Merge tag 'x86_urgent_for_v6.18_rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 fixes from Borislav Petkov:

 - Reset the why-the-system-rebooted register on AMD to avoid stale bits
   remaining from previous boots

 - Add a missing barrier in the TLB flushing code to prevent erroneously
   not flushing a TLB generation

 - Make sure cpa_flush() does not overshoot when computing the end range
   of a flush region

 - Fix resctrl bandwidth counting on AMD systems when the amount of
   monitoring groups created exceeds the number the hardware can track

* tag 'x86_urgent_for_v6.18_rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/CPU/AMD: Prevent reset reasons from being retained across reboot
  x86/mm: Fix SMP ordering in switch_mm_irqs_off()
  x86/mm: Fix overflow in __cpa_addr()
  x86/resctrl: Fix miscount of bandwidth event when reactivating previously unavailable RMID

1 files changed, 14 insertions, 2 deletions

diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
index 5398db4dedb4..ccaa51ce63f6 100644
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -1355,11 +1355,23 @@ static __init int print_s5_reset_status_mmio(void)
 		return 0;
 
 	value = ioread32(addr);
-	iounmap(addr);
 
 	/* Value with "all bits set" is an error response and should be ignored. */
-	if (value == U32_MAX)
+	if (value == U32_MAX) {
+		iounmap(addr);
 		return 0;
+	}
+
+	/*
+	 * Clear all reason bits so they won't be retained if the next reset
+	 * does not update the register. Besides, some bits are never cleared by
+	 * hardware so it's software's responsibility to clear them.
+	 *
+	 * Writing the value back effectively clears all reason bits as they are
+	 * write-1-to-clear.
+	 */
+	iowrite32(value, addr);
+	iounmap(addr);
 
 	for (i = 0; i < ARRAY_SIZE(s5_reset_reason_txt); i++) {
 		if (!(value & BIT(i)))