git: dec79d2b47b3 - main - powerpc/pmap(booke): Fix TLB TID eviction

The branch main has been updated by jhibbits:

URL: https://cgit.FreeBSD.org/src/commit/?id=dec79d2b47b3cb797d45b8bee7a1640dec85ebcc

commit dec79d2b47b3cb797d45b8bee7a1640dec85ebcc
Author:     Justin Hibbits <jhibbits@FreeBSD.org>
AuthorDate: 2026-07-05 23:03:31 +0000
Commit:     Justin Hibbits <jhibbits@FreeBSD.org>
CommitDate: 2026-07-06 21:23:55 +0000

    powerpc/pmap(booke): Fix TLB TID eviction
    
    Fix tid_set_busy() for when `pmap` is NULL. Obviously a NULL pointer
    cannot be correctly used, so I'm not sure how it worked in testing on
    64-bit.
---
 sys/powerpc/booke/pmap.c | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/sys/powerpc/booke/pmap.c b/sys/powerpc/booke/pmap.c
index 310d38d5c450..545416921d09 100644
--- a/sys/powerpc/booke/pmap.c
+++ b/sys/powerpc/booke/pmap.c
@@ -2484,11 +2484,14 @@ mmu_booke_page_array_startup(long pages)
 static __inline void
 tid_set_busy(int cpu, int tid, pmap_t pmap)
 {
-	tidbusy[cpu * (tid_max + 1) + tid] = pmap;
-	if (pmap == NULL)
-		pmap->pm_tid[cpu] = TID_NONE;
-	else
+	volatile pmap_t *pm = &tidbusy[cpu * (tid_max + 1) + tid];
+
+	if (pmap == NULL) {
+		if (*pm != NULL)
+			(*pm)->pm_tid[cpu] = TID_NONE;
+	} else
 		pmap->pm_tid[cpu] = tid;
+	*pm = pmap;
 }
 
 static __inline pmap_t
@@ -2522,7 +2525,7 @@ tid_alloc(pmap_t pmap)
 	/* If we are stealing TID then clear the relevant pmap's field */
 	if (tid_get_busy(thiscpu, tid) != NULL) {
 		CTR2(KTR_PMAP, "%s: warning: stealing tid %d", __func__, tid);
-		
+
 		tid_set_busy(thiscpu, tid, NULL);
 
 		/* Flush all entries from TLB0 matching this TID. */