ARM: pm: no need to save/restore context ID register
There is no need to save and restore the context ID register on ARMv6
and ARMv7 with a temporary page table as we write the context ID
register when we switch back to the real page tables for the thread.
Moreover, the temporary page tables do not contain any non-global
mappings, so the context ID value should not be used. To be safe,
initialize the register to a reserved context ID value.
Tested-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Tested-by: Shawn Guo <shawn.guo@linaro.org>
Tested-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/mm/proc-v7.S b/arch/arm/mm/proc-v7.S
index b56004f..6af366c 100644
--- a/arch/arm/mm/proc-v7.S
+++ b/arch/arm/mm/proc-v7.S
@@ -217,14 +217,13 @@
/* Suspend/resume support: derived from arch/arm/mach-s5pv210/sleep.S */
.globl cpu_v7_suspend_size
-.equ cpu_v7_suspend_size, 4 * 8
+.equ cpu_v7_suspend_size, 4 * 7
#ifdef CONFIG_PM_SLEEP
ENTRY(cpu_v7_do_suspend)
stmfd sp!, {r4 - r10, lr}
mrc p15, 0, r4, c13, c0, 0 @ FCSE/PID
- mrc p15, 0, r5, c13, c0, 1 @ Context ID
- mrc p15, 0, r6, c13, c0, 3 @ User r/o thread ID
- stmia r0!, {r4 - r6}
+ mrc p15, 0, r5, c13, c0, 3 @ User r/o thread ID
+ stmia r0!, {r4 - r5}
mrc p15, 0, r6, c3, c0, 0 @ Domain ID
mrc p15, 0, r7, c2, c0, 1 @ TTB 1
mrc p15, 0, r8, c1, c0, 0 @ Control register
@@ -238,10 +237,10 @@
mov ip, #0
mcr p15, 0, ip, c8, c7, 0 @ invalidate TLBs
mcr p15, 0, ip, c7, c5, 0 @ invalidate I cache
- ldmia r0!, {r4 - r6}
+ mcr p15, 0, ip, c13, c0, 1 @ set reserved context ID
+ ldmia r0!, {r4 - r5}
mcr p15, 0, r4, c13, c0, 0 @ FCSE/PID
- mcr p15, 0, r5, c13, c0, 1 @ Context ID
- mcr p15, 0, r6, c13, c0, 3 @ User r/o thread ID
+ mcr p15, 0, r5, c13, c0, 3 @ User r/o thread ID
ldmia r0, {r6 - r10}
mcr p15, 0, r6, c3, c0, 0 @ Domain ID
ALT_SMP(orr r1, r1, #TTB_FLAGS_SMP)