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authorRussell King <rmk+kernel@arm.linux.org.uk>2015-08-19 21:23:48 +0100
committerRussell King <rmk+kernel@arm.linux.org.uk>2015-08-21 13:55:49 +0100
commit1eef5d2f1b461c120bcd82077edee5ec706ac53b (patch)
treeb95a7132189a44d9a826e7b44fbbe5cae74d75fb /arch/arm/kernel
parentd770e558e21961ad6cfdf0ff7df0eb5d7d4f0754 (diff)
downloadlinux-linaro-stable-1eef5d2f1b461c120bcd82077edee5ec706ac53b.tar.gz
ARM: domains: switch to keeping domain value in register
Rather than modifying both the domain access control register and our per-thread copy, modify only the domain access control register, and use the per-thread copy to save and restore the register over context switches. We can also avoid the explicit initialisation of the init thread_info structure. This allows us to avoid needing to gain access to the thread information at the uaccess control sites. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch/arm/kernel')
-rw-r--r--arch/arm/kernel/entry-armv.S2
-rw-r--r--arch/arm/kernel/process.c13
2 files changed, 12 insertions, 3 deletions
diff --git a/arch/arm/kernel/entry-armv.S b/arch/arm/kernel/entry-armv.S
index 7dac3086e361..d19adcf6c580 100644
--- a/arch/arm/kernel/entry-armv.S
+++ b/arch/arm/kernel/entry-armv.S
@@ -770,6 +770,8 @@ ENTRY(__switch_to)
ldr r4, [r2, #TI_TP_VALUE]
ldr r5, [r2, #TI_TP_VALUE + 4]
#ifdef CONFIG_CPU_USE_DOMAINS
+ mrc p15, 0, r6, c3, c0, 0 @ Get domain register
+ str r6, [r1, #TI_CPU_DOMAIN] @ Save old domain register
ldr r6, [r2, #TI_CPU_DOMAIN]
#endif
switch_tls r1, r4, r5, r3, r7
diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c
index f192a2a41719..e722f9b3c9b1 100644
--- a/arch/arm/kernel/process.c
+++ b/arch/arm/kernel/process.c
@@ -146,10 +146,9 @@ void __show_regs(struct pt_regs *regs)
buf[0] = '\0';
#ifdef CONFIG_CPU_CP15_MMU
{
- unsigned int transbase, dac;
+ unsigned int transbase, dac = get_domain();
asm("mrc p15, 0, %0, c2, c0\n\t"
- "mrc p15, 0, %1, c3, c0\n"
- : "=r" (transbase), "=r" (dac));
+ : "=r" (transbase));
snprintf(buf, sizeof(buf), " Table: %08x DAC: %08x",
transbase, dac);
}
@@ -210,6 +209,14 @@ copy_thread(unsigned long clone_flags, unsigned long stack_start,
memset(&thread->cpu_context, 0, sizeof(struct cpu_context_save));
+ /*
+ * Copy the initial value of the domain access control register
+ * from the current thread: thread->addr_limit will have been
+ * copied from the current thread via setup_thread_stack() in
+ * kernel/fork.c
+ */
+ thread->cpu_domain = get_domain();
+
if (likely(!(p->flags & PF_KTHREAD))) {
*childregs = *current_pt_regs();
childregs->ARM_r0 = 0;