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| author | Yilun Lin <yllin@google.com> | 2019-03-20 17:26:49 +0800 |
|---|---|---|
| committer | chrome-bot <chrome-bot@chromium.org> | 2019-05-02 05:38:25 -0700 |
| commit | 4ffa4bb861612f9debffc9088bac72a1ac611ff5 (patch) | |
| tree | 6b381e78bdec26297d8d04d9f3767f07cd322e3e /core | |
| parent | 19915c08ec2828235d5db7b0d3a990ab165649cd (diff) | |
| download | chrome-ec-4ffa4bb861612f9debffc9088bac72a1ac611ff5.tar.gz | |
kukui_scp: Enable MPU to protect code RAM and data RAM in RW image.
kukui_scp is loaded into SRAM. We would like to protect
the memory from a modified code RAM content and executing injected
code in data RAM.
BRANCH=None
BUG=b:123269246
TEST=Apply MPU test patch https://crrev.com/c/1530265.
Test data ram XN:
1. mpu 0 # disable MPU
2. mpu_test # see it prints
3. mpu 1 # enable MPU
4. mpu_test # memory access violation, and reset.
5. mpu_test # memory access violation, and reset
# again. (MPU enabled by default)
Test code ram RO:
1. rw 0x8 0x5566 # Write to code RAM and see memory
# access violation and reset.
2. mpu 0 # disable MPU
3. rw 0x8 0x5566 # Nothing happended
4. rw 0x8 # Read 0x5566
5. mpu 1 # enable MPU
6. rw 0x8 0x5566 # memory access violation.
Change-Id: I6af5029d8c55d795543d4759b2c9168a06eb9ff1
Signed-off-by: Yilun Lin <yllin@google.com>
Reviewed-on: https://chromium-review.googlesource.com/1530264
Commit-Ready: Yilun Lin <yllin@chromium.org>
Tested-by: Yilun Lin <yllin@chromium.org>
Reviewed-by: Rong Chang <rongchang@chromium.org>
Diffstat (limited to 'core')
| -rw-r--r-- | core/cortex-m/include/mpu.h | 2 | ||||
| -rw-r--r-- | core/cortex-m/mpu.c | 6 |
2 files changed, 5 insertions, 3 deletions
diff --git a/core/cortex-m/include/mpu.h b/core/cortex-m/include/mpu.h index 84a82bb3f8..c252ab6ddc 100644 --- a/core/cortex-m/include/mpu.h +++ b/core/cortex-m/include/mpu.h @@ -58,6 +58,8 @@ enum mpu_region { /* AP bit. See table 3-5 of Stellaris LM4F232H5QC datasheet for details */ #define MPU_ATTR_NO_NO (0 << 8) /* previleged no access, unprev no access */ +#define MPU_ATTR_RW_NO (1 << 8) /* previleged ReadWrite, unprev no access */ +#define MPU_ATTR_RW_RO (2 << 8) /* previleged ReadWrite, unprev Read-only */ #define MPU_ATTR_RW_RW (3 << 8) /* previleged ReadWrite, unprev ReadWrite */ #define MPU_ATTR_RO_NO (5 << 8) /* previleged Read-only, unprev no access */ diff --git a/core/cortex-m/mpu.c b/core/cortex-m/mpu.c index 8376a00b32..b239de3e57 100644 --- a/core/cortex-m/mpu.c +++ b/core/cortex-m/mpu.c @@ -147,7 +147,7 @@ void mpu_enable(void) MPU_CTRL |= MPU_CTRL_PRIVDEFEN | MPU_CTRL_HFNMIENA | MPU_CTRL_ENABLE; } -void mpu_disable(void) +static void mpu_disable(void) { MPU_CTRL &= ~(MPU_CTRL_PRIVDEFEN | MPU_CTRL_HFNMIENA | MPU_CTRL_ENABLE); } @@ -179,13 +179,13 @@ int mpu_protect_data_ram(void) MPU_ATTR_INTERNAL_SRAM); } -#ifdef CONFIG_EXTERNAL_STORAGE +#if defined(CONFIG_EXTERNAL_STORAGE) || !defined(CONFIG_FLASH_PHYSICAL) int mpu_protect_code_ram(void) { /* Prevent write access to code RAM */ return mpu_config_region(REGION_STORAGE, CONFIG_PROGRAM_MEMORY_BASE + CONFIG_RO_MEM_OFF, - CONFIG_RO_SIZE, + CONFIG_CODE_RAM_SIZE, MPU_ATTR_RO_NO | MPU_ATTR_INTERNAL_SRAM, 1); } |