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author | Russell King <rmk+kernel@arm.linux.org.uk> | 2015-08-19 20:23:48 (GMT) |
---|---|---|
committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2015-08-21 12:55:49 (GMT) |
commit | 1eef5d2f1b461c120bcd82077edee5ec706ac53b (patch) | |
tree | b95a7132189a44d9a826e7b44fbbe5cae74d75fb /arch/arm | |
parent | d770e558e21961ad6cfdf0ff7df0eb5d7d4f0754 (diff) | |
download | linux-1eef5d2f1b461c120bcd82077edee5ec706ac53b.tar.xz |
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')
-rw-r--r-- | arch/arm/include/asm/domain.h | 20 | ||||
-rw-r--r-- | arch/arm/include/asm/thread_info.h | 3 | ||||
-rw-r--r-- | arch/arm/kernel/entry-armv.S | 2 | ||||
-rw-r--r-- | arch/arm/kernel/process.c | 13 |
4 files changed, 27 insertions, 11 deletions
diff --git a/arch/arm/include/asm/domain.h b/arch/arm/include/asm/domain.h index 6ddbe44..7f29419 100644 --- a/arch/arm/include/asm/domain.h +++ b/arch/arm/include/asm/domain.h @@ -59,6 +59,17 @@ #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 static inline void set_domain(unsigned val) { @@ -70,11 +81,10 @@ static inline void set_domain(unsigned val) #define modify_domain(dom,type) \ do { \ - struct thread_info *thread = current_thread_info(); \ - unsigned int domain = thread->cpu_domain; \ - domain &= ~domain_val(dom, DOMAIN_MANAGER); \ - thread->cpu_domain = domain | domain_val(dom, type); \ - set_domain(thread->cpu_domain); \ + unsigned int domain = get_domain(); \ + domain &= ~domain_val(dom, DOMAIN_MANAGER); \ + domain = domain | domain_val(dom, type); \ + set_domain(domain); \ } while (0) #else diff --git a/arch/arm/include/asm/thread_info.h b/arch/arm/include/asm/thread_info.h index bd32ede..0a0aec4 100644 --- a/arch/arm/include/asm/thread_info.h +++ b/arch/arm/include/asm/thread_info.h @@ -74,9 +74,6 @@ struct thread_info { .flags = 0, \ .preempt_count = INIT_PREEMPT_COUNT, \ .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) diff --git a/arch/arm/kernel/entry-armv.S b/arch/arm/kernel/entry-armv.S index 7dac308..d19adcf 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 f192a2a..e722f9b 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; |