summaryrefslogtreecommitdiffstats
path: root/arch/s390/kernel/alternative.c
diff options
context:
space:
mode:
authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
commit2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch)
tree848558de17fb3008cdf4d861b01ac7781903ce39 /arch/s390/kernel/alternative.c
parentInitial commit. (diff)
downloadlinux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz
linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip
Adding upstream version 6.1.76.upstream/6.1.76
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'arch/s390/kernel/alternative.c')
-rw-r--r--arch/s390/kernel/alternative.c75
1 files changed, 75 insertions, 0 deletions
diff --git a/arch/s390/kernel/alternative.c b/arch/s390/kernel/alternative.c
new file mode 100644
index 000000000..e7bca29f9
--- /dev/null
+++ b/arch/s390/kernel/alternative.c
@@ -0,0 +1,75 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/module.h>
+#include <linux/cpu.h>
+#include <linux/smp.h>
+#include <asm/text-patching.h>
+#include <asm/alternative.h>
+#include <asm/facility.h>
+#include <asm/nospec-branch.h>
+
+static int __initdata_or_module alt_instr_disabled;
+
+static int __init disable_alternative_instructions(char *str)
+{
+ alt_instr_disabled = 1;
+ return 0;
+}
+
+early_param("noaltinstr", disable_alternative_instructions);
+
+static void __init_or_module __apply_alternatives(struct alt_instr *start,
+ struct alt_instr *end)
+{
+ struct alt_instr *a;
+ u8 *instr, *replacement;
+
+ /*
+ * The scan order should be from start to end. A later scanned
+ * alternative code can overwrite previously scanned alternative code.
+ */
+ 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");
+ continue;
+ }
+
+ s390_kernel_write(instr, replacement, 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();
+}