACCESS_EN;
arch_timer_set_cntkctl(cntkctl);
}
@@ -791,16 +819,7 @@ static void __init arch_counter_register(unsigned type)
else
arch_timer_read_counter = arch_counter_get_cntpct;
- clocksource_counter.archdata.vdso_direct = true;
-
-#ifdef CONFIG_ARM_ARCH_TIMER_OOL_WORKAROUND
- /*
- * Don't use the vdso fastpath if errata require using
- * the out-of-line counter accessor.
- */
- if (static_branch_unlikely(&arch_timer_read_ool_enabled))
- clocksource_counter.archdata.vdso_direct = false;
-#endif
+ clocksource_counter.archdata.vdso_direct = vdso_default;
} else {
arch_timer_read_counter = arch_counter_get_cntvct_mem;
}
--
2.7.4
next prev parent reply other threads:[~2017-04-16 20:31 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-16 20:25 [GIT PULL] timers changes for 4.12 Daniel Lezcano
2017-04-16 20:26 ` [PATCH 01/29] arm64: Allow checking of a CPU-local erratum Daniel Lezcano
2017-04-16 20:26 ` [PATCH 02/29] arm64: Add CNTVCT_EL0 trap handler Daniel Lezcano
2017-04-16 20:26 ` [PATCH 03/29] arm64: Define Cortex-A73 MIDR Daniel Lezcano
2017-04-16 20:26 ` [PATCH 04/29] arm64: cpu_errata: Allow an erratum to be match for all revisions of a core Daniel Lezcano
2017-04-16 20:26 ` [PATCH 05/29] arm64: cpu_errata: Add capability to advertise Cortex-A73 erratum 858921 Daniel Lezcano
2017-04-16 20:26 ` [PATCH 06/29] arm64: arch_timer: Add infrastructure for multiple erratum detection methods Daniel Lezcano
2017-04-16 20:26 ` [PATCH 07/29] arm64: arch_timer: Add erratum handler for CPU-specific capability Daniel Lezcano
2017-04-16 20:26 ` [PATCH 08/29] arm64: arch_timer: Move arch_timer_reg_read/write around Daniel Lezcano
2017-04-16 20:26 ` [PATCH 09/29] arm64: arch_timer: Get rid of erratum_workaround_set_sne Daniel Lezcano
2017-04-16 20:27 ` [PATCH 10/29] arm64: arch_timer: Rework the set_next_event workarounds Daniel Lezcano
2017-04-16 20:27 ` [PATCH 11/29] arm64: arch_timer: Make workaround methods optional Daniel Lezcano
2017-04-16 20:27 ` [PATCH 12/29] arm64: arch_timer: Allows a CPU-specific erratum to only affect a subset of CPUs Daniel Lezcano
2017-04-16 20:27 ` [PATCH 13/29] arm64: arch_timer: Move clocksource_counter and co around Daniel Lezcano
2017-04-16 20:27 ` [PATCH 14/29] arm64: arch_timer: Save cntkctl_el1 as a per-cpu variable Daniel Lezcano
2017-04-16 20:27 ` Daniel Lezcano [this message]
2017-04-16 20:27 ` [PATCH 16/29] arm64: arch_timer: Workaround for Cortex-A73 erratum 858921 Daniel Lezcano
2017-04-16 20:27 ` [PATCH 17/29] arm64: arch_timer: Allow erratum matching with ACPI OEM information Daniel Lezcano
2017-04-16 20:27 ` [PATCH 18/29] arm64: arch_timer: Add HISILICON_ERRATUM_161010101 ACPI matching data Daniel Lezcano
2017-04-16 20:27 ` [PATCH 19/29] clocksource/drivers/orion: Read clock rate once Daniel Lezcano
2017-04-16 20:27 ` [PATCH 20/29] clocksource/drivers/orion: Add delay_timer implementation Daniel Lezcano
2017-04-16 20:27 ` [PATCH 21/29] clocksource: Add missing line break to error messages Daniel Lezcano
2017-04-24 7:45 ` Uwe Kleine-König
2017-04-16 20:27 ` [PATCH 22/29] dt-bindings: Clarify compatible property for rockchip timers Daniel Lezcano
2017-04-20 14:12 ` Rob Herring
2017-04-16 20:27 ` [PATCH 23/29] ARM: dts: rockchip: Update compatible property for rk322x timer Daniel Lezcano
2017-04-16 20:27 ` [PATCH 24/29] clocksource/drivers/rockchip_timer: Implement clocksource timer Daniel Lezcano
2017-04-16 20:27 ` [PATCH 25/29] ARM: dts: rockchip: Add timer entries to rk3188 SoC Daniel Lezcano
2017-04-16 20:27 ` [PATCH 26/29] ARM: dts: rockchip: disable arm-global-timer for rk3188 Daniel Lezcano
2017-04-16 20:27 ` [PATCH 27/29] clocksource: Augment bindings for Faraday timer Daniel Lezcano
2017-04-16 20:27 ` [PATCH 28/29] clocksource/drivers/gemini: Rename Gemini timer to Faraday Daniel Lezcano
2017-04-16 20:27 ` [PATCH 29/29] clocksource/drivers/fttmr010: Refactor to handle clock Daniel Lezcano
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