1 files changed, 70 insertions, 55 deletions

diff --git a/arch/s390/kernel/alternative.c b/arch/s390/kernel/alternative.c
index e7bca29f9c34..90c0e6408992 100644
--- a/arch/s390/kernel/alternative.c
+++ b/arch/s390/kernel/alternative.c
@@ -1,75 +1,90 @@
 // SPDX-License-Identifier: GPL-2.0
-#include <linux/module.h>
-#include <linux/cpu.h>
-#include <linux/smp.h>
-#include <asm/text-patching.h>
+
+#ifndef pr_fmt
+#define pr_fmt(fmt)	"alt: " fmt
+#endif
+
+#include <linux/uaccess.h>
+#include <linux/printk.h>
+#include <asm/nospec-branch.h>
+#include <asm/abs_lowcore.h>
 #include <asm/alternative.h>
 #include <asm/facility.h>
-#include <asm/nospec-branch.h>
+#include <asm/sections.h>
+#include <asm/machine.h>
+
+#ifndef a_debug
+#define a_debug		pr_debug
+#endif
+
+#ifndef __kernel_va
+#define __kernel_va(x)	(void *)(x)
+#endif
+
+unsigned long __bootdata_preserved(machine_features[1]);
+
+struct alt_debug {
+	unsigned long facilities[MAX_FACILITY_BIT / BITS_PER_LONG];
+	unsigned long mfeatures[MAX_MFEATURE_BIT / BITS_PER_LONG];
+	int spec;
+};
 
-static int __initdata_or_module alt_instr_disabled;
+static struct alt_debug __bootdata_preserved(alt_debug);
 
-static int __init disable_alternative_instructions(char *str)
+static void alternative_dump(u8 *old, u8 *new, unsigned int len, unsigned int type, unsigned int data)
 {
-	alt_instr_disabled = 1;
-	return 0;
-}
+	char oinsn[33], ninsn[33];
+	unsigned long kptr;
+	unsigned int pos;
 
-early_param("noaltinstr", disable_alternative_instructions);
+	for (pos = 0; pos < len && 2 * pos < sizeof(oinsn) - 3; pos++)
+		hex_byte_pack(&oinsn[2 * pos], old[pos]);
+	oinsn[2 * pos] = 0;
+	for (pos = 0; pos < len && 2 * pos < sizeof(ninsn) - 3; pos++)
+		hex_byte_pack(&ninsn[2 * pos], new[pos]);
+	ninsn[2 * pos] = 0;
+	kptr = (unsigned long)__kernel_va(old);
+	a_debug("[%d/%3d] %016lx: %s -> %s\n", type, data, kptr, oinsn, ninsn);
+}
 
-static void __init_or_module __apply_alternatives(struct alt_instr *start,
-						  struct alt_instr *end)
+void __apply_alternatives(struct alt_instr *start, struct alt_instr *end, unsigned int ctx)
 {
+	struct alt_debug *d;
 	struct alt_instr *a;
-	u8 *instr, *replacement;
+	bool debug, replace;
+	u8 *old, *new;
 
 	/*
 	 * The scan order should be from start to end. A later scanned
 	 * alternative code can overwrite previously scanned alternative code.
 	 */
+	d = &alt_debug;
 	for (a = start; a < end; a++) {
-		instr = (u8 *)&a->instr_offset + a->instr_offset;
-		replacement = (u8 *)&a->repl_offset + a->repl_offset;
-
-		if (!__test_facility(a->facility, alt_stfle_fac_list))
-			continue;
-
-		if (unlikely(a->instrlen % 2)) {
-			WARN_ONCE(1, "cpu alternatives instructions length is "
-				     "odd, skipping patching\n");
+		if (!(a->ctx & ctx))
 			continue;
+		switch (a->type) {
+		case ALT_TYPE_FACILITY:
+			replace = test_facility(a->data);
+			debug = __test_facility(a->data, d->facilities);
+			break;
+		case ALT_TYPE_FEATURE:
+			replace = test_machine_feature(a->data);
+			debug = __test_machine_feature(a->data, d->mfeatures);
+			break;
+		case ALT_TYPE_SPEC:
+			replace = nobp_enabled();
+			debug = d->spec;
+			break;
+		default:
+			replace = false;
+			debug = false;
 		}
-
-		s390_kernel_write(instr, replacement, a->instrlen);
+		if (!replace)
+			continue;
+		old = (u8 *)&a->instr_offset + a->instr_offset;
+		new = (u8 *)&a->repl_offset + a->repl_offset;
+		if (debug)
+			alternative_dump(old, new, a->instrlen, a->type, a->data);
+		s390_kernel_write(old, new, a->instrlen);
 	}
 }
-
-void __init_or_module apply_alternatives(struct alt_instr *start,
-					 struct alt_instr *end)
-{
-	if (!alt_instr_disabled)
-		__apply_alternatives(start, end);
-}
-
-extern struct alt_instr __alt_instructions[], __alt_instructions_end[];
-void __init apply_alternative_instructions(void)
-{
-	apply_alternatives(__alt_instructions, __alt_instructions_end);
-}
-
-static void do_sync_core(void *info)
-{
-	sync_core();
-}
-
-void text_poke_sync(void)
-{
-	on_each_cpu(do_sync_core, NULL, 1);
-}
-
-void text_poke_sync_lock(void)
-{
-	cpus_read_lock();
-	text_poke_sync();
-	cpus_read_unlock();
-}