4.14-stable review patch. If anyone has any objections, please let me know.
------------------
From: Andy Lutomirski luto@kernel.org
commit 9da78ba6b47b46428cfdfc0851511ab29c869798 upstream.
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... Signed-off-by: Ingo Molnar mingo@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- arch/x86/entry/entry_64.S | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-)
--- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -246,7 +246,6 @@ 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 */
/* @@ -315,6 +314,7 @@ 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 @@ -322,7 +322,7 @@ 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) @@ -639,7 +639,6 @@ 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