From 7290f3b3d3e66b54720f23079ffc60e0b7bbb0cc Mon Sep 17 00:00:00 2001
From: Nicholas Piggin <npiggin@gmail.com>
Date: Fri, 2 Aug 2019 20:56:33 +1000
Subject: [PATCH] powerpc/64s/powernv: machine check dump SLB contents

References: jsc#PM-1334 jsc#SLE-9246 jsc#SLE-9251
Patch-mainline: v5.4-rc1
Git-commit: 7290f3b3d3e66b54720f23079ffc60e0b7bbb0cc

Re-use the code introduced in pseries to save and dump the contents
of the SLB in the case of an SLB involved machine check exception.

This patch also avoids allocating the SLB save array on pseries radix.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190802105709.27696-9-npiggin@gmail.com
Acked-by: Michal Suchanek <msuchanek@suse.de>
---
 arch/powerpc/kernel/mce.c              |  6 ++++++
 arch/powerpc/kernel/mce_power.c        |  4 ++++
 arch/powerpc/platforms/powernv/setup.c |  9 +++++++++
 arch/powerpc/platforms/pseries/setup.c | 24 +++++++++++++-----------
 4 files changed, 32 insertions(+), 11 deletions(-)

diff --git a/arch/powerpc/kernel/mce.c b/arch/powerpc/kernel/mce.c
index ec4b3e1087be..04280a5871fc 100644
--- a/arch/powerpc/kernel/mce.c
+++ b/arch/powerpc/kernel/mce.c
@@ -511,6 +511,12 @@ void machine_check_print_event_info(struct machine_check_event *evt,
 	subtype = evt->error_class < ARRAY_SIZE(mc_error_class) ?
 		mc_error_class[evt->error_class] : "Unknown";
 	printk("%sMCE: CPU%d: %s\n", level, evt->cpu, subtype);
+
+#ifdef CONFIG_PPC_BOOK3S_64
+	/* Display faulty slb contents for SLB errors. */
+	if (evt->error_type == MCE_ERROR_TYPE_SLB)
+		slb_dump_contents(local_paca->mce_faulty_slbs);
+#endif
 }
 EXPORT_SYMBOL_GPL(machine_check_print_event_info);
 
diff --git a/arch/powerpc/kernel/mce_power.c b/arch/powerpc/kernel/mce_power.c
index b6cbe3449358..356e7b99f661 100644
--- a/arch/powerpc/kernel/mce_power.c
+++ b/arch/powerpc/kernel/mce_power.c
@@ -405,6 +405,8 @@ static int mce_handle_ierror(struct pt_regs *regs,
 		/* attempt to correct the error */
 		switch (table[i].error_type) {
 		case MCE_ERROR_TYPE_SLB:
+			if (local_paca->in_mce == 1)
+				slb_save_contents(local_paca->mce_faulty_slbs);
 			handled = mce_flush(MCE_FLUSH_SLB);
 			break;
 		case MCE_ERROR_TYPE_ERAT:
@@ -490,6 +492,8 @@ static int mce_handle_derror(struct pt_regs *regs,
 		/* attempt to correct the error */
 		switch (table[i].error_type) {
 		case MCE_ERROR_TYPE_SLB:
+			if (local_paca->in_mce == 1)
+				slb_save_contents(local_paca->mce_faulty_slbs);
 			if (mce_flush(MCE_FLUSH_SLB))
 				handled = 1;
 			break;
diff --git a/arch/powerpc/platforms/powernv/setup.c b/arch/powerpc/platforms/powernv/setup.c
index a5e52f9eed3c..83498604d322 100644
--- a/arch/powerpc/platforms/powernv/setup.c
+++ b/arch/powerpc/platforms/powernv/setup.c
@@ -24,6 +24,7 @@
 #include <linux/bug.h>
 #include <linux/pci.h>
 #include <linux/cpufreq.h>
+#include <linux/memblock.h>
 
 #include <asm/machdep.h>
 #include <asm/firmware.h>
@@ -166,6 +167,14 @@ static void __init pnv_init(void)
 	else
 #endif
 		add_preferred_console("hvc", 0, NULL);
+
+	if (!radix_enabled()) {
+		int i;
+
+		/* Allocate per cpu area to save old slb contents during MCE */
+		for_each_possible_cpu(i)
+			paca_ptrs[i]->mce_faulty_slbs = memblock_alloc_node(mmu_slb_size, __alignof__(*paca_ptrs[i]->mce_faulty_slbs), cpu_to_node(i));
+	}
 }
 
 static void __init pnv_init_IRQ(void)
diff --git a/arch/powerpc/platforms/pseries/setup.c b/arch/powerpc/platforms/pseries/setup.c
index d8930c3a8a11..b955d54628ff 100644
--- a/arch/powerpc/platforms/pseries/setup.c
+++ b/arch/powerpc/platforms/pseries/setup.c
@@ -142,17 +142,19 @@ static void __init fwnmi_init(void)
 	}
 
 #ifdef CONFIG_PPC_BOOK3S_64
-	/* Allocate per cpu slb area to save old slb contents during MCE */
-	size = sizeof(struct slb_entry) * mmu_slb_size * nr_cpus;
-	slb_ptr = memblock_alloc_try_nid_raw(size, sizeof(struct slb_entry),
-					MEMBLOCK_LOW_LIMIT, ppc64_rma_size,
-					NUMA_NO_NODE);
-	if (!slb_ptr)
-		panic("Failed to allocate %zu bytes below %pa for slb area\n",
-		      size, &ppc64_rma_size);
-
-	for_each_possible_cpu(i)
-		paca_ptrs[i]->mce_faulty_slbs = slb_ptr + (mmu_slb_size * i);
+	if (!radix_enabled()) {
+		/* Allocate per cpu area to save old slb contents during MCE */
+		size = sizeof(struct slb_entry) * mmu_slb_size * nr_cpus;
+		slb_ptr = memblock_alloc_try_nid_raw(size,
+				sizeof(struct slb_entry), MEMBLOCK_LOW_LIMIT,
+				ppc64_rma_size, NUMA_NO_NODE);
+		if (!slb_ptr)
+			panic("Failed to allocate %zu bytes below %pa for slb area\n",
+			      size, &ppc64_rma_size);
+
+		for_each_possible_cpu(i)
+			paca_ptrs[i]->mce_faulty_slbs = slb_ptr + (mmu_slb_size * i);
+	}
 #endif
 }
 
-- 
2.23.0