| David Brazdil | 0f672f6 | 2019-12-10 10:32:29 +0000 | [diff] [blame] | 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 | } |