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ARM: domains: switch to keeping domain value in register

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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>
This commit is contained in:
Russell King 2015-08-19 21:23:48 +01:00
parent d770e558e2
commit 1eef5d2f1b
4 changed files with 27 additions and 11 deletions
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20
arch/arm/include/asm/domain.h
View File

@ -59,6 +59,17 @@
#ifndef __ASSEMBLY__ #ifndef __ASSEMBLY__
static inline unsigned int get_domain(void)
{
unsigned int domain;
asm(
"mrc p15, 0, %0, c3, c0 @ get domain"
: "=r" (domain));
return domain;
}
#ifdef CONFIG_CPU_USE_DOMAINS #ifdef CONFIG_CPU_USE_DOMAINS
static inline void set_domain(unsigned val) static inline void set_domain(unsigned val)
{ {
@ -70,11 +81,10 @@ static inline void set_domain(unsigned val)
#define modify_domain(dom,type) \ #define modify_domain(dom,type) \
do { \ do { \
struct thread_info *thread = current_thread_info(); \ unsigned int domain = get_domain(); \
unsigned int domain = thread->cpu_domain; \ domain &= ~domain_val(dom, DOMAIN_MANAGER); \
domain &= ~domain_val(dom, DOMAIN_MANAGER); \ domain = domain | domain_val(dom, type); \
thread->cpu_domain = domain | domain_val(dom, type); \ set_domain(domain); \
set_domain(thread->cpu_domain); \
} while (0) } while (0)
#else #else

3
arch/arm/include/asm/thread_info.h
View File

@ -74,9 +74,6 @@ struct thread_info {
.flags = 0, \ .flags = 0, \
.preempt_count = INIT_PREEMPT_COUNT, \ .preempt_count = INIT_PREEMPT_COUNT, \
.addr_limit = KERNEL_DS, \ .addr_limit = KERNEL_DS, \
.cpu_domain = domain_val(DOMAIN_USER, DOMAIN_MANAGER) | \
domain_val(DOMAIN_KERNEL, DOMAIN_MANAGER) | \
domain_val(DOMAIN_IO, DOMAIN_CLIENT), \
} }
#define init_thread_info (init_thread_union.thread_info) #define init_thread_info (init_thread_union.thread_info)

2
arch/arm/kernel/entry-armv.S
View File

@ -770,6 +770,8 @@ ENTRY(__switch_to)
ldr r4, [r2, #TI_TP_VALUE] ldr r4, [r2, #TI_TP_VALUE]
ldr r5, [r2, #TI_TP_VALUE + 4] ldr r5, [r2, #TI_TP_VALUE + 4]
#ifdef CONFIG_CPU_USE_DOMAINS #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] ldr r6, [r2, #TI_CPU_DOMAIN]
#endif #endif
switch_tls r1, r4, r5, r3, r7 switch_tls r1, r4, r5, r3, r7

13
arch/arm/kernel/process.c
View File

@ -146,10 +146,9 @@ void __show_regs(struct pt_regs *regs)
buf[0] = '\0'; buf[0] = '\0';
#ifdef CONFIG_CPU_CP15_MMU #ifdef CONFIG_CPU_CP15_MMU
{ {
unsigned int transbase, dac; unsigned int transbase, dac = get_domain();
asm("mrc p15, 0, %0, c2, c0\n\t" asm("mrc p15, 0, %0, c2, c0\n\t"
"mrc p15, 0, %1, c3, c0\n" : "=r" (transbase));
: "=r" (transbase), "=r" (dac));
snprintf(buf, sizeof(buf), " Table: %08x DAC: %08x", snprintf(buf, sizeof(buf), " Table: %08x DAC: %08x",
transbase, dac); 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)); 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))) { if (likely(!(p->flags & PF_KTHREAD))) {
*childregs = *current_pt_regs(); *childregs = *current_pt_regs();
childregs->ARM_r0 = 0; childregs->ARM_r0 = 0;