powerpc/mm: Fixup tlbie vs mtpidr/mtlpidr ordering issue on POWER9

On POWER9, under some circumstances, a broadcast TLB invalidation will
fail to invalidate the ERAT cache on some threads when there are
parallel mtpidr/mtlpidr happening on other threads of the same core.
This can cause stores to continue to go to a page after it's unmapped.

The workaround is to force an ERAT flush using PID=0 or LPID=0 tlbie
flush. This additional TLB flush will cause the ERAT cache
invalidation. Since we are using PID=0 or LPID=0, we don't get
filtered out by the TLB snoop filtering logic.

We need to still follow this up with another tlbie to take care of
store vs tlbie ordering issue explained in commit:
a5d4b5891c2f ("powerpc/mm: Fixup tlbie vs store ordering issue on
POWER9"). The presence of ERAT cache implies we can still get new
stores and they may miss store queue marking flush.

Cc: stable@vger.kernel.org
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190924035254.24612-3-aneesh.kumar@linux.ibm.com

1 files changed, 72 insertions, 8 deletions

diff --git a/arch/powerpc/mm/book3s64/radix_tlb.c b/arch/powerpc/mm/book3s64/radix_tlb.c
index 69fdc004d83f..67af871190c6 100644
--- a/arch/powerpc/mm/book3s64/radix_tlb.c
+++ b/arch/powerpc/mm/book3s64/radix_tlb.c
@@ -196,21 +196,82 @@ static __always_inline void __tlbie_lpid_va(unsigned long va, unsigned long lpid
 	trace_tlbie(lpid, 0, rb, rs, ric, prs, r);
 }
 
-static inline void fixup_tlbie(void)
+
+static inline void fixup_tlbie_va(unsigned long va, unsigned long pid,
+				  unsigned long ap)
+{
+	if (cpu_has_feature(CPU_FTR_P9_TLBIE_ERAT_BUG)) {
+		asm volatile("ptesync": : :"memory");
+		__tlbie_va(va, 0, ap, RIC_FLUSH_TLB);
+	}
+
+	if (cpu_has_feature(CPU_FTR_P9_TLBIE_STQ_BUG)) {
+		asm volatile("ptesync": : :"memory");
+		__tlbie_va(va, pid, ap, RIC_FLUSH_TLB);
+	}
+}
+
+static inline void fixup_tlbie_va_range(unsigned long va, unsigned long pid,
+					unsigned long ap)
+{
+	if (cpu_has_feature(CPU_FTR_P9_TLBIE_ERAT_BUG)) {
+		asm volatile("ptesync": : :"memory");
+		__tlbie_pid(0, RIC_FLUSH_TLB);
+	}
+
+	if (cpu_has_feature(CPU_FTR_P9_TLBIE_STQ_BUG)) {
+		asm volatile("ptesync": : :"memory");
+		__tlbie_va(va, pid, ap, RIC_FLUSH_TLB);
+	}
+}
+
+static inline void fixup_tlbie_pid(unsigned long pid)
 {
-	unsigned long pid = 0;
+	/*
+	 * We can use any address for the invalidation, pick one which is
+	 * probably unused as an optimisation.
+	 */
 	unsigned long va = ((1UL << 52) - 1);
 
+	if (cpu_has_feature(CPU_FTR_P9_TLBIE_ERAT_BUG)) {
+		asm volatile("ptesync": : :"memory");
+		__tlbie_pid(0, RIC_FLUSH_TLB);
+	}
+
 	if (cpu_has_feature(CPU_FTR_P9_TLBIE_STQ_BUG)) {
 		asm volatile("ptesync": : :"memory");
 		__tlbie_va(va, pid, mmu_get_ap(MMU_PAGE_64K), RIC_FLUSH_TLB);
 	}
 }
 
+
+static inline void fixup_tlbie_lpid_va(unsigned long va, unsigned long lpid,
+				       unsigned long ap)
+{
+	if (cpu_has_feature(CPU_FTR_P9_TLBIE_ERAT_BUG)) {
+		asm volatile("ptesync": : :"memory");
+		__tlbie_lpid_va(va, 0, ap, RIC_FLUSH_TLB);
+	}
+
+	if (cpu_has_feature(CPU_FTR_P9_TLBIE_STQ_BUG)) {
+		asm volatile("ptesync": : :"memory");
+		__tlbie_lpid_va(va, lpid, ap, RIC_FLUSH_TLB);
+	}
+}
+
 static inline void fixup_tlbie_lpid(unsigned long lpid)
 {
+	/*
+	 * We can use any address for the invalidation, pick one which is
+	 * probably unused as an optimisation.
+	 */
 	unsigned long va = ((1UL << 52) - 1);
 
+	if (cpu_has_feature(CPU_FTR_P9_TLBIE_ERAT_BUG)) {
+		asm volatile("ptesync": : :"memory");
+		__tlbie_lpid(0, RIC_FLUSH_TLB);
+	}
+
 	if (cpu_has_feature(CPU_FTR_P9_TLBIE_STQ_BUG)) {
 		asm volatile("ptesync": : :"memory");
 		__tlbie_lpid_va(va, lpid, mmu_get_ap(MMU_PAGE_64K), RIC_FLUSH_TLB);
@@ -258,6 +319,7 @@ static inline void _tlbie_pid(unsigned long pid, unsigned long ric)
 	switch (ric) {
 	case RIC_FLUSH_TLB:
 		__tlbie_pid(pid, RIC_FLUSH_TLB);
+		fixup_tlbie_pid(pid);
 		break;
 	case RIC_FLUSH_PWC:
 		__tlbie_pid(pid, RIC_FLUSH_PWC);
@@ -265,8 +327,8 @@ static inline void _tlbie_pid(unsigned long pid, unsigned long ric)
 	case RIC_FLUSH_ALL:
 	default:
 		__tlbie_pid(pid, RIC_FLUSH_ALL);
+		fixup_tlbie_pid(pid);
 	}
-	fixup_tlbie();
 	asm volatile("eieio; tlbsync; ptesync": : :"memory");
 }
 
@@ -315,6 +377,7 @@ static inline void _tlbie_lpid(unsigned long lpid, unsigned long ric)
 	switch (ric) {
 	case RIC_FLUSH_TLB:
 		__tlbie_lpid(lpid, RIC_FLUSH_TLB);
+		fixup_tlbie_lpid(lpid);
 		break;
 	case RIC_FLUSH_PWC:
 		__tlbie_lpid(lpid, RIC_FLUSH_PWC);
@@ -322,8 +385,8 @@ static inline void _tlbie_lpid(unsigned long lpid, unsigned long ric)
 	case RIC_FLUSH_ALL:
 	default:
 		__tlbie_lpid(lpid, RIC_FLUSH_ALL);
+		fixup_tlbie_lpid(lpid);
 	}
-	fixup_tlbie_lpid(lpid);
 	asm volatile("eieio; tlbsync; ptesync": : :"memory");
 }
 
@@ -390,6 +453,8 @@ static inline void __tlbie_va_range(unsigned long start, unsigned long end,
 
 	for (addr = start; addr < end; addr += page_size)
 		__tlbie_va(addr, pid, ap, RIC_FLUSH_TLB);
+
+	fixup_tlbie_va_range(addr - page_size, pid, ap);
 }
 
 static __always_inline void _tlbie_va(unsigned long va, unsigned long pid,
@@ -399,7 +464,7 @@ static __always_inline void _tlbie_va(unsigned long va, unsigned long pid,
 
 	asm volatile("ptesync": : :"memory");
 	__tlbie_va(va, pid, ap, ric);
-	fixup_tlbie();
+	fixup_tlbie_va(va, pid, ap);
 	asm volatile("eieio; tlbsync; ptesync": : :"memory");
 }
 
@@ -457,7 +522,7 @@ static __always_inline void _tlbie_lpid_va(unsigned long va, unsigned long lpid,
 
 	asm volatile("ptesync": : :"memory");
 	__tlbie_lpid_va(va, lpid, ap, ric);
-	fixup_tlbie_lpid(lpid);
+	fixup_tlbie_lpid_va(va, lpid, ap);
 	asm volatile("eieio; tlbsync; ptesync": : :"memory");
 }
 
@@ -469,7 +534,6 @@ static inline void _tlbie_va_range(unsigned long start, unsigned long end,
 	if (also_pwc)
 		__tlbie_pid(pid, RIC_FLUSH_PWC);
 	__tlbie_va_range(start, end, pid, page_size, psize);
-	fixup_tlbie();
 	asm volatile("eieio; tlbsync; ptesync": : :"memory");
 }
 
@@ -856,7 +920,7 @@ is_local:
 			if (gflush)
 				__tlbie_va_range(gstart, gend, pid,
 						PUD_SIZE, MMU_PAGE_1G);
-			fixup_tlbie();
+
 			asm volatile("eieio; tlbsync; ptesync": : :"memory");
 		} else {
 			_tlbiel_va_range_multicast(mm,