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| author | Russell King <rmk+kernel@arm.linux.org.uk> | 2015-08-20 11:32:02 +0200 |
|---|---|---|
| committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2015-08-26 21:27:02 +0200 |
| commit | 2190fed67ba6f3e8129513929f2395843645e928 (patch) | |
| tree | 45a4db5061c12e2926f7a1c89d56c7bbf47f0e61 /arch/arm/mm/abort-lv4t.S | |
| parent | ARM: entry: get rid of multiple macro definitions (diff) | |
| download | linux-2190fed67ba6f3e8129513929f2395843645e928.tar.xz linux-2190fed67ba6f3e8129513929f2395843645e928.zip | |
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-lv4t.S')
| -rw-r--r-- | arch/arm/mm/abort-lv4t.S | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/arm/mm/abort-lv4t.S b/arch/arm/mm/abort-lv4t.S index f3982580c273..6d8e8e3365d1 100644 --- a/arch/arm/mm/abort-lv4t.S +++ b/arch/arm/mm/abort-lv4t.S @@ -26,6 +26,7 @@ ENTRY(v4t_late_abort) #endif bne .data_thumb_abort ldr r8, [r4] @ read arm instruction + uaccess_disable ip @ disable userspace access tst r8, #1 << 20 @ L = 1 -> write? orreq r1, r1, #1 << 11 @ yes. and r7, r8, #15 << 24 @@ -155,6 +156,7 @@ ENTRY(v4t_late_abort) .data_thumb_abort: ldrh r8, [r4] @ read instruction + uaccess_disable ip @ disable userspace access tst r8, #1 << 11 @ L = 1 -> write? orreq r1, r1, #1 << 8 @ yes and r7, r8, #15 << 12 |