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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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#include <linux/vmalloc.h>#include <linux/init.h>
#include <asm/text-patching.h>
static int __init instr_is_branch_to_addr(const u32 *instr, unsigned long addr){ if (instr_is_branch_iform(ppc_inst_read(instr)) || instr_is_branch_bform(ppc_inst_read(instr))) return branch_target(instr) == addr;
return 0;}
static void __init test_trampoline(void){ asm ("nop;nop;\n");}
#define check(x) do { \ if (!(x)) \ pr_err("code-patching: test failed at line %d\n", __LINE__); \} while (0)
static void __init test_branch_iform(void){ int err; ppc_inst_t instr; u32 tmp[2]; u32 *iptr = tmp; unsigned long addr = (unsigned long)tmp;
/* The simplest case, branch to self, no flags */ check(instr_is_branch_iform(ppc_inst(0x48000000))); /* All bits of target set, and flags */ check(instr_is_branch_iform(ppc_inst(0x4bffffff))); /* High bit of opcode set, which is wrong */ check(!instr_is_branch_iform(ppc_inst(0xcbffffff))); /* Middle bits of opcode set, which is wrong */ check(!instr_is_branch_iform(ppc_inst(0x7bffffff)));
/* Simplest case, branch to self with link */ check(instr_is_branch_iform(ppc_inst(0x48000001))); /* All bits of targets set */ check(instr_is_branch_iform(ppc_inst(0x4bfffffd))); /* Some bits of targets set */ check(instr_is_branch_iform(ppc_inst(0x4bff00fd))); /* Must be a valid branch to start with */ check(!instr_is_branch_iform(ppc_inst(0x7bfffffd)));
/* Absolute branch to 0x100 */ ppc_inst_write(iptr, ppc_inst(0x48000103)); check(instr_is_branch_to_addr(iptr, 0x100)); /* Absolute branch to 0x420fc */ ppc_inst_write(iptr, ppc_inst(0x480420ff)); check(instr_is_branch_to_addr(iptr, 0x420fc)); /* Maximum positive relative branch, + 20MB - 4B */ ppc_inst_write(iptr, ppc_inst(0x49fffffc)); check(instr_is_branch_to_addr(iptr, addr + 0x1FFFFFC)); /* Smallest negative relative branch, - 4B */ ppc_inst_write(iptr, ppc_inst(0x4bfffffc)); check(instr_is_branch_to_addr(iptr, addr - 4)); /* Largest negative relative branch, - 32 MB */ ppc_inst_write(iptr, ppc_inst(0x4a000000)); check(instr_is_branch_to_addr(iptr, addr - 0x2000000));
/* Branch to self, with link */ err = create_branch(&instr, iptr, addr, BRANCH_SET_LINK); ppc_inst_write(iptr, instr); check(instr_is_branch_to_addr(iptr, addr));
/* Branch to self - 0x100, with link */ err = create_branch(&instr, iptr, addr - 0x100, BRANCH_SET_LINK); ppc_inst_write(iptr, instr); check(instr_is_branch_to_addr(iptr, addr - 0x100));
/* Branch to self + 0x100, no link */ err = create_branch(&instr, iptr, addr + 0x100, 0); ppc_inst_write(iptr, instr); check(instr_is_branch_to_addr(iptr, addr + 0x100));
/* Maximum relative negative offset, - 32 MB */ err = create_branch(&instr, iptr, addr - 0x2000000, BRANCH_SET_LINK); ppc_inst_write(iptr, instr); check(instr_is_branch_to_addr(iptr, addr - 0x2000000));
/* Out of range relative negative offset, - 32 MB + 4*/ err = create_branch(&instr, iptr, addr - 0x2000004, BRANCH_SET_LINK); check(err);
/* Out of range relative positive offset, + 32 MB */ err = create_branch(&instr, iptr, addr + 0x2000000, BRANCH_SET_LINK); check(err);
/* Unaligned target */ err = create_branch(&instr, iptr, addr + 3, BRANCH_SET_LINK); check(err);
/* Check flags are masked correctly */ err = create_branch(&instr, iptr, addr, 0xFFFFFFFC); ppc_inst_write(iptr, instr); check(instr_is_branch_to_addr(iptr, addr)); check(ppc_inst_equal(instr, ppc_inst(0x48000000)));}
static void __init test_create_function_call(void){ u32 *iptr; unsigned long dest; ppc_inst_t instr;
/* Check we can create a function call */ iptr = (u32 *)ppc_function_entry(test_trampoline); dest = ppc_function_entry(test_create_function_call); create_branch(&instr, iptr, dest, BRANCH_SET_LINK); patch_instruction(iptr, instr); check(instr_is_branch_to_addr(iptr, dest));}
static void __init test_branch_bform(void){ int err; unsigned long addr; ppc_inst_t instr; u32 tmp[2]; u32 *iptr = tmp; unsigned int flags;
addr = (unsigned long)iptr;
/* The simplest case, branch to self, no flags */ check(instr_is_branch_bform(ppc_inst(0x40000000))); /* All bits of target set, and flags */ check(instr_is_branch_bform(ppc_inst(0x43ffffff))); /* High bit of opcode set, which is wrong */ check(!instr_is_branch_bform(ppc_inst(0xc3ffffff))); /* Middle bits of opcode set, which is wrong */ check(!instr_is_branch_bform(ppc_inst(0x7bffffff)));
/* Absolute conditional branch to 0x100 */ ppc_inst_write(iptr, ppc_inst(0x43ff0103)); check(instr_is_branch_to_addr(iptr, 0x100)); /* Absolute conditional branch to 0x20fc */ ppc_inst_write(iptr, ppc_inst(0x43ff20ff)); check(instr_is_branch_to_addr(iptr, 0x20fc)); /* Maximum positive relative conditional branch, + 32 KB - 4B */ ppc_inst_write(iptr, ppc_inst(0x43ff7ffc)); check(instr_is_branch_to_addr(iptr, addr + 0x7FFC)); /* Smallest negative relative conditional branch, - 4B */ ppc_inst_write(iptr, ppc_inst(0x43fffffc)); check(instr_is_branch_to_addr(iptr, addr - 4)); /* Largest negative relative conditional branch, - 32 KB */ ppc_inst_write(iptr, ppc_inst(0x43ff8000)); check(instr_is_branch_to_addr(iptr, addr - 0x8000));
/* All condition code bits set & link */ flags = 0x3ff000 | BRANCH_SET_LINK;
/* Branch to self */ err = create_cond_branch(&instr, iptr, addr, flags); ppc_inst_write(iptr, instr); check(instr_is_branch_to_addr(iptr, addr));
/* Branch to self - 0x100 */ err = create_cond_branch(&instr, iptr, addr - 0x100, flags); ppc_inst_write(iptr, instr); check(instr_is_branch_to_addr(iptr, addr - 0x100));
/* Branch to self + 0x100 */ err = create_cond_branch(&instr, iptr, addr + 0x100, flags); ppc_inst_write(iptr, instr); check(instr_is_branch_to_addr(iptr, addr + 0x100));
/* Maximum relative negative offset, - 32 KB */ err = create_cond_branch(&instr, iptr, addr - 0x8000, flags); ppc_inst_write(iptr, instr); check(instr_is_branch_to_addr(iptr, addr - 0x8000));
/* Out of range relative negative offset, - 32 KB + 4*/ err = create_cond_branch(&instr, iptr, addr - 0x8004, flags); check(err);
/* Out of range relative positive offset, + 32 KB */ err = create_cond_branch(&instr, iptr, addr + 0x8000, flags); check(err);
/* Unaligned target */ err = create_cond_branch(&instr, iptr, addr + 3, flags); check(err);
/* Check flags are masked correctly */ err = create_cond_branch(&instr, iptr, addr, 0xFFFFFFFC); ppc_inst_write(iptr, instr); check(instr_is_branch_to_addr(iptr, addr)); check(ppc_inst_equal(instr, ppc_inst(0x43FF0000)));}
static void __init test_translate_branch(void){ unsigned long addr; void *p, *q; ppc_inst_t instr; void *buf;
buf = vmalloc(PAGE_ALIGN(0x2000000 + 1)); check(buf); if (!buf) return;
/* Simple case, branch to self moved a little */ p = buf; addr = (unsigned long)p; create_branch(&instr, p, addr, 0); ppc_inst_write(p, instr); check(instr_is_branch_to_addr(p, addr)); q = p + 4; translate_branch(&instr, q, p); ppc_inst_write(q, instr); check(instr_is_branch_to_addr(q, addr));
/* Maximum negative case, move b . to addr + 32 MB */ p = buf; addr = (unsigned long)p; create_branch(&instr, p, addr, 0); ppc_inst_write(p, instr); q = buf + 0x2000000; translate_branch(&instr, q, p); ppc_inst_write(q, instr); check(instr_is_branch_to_addr(p, addr)); check(instr_is_branch_to_addr(q, addr)); check(ppc_inst_equal(ppc_inst_read(q), ppc_inst(0x4a000000)));
/* Maximum positive case, move x to x - 32 MB + 4 */ p = buf + 0x2000000; addr = (unsigned long)p; create_branch(&instr, p, addr, 0); ppc_inst_write(p, instr); q = buf + 4; translate_branch(&instr, q, p); ppc_inst_write(q, instr); check(instr_is_branch_to_addr(p, addr)); check(instr_is_branch_to_addr(q, addr)); check(ppc_inst_equal(ppc_inst_read(q), ppc_inst(0x49fffffc)));
/* Jump to x + 16 MB moved to x + 20 MB */ p = buf; addr = 0x1000000 + (unsigned long)buf; create_branch(&instr, p, addr, BRANCH_SET_LINK); ppc_inst_write(p, instr); q = buf + 0x1400000; translate_branch(&instr, q, p); ppc_inst_write(q, instr); check(instr_is_branch_to_addr(p, addr)); check(instr_is_branch_to_addr(q, addr));
/* Jump to x + 16 MB moved to x - 16 MB + 4 */ p = buf + 0x1000000; addr = 0x2000000 + (unsigned long)buf; create_branch(&instr, p, addr, 0); ppc_inst_write(p, instr); q = buf + 4; translate_branch(&instr, q, p); ppc_inst_write(q, instr); check(instr_is_branch_to_addr(p, addr)); check(instr_is_branch_to_addr(q, addr));
/* Conditional branch tests */
/* Simple case, branch to self moved a little */ p = buf; addr = (unsigned long)p; create_cond_branch(&instr, p, addr, 0); ppc_inst_write(p, instr); check(instr_is_branch_to_addr(p, addr)); q = buf + 4; translate_branch(&instr, q, p); ppc_inst_write(q, instr); check(instr_is_branch_to_addr(q, addr));
/* Maximum negative case, move b . to addr + 32 KB */ p = buf; addr = (unsigned long)p; create_cond_branch(&instr, p, addr, 0xFFFFFFFC); ppc_inst_write(p, instr); q = buf + 0x8000; translate_branch(&instr, q, p); ppc_inst_write(q, instr); check(instr_is_branch_to_addr(p, addr)); check(instr_is_branch_to_addr(q, addr)); check(ppc_inst_equal(ppc_inst_read(q), ppc_inst(0x43ff8000)));
/* Maximum positive case, move x to x - 32 KB + 4 */ p = buf + 0x8000; addr = (unsigned long)p; create_cond_branch(&instr, p, addr, 0xFFFFFFFC); ppc_inst_write(p, instr); q = buf + 4; translate_branch(&instr, q, p); ppc_inst_write(q, instr); check(instr_is_branch_to_addr(p, addr)); check(instr_is_branch_to_addr(q, addr)); check(ppc_inst_equal(ppc_inst_read(q), ppc_inst(0x43ff7ffc)));
/* Jump to x + 12 KB moved to x + 20 KB */ p = buf; addr = 0x3000 + (unsigned long)buf; create_cond_branch(&instr, p, addr, BRANCH_SET_LINK); ppc_inst_write(p, instr); q = buf + 0x5000; translate_branch(&instr, q, p); ppc_inst_write(q, instr); check(instr_is_branch_to_addr(p, addr)); check(instr_is_branch_to_addr(q, addr));
/* Jump to x + 8 KB moved to x - 8 KB + 4 */ p = buf + 0x2000; addr = 0x4000 + (unsigned long)buf; create_cond_branch(&instr, p, addr, 0); ppc_inst_write(p, instr); q = buf + 4; translate_branch(&instr, q, p); ppc_inst_write(q, instr); check(instr_is_branch_to_addr(p, addr)); check(instr_is_branch_to_addr(q, addr));
/* Free the buffer we were using */ vfree(buf);}
static void __init test_prefixed_patching(void){ u32 *iptr = (u32 *)ppc_function_entry(test_trampoline); u32 expected[2] = {OP_PREFIX << 26, 0}; ppc_inst_t inst = ppc_inst_prefix(OP_PREFIX << 26, 0);
if (!IS_ENABLED(CONFIG_PPC64)) return;
patch_instruction(iptr, inst);
check(!memcmp(iptr, expected, sizeof(expected)));}
static void __init test_multi_instruction_patching(void){ u32 code[32]; void *buf; u32 *addr32; u64 *addr64; ppc_inst_t inst64 = ppc_inst_prefix(OP_PREFIX << 26 | 3UL << 24, PPC_RAW_TRAP()); u32 inst32 = PPC_RAW_NOP();
buf = vzalloc(PAGE_SIZE * 8); check(buf); if (!buf) return;
/* Test single page 32-bit repeated instruction */ addr32 = buf + PAGE_SIZE; check(!patch_instructions(addr32 + 1, &inst32, 12, true));
check(addr32[0] == 0); check(addr32[1] == inst32); check(addr32[2] == inst32); check(addr32[3] == inst32); check(addr32[4] == 0);
/* Test single page 64-bit repeated instruction */ if (IS_ENABLED(CONFIG_PPC64)) { check(ppc_inst_prefixed(inst64));
addr64 = buf + PAGE_SIZE * 2; ppc_inst_write(code, inst64); check(!patch_instructions((u32 *)(addr64 + 1), code, 24, true));
check(addr64[0] == 0); check(ppc_inst_equal(ppc_inst_read((u32 *)&addr64[1]), inst64)); check(ppc_inst_equal(ppc_inst_read((u32 *)&addr64[2]), inst64)); check(ppc_inst_equal(ppc_inst_read((u32 *)&addr64[3]), inst64)); check(addr64[4] == 0); }
/* Test single page memcpy */ addr32 = buf + PAGE_SIZE * 3;
for (int i = 0; i < ARRAY_SIZE(code); i++) code[i] = i + 1;
check(!patch_instructions(addr32 + 1, code, sizeof(code), false));
check(addr32[0] == 0); check(!memcmp(&addr32[1], code, sizeof(code))); check(addr32[ARRAY_SIZE(code) + 1] == 0);
/* Test multipage 32-bit repeated instruction */ addr32 = buf + PAGE_SIZE * 4 - 8; check(!patch_instructions(addr32 + 1, &inst32, 12, true));
check(addr32[0] == 0); check(addr32[1] == inst32); check(addr32[2] == inst32); check(addr32[3] == inst32); check(addr32[4] == 0);
/* Test multipage 64-bit repeated instruction */ if (IS_ENABLED(CONFIG_PPC64)) { check(ppc_inst_prefixed(inst64));
addr64 = buf + PAGE_SIZE * 5 - 8; ppc_inst_write(code, inst64); check(!patch_instructions((u32 *)(addr64 + 1), code, 24, true));
check(addr64[0] == 0); check(ppc_inst_equal(ppc_inst_read((u32 *)&addr64[1]), inst64)); check(ppc_inst_equal(ppc_inst_read((u32 *)&addr64[2]), inst64)); check(ppc_inst_equal(ppc_inst_read((u32 *)&addr64[3]), inst64)); check(addr64[4] == 0); }
/* Test multipage memcpy */ addr32 = buf + PAGE_SIZE * 6 - 12;
for (int i = 0; i < ARRAY_SIZE(code); i++) code[i] = i + 1;
check(!patch_instructions(addr32 + 1, code, sizeof(code), false));
check(addr32[0] == 0); check(!memcmp(&addr32[1], code, sizeof(code))); check(addr32[ARRAY_SIZE(code) + 1] == 0);
vfree(buf);}
static void __init test_data_patching(void){ void *buf; u32 *addr32;
buf = vzalloc(PAGE_SIZE); check(buf); if (!buf) return;
addr32 = buf + 128;
addr32[1] = 0xA0A1A2A3; addr32[2] = 0xB0B1B2B3;
check(!patch_uint(&addr32[1], 0xC0C1C2C3));
check(addr32[0] == 0); check(addr32[1] == 0xC0C1C2C3); check(addr32[2] == 0xB0B1B2B3); check(addr32[3] == 0);
/* Unaligned patch_ulong() should fail */ if (IS_ENABLED(CONFIG_PPC64)) check(patch_ulong(&addr32[1], 0xD0D1D2D3) == -EINVAL);
check(!patch_ulong(&addr32[2], 0xD0D1D2D3));
check(addr32[0] == 0); check(addr32[1] == 0xC0C1C2C3); check(*(unsigned long *)(&addr32[2]) == 0xD0D1D2D3);
if (!IS_ENABLED(CONFIG_PPC64)) check(addr32[3] == 0);
check(addr32[4] == 0);
vfree(buf);}
static int __init test_code_patching(void){ pr_info("Running code patching self-tests ...\n");
test_branch_iform(); test_branch_bform(); test_create_function_call(); test_translate_branch(); test_prefixed_patching(); test_multi_instruction_patching(); test_data_patching();
return 0;}late_initcall(test_code_patching);