diff options
| author | Jani Nikula <jani.nikula@intel.com> | 2024-08-01 13:06:09 +0300 |
|---|---|---|
| committer | Jani Nikula <jani.nikula@intel.com> | 2024-08-01 13:06:09 +0300 |
| commit | 3663e2c4bc45fcdc71931fcbfcbfbf9b71f55c83 (patch) | |
| tree | 3927fa90c7faa89131fcf2e789ca9de97a65dc5f /include/linux/randomize_kstack.h | |
| parent | 688c43dd6ca9e0cd0568868aefca5b041695c3f4 (diff) | |
| parent | 8400291e289ee6b2bf9779ff1c83a291501f017b (diff) | |
| download | linux-3663e2c4bc45fcdc71931fcbfcbfbf9b71f55c83.tar.xz | |
Merge drm/drm-next into drm-intel-next
Sync with v6.11-rc1 in general, and specifically get the new
BACKLIGHT_POWER_ constants for power states.
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Diffstat (limited to 'include/linux/randomize_kstack.h')
| -rw-r--r-- | include/linux/randomize_kstack.h | 18 |
1 files changed, 12 insertions, 6 deletions
diff --git a/include/linux/randomize_kstack.h b/include/linux/randomize_kstack.h index 6d92b68efbf6..1d982dbdd0d0 100644 --- a/include/linux/randomize_kstack.h +++ b/include/linux/randomize_kstack.h @@ -32,13 +32,19 @@ DECLARE_PER_CPU(u32, kstack_offset); #endif /* - * Use, at most, 10 bits of entropy. We explicitly cap this to keep the - * "VLA" from being unbounded (see above). 10 bits leaves enough room for - * per-arch offset masks to reduce entropy (by removing higher bits, since - * high entropy may overly constrain usable stack space), and for - * compiler/arch-specific stack alignment to remove the lower bits. + * Use, at most, 6 bits of entropy (on 64-bit; 8 on 32-bit). This cap is + * to keep the "VLA" from being unbounded (see above). Additionally clear + * the bottom 4 bits (on 64-bit systems, 2 for 32-bit), since stack + * alignment will always be at least word size. This makes the compiler + * code gen better when it is applying the actual per-arch alignment to + * the final offset. The resulting randomness is reasonable without overly + * constraining usable stack space. */ -#define KSTACK_OFFSET_MAX(x) ((x) & 0x3FF) +#ifdef CONFIG_64BIT +#define KSTACK_OFFSET_MAX(x) ((x) & 0b1111110000) +#else +#define KSTACK_OFFSET_MAX(x) ((x) & 0b1111111100) +#endif /** * add_random_kstack_offset - Increase stack utilization by previously |
