diff options
| author | Russell King <rmk+kernel@arm.linux.org.uk> | 2011-06-09 10:10:27 +0100 |
|---|---|---|
| committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2011-06-09 10:13:04 +0100 |
| commit | 07989b7ad63af424886ff922fd3bcca9e00ffa78 (patch) | |
| tree | 5c3107ae9a50906de180addf6a111dab60e2427d /arch | |
| parent | 17ee083b7897ab27b4949c42de805889ebd2b4c5 (diff) | |
Revert "ARM: 6943/1: mm: use TTBR1 instead of reserved context ID"
This reverts commit 52af9c6cd863fe37d1103035ec7ee22ac1296458.
Will Deacon reports that:
In 52af9c6c ("ARM: 6943/1: mm: use TTBR1 instead of reserved context ID")
I updated the ASID rollover code to use only the kernel page tables
whilst updating the ASID.
Unfortunately, the code to restore the user page tables was part of a
later patch which isn't yet in mainline, so this leaves the code
quite broken.
We're also in the process of eliminating __ARCH_WANT_INTERRUPTS_ON_CTXSW
from ARM, so lets revert these until we can properly sort out what we're
doing with the ARM context switching.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/arm/mm/context.c | 11 | ||||
| -rw-r--r-- | arch/arm/mm/proc-v7.S | 10 |
2 files changed, 11 insertions, 10 deletions
diff --git a/arch/arm/mm/context.c b/arch/arm/mm/context.c index 8bfae964b13..b6c776ae403 100644 --- a/arch/arm/mm/context.c +++ b/arch/arm/mm/context.c @@ -24,7 +24,9 @@ DEFINE_PER_CPU(struct mm_struct *, current_mm); /* * We fork()ed a process, and we need a new context for the child - * to run in. + * to run in. We reserve version 0 for initial tasks so we will + * always allocate an ASID. The ASID 0 is reserved for the TTBR + * register changing sequence. */ void __init_new_context(struct task_struct *tsk, struct mm_struct *mm) { @@ -34,11 +36,8 @@ void __init_new_context(struct task_struct *tsk, struct mm_struct *mm) static void flush_context(void) { - u32 ttb; - /* Copy TTBR1 into TTBR0 */ - asm volatile("mrc p15, 0, %0, c2, c0, 1\n" - "mcr p15, 0, %0, c2, c0, 0" - : "=r" (ttb)); + /* set the reserved ASID before flushing the TLB */ + asm("mcr p15, 0, %0, c13, c0, 1\n" : : "r" (0)); isb(); local_flush_tlb_all(); if (icache_is_vivt_asid_tagged()) { diff --git a/arch/arm/mm/proc-v7.S b/arch/arm/mm/proc-v7.S index b3b566ec83d..3c3867850a3 100644 --- a/arch/arm/mm/proc-v7.S +++ b/arch/arm/mm/proc-v7.S @@ -108,16 +108,18 @@ 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 +#ifdef CONFIG_ARM_ERRATA_754322 + dsb +#endif + mcr p15, 0, r2, c13, c0, 1 @ set reserved context ID + isb +1: mcr p15, 0, r0, c2, c0, 0 @ set TTB 0 isb #ifdef CONFIG_ARM_ERRATA_754322 dsb #endif mcr p15, 0, r1, c13, c0, 1 @ set context ID isb - mcr p15, 0, r0, c2, c0, 0 @ set TTB 0 - isb #endif mov pc, lr ENDPROC(cpu_v7_switch_mm) |