On Fri, May 13, 2016 at 10:32:26AM -0700, Megha Dey wrote: > On Fri, 2016-05-13 at 07:51 +0200, Ingo Molnar wrote: > > * Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx> wrote: > > > > > On Thu, May 12, 2016 at 04:31:06PM -0700, Megha Dey wrote: > > > > Hi, > > > > > > > > When booting latest kernel with the CONFIG_CRYPTO_SHA1_MB enabled, I > > > > observe a panic. > > > > > > > > After having a quick look, on reverting the following patches, I am able > > > > to complete the booting process. > > > > aec4d0e301f17bb143341c82cc44685b8af0b945 > > > > 8691ccd764f9ecc69a6812dfe76214c86ac9ba06 > > > > 68874ac3304ade7ed5ebb12af00d6b9bbbca0a16 > > > > > > > > Of the 3 patches, aec4d0e301f17bb143341c82cc44685b8af0b945 seems wrong. > > > > The r10 to r15 registers are used in sha1_x8_avx2.S, which is called > > > > from sha1_mb_mgr_flush_avx2.S. > > > > > > > > I do not think the functionality of the SHA1-MB crypto algorithm has > > > > been tested after applying these changes. (I am not sure if any of the > > > > other crypto algorithms have been affected by these changes). > > > > > > Josh, Ingo: > > > > > > Any ideas on this? Should we revert? > > > > Yeah, I think so - although another option would be to standardize sha1_x8_avx2() > > - the problem is that it is a function that clobbers registers without > > saving/restoring them, breaking the C function ABI. I realize it's written in > > assembly, but unless there are strong performance reasons to deviate from the > > regular calling convention it might make sense to fix that. > > > > Do any warnings get generated after the revert, if you enable > > CONFIG_STACK_VALIDATION=y? > > After the revert and enabling CONFIG_STACK_VALIDATION: > arch/x86/crypto/sha1-mb/sha1_mb_mgr_flush_avx2.o: warning: objtool: > sha1_mb_mgr_flush_avx2()+0x20d: call without frame pointer save/setup > > arch/x86/crypto/sha1-mb/sha1_mb_mgr_submit_avx2.o: warning: objtool: > sha1_mb_mgr_submit_avx2()+0x115: call without frame pointer save/setup Megha, Sorry for breaking it. I completely missed the fact that the function calls sha1_x8_avx2() which clobbers registers. If the performance penalty isn't too bad, I'll submit a patch to standardize sha1_x8_avx2() to follow the C ABI. Do you have any tips for testing this code? I've tried using the tcrypt module, but no luck. -- Josh -- To unsubscribe from this list: send the line "unsubscribe linux-crypto" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
