[PATCHv5 07/16] arm: arch_timer: add isbs to register accessors

[PATCHv5 00/16] Unify arm_generic and arch_timer drivers · mark.rutland@arm.com (Mark Rutland) · 2013-01-31
[PATCHv5 01/16] arm: arch_timer: balance device_node refcounting · mark.rutland@arm.com (Mark Rutland) · 2013-01-31
[PATCHv5 01/16] arm: arch_timer: balance device_node refcounting · catalin.marinas@arm.com (Catalin Marinas) · 2013-01-31
[PATCHv5 02/16] arm: arch_timer: remove redundant available check · mark.rutland@arm.com (Mark Rutland) · 2013-01-31
[PATCHv5 03/16] arm: arch_timer: use u64/u32 for register data · mark.rutland@arm.com (Mark Rutland) · 2013-01-31
[PATCHv5 04/16] arm: arch_timer: standardise counter reading · mark.rutland@arm.com (Mark Rutland) · 2013-01-31
[PATCHv5 04/16] arm: arch_timer: standardise counter reading · catalin.marinas@arm.com (Catalin Marinas) · 2013-01-31
[PATCHv5 05/16] arm: arch_timer: split cntfrq accessor · mark.rutland@arm.com (Mark Rutland) · 2013-01-31
[PATCHv5 06/16] arm: arch_timer: factor out register accessors · mark.rutland@arm.com (Mark Rutland) · 2013-01-31
[PATCHv5 07/16] arm: arch_timer: add isbs to register accessors · mark.rutland@arm.com (Mark Rutland) · 2013-01-31
[PATCHv5 07/16] arm: arch_timer: add isbs to register accessors · catalin.marinas@arm.com (Catalin Marinas) · 2013-01-31
[PATCHv5 08/16] arm: arch_timer: divorce from local_timer api · mark.rutland@arm.com (Mark Rutland) · 2013-01-31
[PATCHv5 09/16] arm: arch_timer: add arch_counter_set_user_access · mark.rutland@arm.com (Mark Rutland) · 2013-01-31
[PATCHv5 09/16] arm: arch_timer: add arch_counter_set_user_access · catalin.marinas@arm.com (Catalin Marinas) · 2013-01-31
[PATCHv5 10/16] arm: arch_timer: move core to drivers/clocksource · mark.rutland@arm.com (Mark Rutland) · 2013-01-31
[PATCHv5 11/16] arm64: arm_generic: prevent reading stale time · mark.rutland@arm.com (Mark Rutland) · 2013-01-31
[PATCHv5 11/16] arm64: arm_generic: prevent reading stale time · catalin.marinas@arm.com (Catalin Marinas) · 2013-01-31
[PATCHv5 12/16] arm64: move from arm_generic to arm_arch_timer · mark.rutland@arm.com (Mark Rutland) · 2013-01-31
[PATCHv5 13/16] Documentation: Add ARMv8 to arch_timer devicetree · mark.rutland@arm.com (Mark Rutland) · 2013-01-31
[PATCHv5 14/16] ARM: arch_timers: switch to physical timers if HYP mode is available · mark.rutland@arm.com (Mark Rutland) · 2013-01-31
[PATCHv5 14/16] ARM: arch_timers: switch to physical timers if HYP mode is available · catalin.marinas@arm.com (Catalin Marinas) · 2013-01-31
[PATCHv5 15/16] ARM: hyp: initialize CNTVOFF to zero · mark.rutland@arm.com (Mark Rutland) · 2013-01-31
[PATCHv5 15/16] ARM: hyp: initialize CNTVOFF to zero · Dave Martin <hidden> · 2013-02-01
[PATCHv5 15/16] ARM: hyp: initialize CNTVOFF to zero · Marc Zyngier <hidden> · 2013-02-01
[PATCHv5 15/16] ARM: hyp: initialize CNTVOFF to zero · mark.rutland@arm.com (Mark Rutland) · 2013-02-01
[PATCHv5 15/16] ARM: hyp: initialize CNTVOFF to zero · Dave Martin <hidden> · 2013-02-01
[PATCHv5 15/16] ARM: hyp: initialize CNTVOFF to zero · mark.rutland@arm.com (Mark Rutland) · 2013-02-04
[PATCHv5 16/16] clocksource: arch_timer: use virtual counters · mark.rutland@arm.com (Mark Rutland) · 2013-01-31
[PATCHv5 16/16] clocksource: arch_timer: use virtual counters · catalin.marinas@arm.com (Catalin Marinas) · 2013-01-31
[PATCHv5 00/16] Unify arm_generic and arch_timer drivers · Stephen Warren <hidden> · 2013-01-31

From: catalin.marinas@arm.com (Catalin Marinas)
Date: 2013-01-31 15:35:45

On Thu, Jan 31, 2013 at 12:15:30PM +0000, Mark Rutland wrote:

Without the isbs in arch_timer_get_cnt{p,v}ct the cpu may speculate
reads and return stale values. This could be bad for code sensitive to
changes in expected deltas between calls (e.g. the delay loop).

Without isbs in arch_timer_reg_write the processor may reorder
instructions around enabling/disabling of the timer or writing the
compare value, which we probably don't want.

This patch adds isbs to prevent those issues.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>

Acked-by: Catalin Marinas <catalin.marinas@arm.com>

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