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, 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 } 100 101 102 void __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 } 111