[src/trunk]: src/sys/arch/arm/arm32 Make sure to load the FPEXC context on co...

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

details:   https://anonhg.NetBSD.org/src/rev/f153afec8141
branches:  trunk
changeset: 783374:f153afec8141
user:      matt <matt%NetBSD.org@localhost>
date:      Mon Dec 17 17:45:01 2012 +0000

description:
Make sure to load the FPEXC context on context switch (if there a VFP) so
that the VFP state will be what the LWP expects.  (This isn't needed on
PPC or MIPS since their FPU/VEC state is reflected in the PSL/CPO_STATUS
which is handled automatically.)

diffstat:

 sys/arch/arm/arm32/cpuswitch.S |  40 +++++++++++++++++++++++++++-------------
 1 files changed, 27 insertions(+), 13 deletions(-)

diffs (140 lines):

diff -r 3b5301230ea0 -r f153afec8141 sys/arch/arm/arm32/cpuswitch.S
--- a/sys/arch/arm/arm32/cpuswitch.S    Mon Dec 17 17:44:18 2012 +0000
+++ b/sys/arch/arm/arm32/cpuswitch.S    Mon Dec 17 17:45:01 2012 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: cpuswitch.S,v 1.75 2012/12/10 01:37:30 matt Exp $      */
+/*     $NetBSD: cpuswitch.S,v 1.76 2012/12/17 17:45:01 matt Exp $      */
 
 /*
  * Copyright 2003 Wasabi Systems, Inc.
@@ -89,7 +89,7 @@
 #include <machine/asm.h>
 #include <machine/cpu.h>
 
-       RCSID("$NetBSD: cpuswitch.S,v 1.75 2012/12/10 01:37:30 matt Exp $")
+       RCSID("$NetBSD: cpuswitch.S,v 1.76 2012/12/17 17:45:01 matt Exp $")
 
 /* LINTSTUB: include <sys/param.h> */
        
@@ -141,26 +141,26 @@
        mov     r4, r0
 
 #ifdef TPIDRPRW_IS_CURCPU
-       GET_CURCPU(r7)
+       GET_CURCPU(r3)
 #elif defined(TPIDRPRW_IS_CURLWP)
        mcr     p15, 0, r0, c13, c0, 4          /* get old lwp (r4 maybe 0) */
-       ldr     r7, [r0, #(L_CPU)]              /* get cpu from old lwp */
+       ldr     r3, [r0, #(L_CPU)]              /* get cpu from old lwp */
 #elif !defined(MULTIPROCESSOR) 
-       ldr     r7, [r6, #L_CPU]                /* get cpu from new lwp */
+       ldr     r3, [r6, #L_CPU]                /* get cpu from new lwp */
 #else
 #error curcpu() method not defined
 #endif
 
+       /* rem: r3 = curcpu() */
        /* rem: r4 = old lwp */
        /* rem: r6 = new lwp */
-       /* rem: r7 = curcpu() */
        
 #ifndef __HAVE_UNNESTED_INTRS
        IRQdisable
 #endif
 
 #ifdef MULTIPROCESSOR
-       str     r7, [r6, #(L_CPU)]
+       str     r3, [r6, #(L_CPU)]
 #else
        /* l->l_cpu initialized in fork1() for single-processor */
 #endif
@@ -169,7 +169,7 @@
        mcr     p15, 0, r6, c13, c0, 4          /* set current lwp */
 #endif
        /* We have a new curlwp now so make a note it */
-       str     r6, [r7, #(CI_CURLWP)]
+       str     r6, [r3, #(CI_CURLWP)]
 
        /* Get the new pcb */
        ldr     r7, [r6, #(L_PCB)]
@@ -179,6 +179,7 @@
        IRQenable
 #endif
 
+       /* rem: r3 = curlwp */
        /* rem: r4 = old lwp */
        /* rem: r6 = new lwp */
        /* rem: r7 = new pcb */
@@ -193,6 +194,7 @@
        teq     r4, #0
        beq     .Ldo_switch
 
+       /* rem: r3 = curlwp */
        /* rem: r4 = old lwp */
        /* rem: r6 = new lwp */
        /* rem: r7 = new pcb */
@@ -204,7 +206,7 @@
        ldr     r5, [r4, #(L_PCB)]
 
        /* Save all the registers in the old lwp's pcb */
-#if defined(__XSCALE__) || defined(_ARM_ARCH_6)
+#if defined(_ARM_ARCH_DWORD_OK)
        strd    r8, [r5, #(PCB_R8)]
        strd    r10, [r5, #(PCB_R10)]
        strd    r12, [r5, #(PCB_R12)]
@@ -225,6 +227,7 @@
         * them for the new process.
         */
 
+       /* rem: r3 = curlwp */
        /* rem: r4 = old lwp */
        /* rem: r5 = old pcb */
        /* rem: r6 = new lwp */
@@ -234,6 +237,7 @@
        /* Restore saved context */
 
 .Ldo_switch:
+       /* rem: r3 = curlwp */
        /* rem: r4 = old lwp */
        /* rem: r6 = new lwp */
        /* rem: r7 = new pcb */
@@ -249,6 +253,16 @@
        mcr     p15, 0, r0, c13, c0, 3
 #endif
 
+#ifdef FPU_VFP
+       /*
+        * If we have a VFP, we need to load FPEXC.
+        */
+       ldr     r0, [r3, #(CI_VFP_ID)]
+       cmp     r0, #0
+       ldrne   r0, [r7, #(PCB_VFP_FPEXC)]
+       mcrne   p10, 7, r0, c8, c0, 0
+#endif
+
        ldr     r5, [r6, #(L_PROC)]     /* fetch the proc for below */
 
        /* Restore all the saved registers */
@@ -258,18 +272,18 @@
        ldr     r10, [r7, #(PCB_R10)]
        ldr     r11, [r7, #(PCB_R11)]
        ldr     r12, [r7, #(PCB_R12)]
-       ldr     r13, [r7, #(PCB_KSP)]
-#elif defined(_ARM_ARCH_6)
+       ldr     r13, [r7, #(PCB_KSP)]   /* sp */
+#elif defined(_ARM_ARCH_DWORD_OK)
        ldrd    r8, [r7, #(PCB_R8)]
        ldrd    r10, [r7, #(PCB_R10)]
-       ldrd    r12, [r7, #(PCB_R12)]
+       ldrd    r12, [r7, #(PCB_R12)]   /* sp */
 #else
        add     r0, r7, #PCB_R8
        ldmia   r0, {r8-r13}
 #endif
 
        /* Record the old lwp for pmap_activate()'s benefit */
-       ldr     r1, .Lpmap_previous_active_lwp
+       ldr     r1, .Lpmap_previous_active_lwp          /* XXXSMP */
        str     r4, [r1]
 
        /* rem: r4 = old lwp */