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-rw-r--r--arch/powerpc/lib/test-code-patching.c362
1 files changed, 362 insertions, 0 deletions
diff --git a/arch/powerpc/lib/test-code-patching.c b/arch/powerpc/lib/test-code-patching.c
new file mode 100644
index 000000000..c44823292
--- /dev/null
+++ b/arch/powerpc/lib/test-code-patching.c
@@ -0,0 +1,362 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright 2008 Michael Ellerman, IBM Corporation.
+ */
+
+#include <linux/vmalloc.h>
+#include <linux/init.h>
+
+#include <asm/code-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 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();
+
+ return 0;
+}
+late_initcall(test_code_patching);