Messages in this thread | | | Date | Thu, 1 Dec 2011 11:42:32 -0800 | From | Frank Rowand <> | Subject | Re: [RFC PATCH 4/6] ARM: Remove __ARCH_WANT_INTERRUPTS_ON_CTXSW on ASID-capable CPUs |
| |
On 12/01/11 01:26, Catalin Marinas wrote: > On Thu, Dec 01, 2011 at 02:57:07AM +0000, Frank Rowand wrote: >> On 11/29/11 04:22, Catalin Marinas wrote: >>> Since the ASIDs must be unique to an mm across all the CPUs in a system, >>> the __new_context() function needs to broadcast a context reset event to >>> all the CPUs during ASID allocation if a roll-over occurred. Such IPIs >>> cannot be issued with interrupts disabled and ARM had to define >>> __ARCH_WANT_INTERRUPTS_ON_CTXSW. >>> >>> This patch changes the check_context() function to >>> check_and_switch_context() called from switch_mm(). In case of >>> ASID-capable CPUs (ARMv6 onwards), if a new ASID is needed, it defers >>> the __new_context() and cpu_switch_mm() calls to the post-lock switch >>> hook where the interrupts are enabled. Setting the reserved TTBR0 was >>> also moved to check_and_switch_context() from cpu_v7_switch_mm(). >>> >>> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> >>> Cc: Russell King <linux@arm.linux.org.uk> >>> --- >>> arch/arm/include/asm/mmu_context.h | 81 ++++++++++++++++++++++++++++-------- >>> arch/arm/include/asm/system.h | 2 + >>> arch/arm/include/asm/thread_info.h | 1 + >>> arch/arm/mm/context.c | 4 +- >>> arch/arm/mm/proc-v7.S | 3 - >>> 5 files changed, 69 insertions(+), 22 deletions(-) >>> >> >> < snip > >> >>> diff --git a/arch/arm/mm/proc-v7.S b/arch/arm/mm/proc-v7.S >>> index 2faff3b..d5334d9 100644 >>> --- a/arch/arm/mm/proc-v7.S >>> +++ b/arch/arm/mm/proc-v7.S >>> @@ -116,9 +116,6 @@ ENTRY(cpu_v7_switch_mm) >>> #ifdef CONFIG_ARM_ERRATA_430973 >>> mcr p15, 0, r2, c7, c5, 6 @ flush BTAC/BTB >>> #endif >>> - mrc p15, 0, r2, c2, c0, 1 @ load TTB 1 >>> - mcr p15, 0, r2, c2, c0, 0 @ into TTB 0 >>> - isb >>> #ifdef CONFIG_ARM_ERRATA_754322 >>> dsb >>> #endif >> >> I do not have a tree that matches this version of cpu_v7_switch_mm(). >> Can you point me at a tree that I can see this in? > > That's added by the second patch in the series (and removed in a later > patch but it is a logical change in both situations and keeps the code > bisectable). >
Ah, yes! Thanks.
-Frank
| |