From: mark.rutland@arm.com (Mark Rutland)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCHv5 11/16] arm64: arm_generic: prevent reading stale time
Date: Thu, 31 Jan 2013 12:15:34 +0000 [thread overview]
Message-ID: <1359634539-9580-12-git-send-email-mark.rutland@arm.com> (raw)
In-Reply-To: <1359634539-9580-1-git-send-email-mark.rutland@arm.com>
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 <mark.rutland@arm.com>
---
arch/arm64/include/asm/arm_generic.h | 2 ++
1 file changed, 2 insertions(+)
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;
--
1.8.1.1
next prev parent reply other threads:[~2013-01-31 12:15 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-01-31 12:15 [PATCHv5 00/16] Unify arm_generic and arch_timer drivers Mark Rutland
2013-01-31 12:15 ` [PATCHv5 01/16] arm: arch_timer: balance device_node refcounting Mark Rutland
2013-01-31 15:33 ` Catalin Marinas
2013-01-31 12:15 ` [PATCHv5 02/16] arm: arch_timer: remove redundant available check Mark Rutland
2013-01-31 12:15 ` [PATCHv5 03/16] arm: arch_timer: use u64/u32 for register data Mark Rutland
2013-01-31 12:15 ` [PATCHv5 04/16] arm: arch_timer: standardise counter reading Mark Rutland
2013-01-31 15:34 ` Catalin Marinas
2013-01-31 12:15 ` [PATCHv5 05/16] arm: arch_timer: split cntfrq accessor Mark Rutland
2013-01-31 12:15 ` [PATCHv5 06/16] arm: arch_timer: factor out register accessors Mark Rutland
2013-01-31 12:15 ` [PATCHv5 07/16] arm: arch_timer: add isbs to " Mark Rutland
2013-01-31 15:35 ` Catalin Marinas
2013-01-31 12:15 ` [PATCHv5 08/16] arm: arch_timer: divorce from local_timer api Mark Rutland
2013-01-31 12:15 ` [PATCHv5 09/16] arm: arch_timer: add arch_counter_set_user_access Mark Rutland
2013-01-31 15:36 ` Catalin Marinas
2013-01-31 12:15 ` [PATCHv5 10/16] arm: arch_timer: move core to drivers/clocksource Mark Rutland
2013-01-31 12:15 ` Mark Rutland [this message]
2013-01-31 15:36 ` [PATCHv5 11/16] arm64: arm_generic: prevent reading stale time Catalin Marinas
2013-01-31 12:15 ` [PATCHv5 12/16] arm64: move from arm_generic to arm_arch_timer Mark Rutland
2013-01-31 12:15 ` [PATCHv5 13/16] Documentation: Add ARMv8 to arch_timer devicetree Mark Rutland
2013-01-31 12:15 ` [PATCHv5 14/16] ARM: arch_timers: switch to physical timers if HYP mode is available Mark Rutland
2013-01-31 15:37 ` Catalin Marinas
2013-01-31 12:15 ` [PATCHv5 15/16] ARM: hyp: initialize CNTVOFF to zero Mark Rutland
2013-02-01 11:13 ` Dave Martin
2013-02-01 11:43 ` Marc Zyngier
2013-02-01 11:46 ` Mark Rutland
2013-02-01 18:07 ` Dave Martin
2013-02-04 9:29 ` Mark Rutland
2013-01-31 12:15 ` [PATCHv5 16/16] clocksource: arch_timer: use virtual counters Mark Rutland
2013-01-31 15:38 ` Catalin Marinas
2013-01-31 17:39 ` [PATCHv5 00/16] Unify arm_generic and arch_timer drivers Stephen Warren
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