363 lines
11 KiB
C
363 lines
11 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Copyright 2008 Michael Ellerman, IBM Corporation.
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*/
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#include <linux/vmalloc.h>
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#include <linux/init.h>
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#include <asm/code-patching.h>
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static int __init instr_is_branch_to_addr(const u32 *instr, unsigned long addr)
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{
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if (instr_is_branch_iform(ppc_inst_read(instr)) ||
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instr_is_branch_bform(ppc_inst_read(instr)))
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return branch_target(instr) == addr;
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return 0;
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}
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static void __init test_trampoline(void)
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{
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asm ("nop;nop;\n");
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}
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#define check(x) do { \
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if (!(x)) \
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pr_err("code-patching: test failed at line %d\n", __LINE__); \
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} while (0)
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static void __init test_branch_iform(void)
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{
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int err;
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ppc_inst_t instr;
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u32 tmp[2];
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u32 *iptr = tmp;
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unsigned long addr = (unsigned long)tmp;
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/* The simplest case, branch to self, no flags */
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check(instr_is_branch_iform(ppc_inst(0x48000000)));
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/* All bits of target set, and flags */
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check(instr_is_branch_iform(ppc_inst(0x4bffffff)));
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/* High bit of opcode set, which is wrong */
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check(!instr_is_branch_iform(ppc_inst(0xcbffffff)));
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/* Middle bits of opcode set, which is wrong */
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check(!instr_is_branch_iform(ppc_inst(0x7bffffff)));
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/* Simplest case, branch to self with link */
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check(instr_is_branch_iform(ppc_inst(0x48000001)));
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/* All bits of targets set */
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check(instr_is_branch_iform(ppc_inst(0x4bfffffd)));
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/* Some bits of targets set */
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check(instr_is_branch_iform(ppc_inst(0x4bff00fd)));
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/* Must be a valid branch to start with */
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check(!instr_is_branch_iform(ppc_inst(0x7bfffffd)));
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/* Absolute branch to 0x100 */
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ppc_inst_write(iptr, ppc_inst(0x48000103));
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check(instr_is_branch_to_addr(iptr, 0x100));
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/* Absolute branch to 0x420fc */
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ppc_inst_write(iptr, ppc_inst(0x480420ff));
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check(instr_is_branch_to_addr(iptr, 0x420fc));
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/* Maximum positive relative branch, + 20MB - 4B */
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ppc_inst_write(iptr, ppc_inst(0x49fffffc));
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check(instr_is_branch_to_addr(iptr, addr + 0x1FFFFFC));
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/* Smallest negative relative branch, - 4B */
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ppc_inst_write(iptr, ppc_inst(0x4bfffffc));
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check(instr_is_branch_to_addr(iptr, addr - 4));
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/* Largest negative relative branch, - 32 MB */
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ppc_inst_write(iptr, ppc_inst(0x4a000000));
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check(instr_is_branch_to_addr(iptr, addr - 0x2000000));
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/* Branch to self, with link */
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err = create_branch(&instr, iptr, addr, BRANCH_SET_LINK);
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ppc_inst_write(iptr, instr);
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check(instr_is_branch_to_addr(iptr, addr));
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/* Branch to self - 0x100, with link */
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err = create_branch(&instr, iptr, addr - 0x100, BRANCH_SET_LINK);
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ppc_inst_write(iptr, instr);
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check(instr_is_branch_to_addr(iptr, addr - 0x100));
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/* Branch to self + 0x100, no link */
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err = create_branch(&instr, iptr, addr + 0x100, 0);
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ppc_inst_write(iptr, instr);
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check(instr_is_branch_to_addr(iptr, addr + 0x100));
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/* Maximum relative negative offset, - 32 MB */
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err = create_branch(&instr, iptr, addr - 0x2000000, BRANCH_SET_LINK);
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ppc_inst_write(iptr, instr);
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check(instr_is_branch_to_addr(iptr, addr - 0x2000000));
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/* Out of range relative negative offset, - 32 MB + 4*/
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err = create_branch(&instr, iptr, addr - 0x2000004, BRANCH_SET_LINK);
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check(err);
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/* Out of range relative positive offset, + 32 MB */
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err = create_branch(&instr, iptr, addr + 0x2000000, BRANCH_SET_LINK);
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check(err);
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/* Unaligned target */
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err = create_branch(&instr, iptr, addr + 3, BRANCH_SET_LINK);
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check(err);
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/* Check flags are masked correctly */
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err = create_branch(&instr, iptr, addr, 0xFFFFFFFC);
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ppc_inst_write(iptr, instr);
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check(instr_is_branch_to_addr(iptr, addr));
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check(ppc_inst_equal(instr, ppc_inst(0x48000000)));
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}
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static void __init test_create_function_call(void)
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{
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u32 *iptr;
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unsigned long dest;
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ppc_inst_t instr;
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/* Check we can create a function call */
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iptr = (u32 *)ppc_function_entry(test_trampoline);
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dest = ppc_function_entry(test_create_function_call);
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create_branch(&instr, iptr, dest, BRANCH_SET_LINK);
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patch_instruction(iptr, instr);
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check(instr_is_branch_to_addr(iptr, dest));
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}
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static void __init test_branch_bform(void)
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{
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int err;
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unsigned long addr;
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ppc_inst_t instr;
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u32 tmp[2];
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u32 *iptr = tmp;
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unsigned int flags;
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addr = (unsigned long)iptr;
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/* The simplest case, branch to self, no flags */
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check(instr_is_branch_bform(ppc_inst(0x40000000)));
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/* All bits of target set, and flags */
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check(instr_is_branch_bform(ppc_inst(0x43ffffff)));
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/* High bit of opcode set, which is wrong */
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check(!instr_is_branch_bform(ppc_inst(0xc3ffffff)));
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/* Middle bits of opcode set, which is wrong */
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check(!instr_is_branch_bform(ppc_inst(0x7bffffff)));
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/* Absolute conditional branch to 0x100 */
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ppc_inst_write(iptr, ppc_inst(0x43ff0103));
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check(instr_is_branch_to_addr(iptr, 0x100));
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/* Absolute conditional branch to 0x20fc */
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ppc_inst_write(iptr, ppc_inst(0x43ff20ff));
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check(instr_is_branch_to_addr(iptr, 0x20fc));
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/* Maximum positive relative conditional branch, + 32 KB - 4B */
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ppc_inst_write(iptr, ppc_inst(0x43ff7ffc));
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check(instr_is_branch_to_addr(iptr, addr + 0x7FFC));
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/* Smallest negative relative conditional branch, - 4B */
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ppc_inst_write(iptr, ppc_inst(0x43fffffc));
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check(instr_is_branch_to_addr(iptr, addr - 4));
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/* Largest negative relative conditional branch, - 32 KB */
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ppc_inst_write(iptr, ppc_inst(0x43ff8000));
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check(instr_is_branch_to_addr(iptr, addr - 0x8000));
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/* All condition code bits set & link */
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flags = 0x3ff000 | BRANCH_SET_LINK;
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/* Branch to self */
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err = create_cond_branch(&instr, iptr, addr, flags);
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ppc_inst_write(iptr, instr);
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check(instr_is_branch_to_addr(iptr, addr));
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/* Branch to self - 0x100 */
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err = create_cond_branch(&instr, iptr, addr - 0x100, flags);
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ppc_inst_write(iptr, instr);
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check(instr_is_branch_to_addr(iptr, addr - 0x100));
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/* Branch to self + 0x100 */
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err = create_cond_branch(&instr, iptr, addr + 0x100, flags);
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ppc_inst_write(iptr, instr);
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check(instr_is_branch_to_addr(iptr, addr + 0x100));
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/* Maximum relative negative offset, - 32 KB */
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err = create_cond_branch(&instr, iptr, addr - 0x8000, flags);
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ppc_inst_write(iptr, instr);
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check(instr_is_branch_to_addr(iptr, addr - 0x8000));
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/* Out of range relative negative offset, - 32 KB + 4*/
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err = create_cond_branch(&instr, iptr, addr - 0x8004, flags);
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check(err);
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/* Out of range relative positive offset, + 32 KB */
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err = create_cond_branch(&instr, iptr, addr + 0x8000, flags);
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check(err);
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/* Unaligned target */
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err = create_cond_branch(&instr, iptr, addr + 3, flags);
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check(err);
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/* Check flags are masked correctly */
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err = create_cond_branch(&instr, iptr, addr, 0xFFFFFFFC);
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ppc_inst_write(iptr, instr);
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check(instr_is_branch_to_addr(iptr, addr));
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check(ppc_inst_equal(instr, ppc_inst(0x43FF0000)));
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}
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static void __init test_translate_branch(void)
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{
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unsigned long addr;
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void *p, *q;
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ppc_inst_t instr;
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void *buf;
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buf = vmalloc(PAGE_ALIGN(0x2000000 + 1));
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check(buf);
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if (!buf)
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return;
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/* Simple case, branch to self moved a little */
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p = buf;
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addr = (unsigned long)p;
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create_branch(&instr, p, addr, 0);
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ppc_inst_write(p, instr);
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check(instr_is_branch_to_addr(p, addr));
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q = p + 4;
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translate_branch(&instr, q, p);
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ppc_inst_write(q, instr);
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check(instr_is_branch_to_addr(q, addr));
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/* Maximum negative case, move b . to addr + 32 MB */
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p = buf;
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addr = (unsigned long)p;
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create_branch(&instr, p, addr, 0);
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ppc_inst_write(p, instr);
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q = buf + 0x2000000;
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translate_branch(&instr, q, p);
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ppc_inst_write(q, instr);
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check(instr_is_branch_to_addr(p, addr));
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check(instr_is_branch_to_addr(q, addr));
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check(ppc_inst_equal(ppc_inst_read(q), ppc_inst(0x4a000000)));
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/* Maximum positive case, move x to x - 32 MB + 4 */
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p = buf + 0x2000000;
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addr = (unsigned long)p;
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create_branch(&instr, p, addr, 0);
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ppc_inst_write(p, instr);
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q = buf + 4;
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translate_branch(&instr, q, p);
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ppc_inst_write(q, instr);
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check(instr_is_branch_to_addr(p, addr));
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check(instr_is_branch_to_addr(q, addr));
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check(ppc_inst_equal(ppc_inst_read(q), ppc_inst(0x49fffffc)));
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/* Jump to x + 16 MB moved to x + 20 MB */
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p = buf;
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addr = 0x1000000 + (unsigned long)buf;
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create_branch(&instr, p, addr, BRANCH_SET_LINK);
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ppc_inst_write(p, instr);
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q = buf + 0x1400000;
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translate_branch(&instr, q, p);
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ppc_inst_write(q, instr);
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check(instr_is_branch_to_addr(p, addr));
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check(instr_is_branch_to_addr(q, addr));
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/* Jump to x + 16 MB moved to x - 16 MB + 4 */
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p = buf + 0x1000000;
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addr = 0x2000000 + (unsigned long)buf;
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create_branch(&instr, p, addr, 0);
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ppc_inst_write(p, instr);
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q = buf + 4;
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translate_branch(&instr, q, p);
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ppc_inst_write(q, instr);
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check(instr_is_branch_to_addr(p, addr));
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check(instr_is_branch_to_addr(q, addr));
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/* Conditional branch tests */
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/* Simple case, branch to self moved a little */
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p = buf;
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addr = (unsigned long)p;
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create_cond_branch(&instr, p, addr, 0);
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ppc_inst_write(p, instr);
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check(instr_is_branch_to_addr(p, addr));
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q = buf + 4;
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translate_branch(&instr, q, p);
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ppc_inst_write(q, instr);
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check(instr_is_branch_to_addr(q, addr));
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/* Maximum negative case, move b . to addr + 32 KB */
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p = buf;
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addr = (unsigned long)p;
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create_cond_branch(&instr, p, addr, 0xFFFFFFFC);
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ppc_inst_write(p, instr);
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q = buf + 0x8000;
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translate_branch(&instr, q, p);
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ppc_inst_write(q, instr);
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check(instr_is_branch_to_addr(p, addr));
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check(instr_is_branch_to_addr(q, addr));
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check(ppc_inst_equal(ppc_inst_read(q), ppc_inst(0x43ff8000)));
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/* Maximum positive case, move x to x - 32 KB + 4 */
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p = buf + 0x8000;
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addr = (unsigned long)p;
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create_cond_branch(&instr, p, addr, 0xFFFFFFFC);
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ppc_inst_write(p, instr);
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q = buf + 4;
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translate_branch(&instr, q, p);
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ppc_inst_write(q, instr);
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check(instr_is_branch_to_addr(p, addr));
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check(instr_is_branch_to_addr(q, addr));
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check(ppc_inst_equal(ppc_inst_read(q), ppc_inst(0x43ff7ffc)));
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/* Jump to x + 12 KB moved to x + 20 KB */
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p = buf;
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addr = 0x3000 + (unsigned long)buf;
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create_cond_branch(&instr, p, addr, BRANCH_SET_LINK);
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ppc_inst_write(p, instr);
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q = buf + 0x5000;
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translate_branch(&instr, q, p);
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ppc_inst_write(q, instr);
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check(instr_is_branch_to_addr(p, addr));
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check(instr_is_branch_to_addr(q, addr));
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/* Jump to x + 8 KB moved to x - 8 KB + 4 */
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p = buf + 0x2000;
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addr = 0x4000 + (unsigned long)buf;
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create_cond_branch(&instr, p, addr, 0);
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ppc_inst_write(p, instr);
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q = buf + 4;
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translate_branch(&instr, q, p);
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ppc_inst_write(q, instr);
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check(instr_is_branch_to_addr(p, addr));
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check(instr_is_branch_to_addr(q, addr));
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/* Free the buffer we were using */
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vfree(buf);
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}
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static void __init test_prefixed_patching(void)
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{
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u32 *iptr = (u32 *)ppc_function_entry(test_trampoline);
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u32 expected[2] = {OP_PREFIX << 26, 0};
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ppc_inst_t inst = ppc_inst_prefix(OP_PREFIX << 26, 0);
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if (!IS_ENABLED(CONFIG_PPC64))
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return;
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patch_instruction(iptr, inst);
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check(!memcmp(iptr, expected, sizeof(expected)));
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}
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static int __init test_code_patching(void)
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{
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pr_info("Running code patching self-tests ...\n");
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test_branch_iform();
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test_branch_bform();
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test_create_function_call();
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test_translate_branch();
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test_prefixed_patching();
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return 0;
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}
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late_initcall(test_code_patching);
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