diff options
author | Russell King <rmk+kernel@arm.linux.org.uk> | 2015-08-19 21:23:48 +0100 |
---|---|---|
committer | Kees Cook <keescook@chromium.org> | 2015-11-18 11:10:40 -0800 |
commit | aa52a1a1333542cd0808c0671151f52c10c473e7 (patch) | |
tree | 025bb084499fb4eee7023b87347dfa4946177012 | |
parent | 3a3a2f8558f773fce7382651c9aaeb07c9d2cf72 (diff) | |
download | v4.1-aa52a1a1333542cd0808c0671151f52c10c473e7.tar.gz |
UPSTREAM: 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>
Bug: 25672827
Patchset: PAN emulation
(cherry picked from commit 1eef5d2f1b461c120bcd82077edee5ec706ac53b)
Signed-off-by: Kees Cook <keescook@google.com>
Change-Id: If903ec86006c4de1a440bf918c5d2491e34ade05
-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 6ddbe446425..7f294190571 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 bd32eded3e5..0a0aec410d8 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 b953d72ef51..a7f6e2a8446 100644 --- a/arch/arm/kernel/entry-armv.S +++ b/arch/arm/kernel/entry-armv.S @@ -782,6 +782,8 @@ 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 f192a2a4171..e722f9b3c9b 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; |