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x86/entry/64: Remove the restore_c_regs_and_iret label

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The only user was the 64-bit opportunistic SYSRET failure path, and
that path didn't really need it.  This change makes the
opportunistic SYSRET code a bit more straightforward and gets rid of
the label.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Reviewed-by: Borislav Petkov <bp@suse.de>
Cc: Borislav Petkov <bpetkov@suse.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/be3006a7ad3326e3458cf1cc55d416252cbe1986.1509609304.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Andy Lutomirski 2017-11-02 00:58:58 -07:00 committed by Ingo Molnar
parent 50da9d4393
commit 9da78ba6b4
1 changed files with 2 additions and 3 deletions
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5
arch/x86/entry/entry_64.S
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@ -245,7 +245,6 @@ entry_SYSCALL64_slow_path:
call do_syscall_64 /* returns with IRQs disabled */
return_from_SYSCALL_64:
RESTORE_EXTRA_REGS
TRACE_IRQS_IRETQ /* we're about to change IF */
/*
@ -314,6 +313,7 @@ return_from_SYSCALL_64:
*/
syscall_return_via_sysret:
/* rcx and r11 are already restored (see code above) */
RESTORE_EXTRA_REGS
RESTORE_C_REGS_EXCEPT_RCX_R11
movq RSP(%rsp), %rsp
UNWIND_HINT_EMPTY
@ -321,7 +321,7 @@ syscall_return_via_sysret:
opportunistic_sysret_failed:
SWAPGS
jmp restore_c_regs_and_iret
jmp restore_regs_and_iret
END(entry_SYSCALL_64)
ENTRY(stub_ptregs_64)
@ -638,7 +638,6 @@ retint_kernel:
*/
GLOBAL(restore_regs_and_iret)
RESTORE_EXTRA_REGS
restore_c_regs_and_iret:
RESTORE_C_REGS
REMOVE_PT_GPREGS_FROM_STACK 8
INTERRUPT_RETURN