--- zzzz-none-000/linux-3.10.107/arch/arm/kernel/smp_tlb.c	2017-06-27 09:49:32.000000000 +0000
+++ scorpion-7490-727/linux-3.10.107/arch/arm/kernel/smp_tlb.c	2021-02-04 17:41:59.000000000 +0000
@@ -9,6 +9,7 @@
  */
 #include <linux/preempt.h>
 #include <linux/smp.h>
+#include <linux/uaccess.h>
 
 #include <asm/smp_plat.h>
 #include <asm/tlbflush.h>
@@ -40,8 +41,11 @@
 static inline void ipi_flush_tlb_page(void *arg)
 {
 	struct tlb_args *ta = (struct tlb_args *)arg;
+	unsigned int __ua_flags = uaccess_save_and_enable();
 
 	local_flush_tlb_page(ta->ta_vma, ta->ta_start);
+
+	uaccess_restore(__ua_flags);
 }
 
 static inline void ipi_flush_tlb_kernel_page(void *arg)
@@ -54,8 +58,11 @@
 static inline void ipi_flush_tlb_range(void *arg)
 {
 	struct tlb_args *ta = (struct tlb_args *)arg;
+	unsigned int __ua_flags = uaccess_save_and_enable();
 
 	local_flush_tlb_range(ta->ta_vma, ta->ta_start, ta->ta_end);
+
+	uaccess_restore(__ua_flags);
 }
 
 static inline void ipi_flush_tlb_kernel_range(void *arg)
@@ -71,19 +78,40 @@
 }
 
 #ifdef CONFIG_ARM_ERRATA_798181
-static int erratum_a15_798181(void)
+bool (*erratum_a15_798181_handler)(void);
+
+static bool erratum_a15_798181_partial(void)
 {
-	unsigned int midr = read_cpuid_id();
+	asm("mcr p15, 0, %0, c8, c3, 1" : : "r" (0));
+	dsb(ish);
+	return false;
+}
 
-	/* Cortex-A15 r0p0..r3p2 affected */
-	if ((midr & 0xff0ffff0) != 0x410fc0f0 || midr > 0x413fc0f2)
-		return 0;
-	return 1;
+static bool erratum_a15_798181_broadcast(void)
+{
+	asm("mcr p15, 0, %0, c8, c3, 1" : : "r" (0));
+	dsb(ish);
+	return true;
 }
-#else
-static int erratum_a15_798181(void)
+
+void erratum_a15_798181_init(void)
 {
-	return 0;
+	unsigned int midr = read_cpuid_id();
+	unsigned int revidr = read_cpuid(CPUID_REVIDR);
+
+	/* Brahma-B15 r0p0..r0p2 affected
+	 * Cortex-A15 r0p0..r3p2 w/o ECO fix affected */
+	if ((midr & 0xff0ffff0) == 0x420f00f0 && midr <= 0x420f00f2)
+		erratum_a15_798181_handler = erratum_a15_798181_broadcast;
+	else if ((midr & 0xff0ffff0) == 0x410fc0f0 && midr <= 0x413fc0f2 &&
+		 (revidr & 0x210) != 0x210) {
+		if (revidr & 0x10)
+			erratum_a15_798181_handler =
+				erratum_a15_798181_partial;
+		else
+			erratum_a15_798181_handler =
+				erratum_a15_798181_broadcast;
+	}
 }
 #endif
 
@@ -97,7 +125,6 @@
 	if (!erratum_a15_798181())
 		return;
 
-	dummy_flush_tlb_a15_erratum();
 	smp_call_function(ipi_flush_tlb_a15_erratum, NULL, 1);
 }
 
@@ -109,7 +136,6 @@
 	if (!erratum_a15_798181())
 		return;
 
-	dummy_flush_tlb_a15_erratum();
 	this_cpu = get_cpu();
 	a15_erratum_get_cpumask(this_cpu, mm, &mask);
 	smp_call_function_many(&mask, ipi_flush_tlb_a15_erratum, NULL, 1);
@@ -121,7 +147,7 @@
 	if (tlb_ops_need_broadcast())
 		on_each_cpu(ipi_flush_tlb_all, NULL, 1);
 	else
-		local_flush_tlb_all();
+		__flush_tlb_all();
 	broadcast_tlb_a15_erratum();
 }
 
@@ -130,7 +156,7 @@
 	if (tlb_ops_need_broadcast())
 		on_each_cpu_mask(mm_cpumask(mm), ipi_flush_tlb_mm, mm, 1);
 	else
-		local_flush_tlb_mm(mm);
+		__flush_tlb_mm(mm);
 	broadcast_tlb_mm_a15_erratum(mm);
 }
 
@@ -143,7 +169,7 @@
 		on_each_cpu_mask(mm_cpumask(vma->vm_mm), ipi_flush_tlb_page,
 					&ta, 1);
 	} else
-		local_flush_tlb_page(vma, uaddr);
+		__flush_tlb_page(vma, uaddr);
 	broadcast_tlb_mm_a15_erratum(vma->vm_mm);
 }
 
@@ -154,7 +180,7 @@
 		ta.ta_start = kaddr;
 		on_each_cpu(ipi_flush_tlb_kernel_page, &ta, 1);
 	} else
-		local_flush_tlb_kernel_page(kaddr);
+		__flush_tlb_kernel_page(kaddr);
 	broadcast_tlb_a15_erratum();
 }
 
@@ -190,5 +216,5 @@
 	if (tlb_ops_need_broadcast())
 		on_each_cpu(ipi_flush_bp_all, NULL, 1);
 	else
-		local_flush_bp_all();
+		__flush_bp_all();
 }