x86/entry/64: Migrate 64-bit and compat syscalls to the new exit handlers and remove old assembly code

These need to be migrated together, as the compat case used to
jump into the middle of the 64-bit exit code.

Remove the old assembly code.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Denys Vlasenko <vda.linux@googlemail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: paulmck@linux.vnet.ibm.com
Link: http://lkml.kernel.org/r/d4d1d70de08ac3640badf50048a9e8f18fe2497f.1435952415.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 8 insertions, 61 deletions

diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index ccfcba90de6e..4ca5b782ed70 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -229,6 +229,11 @@ entry_SYSCALL_64_fastpath:
          */
         USERGS_SYSRET64
 
+GLOBAL(int_ret_from_sys_call_irqs_off)
+        TRACE_IRQS_ON
+        ENABLE_INTERRUPTS(CLBR_NONE)
+        jmp int_ret_from_sys_call
+
         /* Do syscall entry tracing */
 tracesys:
         movq    %rsp, %rdi
@@ -272,69 +277,11 @@ tracesys_phase2:
  * Has correct iret frame.
  */
 GLOBAL(int_ret_from_sys_call)
-        DISABLE_INTERRUPTS(CLBR_NONE)
-int_ret_from_sys_call_irqs_off: /* jumps come here from the irqs-off SYSRET path */
-        TRACE_IRQS_OFF
-        movl    $_TIF_ALLWORK_MASK, %edi
-        /* edi: mask to check */
-GLOBAL(int_with_check)
-        LOCKDEP_SYS_EXIT_IRQ
-        GET_THREAD_INFO(%rcx)
-        movl    TI_flags(%rcx), %edx
-        andl    %edi, %edx
-        jnz     int_careful
-        andl    $~TS_COMPAT, TI_status(%rcx)
-        jmp     syscall_return
-
-        /*
-         * Either reschedule or signal or syscall exit tracking needed.
-         * First do a reschedule test.
-         * edx: work, edi: workmask
-         */
-int_careful:
-        bt      $TIF_NEED_RESCHED, %edx
-        jnc     int_very_careful
-        TRACE_IRQS_ON
-        ENABLE_INTERRUPTS(CLBR_NONE)
-        pushq   %rdi
-        SCHEDULE_USER
-        popq    %rdi
-        DISABLE_INTERRUPTS(CLBR_NONE)
-        TRACE_IRQS_OFF
-        jmp     int_with_check
-
-        /* handle signals and tracing -- both require a full pt_regs */
-int_very_careful:
-        TRACE_IRQS_ON
-        ENABLE_INTERRUPTS(CLBR_NONE)
         SAVE_EXTRA_REGS
-        /* Check for syscall exit trace */
-        testl   $_TIF_WORK_SYSCALL_EXIT, %edx
-        jz      int_signal
-        pushq   %rdi
-        leaq    8(%rsp), %rdi                   /* &ptregs -> arg1 */
-        call    syscall_trace_leave
-        popq    %rdi
-        andl    $~(_TIF_WORK_SYSCALL_EXIT|_TIF_SYSCALL_EMU), %edi
-        jmp     int_restore_rest
-
-int_signal:
-        testl   $_TIF_DO_NOTIFY_MASK, %edx
-        jz      1f
-        movq    %rsp, %rdi                      /* &ptregs -> arg1 */
-        xorl    %esi, %esi                      /* oldset -> arg2 */
-        call    do_notify_resume
-1:      movl    $_TIF_WORK_MASK, %edi
-int_restore_rest:
+        movq    %rsp, %rdi
+        call    syscall_return_slowpath /* returns with IRQs disabled */
         RESTORE_EXTRA_REGS
-        DISABLE_INTERRUPTS(CLBR_NONE)
-        TRACE_IRQS_OFF
-        jmp     int_with_check
-
-syscall_return:
-        /* The IRETQ could re-enable interrupts: */
-        DISABLE_INTERRUPTS(CLBR_ANY)
-        TRACE_IRQS_IRETQ
+        TRACE_IRQS_IRETQ                /* we're about to change IF */
 
         /*
          * Try to use SYSRET instead of IRET if we're returning to