1 files changed, 77 insertions, 19 deletions

diff --git a/arch/arm64/kernel/alternative.c b/arch/arm64/kernel/alternative.c
index 414288a558c8..b5d603992d40 100644
--- a/arch/arm64/kernel/alternative.c
+++ b/arch/arm64/kernel/alternative.c
@@ -47,11 +47,11 @@ static bool branch_insn_requires_update(struct alt_instr *alt, unsigned long pc)
 	unsigned long replptr;
 
 	if (kernel_text_address(pc))
-		return 1;
+		return true;
 
 	replptr = (unsigned long)ALT_REPL_PTR(alt);
 	if (pc >= replptr && pc <= (replptr + alt->alt_len))
-		return 0;
+		return false;
 
 	/*
 	 * Branching into *another* alternate sequence is doomed, and
@@ -107,35 +107,91 @@ static u32 get_alt_insn(struct alt_instr *alt, __le32 *insnptr, __le32 *altinsnp
 	return insn;
 }
 
-static void __apply_alternatives(void *alt_region, bool use_linear_alias)
+static void patch_alternative(struct alt_instr *alt,
+			      __le32 *origptr, __le32 *updptr, int nr_inst)
+{
+	__le32 *replptr;
+	int i;
+
+	replptr = ALT_REPL_PTR(alt);
+	for (i = 0; i < nr_inst; i++) {
+		u32 insn;
+
+		insn = get_alt_insn(alt, origptr + i, replptr + i);
+		updptr[i] = cpu_to_le32(insn);
+	}
+}
+
+/*
+ * We provide our own, private D-cache cleaning function so that we don't
+ * accidentally call into the cache.S code, which is patched by us at
+ * runtime.
+ */
+static void clean_dcache_range_nopatch(u64 start, u64 end)
+{
+	u64 cur, d_size, ctr_el0;
+
+	ctr_el0 = read_sanitised_ftr_reg(SYS_CTR_EL0);
+	d_size = 4 << cpuid_feature_extract_unsigned_field(ctr_el0,
+							   CTR_DMINLINE_SHIFT);
+	cur = start & ~(d_size - 1);
+	do {
+		/*
+		 * We must clean+invalidate to the PoC in order to avoid
+		 * Cortex-A53 errata 826319, 827319, 824069 and 819472
+		 * (this corresponds to ARM64_WORKAROUND_CLEAN_CACHE)
+		 */
+		asm volatile("dc civac, %0" : : "r" (cur) : "memory");
+	} while (cur += d_size, cur < end);
+}
+
+static void __apply_alternatives(void *alt_region, bool is_module)
 {
 	struct alt_instr *alt;
 	struct alt_region *region = alt_region;
-	__le32 *origptr, *replptr, *updptr;
+	__le32 *origptr, *updptr;
+	alternative_cb_t alt_cb;
 
 	for (alt = region->begin; alt < region->end; alt++) {
-		u32 insn;
-		int i, nr_inst;
+		int nr_inst;
 
-		if (!cpus_have_cap(alt->cpufeature))
+		/* Use ARM64_CB_PATCH as an unconditional patch */
+		if (alt->cpufeature < ARM64_CB_PATCH &&
+		    !cpus_have_cap(alt->cpufeature))
 			continue;
 
-		BUG_ON(alt->alt_len != alt->orig_len);
+		if (alt->cpufeature == ARM64_CB_PATCH)
+			BUG_ON(alt->alt_len != 0);
+		else
+			BUG_ON(alt->alt_len != alt->orig_len);
 
 		pr_info_once("patching kernel code\n");
 
 		origptr = ALT_ORIG_PTR(alt);
-		replptr = ALT_REPL_PTR(alt);
-		updptr = use_linear_alias ? lm_alias(origptr) : origptr;
-		nr_inst = alt->alt_len / sizeof(insn);
+		updptr = is_module ? origptr : lm_alias(origptr);
+		nr_inst = alt->orig_len / AARCH64_INSN_SIZE;
+
+		if (alt->cpufeature < ARM64_CB_PATCH)
+			alt_cb = patch_alternative;
+		else
+			alt_cb  = ALT_REPL_PTR(alt);
 
-		for (i = 0; i < nr_inst; i++) {
-			insn = get_alt_insn(alt, origptr + i, replptr + i);
-			updptr[i] = cpu_to_le32(insn);
+		alt_cb(alt, origptr, updptr, nr_inst);
+
+		if (!is_module) {
+			clean_dcache_range_nopatch((u64)origptr,
+						   (u64)(origptr + nr_inst));
 		}
+	}
 
-		flush_icache_range((uintptr_t)origptr,
-				   (uintptr_t)(origptr + nr_inst));
+	/*
+	 * The core module code takes care of cache maintenance in
+	 * flush_module_icache().
+	 */
+	if (!is_module) {
+		dsb(ish);
+		__flush_icache_all();
+		isb();
 	}
 }
 
@@ -157,7 +213,7 @@ static int __apply_alternatives_multi_stop(void *unused)
 		isb();
 	} else {
 		BUG_ON(alternatives_applied);
-		__apply_alternatives(&region, true);
+		__apply_alternatives(&region, false);
 		/* Barriers provided by the cache flushing */
 		WRITE_ONCE(alternatives_applied, 1);
 	}
@@ -171,12 +227,14 @@ void __init apply_alternatives_all(void)
 	stop_machine(__apply_alternatives_multi_stop, NULL, cpu_online_mask);
 }
 
-void apply_alternatives(void *start, size_t length)
+#ifdef CONFIG_MODULES
+void apply_alternatives_module(void *start, size_t length)
 {
 	struct alt_region region = {
 		.begin	= start,
 		.end	= start + length,
 	};
 
-	__apply_alternatives(&region, false);
+	__apply_alternatives(&region, true);
 }
+#endif