1 files changed, 98 insertions, 0 deletions
diff --git a/arch/parisc/kernel/alternative.c b/arch/parisc/kernel/alternative.c
new file mode 100644
index 000000000000..bf2274e01a96
--- /dev/null
+++ b/arch/parisc/kernel/alternative.c
@@ -0,0 +1,98 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *    Alternative live-patching for parisc.
+ *    Copyright (C) 2018 Helge Deller <deller@gmx.de>
+ *
+ */
+
+#include <asm/processor.h>
+#include <asm/sections.h>
+#include <asm/alternative.h>
+
+#include <linux/module.h>
+
+static int no_alternatives;
+static int __init setup_no_alternatives(char *str)
+{
+	no_alternatives = 1;
+	return 1;
+}
+__setup("no-alternatives", setup_no_alternatives);
+
+void __init_or_module apply_alternatives(struct alt_instr *start,
+		 struct alt_instr *end, const char *module_name)
+{
+	struct alt_instr *entry;
+	int index = 0, applied = 0;
+	int num_cpus = num_online_cpus();
+
+	for (entry = start; entry < end; entry++, index++) {
+
+		u32 *from, len, cond, replacement;
+
+		from = (u32 *)((ulong)&entry->orig_offset + entry->orig_offset);
+		len = entry->len;
+		cond = entry->cond;
+		replacement = entry->replacement;
+
+		WARN_ON(!cond);
+
+		if (cond != ALT_COND_ALWAYS && no_alternatives)
+			continue;
+
+		pr_debug("Check %d: Cond 0x%x, Replace %02d instructions @ 0x%px with 0x%08x\n",
+			index, cond, len, from, replacement);
+
+		if ((cond & ALT_COND_NO_SMP) && (num_cpus != 1))
+			continue;
+		if ((cond & ALT_COND_NO_DCACHE) && (cache_info.dc_size != 0))
+			continue;
+		if ((cond & ALT_COND_NO_ICACHE) && (cache_info.ic_size != 0))
+			continue;
+
+		/*
+		 * If the PDC_MODEL capabilities has Non-coherent IO-PDIR bit
+		 * set (bit #61, big endian), we have to flush and sync every
+		 * time IO-PDIR is changed in Ike/Astro.
+		 */
+		if ((cond & ALT_COND_NO_IOC_FDC) &&
+			(boot_cpu_data.pdc.capabilities & PDC_MODEL_IOPDIR_FDC))
+			continue;
+
+		/* Want to replace pdtlb by a pdtlb,l instruction? */
+		if (replacement == INSN_PxTLB) {
+			replacement = *from;
+			if (boot_cpu_data.cpu_type >= pcxu) /* >= pa2.0 ? */
+				replacement |= (1 << 10); /* set el bit */
+		}
+
+		/*
+		 * Replace instruction with NOPs?
+		 * For long distance insert a branch instruction instead.
+		 */
+		if (replacement == INSN_NOP && len > 1)
+			replacement = 0xe8000002 + (len-2)*8; /* "b,n .+8" */
+
+		pr_debug("Do    %d: Cond 0x%x, Replace %02d instructions @ 0x%px with 0x%08x\n",
+			index, cond, len, from, replacement);
+
+		/* Replace instruction */
+		*from = replacement;
+		applied++;
+	}
+
+	pr_info("%s%salternatives: applied %d out of %d patches\n",
+		module_name ? : "", module_name ? " " : "",
+		applied, index);
+}
+
+
+void __init apply_alternatives_all(void)
+{
+	set_kernel_text_rw(1);
+
+	apply_alternatives((struct alt_instr *) &__alt_instructions,
+		(struct alt_instr *) &__alt_instructions_end, NULL);
+
+	set_kernel_text_rw(0);
+}