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| author | Linus Walleij <linus.walleij@linaro.org> | 2020-05-19 12:59:12 +0100 |
|---|---|---|
| committer | Russell King <rmk+kernel@armlinux.org.uk> | 2020-05-26 12:02:39 +0100 |
| commit | e1de94380af588bdf6ad6f0cc1f75004c35bc096 (patch) | |
| tree | cfee95f272b0fa026757140f1f9078b88c4564e8 /arch/arm/mm | |
| parent | fce2bc254adbfe0449ab6bfb51bffba9d3c42689 (diff) | |
| download | lwn-e1de94380af588bdf6ad6f0cc1f75004c35bc096.tar.gz lwn-e1de94380af588bdf6ad6f0cc1f75004c35bc096.zip | |
ARM: 8978/1: mm: make act_mm() respect THREAD_SIZE
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>
Diffstat (limited to 'arch/arm/mm')
| -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 5461d589a1e2..60ac7c5999a9 100644 --- a/arch/arm/mm/proc-macros.S +++ b/arch/arm/mm/proc-macros.S @@ -5,6 +5,7 @@ * 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] .if (TSK_ACTIVE_MM > IMM12_MASK) |