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 14 static int no_alternatives; 15 static int __init setup_no_alternatives(char *str) 16 { 17 no_alternatives = 1; 18 return 1; 19 } 20 __setup("no-alternatives", setup_no_alternatives); 21 22 void __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, len, cond, replacement; 32 33 from = (u32 *)((ulong)&entry->orig_offset + entry->orig_offset); 34 len = entry->len; 35 cond = entry->cond; 36 replacement = entry->replacement; 37 38 WARN_ON(!cond); 39 40 if (cond != ALT_COND_ALWAYS && no_alternatives) 41 continue; 42 43 pr_debug("Check %d: Cond 0x%x, Replace %02d instructions @ 0x%px with 0x%08x\n", 44 index, cond, len, from, replacement); 45 46 if ((cond & ALT_COND_NO_SMP) && (num_cpus != 1)) 47 continue; 48 if ((cond & ALT_COND_NO_DCACHE) && (cache_info.dc_size != 0)) 49 continue; 50 if ((cond & ALT_COND_NO_ICACHE) && (cache_info.ic_size != 0)) 51 continue; 52 53 /* 54 * If the PDC_MODEL capabilities has Non-coherent IO-PDIR bit 55 * set (bit #61, big endian), we have to flush and sync every 56 * time IO-PDIR is changed in Ike/Astro. 57 */ 58 if ((cond & ALT_COND_NO_IOC_FDC) && 59 (boot_cpu_data.pdc.capabilities & PDC_MODEL_IOPDIR_FDC)) 60 continue; 61 62 /* Want to replace pdtlb by a pdtlb,l instruction? */ 63 if (replacement == INSN_PxTLB) { 64 replacement = *from; 65 if (boot_cpu_data.cpu_type >= pcxu) /* >= pa2.0 ? */ 66 replacement |= (1 << 10); /* set el bit */ 67 } 68 69 /* 70 * Replace instruction with NOPs? 71 * For long distance insert a branch instruction instead. 72 */ 73 if (replacement == INSN_NOP && len > 1) 74 replacement = 0xe8000002 + (len-2)*8; /* "b,n .+8" */ 75 76 pr_debug("Do %d: Cond 0x%x, Replace %02d instructions @ 0x%px with 0x%08x\n", 77 index, cond, len, from, replacement); 78 79 /* Replace instruction */ 80 *from = replacement; 81 applied++; 82 } 83 84 pr_info("%s%salternatives: applied %d out of %d patches\n", 85 module_name ? : "", module_name ? " " : "", 86 applied, index); 87 } 88 89 90 void __init apply_alternatives_all(void) 91 { 92 set_kernel_text_rw(1); 93 94 apply_alternatives((struct alt_instr *) &__alt_instructions, 95 (struct alt_instr *) &__alt_instructions_end, NULL); 96 97 set_kernel_text_rw(0); 98 } 99