1 files changed, 122 insertions, 0 deletions
diff --git a/arch/parisc/kernel/alternative.c b/arch/parisc/kernel/alternative.c
new file mode 100644
index 000000000..25c4d6c33
--- /dev/null
+++ b/arch/parisc/kernel/alternative.c
@@ -0,0 +1,122 @@
+// 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 <asm/cacheflush.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_present_cpus();
+	u16 cond_check;
+
+	cond_check = ALT_COND_ALWAYS |
+		((num_cpus == 1) ? ALT_COND_NO_SMP : 0) |
+		((cache_info.dc_size == 0) ? ALT_COND_NO_DCACHE : 0) |
+		((cache_info.ic_size == 0) ? ALT_COND_NO_ICACHE : 0) |
+		(running_on_qemu ? ALT_COND_RUN_ON_QEMU : 0) |
+		((split_tlb == 0) ? ALT_COND_NO_SPLIT_TLB : 0) |
+		/*
+		 * 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.
+		 */
+		(((boot_cpu_data.cpu_type > pcxw_) &&
+		  ((boot_cpu_data.pdc.capabilities & PDC_MODEL_IOPDIR_FDC) == 0))
+			? ALT_COND_NO_IOC_FDC : 0);
+
+	for (entry = start; entry < end; entry++, index++) {
+
+		u32 *from, replacement;
+		u16 cond;
+		s16 len;
+
+		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) == 0 && no_alternatives)
+			continue;
+
+		pr_debug("Check %d: Cond 0x%x, Replace %02d instructions @ 0x%px with 0x%08x\n",
+			index, cond, len, from, replacement);
+
+		/* Bounce out if none of the conditions are true. */
+		if ((cond & cond_check) == 0)
+			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("ALTERNATIVE %3d: Cond %2x, Replace %2d instructions to 0x%08x @ 0x%px (%pS)\n",
+			index, cond, len, replacement, from, from);
+
+		if (len < 0) {
+			/* Replace multiple instruction by new code */
+			u32 *source;
+			len = -len;
+			source = (u32 *)((ulong)&entry->replacement + entry->replacement);
+			memcpy(from, source, 4 * len);
+		} else {
+			/* Replace by one 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);
+
+	if (cache_info.dc_size == 0 && cache_info.ic_size == 0) {
+		pr_info("alternatives: optimizing cache-flushes.\n");
+		static_branch_disable(&parisc_has_cache);
+	}
+	if (cache_info.dc_size == 0)
+		static_branch_disable(&parisc_has_dcache);
+	if (cache_info.ic_size == 0)
+		static_branch_disable(&parisc_has_icache);
+
+	set_kernel_text_rw(0);
+}