diff options
| author | Linus Walleij <linus.walleij@linaro.org> | 2020-05-19 12:59:12 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-06-20 10:23:20 +0200 |
| commit | 7f19f9025fb3514f5d22fb6570e961425dcc0d08 (patch) | |
| tree | 77807395a766e8187c433ad51096de3f2fd17dee | |
| parent | 20fdc3da105de47486296a255c243844dad97199 (diff) | |
ARM: 8978/1: mm: make act_mm() respect THREAD_SIZE
[ Upstream commit e1de94380af588bdf6ad6f0cc1f75004c35bc096 ]
Recent work with KASan exposed the folling hard-coded bitmask
in arch/arm/mm/proc-macros.S:
bic rd, sp, #8128
bic rd, rd, #63
This forms the bitmask 0x1FFF that is coinciding with
(PAGE_SIZE << THREAD_SIZE_ORDER) - 1, this code was assuming
that THREAD_SIZE is always 8K (8192).
As KASan was increasing THREAD_SIZE_ORDER to 2, I ran into
this bug.
Fix it by this little oneline suggested by Ard:
bic rd, sp, #(THREAD_SIZE - 1) & ~63
Where THREAD_SIZE is defined using THREAD_SIZE_ORDER.
We have to also include <linux/const.h> since the THREAD_SIZE
expands to use the _AC() macro.
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Suggested-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -rw-r--r-- | arch/arm/mm/proc-macros.S | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/arch/arm/mm/proc-macros.S b/arch/arm/mm/proc-macros.S index e6bfdcc381f8..1da55d34f4d6 100644 --- a/arch/arm/mm/proc-macros.S +++ b/arch/arm/mm/proc-macros.S @@ -4,6 +4,7 @@ * VMA_VM_FLAGS * VM_EXEC */ +#include <linux/const.h> #include <asm/asm-offsets.h> #include <asm/thread_info.h> @@ -30,7 +31,7 @@ * act_mm - get current->active_mm */ .macro act_mm, rd - bic \rd, sp, #8128 + bic \rd, sp, #(THREAD_SIZE - 1) & ~63 bic \rd, \rd, #63 ldr \rd, [\rd, #TI_TASK] ldr \rd, [\rd, #TSK_ACTIVE_MM] |