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authorCatalin Marinas <catalin.marinas@arm.com>2010-09-13 16:03:21 +0100
committerRussell King <rmk+kernel@arm.linux.org.uk>2010-11-04 15:44:31 +0000
commit247055aa21ffef1c49dd64710d5e94c2aee19b58 (patch)
treee9e026b96597d080de4c16bb88c17b0495c61904 /arch/arm/include/asm/uaccess.h
parentff8b16d7e15a8ba2a6086645614a483e048e3fbf (diff)
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/include/asm/uaccess.h')
-rw-r--r--arch/arm/include/asm/uaccess.h16
1 files changed, 8 insertions, 8 deletions
diff --git a/arch/arm/include/asm/uaccess.h b/arch/arm/include/asm/uaccess.h
index 33e4a48fe10..b293616a1a1 100644
--- a/arch/arm/include/asm/uaccess.h
+++ b/arch/arm/include/asm/uaccess.h
@@ -227,7 +227,7 @@ do { \
#define __get_user_asm_byte(x,addr,err) \
__asm__ __volatile__( \
- "1: ldrbt %1,[%2]\n" \
+ "1: " T(ldrb) " %1,[%2],#0\n" \
"2:\n" \
" .pushsection .fixup,\"ax\"\n" \
" .align 2\n" \
@@ -263,7 +263,7 @@ do { \
#define __get_user_asm_word(x,addr,err) \
__asm__ __volatile__( \
- "1: ldrt %1,[%2]\n" \
+ "1: " T(ldr) " %1,[%2],#0\n" \
"2:\n" \
" .pushsection .fixup,\"ax\"\n" \
" .align 2\n" \
@@ -308,7 +308,7 @@ do { \
#define __put_user_asm_byte(x,__pu_addr,err) \
__asm__ __volatile__( \
- "1: strbt %1,[%2]\n" \
+ "1: " T(strb) " %1,[%2],#0\n" \
"2:\n" \
" .pushsection .fixup,\"ax\"\n" \
" .align 2\n" \
@@ -341,7 +341,7 @@ do { \
#define __put_user_asm_word(x,__pu_addr,err) \
__asm__ __volatile__( \
- "1: strt %1,[%2]\n" \
+ "1: " T(str) " %1,[%2],#0\n" \
"2:\n" \
" .pushsection .fixup,\"ax\"\n" \
" .align 2\n" \
@@ -366,10 +366,10 @@ do { \
#define __put_user_asm_dword(x,__pu_addr,err) \
__asm__ __volatile__( \
- ARM( "1: strt " __reg_oper1 ", [%1], #4\n" ) \
- ARM( "2: strt " __reg_oper0 ", [%1]\n" ) \
- THUMB( "1: strt " __reg_oper1 ", [%1]\n" ) \
- THUMB( "2: strt " __reg_oper0 ", [%1, #4]\n" ) \
+ ARM( "1: " T(str) " " __reg_oper1 ", [%1], #4\n" ) \
+ ARM( "2: " T(str) " " __reg_oper0 ", [%1]\n" ) \
+ THUMB( "1: " T(str) " " __reg_oper1 ", [%1]\n" ) \
+ THUMB( "2: " T(str) " " __reg_oper0 ", [%1, #4]\n" ) \
"3:\n" \
" .pushsection .fixup,\"ax\"\n" \
" .align 2\n" \