The branch main has been updated by mhorne:

URL: 
https://cgit.FreeBSD.org/src/commit/?id=7a1aaca06c3384f90202dafa60440081d67d00fd

commit 7a1aaca06c3384f90202dafa60440081d67d00fd
Author:     Ali Mashtizadeh <[email protected]>
AuthorDate: 2026-04-04 21:30:03 +0000
Commit:     Mitchell Horne <[email protected]>
CommitDate: 2026-04-09 16:35:26 +0000

    hwpmc: Fix bug when stopping ibs-op
    
    In ibs_stop_pmc I accidently cleared the fetch max count value rather
    than the op max count value, when stopping the op counter.  This
    mitigates a bug in early pre-zen processors, but breaks using both
    counters simultaneously.  I also found that the max op count mask needs
    to be extended for recent zen processors.
    
    Reported by:    Andre Fernando da Silva
    Reviewed by:    mhorne
    Sponsored by:   Netflix
    Fixes:  e51ef8ae490f ("hwpmc: Initial support for AMD IBS")
    Pull Request:   https://github.com/freebsd/freebsd-src/pull/2120
---
 sys/dev/hwpmc/hwpmc_ibs.c | 4 ++--
 sys/dev/hwpmc/hwpmc_ibs.h | 2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/sys/dev/hwpmc/hwpmc_ibs.c b/sys/dev/hwpmc/hwpmc_ibs.c
index bfc135f06884..ec1afcb47666 100644
--- a/sys/dev/hwpmc/hwpmc_ibs.c
+++ b/sys/dev/hwpmc/hwpmc_ibs.c
@@ -270,7 +270,7 @@ ibs_stop_pmc(int cpu __diagused, int ri, struct pmc *pm)
         * Turn off the ENABLE bit, but unfortunately there are a few quirks
         * that generate excess NMIs.  Workaround #420 in the Revision Guide
         * for AMD Family 10h Processors 41322 Rev. 3.92 March 2012. requires
-        * that we clear the count before clearing enable.
+        * that we clear the max count before clearing enable.
         *
         * Even after clearing the counter spurious NMIs are still possible so
         * we use a per-CPU atomic variable to notify the interrupt handler we
@@ -290,7 +290,7 @@ ibs_stop_pmc(int cpu __diagused, int ri, struct pmc *pm)
                wrmsr(IBS_FETCH_CTL, config);
                break;
        case IBS_PMC_OP:
-               wrmsr(IBS_FETCH_CTL, config & ~IBS_FETCH_CTL_MAXCNTMASK);
+               wrmsr(IBS_OP_CTL, config & ~IBS_OP_CTL_MAXCNTMASK);
                DELAY(1);
                config &= ~IBS_OP_CTL_ENABLE;
                wrmsr(IBS_OP_CTL, config);
diff --git a/sys/dev/hwpmc/hwpmc_ibs.h b/sys/dev/hwpmc/hwpmc_ibs.h
index c66d54672543..1616a746ffef 100644
--- a/sys/dev/hwpmc/hwpmc_ibs.h
+++ b/sys/dev/hwpmc/hwpmc_ibs.h
@@ -112,7 +112,7 @@
 #define IBS_OP_CTL_VALID               (1ULL << 18) /* Valid */
 #define IBS_OP_CTL_ENABLE              (1ULL << 17) /* Enable */
 #define IBS_OP_CTL_L3MISSONLY          (1ULL << 16) /* L3 Miss Filtering */
-#define IBS_OP_CTL_MAXCNTMASK          0x0000FFFFULL
+#define IBS_OP_CTL_MAXCNTMASK          0x07F0FFFFULL
 
 #define IBS_OP_CTL_LDLAT_TO_CTL(_c)    ((((ldlat) >> 7) - 1) << 59)
 #define IBS_OP_INTERVAL_TO_CTL(_c)     ((((_c) >> 4) & 0x0000FFFFULL) | ((_c) 
& 0x07F00000))

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