83 lines
2.0 KiB
C
83 lines
2.0 KiB
C
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// SPDX-License-Identifier: GPL-2.0
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/*
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* Jump label s390 support
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*
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* Copyright IBM Corp. 2011
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* Author(s): Jan Glauber <jang@linux.vnet.ibm.com>
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*/
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#include <linux/uaccess.h>
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#include <linux/jump_label.h>
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#include <linux/module.h>
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#include <asm/text-patching.h>
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#include <asm/ipl.h>
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struct insn {
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u16 opcode;
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s32 offset;
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} __packed;
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static void jump_label_make_nop(struct jump_entry *entry, struct insn *insn)
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{
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/* brcl 0,offset */
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insn->opcode = 0xc004;
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insn->offset = (jump_entry_target(entry) - jump_entry_code(entry)) >> 1;
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}
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static void jump_label_make_branch(struct jump_entry *entry, struct insn *insn)
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{
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/* brcl 15,offset */
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insn->opcode = 0xc0f4;
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insn->offset = (jump_entry_target(entry) - jump_entry_code(entry)) >> 1;
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}
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static void jump_label_bug(struct jump_entry *entry, struct insn *expected,
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struct insn *new)
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{
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unsigned char *ipc = (unsigned char *)jump_entry_code(entry);
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unsigned char *ipe = (unsigned char *)expected;
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unsigned char *ipn = (unsigned char *)new;
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pr_emerg("Jump label code mismatch at %pS [%px]\n", ipc, ipc);
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pr_emerg("Found: %6ph\n", ipc);
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pr_emerg("Expected: %6ph\n", ipe);
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pr_emerg("New: %6ph\n", ipn);
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panic("Corrupted kernel text");
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}
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static void jump_label_transform(struct jump_entry *entry,
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enum jump_label_type type)
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{
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void *code = (void *)jump_entry_code(entry);
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struct insn old, new;
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if (type == JUMP_LABEL_JMP) {
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jump_label_make_nop(entry, &old);
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jump_label_make_branch(entry, &new);
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} else {
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jump_label_make_branch(entry, &old);
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jump_label_make_nop(entry, &new);
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}
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if (memcmp(code, &old, sizeof(old)))
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jump_label_bug(entry, &old, &new);
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s390_kernel_write(code, &new, sizeof(new));
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}
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void arch_jump_label_transform(struct jump_entry *entry,
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enum jump_label_type type)
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{
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jump_label_transform(entry, type);
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text_poke_sync();
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}
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bool arch_jump_label_transform_queue(struct jump_entry *entry,
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enum jump_label_type type)
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{
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jump_label_transform(entry, type);
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return true;
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}
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void arch_jump_label_transform_apply(void)
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{
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text_poke_sync();
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}
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