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| author | Catalin Marinas <catalin.marinas@arm.com> | 2010-09-13 17:03:21 +0200 |
|---|---|---|
| committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2010-11-04 16:44:31 +0100 |
| commit | 247055aa21ffef1c49dd64710d5e94c2aee19b58 (patch) | |
| tree | e9e026b96597d080de4c16bb88c17b0495c61904 /arch/arm/lib/putuser.S | |
| parent | vmstat: fix offset calculation on void* (diff) | |
| download | linux-247055aa21ffef1c49dd64710d5e94c2aee19b58.tar.xz linux-247055aa21ffef1c49dd64710d5e94c2aee19b58.zip | |
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/lib/putuser.S')
| -rw-r--r-- | arch/arm/lib/putuser.S | 29 |
1 files changed, 15 insertions, 14 deletions
diff --git a/arch/arm/lib/putuser.S b/arch/arm/lib/putuser.S index 5a01a23c6c06..c023fc11e86c 100644 --- a/arch/arm/lib/putuser.S +++ b/arch/arm/lib/putuser.S @@ -28,9 +28,10 @@ */ #include <linux/linkage.h> #include <asm/errno.h> +#include <asm/domain.h> ENTRY(__put_user_1) -1: strbt r2, [r0] +1: T(strb) r2, [r0] mov r0, #0 mov pc, lr ENDPROC(__put_user_1) @@ -39,19 +40,19 @@ ENTRY(__put_user_2) mov ip, r2, lsr #8 #ifdef CONFIG_THUMB2_KERNEL #ifndef __ARMEB__ -2: strbt r2, [r0] -3: strbt ip, [r0, #1] +2: T(strb) r2, [r0] +3: T(strb) ip, [r0, #1] #else -2: strbt ip, [r0] -3: strbt r2, [r0, #1] +2: T(strb) ip, [r0] +3: T(strb) r2, [r0, #1] #endif #else /* !CONFIG_THUMB2_KERNEL */ #ifndef __ARMEB__ -2: strbt r2, [r0], #1 -3: strbt ip, [r0] +2: T(strb) r2, [r0], #1 +3: T(strb) ip, [r0] #else -2: strbt ip, [r0], #1 -3: strbt r2, [r0] +2: T(strb) ip, [r0], #1 +3: T(strb) r2, [r0] #endif #endif /* CONFIG_THUMB2_KERNEL */ mov r0, #0 @@ -59,18 +60,18 @@ ENTRY(__put_user_2) ENDPROC(__put_user_2) ENTRY(__put_user_4) -4: strt r2, [r0] +4: T(str) r2, [r0] mov r0, #0 mov pc, lr ENDPROC(__put_user_4) ENTRY(__put_user_8) #ifdef CONFIG_THUMB2_KERNEL -5: strt r2, [r0] -6: strt r3, [r0, #4] +5: T(str) r2, [r0] +6: T(str) r3, [r0, #4] #else -5: strt r2, [r0], #4 -6: strt r3, [r0] +5: T(str) r2, [r0], #4 +6: T(str) r3, [r0] #endif mov r0, #0 mov pc, lr |