diff options
| author | David Laight <david.laight.linux@gmail.com> | 2025-12-14 12:58:57 +0000 |
|---|---|---|
| committer | Kees Cook <kees@kernel.org> | 2026-01-14 19:49:52 -0800 |
| commit | 995ddc58d791bb85b1b044d295e1fe4fad48ba72 (patch) | |
| tree | 591bc1c238cad1a2a3b354202946c2e28c2d4744 /include | |
| parent | cc34c669abe0c198daec20de5185c8187f4b240d (diff) | |
fortify: Use C arithmetic not FIELD_xxx() in FORTIFY_REASON defines
FIELD_GET() and FIELD_PREP() are mainly useful for hardware register
accesses, but here they are being used for some very simple oprations.
This wouldn't matter much, but they contain a lot of compile-time
checks (that really aren't needed here) that bloat the expansion
of FIELD_GET(GENMASK(7, 1), func) to over 18KB.
Even with the 'bloat reduced' FIELD_GET/PREP they are still hundreds of
characters.
Replace FIELD_GET(BIT(0), r) with ((r) & 1), FIELD_GET(GENMASK(7, 1), r) with
(r) >> 1), and (FIELD_PREP(BIT(0), write) | FIELD_PREP(GENMASK(7, 1), func))
with ((func) << 1 | (write)).
The generated code is the same, but it makes the .c file less obfuctaced,
the .i file much easier to read, and should marginally decrease compilation
time.
Signed-off-by: David Laight <david.laight.linux@gmail.com>
Link: https://patch.msgid.link/20251214125857.3308-1-david.laight.linux@gmail.com
Signed-off-by: Kees Cook <kees@kernel.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/fortify-string.h | 8 |
1 files changed, 3 insertions, 5 deletions
diff --git a/include/linux/fortify-string.h b/include/linux/fortify-string.h index b3b53f8c1b28..171982e53c9a 100644 --- a/include/linux/fortify-string.h +++ b/include/linux/fortify-string.h @@ -2,7 +2,6 @@ #ifndef _LINUX_FORTIFY_STRING_H_ #define _LINUX_FORTIFY_STRING_H_ -#include <linux/bitfield.h> #include <linux/bug.h> #include <linux/const.h> #include <linux/limits.h> @@ -10,10 +9,9 @@ #define __FORTIFY_INLINE extern __always_inline __gnu_inline __overloadable #define __RENAME(x) __asm__(#x) -#define FORTIFY_REASON_DIR(r) FIELD_GET(BIT(0), r) -#define FORTIFY_REASON_FUNC(r) FIELD_GET(GENMASK(7, 1), r) -#define FORTIFY_REASON(func, write) (FIELD_PREP(BIT(0), write) | \ - FIELD_PREP(GENMASK(7, 1), func)) +#define FORTIFY_REASON_DIR(r) ((r) & 1) +#define FORTIFY_REASON_FUNC(r) ((r) >> 1) +#define FORTIFY_REASON(func, write) ((func) << 1 | (write)) /* Overridden by KUnit tests. */ #ifndef fortify_panic |