x86/asm/entry/64: Get rid of the FIXUP_TOP_OF_STACK/RESTORE_TOP_OF_STACK macros

The FIXUP_TOP_OF_STACK macro is only necessary because we don't save %r11
to pt_regs->r11 on SYSCALL64 fast path, but we want ptrace to see it populated.

Bite the bullet, add a single additional PUSH instruction, and remove
the FIXUP_TOP_OF_STACK macro.

The RESTORE_TOP_OF_STACK macro is already a nop. Remove it too.

On SandyBridge CPU, it does not get slower:
measured 54.22 ns per getpid syscall before and after last two
changes on defconfig kernel.

Signed-off-by: Denys Vlasenko <[email protected]>
Acked-by: Borislav Petkov <[email protected]>
Acked-by: Andy Lutomirski <[email protected]>
Cc: Alexei Starovoitov <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Frederic Weisbecker <[email protected]>
Cc: H. Peter Anvin <[email protected]>
Cc: Kees Cook <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Oleg Nesterov <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Will Drewry <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>

0 files changed, 0 insertions, 0 deletions