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 u32 cond_check; 29 30 cond_check = ALT_COND_ALWAYS | 31 ((num_cpus == 1) ? ALT_COND_NO_SMP : 0) | 32 ((cache_info.dc_size == 0) ? ALT_COND_NO_DCACHE : 0) | 33 ((cache_info.ic_size == 0) ? ALT_COND_NO_ICACHE : 0) | 34 (running_on_qemu ? ALT_COND_RUN_ON_QEMU : 0) | 35 ((split_tlb == 0) ? ALT_COND_NO_SPLIT_TLB : 0) | 36 /* 37 * If the PDC_MODEL capabilities has Non-coherent IO-PDIR bit 38 * set (bit #61, big endian), we have to flush and sync every 39 * time IO-PDIR is changed in Ike/Astro. 40 */ 41 (((boot_cpu_data.cpu_type > pcxw_) && 42 ((boot_cpu_data.pdc.capabilities & PDC_MODEL_IOPDIR_FDC) == 0)) 43 ? ALT_COND_NO_IOC_FDC : 0); 44 45 for (entry = start; entry < end; entry++, index++) { 46 47 u32 *from, cond, replacement; 48 s32 len; 49 50 from = (u32 *)((ulong)&entry->orig_offset + entry->orig_offset); 51 len = entry->len; 52 cond = entry->cond; 53 replacement = entry->replacement; 54 55 WARN_ON(!cond); 56 57 if ((cond & ALT_COND_ALWAYS) == 0 && no_alternatives) 58 continue; 59 60 pr_debug("Check %d: Cond 0x%x, Replace %02d instructions @ 0x%px with 0x%08x\n", 61 index, cond, len, from, replacement); 62 63 /* Bounce out if none of the conditions are true. */ 64 if ((cond & cond_check) == 0) 65 continue; 66 67 /* Want to replace pdtlb by a pdtlb,l instruction? */ 68 if (replacement == INSN_PxTLB) { 69 replacement = *from; 70 if (boot_cpu_data.cpu_type >= pcxu) /* >= pa2.0 ? */ 71 replacement |= (1 << 10); /* set el bit */ 72 } 73 74 /* 75 * Replace instruction with NOPs? 76 * For long distance insert a branch instruction instead. 77 */ 78 if (replacement == INSN_NOP && len > 1) 79 replacement = 0xe8000002 + (len-2)*8; /* "b,n .+8" */ 80 81 pr_debug("ALTERNATIVE %3d: Cond %2x, Replace %2d instructions to 0x%08x @ 0x%px (%pS)\n", 82 index, cond, len, replacement, from, from); 83 84 if (len < 0) { 85 /* Replace multiple instruction by new code */ 86 u32 *source; 87 len = -len; 88 source = (u32 *)((ulong)&entry->replacement + entry->replacement); 89 memcpy(from, source, 4 * len); 90 } else { 91 /* Replace by one instruction */ 92 *from = replacement; 93 } 94 applied++; 95 } 96 97 pr_info("%s%salternatives: applied %d out of %d patches\n", 98 module_name ? : "", module_name ? " " : "", 99 applied, index); 100 } 101 102 103 void __init apply_alternatives_all(void) 104 { 105 set_kernel_text_rw(1); 106 107 apply_alternatives((struct alt_instr *) &__alt_instructions, 108 (struct alt_instr *) &__alt_instructions_end, NULL); 109 110 set_kernel_text_rw(0); 111 } 112