Revert "ARM: 6944/1: mm: allow ASID 0 to be allocated to tasks"
Russell King [Thu, 9 Jun 2011 09:12:41 +0000 (10:12 +0100)]
This reverts commit 45b95235b0ac86cef2ad4480b0618b8778847479.

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 context switching.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
(cherry picked from commit a0a54d37b4b1d1f55d1e81e8ffc223bb85472fa3)
Change-Id: Id3bd7c795bb84269b646e6a1344d1974d85bf094
Signed-off-by: Bo Yan <byan@nvidia.com>
Reviewed-on: http://git-master/r/209825
GVS: Gerrit_Virtual_Submit
Reviewed-by: Krishna Reddy <vdumpa@nvidia.com>
Reviewed-by: Yu-Huan Hsu <yhsu@nvidia.com>

arch/arm/mm/context.c

index 8df5830..806cc4f 100644 (file)
@@ -108,7 +108,7 @@ static void reset_context(void *info)
        struct mm_struct *mm = current->active_mm;
 
        smp_rmb();
-       asid = cpu_last_asid + cpu;
+       asid = cpu_last_asid + cpu + 1;
 
        flush_context();
        set_mm_context(mm, asid);
@@ -157,13 +157,13 @@ void __new_context(struct mm_struct *mm)
         * to start a new version and flush the TLB.
         */
        if (unlikely((asid & ~ASID_MASK) == 0)) {
-               asid = cpu_last_asid + smp_processor_id();
+               asid = cpu_last_asid + smp_processor_id() + 1;
                flush_context();
 #ifdef CONFIG_SMP
                smp_wmb();
                smp_call_function(reset_context, NULL, 1);
 #endif
-               cpu_last_asid += NR_CPUS - 1;
+               cpu_last_asid += NR_CPUS;
        }
 
        set_mm_context(mm, asid);