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[PATCH] ARM: 2698/1: Enable kernel r/w access to user pages on ARMv6
Patch from Catalin Marinas
cpu_v6_set_pte() sets the kernel access rights to r/o for user
pages (L_PTE_USER) when neither L_PTE_WRITE nor L_PTE_DIRTY are
set. This causes a kernel data abort when writing the TLS value
in the 0xffff0000 page. This patch enables the kernel r/w access.
Signed-off-by: Catalin Marinas
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
authored by Catalin Marinas and committed by Russell King 79042f08 5932ae3f
+3
-3
arch/arm/mm/proc-v6.S
+3
-3
arch/arm/mm/proc-v6.S
···
132
* 100x 1 0 1 r/o no acc
133
* 10x0 1 0 1 r/o no acc
134
* 1011 0 0 1 r/w no acc
135
-
* 110x 1 1 0 r/o r/o
136
-
* 11x0 1 1 0 r/o r/o
137
* 1111 0 1 1 r/w r/w
138
*/
139
ENTRY(cpu_v6_set_pte)
···
150
tst r1, #L_PTE_USER
151
orrne r2, r2, #AP1 | nG
152
tstne r2, #APX
153
-
eorne r2, r2, #AP0
154
155
tst r1, #L_PTE_YOUNG
156
biceq r2, r2, #APX | AP1 | AP0
···
132
* 100x 1 0 1 r/o no acc
133
* 10x0 1 0 1 r/o no acc
134
* 1011 0 0 1 r/w no acc
135
+
* 110x 0 1 0 r/w r/o
136
+
* 11x0 0 1 0 r/w r/o
137
* 1111 0 1 1 r/w r/w
138
*/
139
ENTRY(cpu_v6_set_pte)
···
150
tst r1, #L_PTE_USER
151
orrne r2, r2, #AP1 | nG
152
tstne r2, #APX
153
+
bicne r2, r2, #APX | AP0
154
155
tst r1, #L_PTE_YOUNG
156
biceq r2, r2, #APX | AP1 | AP0