FRV: Optimise the system call exit path in entry.S [ver #2]
David Howells [Tue, 1 May 2012 20:31:42 +0000 (21:31 +0100)]
Optimise the system call exit path in entry.S by packing some instructions.

Suggested-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

arch/frv/kernel/entry.S

index 03da263..7d5e000 100644 (file)
@@ -905,18 +905,19 @@ __syscall_call:
 __syscall_exit:
        LEDS            0x6300
 
-       sti             gr8,@(gr28,#REG_GR(8))  ; save return value
+       # keep current PSR in GR23
+       movsg           psr,gr23
 
-       # rebuild saved psr - execve will change it for init/main.c
        ldi             @(gr28,#REG_PSR),gr22
+
+       sti.p           gr8,@(gr28,#REG_GR(8))  ; save return value
+
+       # rebuild saved psr - execve will change it for init/main.c
        srli            gr22,#1,gr5
        andi.p          gr22,#~PSR_PS,gr22
        andi            gr5,#PSR_PS,gr5
        or              gr5,gr22,gr22
-       ori             gr22,#PSR_S,gr22
-
-       # keep current PSR in GR23
-       movsg           psr,gr23
+       ori.p           gr22,#PSR_S,gr22
 
        # make sure we don't miss an interrupt setting need_resched or sigpending between
        # sampling and the RETT