Date: Wed, 10 Nov 2010 17:14:32 -0500 From: John Baldwin <jhb@freebsd.org> To: powerpc@freebsd.org Cc: raj@freebsd.org, dim@freebsd.org Subject: Use of MTX_UNOWNED in booke/trap_subr.S Message-ID: <201011101714.33194.jhb@freebsd.org>
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First of, sorry for breaking the build. I built a powerpc GENERIC and a
powerpc64 GENERIC before I committed, but that obviously wasn't sufficient.
dim@ pointed me at the use of MTX_UNOWNED in booke/trap_subr.S. The first
thought I had was to re-allow <sys/mutex.h> in assembly code, or to expose
MTX_UNOWNED via assym.s. However, it looks like the tlb lock in trap_subr.S
is a home-grown spinlock rather than an actual 'struct mtx'. For that reason,
I'd prefer it use its own constant to avoid confusion. To that end, the patch
below adds a TLB_UNLOCKED constant to <machine/tlb.h> and uses it for the tlb
locks.
(I do wonder if we couldn't put the tlb_lock/unlock prototypes in
machine/tlb.h as well rather than booke/pmap.c? Then it could all be grouped
together to be more consistent.)
Index: powerpc/booke/machdep.c
===================================================================
--- powerpc/booke/machdep.c (revision 215090)
+++ powerpc/booke/machdep.c (working copy)
@@ -453,7 +453,7 @@
ptr = &tlb0_miss_locks[cpuid * words_per_gran];
pcpu->pc_booke_tlb_lock = ptr;
- *ptr = MTX_UNOWNED;
+ *ptr = TLB_UNLOCKED;
*(ptr + 1) = 0; /* recurse counter */
#endif
}
Index: powerpc/booke/trap_subr.S
===================================================================
--- powerpc/booke/trap_subr.S (revision 215090)
+++ powerpc/booke/trap_subr.S (working copy)
@@ -330,7 +330,7 @@
lwz %r22, PC_BOOKE_TLB_LOCK(%r20); \
\
1: lwarx %r23, 0, %r22; \
- cmpwi %r23, MTX_UNOWNED; \
+ cmpwi %r23, TLB_UNLOCKED; \
beq 2f; \
\
/* check if this is recursion */ \
@@ -364,7 +364,7 @@
msync; \
\
/* release the lock */ \
- li %r23, MTX_UNOWNED; \
+ li %r23, TLB_UNLOCKED; \
stw %r23, 0(%r22); \
1: isync; \
msync
@@ -860,7 +860,7 @@
GET_CPUINFO(%r5)
lwz %r5, PC_CURTHREAD(%r5)
1: lwarx %r4, 0, %r3
- cmpwi %r4, MTX_UNOWNED
+ cmpwi %r4, TLB_UNLOCKED
bne 1b
stwcx. %r5, 0, %r3
bne- 1b
@@ -871,7 +871,7 @@
ENTRY(tlb_unlock)
isync
msync
- li %r4, MTX_UNOWNED
+ li %r4, TLB_UNLOCKED
stw %r4, 0(%r3)
isync
msync
Index: powerpc/include/tlb.h
===================================================================
--- powerpc/include/tlb.h (revision 215090)
+++ powerpc/include/tlb.h (working copy)
@@ -129,6 +129,9 @@
#define TID_MAX 255
#define TID_NONE -1
+/* Lock value for an unlocked per-CPU TLB lock for BookE. */
+#define TLB_UNLOCKED 4
+
#if !defined(LOCORE)
typedef struct tlb_entry {
uint32_t mas1;
--
John Baldwin
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