diff options
authorMathias Krause2017-10-05 13:30:12 -0500
committerGreg Kroah-Hartman2017-10-18 02:20:43 -0500
commitad505a7b4fb0fd8d533f78083df203d88cdf1a27 (patch)
tree72fe8f150c5b36bd7967af6380e61b1f974eae29 /Documentation/devicetree/bindings/sound/cs35l32.txt
parent208563455aac7540755bb9d8e8edaf7c5ef61d8c (diff)
x86/alternatives: Fix alt_max_short macro to really be a max()
commit 6b32c126d33d5cb379bca280ab8acedc1ca978ff upstream. The alt_max_short() macro in asm/alternative.h does not work as intended, leading to nasty bugs. E.g. alt_max_short("1", "3") evaluates to 3, but alt_max_short("3", "1") evaluates to 1 -- not exactly the maximum of 1 and 3. In fact, I had to learn it the hard way by crashing my kernel in not so funny ways by attempting to make use of the ALTENATIVE_2 macro with alternatives where the first one was larger than the second one. According to [1] and commit dbe4058a6a44 ("x86/alternatives: Fix ALTERNATIVE_2 padding generation properly") the right handed side should read "-(-(a < b))" not "-(-(a - b))". Fix that, to make the macro work as intended. While at it, fix up the comments regarding the additional "-", too. It's not about gas' usage of s32 but brain dead logic of having a "true" value of -1 for the < operator ... *sigh* Btw., the one in asm/alternative-asm.h is correct. And, apparently, all current users of ALTERNATIVE_2() pass same sized alternatives, avoiding to hit the bug. [1] http://graphics.stanford.edu/~seander/bithacks.html#IntegerMinOrMax Reviewed-and-tested-by: Borislav Petkov <bp@suse.de> Fixes: dbe4058a6a44 ("x86/alternatives: Fix ALTERNATIVE_2 padding generation properly") Signed-off-by: Mathias Krause <minipli@googlemail.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/1507228213-13095-1-git-send-email-minipli@googlemail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'Documentation/devicetree/bindings/sound/cs35l32.txt')
0 files changed, 0 insertions, 0 deletions