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    x86/entry/32: Remove 32-bit syscall audit optimizations · c5f69fde
    Andy Lutomirski 提交于
    The asm audit optimizations are ugly and obfuscate the code too
    much. Remove them.
    
    This will regress performance if syscall auditing is enabled on
    32-bit kernels and SYSENTER is in use. If this becomes a
    problem, interested parties are encouraged to implement the
    equivalent of the 64-bit opportunistic SYSRET optimization.
    
    Alternatively, a case could be made that, on 32-bit kernels, a
    less messy asm audit optimization could be done. 32-bit kernels
    don't have the complicated partial register saving tricks that
    64-bit kernels have, so the SYSENTER post-syscall path could
    just call the audit hooks directly.  Any reimplementation of
    this ought to demonstrate that it only calls the audit hook once
    per syscall, though, which does not currently appear to be true.
    
    Someone would have to make the case that doing so would be
    better than implementing opportunistic SYSEXIT, though.
    Signed-off-by: NAndy Lutomirski <luto@kernel.org>
    Cc: Borislav Petkov <bp@alien8.de>
    Cc: Brian Gerst <brgerst@gmail.com>
    Cc: Denys Vlasenko <dvlasenk@redhat.com>
    Cc: Eric Paris <eparis@parisplace.org>
    Cc: Linus Torvalds <torvalds@linux-foundation.org>
    Cc: Oleg Nesterov <oleg@redhat.com>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Cc: Thomas Gleixner <tglx@linutronix.de>
    Link: http://lkml.kernel.org/r/212be39dd8c90b44c4b7bbc678128d6b88bdb9912.1438378274.git.luto@kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>
    c5f69fde
entry_32.S 26.3 KB