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2019-02-13locking/atomics: Check atomic headers with sha1sumMark Rutland1-0/+1
We currently check the atomic headers at build-time to ensure they haven't been modified directly, and these checks require regenerating the headers in full. As this takes a few seconds, even when parallelized, this is too slow to run for every kernel build. Instead, we can generate a hash of each header as we generate them, which we can cheaply check at build time (~0.16s for all headers). This patch does so, updating headers with their hashes using the new gen-atomics.sh script. As some users apparently build the kernel wihout coreutils, lacking sha1sum, the checks are skipped in this case. Presumably, most developers have a working coreutils installation. Signed-off-by: Mark Rutland <[email protected]> Acked-by: Will Deacon <[email protected]> Cc: Andrew Morton <[email protected]> Cc: Boqun Feng <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: [email protected] Cc: [email protected] Cc: [email protected] Signed-off-by: Ingo Molnar <[email protected]>
2018-11-01locking/atomics: Switch to generated fallbacksMark Rutland1-0/+2294
As a step to ensuring the atomic* APIs are consistent, switch to fallbacks generated by gen-atomic-fallback.sh. These are checked in rather than generated with Kbuild, since: * This allows inspection of the atomics with git grep and ctags on a pristine tree, which Linus strongly prefers being able to do. * The fallbacks are not affected by machine details or configuration options, so it is not necessary to regenerate them to take these into account. * These are included by files required *very* early in the build process (e.g. for generating bounds.h), and we'd rather not complicate the top-level Kbuild file with dependencies. The new fallback header should be equivalent to the old fallbacks in <linux/atomic.h>, but: * It is formatted a little differently due to scripting ensuring things are more regular than they used to be. * Fallbacks are now expanded in-place as static inline functions rather than macros. * The prototypes for fallbacks are arragned consistently with the return type on a separate line to try to keep to a sensible line length. There should be no functional change as a result of this patch. Signed-off-by: Mark Rutland <[email protected]> Signed-off-by: Peter Zijlstra (Intel) <[email protected]> Acked-by: Will Deacon <[email protected]> Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: Boqun Feng <[email protected]> Cc: [email protected] Cc: [email protected] Cc: [email protected] Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Ingo Molnar <[email protected]>