1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * Copyright 2008 Michael Ellerman, IBM Corporation.
6 #include <linux/vmalloc.h>
7 #include <linux/init.h>
9 #include <asm/code-patching.h>
11 static int __init instr_is_branch_to_addr(const u32 *instr, unsigned long addr)
13 if (instr_is_branch_iform(ppc_inst_read(instr)) ||
14 instr_is_branch_bform(ppc_inst_read(instr)))
15 return branch_target(instr) == addr;
20 static void __init test_trampoline(void)
25 #define check(x) do { \
27 pr_err("code-patching: test failed at line %d\n", __LINE__); \
30 static void __init test_branch_iform(void)
36 unsigned long addr = (unsigned long)tmp;
38 /* The simplest case, branch to self, no flags */
39 check(instr_is_branch_iform(ppc_inst(0x48000000)));
40 /* All bits of target set, and flags */
41 check(instr_is_branch_iform(ppc_inst(0x4bffffff)));
42 /* High bit of opcode set, which is wrong */
43 check(!instr_is_branch_iform(ppc_inst(0xcbffffff)));
44 /* Middle bits of opcode set, which is wrong */
45 check(!instr_is_branch_iform(ppc_inst(0x7bffffff)));
47 /* Simplest case, branch to self with link */
48 check(instr_is_branch_iform(ppc_inst(0x48000001)));
49 /* All bits of targets set */
50 check(instr_is_branch_iform(ppc_inst(0x4bfffffd)));
51 /* Some bits of targets set */
52 check(instr_is_branch_iform(ppc_inst(0x4bff00fd)));
53 /* Must be a valid branch to start with */
54 check(!instr_is_branch_iform(ppc_inst(0x7bfffffd)));
56 /* Absolute branch to 0x100 */
57 ppc_inst_write(iptr, ppc_inst(0x48000103));
58 check(instr_is_branch_to_addr(iptr, 0x100));
59 /* Absolute branch to 0x420fc */
60 ppc_inst_write(iptr, ppc_inst(0x480420ff));
61 check(instr_is_branch_to_addr(iptr, 0x420fc));
62 /* Maximum positive relative branch, + 20MB - 4B */
63 ppc_inst_write(iptr, ppc_inst(0x49fffffc));
64 check(instr_is_branch_to_addr(iptr, addr + 0x1FFFFFC));
65 /* Smallest negative relative branch, - 4B */
66 ppc_inst_write(iptr, ppc_inst(0x4bfffffc));
67 check(instr_is_branch_to_addr(iptr, addr - 4));
68 /* Largest negative relative branch, - 32 MB */
69 ppc_inst_write(iptr, ppc_inst(0x4a000000));
70 check(instr_is_branch_to_addr(iptr, addr - 0x2000000));
72 /* Branch to self, with link */
73 err = create_branch(&instr, iptr, addr, BRANCH_SET_LINK);
74 ppc_inst_write(iptr, instr);
75 check(instr_is_branch_to_addr(iptr, addr));
77 /* Branch to self - 0x100, with link */
78 err = create_branch(&instr, iptr, addr - 0x100, BRANCH_SET_LINK);
79 ppc_inst_write(iptr, instr);
80 check(instr_is_branch_to_addr(iptr, addr - 0x100));
82 /* Branch to self + 0x100, no link */
83 err = create_branch(&instr, iptr, addr + 0x100, 0);
84 ppc_inst_write(iptr, instr);
85 check(instr_is_branch_to_addr(iptr, addr + 0x100));
87 /* Maximum relative negative offset, - 32 MB */
88 err = create_branch(&instr, iptr, addr - 0x2000000, BRANCH_SET_LINK);
89 ppc_inst_write(iptr, instr);
90 check(instr_is_branch_to_addr(iptr, addr - 0x2000000));
92 /* Out of range relative negative offset, - 32 MB + 4*/
93 err = create_branch(&instr, iptr, addr - 0x2000004, BRANCH_SET_LINK);
96 /* Out of range relative positive offset, + 32 MB */
97 err = create_branch(&instr, iptr, addr + 0x2000000, BRANCH_SET_LINK);
100 /* Unaligned target */
101 err = create_branch(&instr, iptr, addr + 3, BRANCH_SET_LINK);
104 /* Check flags are masked correctly */
105 err = create_branch(&instr, iptr, addr, 0xFFFFFFFC);
106 ppc_inst_write(iptr, instr);
107 check(instr_is_branch_to_addr(iptr, addr));
108 check(ppc_inst_equal(instr, ppc_inst(0x48000000)));
111 static void __init test_create_function_call(void)
117 /* Check we can create a function call */
118 iptr = (u32 *)ppc_function_entry(test_trampoline);
119 dest = ppc_function_entry(test_create_function_call);
120 create_branch(&instr, iptr, dest, BRANCH_SET_LINK);
121 patch_instruction(iptr, instr);
122 check(instr_is_branch_to_addr(iptr, dest));
125 static void __init test_branch_bform(void)
134 addr = (unsigned long)iptr;
136 /* The simplest case, branch to self, no flags */
137 check(instr_is_branch_bform(ppc_inst(0x40000000)));
138 /* All bits of target set, and flags */
139 check(instr_is_branch_bform(ppc_inst(0x43ffffff)));
140 /* High bit of opcode set, which is wrong */
141 check(!instr_is_branch_bform(ppc_inst(0xc3ffffff)));
142 /* Middle bits of opcode set, which is wrong */
143 check(!instr_is_branch_bform(ppc_inst(0x7bffffff)));
145 /* Absolute conditional branch to 0x100 */
146 ppc_inst_write(iptr, ppc_inst(0x43ff0103));
147 check(instr_is_branch_to_addr(iptr, 0x100));
148 /* Absolute conditional branch to 0x20fc */
149 ppc_inst_write(iptr, ppc_inst(0x43ff20ff));
150 check(instr_is_branch_to_addr(iptr, 0x20fc));
151 /* Maximum positive relative conditional branch, + 32 KB - 4B */
152 ppc_inst_write(iptr, ppc_inst(0x43ff7ffc));
153 check(instr_is_branch_to_addr(iptr, addr + 0x7FFC));
154 /* Smallest negative relative conditional branch, - 4B */
155 ppc_inst_write(iptr, ppc_inst(0x43fffffc));
156 check(instr_is_branch_to_addr(iptr, addr - 4));
157 /* Largest negative relative conditional branch, - 32 KB */
158 ppc_inst_write(iptr, ppc_inst(0x43ff8000));
159 check(instr_is_branch_to_addr(iptr, addr - 0x8000));
161 /* All condition code bits set & link */
162 flags = 0x3ff000 | BRANCH_SET_LINK;
165 err = create_cond_branch(&instr, iptr, addr, flags);
166 ppc_inst_write(iptr, instr);
167 check(instr_is_branch_to_addr(iptr, addr));
169 /* Branch to self - 0x100 */
170 err = create_cond_branch(&instr, iptr, addr - 0x100, flags);
171 ppc_inst_write(iptr, instr);
172 check(instr_is_branch_to_addr(iptr, addr - 0x100));
174 /* Branch to self + 0x100 */
175 err = create_cond_branch(&instr, iptr, addr + 0x100, flags);
176 ppc_inst_write(iptr, instr);
177 check(instr_is_branch_to_addr(iptr, addr + 0x100));
179 /* Maximum relative negative offset, - 32 KB */
180 err = create_cond_branch(&instr, iptr, addr - 0x8000, flags);
181 ppc_inst_write(iptr, instr);
182 check(instr_is_branch_to_addr(iptr, addr - 0x8000));
184 /* Out of range relative negative offset, - 32 KB + 4*/
185 err = create_cond_branch(&instr, iptr, addr - 0x8004, flags);
188 /* Out of range relative positive offset, + 32 KB */
189 err = create_cond_branch(&instr, iptr, addr + 0x8000, flags);
192 /* Unaligned target */
193 err = create_cond_branch(&instr, iptr, addr + 3, flags);
196 /* Check flags are masked correctly */
197 err = create_cond_branch(&instr, iptr, addr, 0xFFFFFFFC);
198 ppc_inst_write(iptr, instr);
199 check(instr_is_branch_to_addr(iptr, addr));
200 check(ppc_inst_equal(instr, ppc_inst(0x43FF0000)));
203 static void __init test_translate_branch(void)
210 buf = vmalloc(PAGE_ALIGN(0x2000000 + 1));
215 /* Simple case, branch to self moved a little */
217 addr = (unsigned long)p;
218 create_branch(&instr, p, addr, 0);
219 ppc_inst_write(p, instr);
220 check(instr_is_branch_to_addr(p, addr));
222 translate_branch(&instr, q, p);
223 ppc_inst_write(q, instr);
224 check(instr_is_branch_to_addr(q, addr));
226 /* Maximum negative case, move b . to addr + 32 MB */
228 addr = (unsigned long)p;
229 create_branch(&instr, p, addr, 0);
230 ppc_inst_write(p, instr);
232 translate_branch(&instr, q, p);
233 ppc_inst_write(q, instr);
234 check(instr_is_branch_to_addr(p, addr));
235 check(instr_is_branch_to_addr(q, addr));
236 check(ppc_inst_equal(ppc_inst_read(q), ppc_inst(0x4a000000)));
238 /* Maximum positive case, move x to x - 32 MB + 4 */
240 addr = (unsigned long)p;
241 create_branch(&instr, p, addr, 0);
242 ppc_inst_write(p, instr);
244 translate_branch(&instr, q, p);
245 ppc_inst_write(q, instr);
246 check(instr_is_branch_to_addr(p, addr));
247 check(instr_is_branch_to_addr(q, addr));
248 check(ppc_inst_equal(ppc_inst_read(q), ppc_inst(0x49fffffc)));
250 /* Jump to x + 16 MB moved to x + 20 MB */
252 addr = 0x1000000 + (unsigned long)buf;
253 create_branch(&instr, p, addr, BRANCH_SET_LINK);
254 ppc_inst_write(p, instr);
256 translate_branch(&instr, q, p);
257 ppc_inst_write(q, instr);
258 check(instr_is_branch_to_addr(p, addr));
259 check(instr_is_branch_to_addr(q, addr));
261 /* Jump to x + 16 MB moved to x - 16 MB + 4 */
263 addr = 0x2000000 + (unsigned long)buf;
264 create_branch(&instr, p, addr, 0);
265 ppc_inst_write(p, instr);
267 translate_branch(&instr, q, p);
268 ppc_inst_write(q, instr);
269 check(instr_is_branch_to_addr(p, addr));
270 check(instr_is_branch_to_addr(q, addr));
273 /* Conditional branch tests */
275 /* Simple case, branch to self moved a little */
277 addr = (unsigned long)p;
278 create_cond_branch(&instr, p, addr, 0);
279 ppc_inst_write(p, instr);
280 check(instr_is_branch_to_addr(p, addr));
282 translate_branch(&instr, q, p);
283 ppc_inst_write(q, instr);
284 check(instr_is_branch_to_addr(q, addr));
286 /* Maximum negative case, move b . to addr + 32 KB */
288 addr = (unsigned long)p;
289 create_cond_branch(&instr, p, addr, 0xFFFFFFFC);
290 ppc_inst_write(p, instr);
292 translate_branch(&instr, q, p);
293 ppc_inst_write(q, instr);
294 check(instr_is_branch_to_addr(p, addr));
295 check(instr_is_branch_to_addr(q, addr));
296 check(ppc_inst_equal(ppc_inst_read(q), ppc_inst(0x43ff8000)));
298 /* Maximum positive case, move x to x - 32 KB + 4 */
300 addr = (unsigned long)p;
301 create_cond_branch(&instr, p, addr, 0xFFFFFFFC);
302 ppc_inst_write(p, instr);
304 translate_branch(&instr, q, p);
305 ppc_inst_write(q, instr);
306 check(instr_is_branch_to_addr(p, addr));
307 check(instr_is_branch_to_addr(q, addr));
308 check(ppc_inst_equal(ppc_inst_read(q), ppc_inst(0x43ff7ffc)));
310 /* Jump to x + 12 KB moved to x + 20 KB */
312 addr = 0x3000 + (unsigned long)buf;
313 create_cond_branch(&instr, p, addr, BRANCH_SET_LINK);
314 ppc_inst_write(p, instr);
316 translate_branch(&instr, q, p);
317 ppc_inst_write(q, instr);
318 check(instr_is_branch_to_addr(p, addr));
319 check(instr_is_branch_to_addr(q, addr));
321 /* Jump to x + 8 KB moved to x - 8 KB + 4 */
323 addr = 0x4000 + (unsigned long)buf;
324 create_cond_branch(&instr, p, addr, 0);
325 ppc_inst_write(p, instr);
327 translate_branch(&instr, q, p);
328 ppc_inst_write(q, instr);
329 check(instr_is_branch_to_addr(p, addr));
330 check(instr_is_branch_to_addr(q, addr));
332 /* Free the buffer we were using */
336 static void __init test_prefixed_patching(void)
338 u32 *iptr = (u32 *)ppc_function_entry(test_trampoline);
339 u32 expected[2] = {OP_PREFIX << 26, 0};
340 ppc_inst_t inst = ppc_inst_prefix(OP_PREFIX << 26, 0);
342 if (!IS_ENABLED(CONFIG_PPC64))
345 patch_instruction(iptr, inst);
347 check(!memcmp(iptr, expected, sizeof(expected)));
350 static int __init test_code_patching(void)
352 pr_info("Running code patching self-tests ...\n");
356 test_create_function_call();
357 test_translate_branch();
358 test_prefixed_patching();
362 late_initcall(test_code_patching);