powerpc/code-patching: Test patch_instructions() during boot

patch_instructions() introduces new behaviour with a couple of
variations. Test each case of

  * a repeated 32-bit instruction,
  * a repeated 64-bit instruction (ppc64), and
  * a copied sequence of instructions

for both on a single page and when it crosses a page boundary.

Signed-off-by: Benjamin Gray <bgray@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20240325052815.854044-1-bgray@linux.ibm.com

diff --git a/arch/powerpc/lib/test-code-patching.c b/arch/powerpc/lib/test-code-patching.c
index c44823292f739dc526b4a7c07fe203c03d62bd53..f76030087f9836e821783a6ef35c85d4944f8613 100644 (file)
--- a/arch/powerpc/lib/test-code-patching.c
+++ b/arch/powerpc/lib/test-code-patching.c
@@ -347,6 +347,97 @@ static void __init test_prefixed_patching(void)
        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 int __init test_code_patching(void)
 {
        pr_info("Running code patching self-tests ...\n");
@@ -356,6 +447,7 @@ static int __init test_code_patching(void)
        test_create_function_call();
        test_translate_branch();
        test_prefixed_patching();
+       test_multi_instruction_patching();
 
        return 0;
 }