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author | Catalin Marinas <catalin.marinas@arm.com> | 2010-09-13 16:03:21 +0100 |
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committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2010-11-04 15:44:31 +0000 |
commit | 247055aa21ffef1c49dd64710d5e94c2aee19b58 (patch) | |
tree | e9e026b96597d080de4c16bb88c17b0495c61904 /arch/arm/kernel | |
parent | ff8b16d7e15a8ba2a6086645614a483e048e3fbf (diff) | |
download | op-kernel-dev-247055aa21ffef1c49dd64710d5e94c2aee19b58.zip op-kernel-dev-247055aa21ffef1c49dd64710d5e94c2aee19b58.tar.gz |
ARM: 6384/1: Remove the domain switching on ARMv6k/v7 CPUs
This patch removes the domain switching functionality via the set_fs and
__switch_to functions on cores that have a TLS register.
Currently, the ioremap and vmalloc areas share the same level 1 page
tables and therefore have the same domain (DOMAIN_KERNEL). When the
kernel domain is modified from Client to Manager (via the __set_fs or in
the __switch_to function), the XN (eXecute Never) bit is overridden and
newer CPUs can speculatively prefetch the ioremap'ed memory.
Linux performs the kernel domain switching to allow user-specific
functions (copy_to/from_user, get/put_user etc.) to access kernel
memory. In order for these functions to work with the kernel domain set
to Client, the patch modifies the LDRT/STRT and related instructions to
the LDR/STR ones.
The user pages access rights are also modified for kernel read-only
access rather than read/write so that the copy-on-write mechanism still
works. CPU_USE_DOMAINS gets disabled only if the hardware has a TLS register
(CPU_32v6K is defined) since writing the TLS value to the high vectors page
isn't possible.
The user addresses passed to the kernel are checked by the access_ok()
function so that they do not point to the kernel space.
Tested-by: Anton Vorontsov <cbouatmailru@gmail.com>
Cc: Tony Lindgren <tony@atomide.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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.S | 4 | ||||
-rw-r--r-- | arch/arm/kernel/fiq.c | 5 | ||||
-rw-r--r-- | arch/arm/kernel/traps.c | 14 |
3 files changed, 17 insertions, 6 deletions
diff --git a/arch/arm/kernel/entry-armv.S b/arch/arm/kernel/entry-armv.S index c09e357..35f3f20 100644 --- a/arch/arm/kernel/entry-armv.S +++ b/arch/arm/kernel/entry-armv.S @@ -735,7 +735,7 @@ ENTRY(__switch_to) THUMB( stmia ip!, {r4 - sl, fp} ) @ Store most regs on stack THUMB( str sp, [ip], #4 ) THUMB( str lr, [ip], #4 ) -#ifdef CONFIG_MMU +#ifdef CONFIG_CPU_USE_DOMAINS ldr r6, [r2, #TI_CPU_DOMAIN] #endif set_tls r3, r4, r5 @@ -744,7 +744,7 @@ ENTRY(__switch_to) ldr r8, =__stack_chk_guard ldr r7, [r7, #TSK_STACK_CANARY] #endif -#ifdef CONFIG_MMU +#ifdef CONFIG_CPU_USE_DOMAINS mcr p15, 0, r6, c3, c0, 0 @ Set domain register #endif mov r5, r0 diff --git a/arch/arm/kernel/fiq.c b/arch/arm/kernel/fiq.c index 6ff7919..d601ef2 100644 --- a/arch/arm/kernel/fiq.c +++ b/arch/arm/kernel/fiq.c @@ -45,6 +45,7 @@ #include <asm/fiq.h> #include <asm/irq.h> #include <asm/system.h> +#include <asm/traps.h> static unsigned long no_fiq_insn; @@ -77,7 +78,11 @@ int show_fiq_list(struct seq_file *p, void *v) void set_fiq_handler(void *start, unsigned int length) { +#if defined(CONFIG_CPU_USE_DOMAINS) memcpy((void *)0xffff001c, start, length); +#else + memcpy(vectors_page + 0x1c, start, length); +#endif flush_icache_range(0xffff001c, 0xffff001c + length); if (!vectors_high()) flush_icache_range(0x1c, 0x1c + length); diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c index cda78d5..87abca0 100644 --- a/arch/arm/kernel/traps.c +++ b/arch/arm/kernel/traps.c @@ -37,6 +37,8 @@ static const char *handler[]= { "prefetch abort", "data abort", "address exception", "interrupt" }; +void *vectors_page; + #ifdef CONFIG_DEBUG_USER unsigned int user_debug; @@ -759,7 +761,11 @@ static void __init kuser_get_tls_init(unsigned long vectors) void __init early_trap_init(void) { +#if defined(CONFIG_CPU_USE_DOMAINS) unsigned long vectors = CONFIG_VECTORS_BASE; +#else + unsigned long vectors = (unsigned long)vectors_page; +#endif extern char __stubs_start[], __stubs_end[]; extern char __vectors_start[], __vectors_end[]; extern char __kuser_helper_start[], __kuser_helper_end[]; @@ -783,10 +789,10 @@ void __init early_trap_init(void) * Copy signal return handlers into the vector page, and * set sigreturn to be a pointer to these. */ - memcpy((void *)KERN_SIGRETURN_CODE, sigreturn_codes, - sizeof(sigreturn_codes)); - memcpy((void *)KERN_RESTART_CODE, syscall_restart_code, - sizeof(syscall_restart_code)); + memcpy((void *)(vectors + KERN_SIGRETURN_CODE - CONFIG_VECTORS_BASE), + sigreturn_codes, sizeof(sigreturn_codes)); + memcpy((void *)(vectors + KERN_RESTART_CODE - CONFIG_VECTORS_BASE), + syscall_restart_code, sizeof(syscall_restart_code)); flush_icache_range(vectors, vectors + PAGE_SIZE); modify_domain(DOMAIN_USER, DOMAIN_CLIENT); |