x86/entry/64: Push extra regs right away
authorAndy Lutomirski <luto@kernel.org>
Sun, 28 Jan 2018 18:38:49 +0000 (10:38 -0800)
committerThomas Gleixner <tglx@linutronix.de>
Tue, 30 Jan 2018 14:30:36 +0000 (15:30 +0100)
With the fast path removed there is no point in splitting the push of the
normal and the extra register set. Just push the extra regs right away.

[ tglx: Split out from 'x86/entry/64: Remove the SYSCALL64 fast path' ]

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Ingo Molnar <mingo@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Kernel Hardening <kernel-hardening@lists.openwall.com>
Link: https://lkml.kernel.org/r/462dff8d4d64dfbfc851fbf3130641809d980ecd.1517164461.git.luto@kernel.org
arch/x86/entry/entry_64.S

index c46c755..c752abe 100644 (file)
@@ -236,13 +236,17 @@ GLOBAL(entry_SYSCALL_64_after_hwframe)
        pushq   %r9                             /* pt_regs->r9 */
        pushq   %r10                            /* pt_regs->r10 */
        pushq   %r11                            /* pt_regs->r11 */
-       sub     $(6*8), %rsp                    /* pt_regs->bp, bx, r12-15 not saved */
-       UNWIND_HINT_REGS extra=0
+       pushq   %rbx                            /* pt_regs->rbx */
+       pushq   %rbp                            /* pt_regs->rbp */
+       pushq   %r12                            /* pt_regs->r12 */
+       pushq   %r13                            /* pt_regs->r13 */
+       pushq   %r14                            /* pt_regs->r14 */
+       pushq   %r15                            /* pt_regs->r15 */
+       UNWIND_HINT_REGS
 
        TRACE_IRQS_OFF
 
        /* IRQs are off. */
-       SAVE_EXTRA_REGS
        movq    %rsp, %rdi
        call    do_syscall_64           /* returns with IRQs disabled */