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-rw-r--r--arch/powerpc/kernel/mce.c142
1 files changed, 114 insertions, 28 deletions
diff --git a/arch/powerpc/kernel/mce.c b/arch/powerpc/kernel/mce.c
index 742e4658c5dc..d2fecaec4fec 100644
--- a/arch/powerpc/kernel/mce.c
+++ b/arch/powerpc/kernel/mce.c
@@ -495,37 +495,123 @@ long machine_check_early(struct pt_regs *regs)
return handled;
}
-long hmi_exception_realmode(struct pt_regs *regs)
+/* Possible meanings for HMER_DEBUG_TRIG bit being set on POWER9 */
+static enum {
+ DTRIG_UNKNOWN,
+ DTRIG_VECTOR_CI, /* need to emulate vector CI load instr */
+ DTRIG_SUSPEND_ESCAPE, /* need to escape from TM suspend mode */
+} hmer_debug_trig_function;
+
+static int init_debug_trig_function(void)
{
- __this_cpu_inc(irq_stat.hmi_exceptions);
-
-#ifdef CONFIG_PPC_BOOK3S_64
- /* Workaround for P9 vector CI loads (see p9_hmi_special_emu) */
- if (pvr_version_is(PVR_POWER9)) {
- unsigned long hmer = mfspr(SPRN_HMER);
-
- /* Do we have the debug bit set */
- if (hmer & PPC_BIT(17)) {
- hmer &= ~PPC_BIT(17);
- mtspr(SPRN_HMER, hmer);
-
- /*
- * Now to avoid problems with soft-disable we
- * only do the emulation if we are coming from
- * user space
- */
- if (user_mode(regs))
- local_paca->hmi_p9_special_emu = 1;
-
- /*
- * Don't bother going to OPAL if that's the
- * only relevant bit.
- */
- if (!(hmer & mfspr(SPRN_HMEER)))
- return local_paca->hmi_p9_special_emu;
+ int pvr;
+ struct device_node *cpun;
+ struct property *prop = NULL;
+ const char *str;
+
+ /* First look in the device tree */
+ preempt_disable();
+ cpun = of_get_cpu_node(smp_processor_id(), NULL);
+ if (cpun) {
+ of_property_for_each_string(cpun, "ibm,hmi-special-triggers",
+ prop, str) {
+ if (strcmp(str, "bit17-vector-ci-load") == 0)
+ hmer_debug_trig_function = DTRIG_VECTOR_CI;
+ else if (strcmp(str, "bit17-tm-suspend-escape") == 0)
+ hmer_debug_trig_function = DTRIG_SUSPEND_ESCAPE;
}
+ of_node_put(cpun);
+ }
+ preempt_enable();
+
+ /* If we found the property, don't look at PVR */
+ if (prop)
+ goto out;
+
+ pvr = mfspr(SPRN_PVR);
+ /* Check for POWER9 Nimbus (scale-out) */
+ if ((PVR_VER(pvr) == PVR_POWER9) && (pvr & 0xe000) == 0) {
+ /* DD2.2 and later */
+ if ((pvr & 0xfff) >= 0x202)
+ hmer_debug_trig_function = DTRIG_SUSPEND_ESCAPE;
+ /* DD2.0 and DD2.1 - used for vector CI load emulation */
+ else if ((pvr & 0xfff) >= 0x200)
+ hmer_debug_trig_function = DTRIG_VECTOR_CI;
+ }
+
+ out:
+ switch (hmer_debug_trig_function) {
+ case DTRIG_VECTOR_CI:
+ pr_debug("HMI debug trigger used for vector CI load\n");
+ break;
+ case DTRIG_SUSPEND_ESCAPE:
+ pr_debug("HMI debug trigger used for TM suspend escape\n");
+ break;
+ default:
+ break;
}
-#endif /* CONFIG_PPC_BOOK3S_64 */
+ return 0;
+}
+__initcall(init_debug_trig_function);
+
+/*
+ * Handle HMIs that occur as a result of a debug trigger.
+ * Return values:
+ * -1 means this is not a HMI cause that we know about
+ * 0 means no further handling is required
+ * 1 means further handling is required
+ */
+long hmi_handle_debugtrig(struct pt_regs *regs)
+{
+ unsigned long hmer = mfspr(SPRN_HMER);
+ long ret = 0;
+
+ /* HMER_DEBUG_TRIG bit is used for various workarounds on P9 */
+ if (!((hmer & HMER_DEBUG_TRIG)
+ && hmer_debug_trig_function != DTRIG_UNKNOWN))
+ return -1;
+
+ hmer &= ~HMER_DEBUG_TRIG;
+ /* HMER is a write-AND register */
+ mtspr(SPRN_HMER, ~HMER_DEBUG_TRIG);
+
+ switch (hmer_debug_trig_function) {
+ case DTRIG_VECTOR_CI:
+ /*
+ * Now to avoid problems with soft-disable we
+ * only do the emulation if we are coming from
+ * host user space
+ */
+ if (regs && user_mode(regs))
+ ret = local_paca->hmi_p9_special_emu = 1;
+
+ break;
+
+ default:
+ break;
+ }
+
+ /*
+ * See if any other HMI causes remain to be handled
+ */
+ if (hmer & mfspr(SPRN_HMEER))
+ return -1;
+
+ return ret;
+}
+
+/*
+ * Return values:
+ */
+long hmi_exception_realmode(struct pt_regs *regs)
+{
+ int ret;
+
+ __this_cpu_inc(irq_stat.hmi_exceptions);
+
+ ret = hmi_handle_debugtrig(regs);
+ if (ret >= 0)
+ return ret;
wait_for_subcore_guest_exit();