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

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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
This commit is contained in:
Benjamin Gray
2024-03-25 16:28:14 +11:00
committed by Michael Ellerman
parent 295454eda9
commit c5ef5e3584
1 changed files with 92 additions and 0 deletions
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92
arch/powerpc/lib/test-code-patching.c
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@@ -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;
}