Messages in this thread Patch in this message | | | Date | Thu, 1 Dec 2011 09:26:39 +0000 | From | Catalin Marinas <> | Subject | Re: [RFC PATCH 4/6] ARM: Remove __ARCH_WANT_INTERRUPTS_ON_CTXSW on ASID-capable CPUs |
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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).
-- Catalin
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