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author | Jay Vosburgh <jay.vosburgh@canonical.com> | 2014-11-14 11:05:06 -0800 |
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committer | David S. Miller <davem@davemloft.net> | 2014-11-14 16:36:25 -0500 |
commit | a77f9c5dcdf8480a93332792c336fa2bf9d31229 (patch) | |
tree | 003964de0cc772f361d254385406fa75f3fcbff2 /crypto/michael_mic.c | |
parent | 8cd4313aa775537f724486d5b7503b4d46c9f012 (diff) |
Revert "fast_hash: avoid indirect function calls"
This reverts commit e5a2c899957659cd1a9f789bc462f9c0b35f5150.
Commit e5a2c899 introduced an alternative_call, arch_fast_hash2,
that selects between __jhash2 and __intel_crc4_2_hash based on the
X86_FEATURE_XMM4_2.
Unfortunately, the alternative_call system does not appear to be
suitable for use with C functions, as register usage is not handled
properly for the called functions. The __jhash2 function in particular
clobbers registers that are not preserved when called via
alternative_call, resulting in a panic for direct callers of
arch_fast_hash2 on older CPUs lacking sse4_2. It is possible that
__intel_crc4_2_hash works merely by chance because it uses fewer
registers.
This commit was suggested as the source of the problem by Jesse
Gross <jesse@nicira.com>.
Signed-off-by: Jay Vosburgh <jay.vosburgh@canonical.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'crypto/michael_mic.c')
0 files changed, 0 insertions, 0 deletions