[src/trunk]: src/sys/arch/sparc64/sparc64 XXX: workaround we'd like to remove...

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

details:   https://anonhg.NetBSD.org/src/rev/350b67a361e2
branches:  trunk
changeset: 752889:350b67a361e2
user:      mrg <mrg%NetBSD.org@localhost>
date:      Wed Mar 10 06:57:22 2010 +0000

description:
XXX: workaround we'd like to remove when pmap / uvm locking is cleaned up:

- rename pseg_get() and pseg_set() to pseg_get_real() and pseg_set_real().
- if USE_LOCKSAFE_PSEG_GETSET is defined, which it current is by default,
  define pseg_[gs]et() in terms of functions that take a new pseg_lock
  mutex at IPL_VM while calling into the real functions.

this seems to avoid the pseg_set() crashes we've seen:
  1 - spare needed, when pseg_get() just worked for this pmap
  2 - the 2rd ldxa via ASI_PHYS_CACHED in pseg_set() loads garbage
      into %o4, and causes the 3rd ldxa to fault

diffstat:

 sys/arch/sparc64/sparc64/db_interface.c |   9 ++--
 sys/arch/sparc64/sparc64/locore.s       |  17 +++++----
 sys/arch/sparc64/sparc64/pmap.c         |  58 ++++++++++++++++++++++++++++++--
 3 files changed, 68 insertions(+), 16 deletions(-)

diffs (184 lines):

diff -r cd3422b7bc05 -r 350b67a361e2 sys/arch/sparc64/sparc64/db_interface.c
--- a/sys/arch/sparc64/sparc64/db_interface.c   Wed Mar 10 05:16:17 2010 +0000
+++ b/sys/arch/sparc64/sparc64/db_interface.c   Wed Mar 10 06:57:22 2010 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: db_interface.c,v 1.123 2010/03/06 08:08:29 mrg Exp $ */
+/*     $NetBSD: db_interface.c,v 1.124 2010/03/10 06:57:22 mrg Exp $ */
 
 /*
  * Copyright (c) 1996-2002 Eduardo Horvath.  All rights reserved.
@@ -34,7 +34,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: db_interface.c,v 1.123 2010/03/06 08:08:29 mrg Exp $");
+__KERNEL_RCSID(0, "$NetBSD: db_interface.c,v 1.124 2010/03/10 06:57:22 mrg Exp $");
 
 #include "opt_ddb.h"
 #include "opt_multiprocessor.h"
@@ -650,7 +650,8 @@
        }
 }
 
-int64_t pseg_get(struct pmap *, vaddr_t);
+/* XXX no locking; shouldn't matter */
+int64_t pseg_get_real(struct pmap *, vaddr_t);
 
 void
 db_dump_pmap(struct pmap *pm)
@@ -706,7 +707,7 @@
        if (have_addr) {
                /* lookup an entry for this VA */
                
-               if ((data = pseg_get(pmap_kernel(), (vaddr_t)addr))) {
+               if ((data = pseg_get_real(pmap_kernel(), (vaddr_t)addr))) {
                        db_printf("pmap_kernel(%p)->pm_segs[%lx][%lx][%lx]=>%qx\n",
                                  (void *)(uintptr_t)addr, (u_long)va_to_seg(addr),
                                  (u_long)va_to_dir(addr), (u_long)va_to_pte(addr),
diff -r cd3422b7bc05 -r 350b67a361e2 sys/arch/sparc64/sparc64/locore.s
--- a/sys/arch/sparc64/sparc64/locore.s Wed Mar 10 05:16:17 2010 +0000
+++ b/sys/arch/sparc64/sparc64/locore.s Wed Mar 10 06:57:22 2010 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: locore.s,v 1.326 2010/03/08 08:59:06 mrg Exp $ */
+/*     $NetBSD: locore.s,v 1.327 2010/03/10 06:57:22 mrg Exp $ */
 
 /*
  * Copyright (c) 2006-2010 Matthew R. Green
@@ -6568,14 +6568,15 @@
        retl
         mov    %o4, %g1                ! Restore g1
 #endif
+
 /*
- * extern int64_t pseg_get(struct pmap *pm, vaddr_t addr);
+ * extern int64_t pseg_get_real(struct pmap *pm, vaddr_t addr);
  *
  * Return TTE at addr in pmap.  Uses physical addressing only.
  * pmap->pm_physaddr must by the physical address of pm_segs
  *
  */
-ENTRY(pseg_get)
+ENTRY(pseg_get_real)
 !      flushw                  ! Make sure we don't have stack probs & lose hibits of %o
        ldx     [%o0 + PM_PHYS], %o2                    ! pmap->pm_segs
 
@@ -6637,13 +6638,13 @@
 /*
  * In 32-bit mode:
  *
- * extern int pseg_set(struct pmap* %o0, vaddr_t addr %o1, int64_t tte %o2:%o3,
- *                      paddr_t spare %o4:%o5);
+ * extern int pseg_set_real(struct pmap* %o0, vaddr_t addr %o1,
+ *                         int64_t tte %o2:%o3, paddr_t spare %o4:%o5);
  *
  * In 64-bit mode:
  *
- * extern int pseg_set(struct pmap* %o0, vaddr_t addr %o1, int64_t tte %o2,
- *                     paddr_t spare %o3);
+ * extern int pseg_set_real(struct pmap* %o0, vaddr_t addr %o1,
+ *                         int64_t tte %o2, paddr_t spare %o3);
  *
  * Set a pseg entry to a particular TTE value.  Return values are:
  *
@@ -6673,7 +6674,7 @@
  * The counters are 32 bit or 64 bit wide, depending on the kernel type we are
  * running!
  */
-ENTRY(pseg_set)
+ENTRY(pseg_set_real)
 #ifndef _LP64
        sllx    %o4, 32, %o4                            ! Put args into 64-bit format
        sllx    %o2, 32, %o2                            ! Shift to high 32-bits
diff -r cd3422b7bc05 -r 350b67a361e2 sys/arch/sparc64/sparc64/pmap.c
--- a/sys/arch/sparc64/sparc64/pmap.c   Wed Mar 10 05:16:17 2010 +0000
+++ b/sys/arch/sparc64/sparc64/pmap.c   Wed Mar 10 06:57:22 2010 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: pmap.c,v 1.258 2010/03/08 08:59:06 mrg Exp $   */
+/*     $NetBSD: pmap.c,v 1.259 2010/03/10 06:57:22 mrg Exp $   */
 /*
  *
  * Copyright (C) 1996-1999 Eduardo Horvath.
@@ -26,7 +26,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: pmap.c,v 1.258 2010/03/08 08:59:06 mrg Exp $");
+__KERNEL_RCSID(0, "$NetBSD: pmap.c,v 1.259 2010/03/10 06:57:22 mrg Exp $");
 
 #undef NO_VCACHE /* Don't forget the locked TLB in dostart */
 #define        HWREF
@@ -79,8 +79,8 @@
 paddr_t cpu0paddr;             /* contigious phys memory preallocated for cpus */
 
 /* These routines are in assembly to allow access thru physical mappings */
-extern int64_t pseg_get(struct pmap *, vaddr_t);
-extern int pseg_set(struct pmap *, vaddr_t, int64_t, paddr_t);
+extern int64_t pseg_get_real(struct pmap *, vaddr_t);
+extern int pseg_set_real(struct pmap *, vaddr_t, int64_t, paddr_t);
 
 /*
  * Diatribe on ref/mod counting:
@@ -350,6 +350,53 @@
 };
 
 /*
+ * This probably shouldn't be necessary, but it stops USIII machines from
+ * breaking in general, and not just for MULTIPROCESSOR.
+ */
+#define USE_LOCKSAFE_PSEG_GETSET
+#if defined(USE_LOCKSAFE_PSEG_GETSET)
+
+static kmutex_t pseg_lock;
+
+static __inline__ int64_t
+pseg_get_locksafe(struct pmap *pm, vaddr_t va)
+{
+       int64_t rv;
+       bool took_lock = lock_available /*&& pm == pmap_kernel()*/;
+
+       if (__predict_true(took_lock))
+               mutex_enter(&pseg_lock);
+       rv = pseg_get_real(pm, va);
+       if (__predict_true(took_lock))
+               mutex_exit(&pseg_lock);
+       return rv;
+}
+
+static __inline__ int
+pseg_set_locksafe(struct pmap *pm, vaddr_t va, int64_t data, paddr_t ptp)
+{
+       int rv;
+       bool took_lock = lock_available /*&& pm == pmap_kernel()*/;
+
+       if (__predict_true(took_lock))
+               mutex_enter(&pseg_lock);
+       rv = pseg_set_real(pm, va, data, ptp);
+       if (__predict_true(took_lock))
+               mutex_exit(&pseg_lock);
+       return rv;
+}
+
+#define pseg_get(pm, va)               pseg_get_locksafe(pm, va)
+#define pseg_set(pm, va, data, ptp)    pseg_set_locksafe(pm, va, data, ptp)
+
+#else /* USE_LOCKSAFE_PSEG_GETSET */
+
+#define pseg_get(pm, va)               pseg_get_real(pm, va)
+#define pseg_set(pm, va, data, ptp)    pseg_set_real(pm, va, data, ptp)
+
+#endif /* USE_LOCKSAFE_PSEG_GETSET */
+
+/*
  * Enter a TTE into the kernel pmap only.  Don't do anything else.
  *
  * Use only during bootstrapping since it does no locking and
@@ -1247,6 +1294,9 @@
        vm_num_phys = avail_end - avail_start;
 
        mutex_init(&pmap_lock, MUTEX_DEFAULT, IPL_NONE);
+#if defined(USE_LOCKSAFE_PSEG_GETSET)
+       mutex_init(&pseg_lock, MUTEX_SPIN, IPL_VM);
+#endif
        lock_available = true;
 }