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111 lines
3.0 KiB
111 lines
3.0 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* Alternative live-patching for parisc. |
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* Copyright (C) 2018 Helge Deller <[email protected]> |
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* |
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*/ |
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#include <asm/processor.h> |
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#include <asm/sections.h> |
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#include <asm/alternative.h> |
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#include <linux/module.h> |
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static int no_alternatives; |
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static int __init setup_no_alternatives(char *str) |
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{ |
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no_alternatives = 1; |
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return 1; |
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} |
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__setup("no-alternatives", setup_no_alternatives); |
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void __init_or_module apply_alternatives(struct alt_instr *start, |
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struct alt_instr *end, const char *module_name) |
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{ |
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struct alt_instr *entry; |
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int index = 0, applied = 0; |
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int num_cpus = num_online_cpus(); |
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u32 cond_check; |
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cond_check = ALT_COND_ALWAYS | |
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((num_cpus == 1) ? ALT_COND_NO_SMP : 0) | |
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((cache_info.dc_size == 0) ? ALT_COND_NO_DCACHE : 0) | |
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((cache_info.ic_size == 0) ? ALT_COND_NO_ICACHE : 0) | |
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(running_on_qemu ? ALT_COND_RUN_ON_QEMU : 0) | |
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((split_tlb == 0) ? ALT_COND_NO_SPLIT_TLB : 0) | |
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/* |
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* If the PDC_MODEL capabilities has Non-coherent IO-PDIR bit |
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* set (bit #61, big endian), we have to flush and sync every |
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* time IO-PDIR is changed in Ike/Astro. |
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*/ |
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(((boot_cpu_data.cpu_type > pcxw_) && |
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((boot_cpu_data.pdc.capabilities & PDC_MODEL_IOPDIR_FDC) == 0)) |
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? ALT_COND_NO_IOC_FDC : 0); |
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for (entry = start; entry < end; entry++, index++) { |
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u32 *from, cond, replacement; |
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s32 len; |
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from = (u32 *)((ulong)&entry->orig_offset + entry->orig_offset); |
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len = entry->len; |
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cond = entry->cond; |
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replacement = entry->replacement; |
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WARN_ON(!cond); |
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if ((cond & ALT_COND_ALWAYS) == 0 && no_alternatives) |
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continue; |
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pr_debug("Check %d: Cond 0x%x, Replace %02d instructions @ 0x%px with 0x%08x\n", |
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index, cond, len, from, replacement); |
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/* Bounce out if none of the conditions are true. */ |
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if ((cond & cond_check) == 0) |
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continue; |
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/* Want to replace pdtlb by a pdtlb,l instruction? */ |
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if (replacement == INSN_PxTLB) { |
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replacement = *from; |
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if (boot_cpu_data.cpu_type >= pcxu) /* >= pa2.0 ? */ |
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replacement |= (1 << 10); /* set el bit */ |
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} |
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/* |
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* Replace instruction with NOPs? |
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* For long distance insert a branch instruction instead. |
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*/ |
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if (replacement == INSN_NOP && len > 1) |
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replacement = 0xe8000002 + (len-2)*8; /* "b,n .+8" */ |
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pr_debug("ALTERNATIVE %3d: Cond %2x, Replace %2d instructions to 0x%08x @ 0x%px (%pS)\n", |
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index, cond, len, replacement, from, from); |
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if (len < 0) { |
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/* Replace multiple instruction by new code */ |
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u32 *source; |
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len = -len; |
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source = (u32 *)((ulong)&entry->replacement + entry->replacement); |
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memcpy(from, source, 4 * len); |
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} else { |
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/* Replace by one instruction */ |
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*from = replacement; |
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} |
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applied++; |
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} |
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pr_info("%s%salternatives: applied %d out of %d patches\n", |
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module_name ? : "", module_name ? " " : "", |
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applied, index); |
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} |
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void __init apply_alternatives_all(void) |
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{ |
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set_kernel_text_rw(1); |
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apply_alternatives((struct alt_instr *) &__alt_instructions, |
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(struct alt_instr *) &__alt_instructions_end, NULL); |
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set_kernel_text_rw(0); |
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}
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