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authorRussell King <rmk+kernel@arm.linux.org.uk>2015-08-20 10:32:02 +0100
committerRussell King <rmk+kernel@arm.linux.org.uk>2015-08-26 20:27:02 +0100
commit2190fed67ba6f3e8129513929f2395843645e928 (patch)
tree45a4db5061c12e2926f7a1c89d56c7bbf47f0e61 /arch/arm/mm/abort-ev5t.S
parentaa06e5c1f9c2b466712be904cc5b56a813e24cfd (diff)
ARM: entry: provide uaccess assembly macro hooks
Provide hooks into the kernel entry and exit paths to permit control of userspace visibility to the kernel. The intended use is: - on entry to kernel from user, uaccess_disable will be called to disable userspace visibility - on exit from kernel to user, uaccess_enable will be called to enable userspace visibility - on entry from a kernel exception, uaccess_save_and_disable will be called to save the current userspace visibility setting, and disable access - on exit from a kernel exception, uaccess_restore will be called to restore the userspace visibility as it was before the exception occurred. These hooks allows us to keep userspace visibility disabled for the vast majority of the kernel, except for localised regions where we want to explicitly access userspace. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch/arm/mm/abort-ev5t.S')
-rw-r--r--arch/arm/mm/abort-ev5t.S1
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/arm/mm/abort-ev5t.S b/arch/arm/mm/abort-ev5t.S
index c913031b79cc..a6a381a6caa5 100644
--- a/arch/arm/mm/abort-ev5t.S
+++ b/arch/arm/mm/abort-ev5t.S
@@ -21,6 +21,7 @@ ENTRY(v5t_early_abort)
mrc p15, 0, r0, c6, c0, 0 @ get FAR
do_thumb_abort fsr=r1, pc=r4, psr=r5, tmp=r3
ldreq r3, [r4] @ read aborted ARM instruction
+ uaccess_disable ip @ disable user access
bic r1, r1, #1 << 11 @ clear bits 11 of FSR
teq_ldrd tmp=ip, insn=r3 @ insn was LDRD?
beq do_DataAbort @ yes