1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 *    Alternative live-patching for parisc.
  4 *    Copyright (C) 2018 Helge Deller <deller@gmx.de>
  5 *
  6 */
  7
  8#include <asm/processor.h>
  9#include <asm/sections.h>
 10#include <asm/alternative.h>
 11
 12#include <linux/module.h>
 13
 14static int no_alternatives;
 15static int __init setup_no_alternatives(char *str)
 16{
 17	no_alternatives = 1;
 18	return 1;
 19}
 20__setup("no-alternatives", setup_no_alternatives);
 21
 22void __init_or_module apply_alternatives(struct alt_instr *start,
 23		 struct alt_instr *end, const char *module_name)
 24{
 25	struct alt_instr *entry;
 26	int index = 0, applied = 0;
 27	int num_cpus = num_online_cpus();
 28
 29	for (entry = start; entry < end; entry++, index++) {
 30
 31		u32 *from, cond, replacement;
 32		s32 len;
 33
 34		from = (u32 *)((ulong)&entry->orig_offset + entry->orig_offset);
 35		len = entry->len;
 36		cond = entry->cond;
 37		replacement = entry->replacement;
 38
 39		WARN_ON(!cond);
 40
 41		if (cond != ALT_COND_ALWAYS && no_alternatives)
 42			continue;
 43
 44		pr_debug("Check %d: Cond 0x%x, Replace %02d instructions @ 0x%px with 0x%08x\n",
 45			index, cond, len, from, replacement);
 46
 47		if ((cond & ALT_COND_NO_SMP) && (num_cpus != 1))
 48			continue;
 49		if ((cond & ALT_COND_NO_DCACHE) && (cache_info.dc_size != 0))
 50			continue;
 51		if ((cond & ALT_COND_NO_ICACHE) && (cache_info.ic_size != 0))
 52			continue;
 53		if ((cond & ALT_COND_RUN_ON_QEMU) && !running_on_qemu)
 54			continue;
 55
 56		/*
 57		 * If the PDC_MODEL capabilities has Non-coherent IO-PDIR bit
 58		 * set (bit #61, big endian), we have to flush and sync every
 59		 * time IO-PDIR is changed in Ike/Astro.
 60		 */
 61		if ((cond & ALT_COND_NO_IOC_FDC) &&
 62			((boot_cpu_data.cpu_type <= pcxw_) ||
 63			 (boot_cpu_data.pdc.capabilities & PDC_MODEL_IOPDIR_FDC)))
 64			continue;
 65
 66		/* Want to replace pdtlb by a pdtlb,l instruction? */
 67		if (replacement == INSN_PxTLB) {
 68			replacement = *from;
 69			if (boot_cpu_data.cpu_type >= pcxu) /* >= pa2.0 ? */
 70				replacement |= (1 << 10); /* set el bit */
 71		}
 72
 73		/*
 74		 * Replace instruction with NOPs?
 75		 * For long distance insert a branch instruction instead.
 76		 */
 77		if (replacement == INSN_NOP && len > 1)
 78			replacement = 0xe8000002 + (len-2)*8; /* "b,n .+8" */
 79
 80		pr_debug("ALTERNATIVE %3d: Cond %2x, Replace %2d instructions to 0x%08x @ 0x%px (%pS)\n",
 81			index, cond, len, replacement, from, from);
 82
 83		if (len < 0) {
 84			/* Replace multiple instruction by new code */
 85			u32 *source;
 86			len = -len;
 87			source = (u32 *)((ulong)&entry->replacement + entry->replacement);
 88			memcpy(from, source, 4 * len);
 89		} else {
 90			/* Replace by one instruction */
 91			*from = replacement;
 92		}
 93		applied++;
 94	}
 95
 96	pr_info("%s%salternatives: applied %d out of %d patches\n",
 97		module_name ? : "", module_name ? " " : "",
 98		applied, index);
 99}
100
101
102void __init apply_alternatives_all(void)
103{
104	set_kernel_text_rw(1);
105
106	apply_alternatives((struct alt_instr *) &__alt_instructions,
107		(struct alt_instr *) &__alt_instructions_end, NULL);
108
109	set_kernel_text_rw(0);
110}