Subject: [PATCH 1/2] powerpc/64s: move machine check SLB flushing to mm/slb.c

From: Nicholas Piggin <[email-masked]>
Date: Fri, 3 Aug 2018 14:13:49 +1000

The machine check code that flushes and restores bolted segments in
real mode belongs in mm/slb.c. This will be used by pseries machine
check and idle code.

Signed-off-by: Nicholas Piggin <[email-masked]>
---
 arch/powerpc/include/asm/book3s/64/mmu-hash.h |  3 ++
 arch/powerpc/kernel/mce_power.c               | 21 ++--------
 arch/powerpc/mm/slb.c                         | 38 +++++++++++++++++++
 3 files changed, 44 insertions(+), 18 deletions(-)

diff --git a/arch/powerpc/include/asm/book3s/64/mmu-hash.h b/arch/powerpc/include/asm/book3s/64/mmu-hash.h
index 2f74bdc805e0..d4e398185b3a 100644
--- a/arch/powerpc/include/asm/book3s/64/mmu-hash.h
+++ b/arch/powerpc/include/asm/book3s/64/mmu-hash.h
@@ -497,6 +497,9 @@ extern void hpte_init_native(void);
 
 extern void slb_initialize(void);
 extern void slb_flush_and_rebolt(void);
+extern void slb_flush_all_realmode(void);
+extern void __slb_restore_bolted_realmode(void);
+extern void slb_restore_bolted_realmode(void);
 
 extern void slb_vmalloc_update(void);
 extern void slb_set_size(u16 size);
diff --git a/arch/powerpc/kernel/mce_power.c b/arch/powerpc/kernel/mce_power.c
index d6756af6ec78..50f7b9817246 100644
--- a/arch/powerpc/kernel/mce_power.c
+++ b/arch/powerpc/kernel/mce_power.c
@@ -62,11 +62,8 @@ static unsigned long addr_to_pfn(struct pt_regs *regs, unsigned long addr)
 #ifdef CONFIG_PPC_BOOK3S_64
 static void flush_and_reload_slb(void)
 {
-	struct slb_shadow *slb;
-	unsigned long i, n;
-
 	/* Invalidate all SLBs */
-	asm volatile("slbmte %0,%0; slbia" : : "r" (0));
+	slb_flush_all_realmode();
 
 #ifdef CONFIG_KVM_BOOK3S_HANDLER
 	/*
@@ -76,22 +73,10 @@ static void flush_and_reload_slb(void)
 	if (get_paca()->kvm_hstate.in_guest)
 		return;
 #endif
-
-	/* For host kernel, reload the SLBs from shadow SLB buffer. */
-	slb = get_slb_shadow();
-	if (!slb)
+	if (early_radix_enabled())
 		return;
 
-	n = min_t(u32, be32_to_cpu(slb->persistent), SLB_MIN_SIZE);
-
-	/* Load up the SLB entries from shadow SLB */
-	for (i = 0; i < n; i++) {
-		unsigned long rb = be64_to_cpu(slb->save_area[i].esid);
-		unsigned long rs = be64_to_cpu(slb->save_area[i].vsid);
-
-		rb = (rb & ~0xFFFul) | i;
-		asm volatile("slbmte %0,%1" : : "r" (rs), "r" (rb));
-	}
+	slb_restore_bolted_realmode();
 }
 #endif
 
diff --git a/arch/powerpc/mm/slb.c b/arch/powerpc/mm/slb.c
index cb796724a6fc..136db8652577 100644
--- a/arch/powerpc/mm/slb.c
+++ b/arch/powerpc/mm/slb.c
@@ -90,6 +90,44 @@ static inline void create_shadowed_slbe(unsigned long ea, int ssize,
 		     : "memory" );
 }
 
+/*
+ * Insert bolted entries into SLB (which may not be empty).
+ */
+void __slb_restore_bolted_realmode(void)
+{
+	struct slb_shadow *p = get_slb_shadow();
+	enum slb_index index;
+
+	 /* No isync needed because realmode. */
+	for (index = 0; index < SLB_NUM_BOLTED; index++) {
+		asm volatile("slbmte  %0,%1" :
+		     : "r" (be64_to_cpu(p->save_area[index].vsid)),
+		       "r" (be64_to_cpu(p->save_area[index].esid)));
+	}
+}
+
+/*
+ * Insert bolted entries into an empty SLB.
+ * This is not the same as rebolt because the bolted segments
+ * (e.g., kstack) are not changed (rebolted).
+ */
+void slb_restore_bolted_realmode(void)
+{
+	__slb_restore_bolted_realmode();
+	get_paca()->slb_cache_ptr = 0;
+}
+
+/*
+ * This flushes all SLB entries including 0, so it must be realmode.
+ */
+void slb_flush_all_realmode(void)
+{
+	/*
+	 * This flushes all SLB entries including 0, so it must be realmode.
+	 */
+	asm volatile("slbmte %0,%0; slbia" : : "r" (0));
+}
+
 static void __slb_flush_and_rebolt(void)
 {
 	/* If you change this make sure you change SLB_NUM_BOLTED
-- 
2.17.0