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>
diff --git a/arch/arm/lib/uaccess.S b/arch/arm/lib/uaccess.S
index fee9f6f..d0ece2a 100644
--- a/arch/arm/lib/uaccess.S
+++ b/arch/arm/lib/uaccess.S
@@ -14,6 +14,7 @@
#include <linux/linkage.h>
#include <asm/assembler.h>
#include <asm/errno.h>
+#include <asm/domain.h>
.text
@@ -31,11 +32,11 @@
rsb ip, ip, #4
cmp ip, #2
ldrb r3, [r1], #1
-USER( strbt r3, [r0], #1) @ May fault
+USER( T(strb) r3, [r0], #1) @ May fault
ldrgeb r3, [r1], #1
-USER( strgebt r3, [r0], #1) @ May fault
+USER( T(strgeb) r3, [r0], #1) @ May fault
ldrgtb r3, [r1], #1
-USER( strgtbt r3, [r0], #1) @ May fault
+USER( T(strgtb) r3, [r0], #1) @ May fault
sub r2, r2, ip
b .Lc2u_dest_aligned
@@ -58,7 +59,7 @@
addmi ip, r2, #4
bmi .Lc2u_0nowords
ldr r3, [r1], #4
-USER( strt r3, [r0], #4) @ May fault
+USER( T(str) r3, [r0], #4) @ May fault
mov ip, r0, lsl #32 - PAGE_SHIFT @ On each page, use a ld/st??t instruction
rsb ip, ip, #0
movs ip, ip, lsr #32 - PAGE_SHIFT
@@ -87,18 +88,18 @@
stmneia r0!, {r3 - r4} @ Shouldnt fault
tst ip, #4
ldrne r3, [r1], #4
- strnet r3, [r0], #4 @ Shouldnt fault
+ T(strne) r3, [r0], #4 @ Shouldnt fault
ands ip, ip, #3
beq .Lc2u_0fupi
.Lc2u_0nowords: teq ip, #0
beq .Lc2u_finished
.Lc2u_nowords: cmp ip, #2
ldrb r3, [r1], #1
-USER( strbt r3, [r0], #1) @ May fault
+USER( T(strb) r3, [r0], #1) @ May fault
ldrgeb r3, [r1], #1
-USER( strgebt r3, [r0], #1) @ May fault
+USER( T(strgeb) r3, [r0], #1) @ May fault
ldrgtb r3, [r1], #1
-USER( strgtbt r3, [r0], #1) @ May fault
+USER( T(strgtb) r3, [r0], #1) @ May fault
b .Lc2u_finished
.Lc2u_not_enough:
@@ -119,7 +120,7 @@
mov r3, r7, pull #8
ldr r7, [r1], #4
orr r3, r3, r7, push #24
-USER( strt r3, [r0], #4) @ May fault
+USER( T(str) r3, [r0], #4) @ May fault
mov ip, r0, lsl #32 - PAGE_SHIFT
rsb ip, ip, #0
movs ip, ip, lsr #32 - PAGE_SHIFT
@@ -154,18 +155,18 @@
movne r3, r7, pull #8
ldrne r7, [r1], #4
orrne r3, r3, r7, push #24
- strnet r3, [r0], #4 @ Shouldnt fault
+ T(strne) r3, [r0], #4 @ Shouldnt fault
ands ip, ip, #3
beq .Lc2u_1fupi
.Lc2u_1nowords: mov r3, r7, get_byte_1
teq ip, #0
beq .Lc2u_finished
cmp ip, #2
-USER( strbt r3, [r0], #1) @ May fault
+USER( T(strb) r3, [r0], #1) @ May fault
movge r3, r7, get_byte_2
-USER( strgebt r3, [r0], #1) @ May fault
+USER( T(strgeb) r3, [r0], #1) @ May fault
movgt r3, r7, get_byte_3
-USER( strgtbt r3, [r0], #1) @ May fault
+USER( T(strgtb) r3, [r0], #1) @ May fault
b .Lc2u_finished
.Lc2u_2fupi: subs r2, r2, #4
@@ -174,7 +175,7 @@
mov r3, r7, pull #16
ldr r7, [r1], #4
orr r3, r3, r7, push #16
-USER( strt r3, [r0], #4) @ May fault
+USER( T(str) r3, [r0], #4) @ May fault
mov ip, r0, lsl #32 - PAGE_SHIFT
rsb ip, ip, #0
movs ip, ip, lsr #32 - PAGE_SHIFT
@@ -209,18 +210,18 @@
movne r3, r7, pull #16
ldrne r7, [r1], #4
orrne r3, r3, r7, push #16
- strnet r3, [r0], #4 @ Shouldnt fault
+ T(strne) r3, [r0], #4 @ Shouldnt fault
ands ip, ip, #3
beq .Lc2u_2fupi
.Lc2u_2nowords: mov r3, r7, get_byte_2
teq ip, #0
beq .Lc2u_finished
cmp ip, #2
-USER( strbt r3, [r0], #1) @ May fault
+USER( T(strb) r3, [r0], #1) @ May fault
movge r3, r7, get_byte_3
-USER( strgebt r3, [r0], #1) @ May fault
+USER( T(strgeb) r3, [r0], #1) @ May fault
ldrgtb r3, [r1], #0
-USER( strgtbt r3, [r0], #1) @ May fault
+USER( T(strgtb) r3, [r0], #1) @ May fault
b .Lc2u_finished
.Lc2u_3fupi: subs r2, r2, #4
@@ -229,7 +230,7 @@
mov r3, r7, pull #24
ldr r7, [r1], #4
orr r3, r3, r7, push #8
-USER( strt r3, [r0], #4) @ May fault
+USER( T(str) r3, [r0], #4) @ May fault
mov ip, r0, lsl #32 - PAGE_SHIFT
rsb ip, ip, #0
movs ip, ip, lsr #32 - PAGE_SHIFT
@@ -264,18 +265,18 @@
movne r3, r7, pull #24
ldrne r7, [r1], #4
orrne r3, r3, r7, push #8
- strnet r3, [r0], #4 @ Shouldnt fault
+ T(strne) r3, [r0], #4 @ Shouldnt fault
ands ip, ip, #3
beq .Lc2u_3fupi
.Lc2u_3nowords: mov r3, r7, get_byte_3
teq ip, #0
beq .Lc2u_finished
cmp ip, #2
-USER( strbt r3, [r0], #1) @ May fault
+USER( T(strb) r3, [r0], #1) @ May fault
ldrgeb r3, [r1], #1
-USER( strgebt r3, [r0], #1) @ May fault
+USER( T(strgeb) r3, [r0], #1) @ May fault
ldrgtb r3, [r1], #0
-USER( strgtbt r3, [r0], #1) @ May fault
+USER( T(strgtb) r3, [r0], #1) @ May fault
b .Lc2u_finished
ENDPROC(__copy_to_user)
@@ -294,11 +295,11 @@
.Lcfu_dest_not_aligned:
rsb ip, ip, #4
cmp ip, #2
-USER( ldrbt r3, [r1], #1) @ May fault
+USER( T(ldrb) r3, [r1], #1) @ May fault
strb r3, [r0], #1
-USER( ldrgebt r3, [r1], #1) @ May fault
+USER( T(ldrgeb) r3, [r1], #1) @ May fault
strgeb r3, [r0], #1
-USER( ldrgtbt r3, [r1], #1) @ May fault
+USER( T(ldrgtb) r3, [r1], #1) @ May fault
strgtb r3, [r0], #1
sub r2, r2, ip
b .Lcfu_dest_aligned
@@ -321,7 +322,7 @@
.Lcfu_0fupi: subs r2, r2, #4
addmi ip, r2, #4
bmi .Lcfu_0nowords
-USER( ldrt r3, [r1], #4)
+USER( T(ldr) r3, [r1], #4)
str r3, [r0], #4
mov ip, r1, lsl #32 - PAGE_SHIFT @ On each page, use a ld/st??t instruction
rsb ip, ip, #0
@@ -350,18 +351,18 @@
ldmneia r1!, {r3 - r4} @ Shouldnt fault
stmneia r0!, {r3 - r4}
tst ip, #4
- ldrnet r3, [r1], #4 @ Shouldnt fault
+ T(ldrne) r3, [r1], #4 @ Shouldnt fault
strne r3, [r0], #4
ands ip, ip, #3
beq .Lcfu_0fupi
.Lcfu_0nowords: teq ip, #0
beq .Lcfu_finished
.Lcfu_nowords: cmp ip, #2
-USER( ldrbt r3, [r1], #1) @ May fault
+USER( T(ldrb) r3, [r1], #1) @ May fault
strb r3, [r0], #1
-USER( ldrgebt r3, [r1], #1) @ May fault
+USER( T(ldrgeb) r3, [r1], #1) @ May fault
strgeb r3, [r0], #1
-USER( ldrgtbt r3, [r1], #1) @ May fault
+USER( T(ldrgtb) r3, [r1], #1) @ May fault
strgtb r3, [r0], #1
b .Lcfu_finished
@@ -374,7 +375,7 @@
.Lcfu_src_not_aligned:
bic r1, r1, #3
-USER( ldrt r7, [r1], #4) @ May fault
+USER( T(ldr) r7, [r1], #4) @ May fault
cmp ip, #2
bgt .Lcfu_3fupi
beq .Lcfu_2fupi
@@ -382,7 +383,7 @@
addmi ip, r2, #4
bmi .Lcfu_1nowords
mov r3, r7, pull #8
-USER( ldrt r7, [r1], #4) @ May fault
+USER( T(ldr) r7, [r1], #4) @ May fault
orr r3, r3, r7, push #24
str r3, [r0], #4
mov ip, r1, lsl #32 - PAGE_SHIFT
@@ -417,7 +418,7 @@
stmneia r0!, {r3 - r4}
tst ip, #4
movne r3, r7, pull #8
-USER( ldrnet r7, [r1], #4) @ May fault
+USER( T(ldrne) r7, [r1], #4) @ May fault
orrne r3, r3, r7, push #24
strne r3, [r0], #4
ands ip, ip, #3
@@ -437,7 +438,7 @@
addmi ip, r2, #4
bmi .Lcfu_2nowords
mov r3, r7, pull #16
-USER( ldrt r7, [r1], #4) @ May fault
+USER( T(ldr) r7, [r1], #4) @ May fault
orr r3, r3, r7, push #16
str r3, [r0], #4
mov ip, r1, lsl #32 - PAGE_SHIFT
@@ -473,7 +474,7 @@
stmneia r0!, {r3 - r4}
tst ip, #4
movne r3, r7, pull #16
-USER( ldrnet r7, [r1], #4) @ May fault
+USER( T(ldrne) r7, [r1], #4) @ May fault
orrne r3, r3, r7, push #16
strne r3, [r0], #4
ands ip, ip, #3
@@ -485,7 +486,7 @@
strb r3, [r0], #1
movge r3, r7, get_byte_3
strgeb r3, [r0], #1
-USER( ldrgtbt r3, [r1], #0) @ May fault
+USER( T(ldrgtb) r3, [r1], #0) @ May fault
strgtb r3, [r0], #1
b .Lcfu_finished
@@ -493,7 +494,7 @@
addmi ip, r2, #4
bmi .Lcfu_3nowords
mov r3, r7, pull #24
-USER( ldrt r7, [r1], #4) @ May fault
+USER( T(ldr) r7, [r1], #4) @ May fault
orr r3, r3, r7, push #8
str r3, [r0], #4
mov ip, r1, lsl #32 - PAGE_SHIFT
@@ -528,7 +529,7 @@
stmneia r0!, {r3 - r4}
tst ip, #4
movne r3, r7, pull #24
-USER( ldrnet r7, [r1], #4) @ May fault
+USER( T(ldrne) r7, [r1], #4) @ May fault
orrne r3, r3, r7, push #8
strne r3, [r0], #4
ands ip, ip, #3
@@ -538,9 +539,9 @@
beq .Lcfu_finished
cmp ip, #2
strb r3, [r0], #1
-USER( ldrgebt r3, [r1], #1) @ May fault
+USER( T(ldrgeb) r3, [r1], #1) @ May fault
strgeb r3, [r0], #1
-USER( ldrgtbt r3, [r1], #1) @ May fault
+USER( T(ldrgtb) r3, [r1], #1) @ May fault
strgtb r3, [r0], #1
b .Lcfu_finished
ENDPROC(__copy_from_user)