[src/trunk]: src/sys/arch/powerpc/ibm4xx copy{in,out}(): Tiny optimizations f...

[rin <rin%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/3a8767a6b736
branches:  trunk
changeset: 369978:3a8767a6b736
user:      rin <rin%NetBSD.org@localhost>
date:      Sun Sep 11 09:08:04 2022 +0000

description:
copy{in,out}(): Tiny optimizations for __asm codes.
No regressions for full ATF run.

- Use {l,st}swx instead of loop for remaining bytes.
- Drop needless "mtpid %[x]; isync;".

diffstat:

 sys/arch/powerpc/ibm4xx/trap.c |  42 ++++++++++++++++--------------------------
 1 files changed, 16 insertions(+), 26 deletions(-)

diffs (110 lines):

diff -r 122df34c5cbc -r 3a8767a6b736 sys/arch/powerpc/ibm4xx/trap.c
--- a/sys/arch/powerpc/ibm4xx/trap.c    Sun Sep 11 09:03:25 2022 +0000
+++ b/sys/arch/powerpc/ibm4xx/trap.c    Sun Sep 11 09:08:04 2022 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: trap.c,v 1.93 2022/09/11 09:03:25 rin Exp $    */
+/*     $NetBSD: trap.c,v 1.94 2022/09/11 09:08:04 rin Exp $    */
 
 /*
  * Copyright 2001 Wasabi Systems, Inc.
@@ -69,7 +69,7 @@
 #define        __UFETCHSTORE_PRIVATE
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: trap.c,v 1.93 2022/09/11 09:03:25 rin Exp $");
+__KERNEL_RCSID(0, "$NetBSD: trap.c,v 1.94 2022/09/11 09:08:04 rin Exp $");
 
 #ifdef _KERNEL_OPT
 #include "opt_ddb.h"
@@ -485,23 +485,18 @@
 
        "2:"    "andi.  %[count],%[len],0x3;"   /* How many remaining bytes? */
                "beq    10f;"
-               "addi   %[count],%[count],0x1;"
-               "mtctr  %[count];"
-       "3:"    "bdz    10f;"                   /* while count */
+               "mtxer  %[count];"
 
                "mtpid  %[ctx];"
                "isync;"
-               "lbz    %[tmp],0(%[uaddr]);"    /* Load user byte */
-               "addi   %[uaddr],%[uaddr],0x1;" /* next uaddr byte */
+               "lswx   %[tmp],0,%[uaddr];"     /* Load user bytes */
                "sync;"
 
                "mtpid  %[pid];"
                "isync;"
-               "stb    %[tmp],0(%[kaddr]);"    /* Store kernel byte */
+               "stswx  %[tmp],0,%[kaddr];"     /* Store kernel byte */
                "dcbst  0,%[kaddr];"            /* flush cache */
-               "addi   %[kaddr],%[kaddr],0x1;"
                "sync;"
-               "b      3b;"
 
        "10:"   "mtpid  %[pid];"                /* Restore PID and MSR */
                "mtmsr  %[msr];"
@@ -510,7 +505,7 @@
                : [msr] "=&r" (msr), [pid] "=&r" (pid), [tmp] "=&r" (tmp)
                : [uaddr] "b" (uaddr), [ctx] "b" (ctx), [kaddr] "b" (kaddr),
                  [len] "b" (len), [count] "b" (count)
-               : "cr0", "ctr");
+               : "cr0", "ctr", "xer");
 
        curpcb->pcb_onfault = NULL;
        return 0;
@@ -582,8 +577,7 @@
                "beq-   2f;"                    /* No words. Go do bytes */
                "mtctr  %[count];"
 
-       "1:"    "mtpid  %[pid];"
-               "isync;"
+       "1:"
 #ifdef PPC_IBM403
                "lswi   %[tmp],%[kaddr],4;"     /* Load kernel word */
 #else
@@ -602,36 +596,32 @@
                "dcbst  0,%[uaddr];"            /* flush cache */
                "addi   %[uaddr],%[uaddr],0x4;" /* next uaddr word */
                "sync;"
+
+               "mtpid  %[pid];"
+               "isync;"
                "bdnz   1b;"                    /* repeat */
 
        "2:"    "andi.  %[count],%[len],0x3;"   /* How many remaining bytes? */
                "beq    10f;"
-               "addi   %[count],%[count],0x1;"
-               "mtctr  %[count];"
-       "3:"    "bdz    10f;"                   /* while count */
+               "mtxer  %[count];"
 
-               "mtpid  %[pid];"
-               "isync;"
-               "lbz    %[tmp],0(%[kaddr]);"    /* Load kernel byte */
-               "addi   %[kaddr],%[kaddr],0x1;" /* next kaddr byte */
+               "lswx   %[tmp],0,%[kaddr];"     /* Load kernel bytes */
                "sync;"
 
                "mtpid  %[ctx];"
                "isync;"
-               "stb    %[tmp],0(%[uaddr]);"    /* Store user byte */
+               "stswx  %[tmp],0,%[uaddr];"     /* Store user bytes */
                "dcbst  0,%[uaddr];"            /* flush cache */
-               "addi   %[uaddr],%[uaddr],0x1;"
                "sync;"
-               "b 3b;"
 
-       "10:"   "mtpid  %[pid];"                /* Restore PID and MSR */
-               "mtmsr  %[msr];"
+               "mtpid  %[pid];"                /* Restore PID and MSR */
+       "10:"   "mtmsr  %[msr];"
                "isync;"
 
                : [msr] "=&r" (msr), [pid] "=&r" (pid), [tmp] "=&r" (tmp)
                : [uaddr] "b" (uaddr), [ctx] "b" (ctx), [kaddr] "b" (kaddr),
                  [len] "b" (len), [count] "b" (count)
-               : "cr0", "ctr");
+               : "cr0", "ctr", "xer");
 
        curpcb->pcb_onfault = NULL;
        return 0;