[PATCHv11 13/16] selftests/x86/lam: Add mmap and SYSCALL test cases for linear-address masking

From: Kirill A. Shutemov
Date: Mon Oct 24 2022 - 21:10:18 EST

From: Weihong Zhang <weihong.zhang@xxxxxxxxx>

Add mmap and SYSCALL test cases.

SYSCALL test cases:

- LAM supports set metadata in high bits 62:57 (LAM_U57) of a user pointer, pass
the pointer to SYSCALL, SYSCALL can dereference the pointer and return correct
result.

- Disable LAM, pass a pointer with metadata in high bits to SYSCALL,
SYSCALL returns -1 (EFAULT).

MMAP test cases:

- Enable LAM_U57, MMAP with low address (below bits 47), set metadata
in high bits of the address, dereference the address should be
allowed.

- Enable LAM_U57, MMAP with high address (above bits 47), set metadata
in high bits of the address, dereference the address should be
allowed.

Signed-off-by: Weihong Zhang <weihong.zhang@xxxxxxxxx>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
---
tools/testing/selftests/x86/lam.c | 144 +++++++++++++++++++++++++++++-
1 file changed, 140 insertions(+), 4 deletions(-)

diff --git a/tools/testing/selftests/x86/lam.c b/tools/testing/selftests/x86/lam.c
index 900a3a0fb709..cdc6e40e00e0 100644
--- a/tools/testing/selftests/x86/lam.c
+++ b/tools/testing/selftests/x86/lam.c
@@ -7,6 +7,7 @@
#include <signal.h>
#include <setjmp.h>
#include <sys/mman.h>
+#include <sys/utsname.h>
#include <sys/wait.h>
#include <inttypes.h>

@@ -29,11 +30,18 @@
/* Specified test function bits */
#define FUNC_MALLOC 0x1
#define FUNC_BITS 0x2
+#define FUNC_MMAP 0x4
+#define FUNC_SYSCALL 0x8

-#define TEST_MASK 0x3
+#define TEST_MASK 0xf
+
+#define LOW_ADDR (0x1UL << 30)
+#define HIGH_ADDR (0x3UL << 48)

#define MALLOC_LEN 32

+#define PAGE_SIZE (4 << 10)
+
struct testcases {
unsigned int later;
int expected; /* 2: SIGSEGV Error; 1: other errors */
@@ -49,6 +57,7 @@ jmp_buf segv_env;
static void segv_handler(int sig)
{
ksft_print_msg("Get segmentation fault(%d).", sig);
+
siglongjmp(segv_env, 1);
}

@@ -61,6 +70,16 @@ static inline int cpu_has_lam(void)
return (cpuinfo[0] & (1 << 26));
}

+/* Check 5-level page table feature in CPUID.(EAX=07H, ECX=00H):ECX.[bit 16] */
+static inline int cpu_has_la57(void)
+{
+ unsigned int cpuinfo[4];
+
+ __cpuid_count(0x7, 0, cpuinfo[0], cpuinfo[1], cpuinfo[2], cpuinfo[3]);
+
+ return (cpuinfo[2] & (1 << 16));
+}
+
/*
* Set tagged address and read back untag mask.
* check if the untagged mask is expected.
@@ -213,6 +232,68 @@ static int handle_malloc(struct testcases *test)
return ret;
}

+static int handle_mmap(struct testcases *test)
+{
+ void *ptr;
+ unsigned int flags = MAP_PRIVATE | MAP_ANONYMOUS | MAP_FIXED;
+ int ret = 0;
+
+ if (test->later == 0 && test->lam != 0)
+ if (set_lam(test->lam) != 0)
+ return 1;
+
+ ptr = mmap((void *)test->addr, PAGE_SIZE, PROT_READ | PROT_WRITE,
+ flags, -1, 0);
+ if (ptr == MAP_FAILED) {
+ if (test->addr == HIGH_ADDR)
+ if (!cpu_has_la57())
+ return 3; /* unsupport LA57 */
+ return 1;
+ }
+
+ if (test->later != 0 && test->lam != 0)
+ if (set_lam(test->lam) != 0)
+ ret = 1;
+
+ if (ret == 0) {
+ if (sigsetjmp(segv_env, 1) == 0) {
+ signal(SIGSEGV, segv_handler);
+ ret = handle_lam_test(ptr, test->lam);
+ } else {
+ ret = 2;
+ }
+ }
+
+ munmap(ptr, PAGE_SIZE);
+ return ret;
+}
+
+static int handle_syscall(struct testcases *test)
+{
+ struct utsname unme, *pu;
+ int ret = 0;
+
+ if (test->later == 0 && test->lam != 0)
+ if (set_lam(test->lam) != 0)
+ return 1;
+
+ if (sigsetjmp(segv_env, 1) == 0) {
+ signal(SIGSEGV, segv_handler);
+ pu = (struct utsname *)set_metadata((uint64_t)&unme, test->lam);
+ ret = uname(pu);
+ if (ret < 0)
+ ret = 1;
+ } else {
+ ret = 2;
+ }
+
+ if (test->later != 0 && test->lam != 0)
+ if (set_lam(test->lam) != -1 && ret == 0)
+ ret = 1;
+
+ return ret;
+}
+
static int fork_test(struct testcases *test)
{
int ret, child_ret;
@@ -241,13 +322,20 @@ static void run_test(struct testcases *test, int count)
struct testcases *t = test + i;

/* fork a process to run test case */
+ tests_cnt++;
ret = fork_test(t);
+
+ /* return 3 is not support LA57, the case should be skipped */
+ if (ret == 3) {
+ ksft_test_result_skip(t->msg);
+ continue;
+ }
+
if (ret != 0)
ret = (t->expected == ret);
else
ret = !(t->expected);

- tests_cnt++;
ksft_test_result(ret, t->msg);
}
}
@@ -268,7 +356,6 @@ static struct testcases malloc_cases[] = {
},
};

-
static struct testcases bits_cases[] = {
{
.test_func = handle_max_bits,
@@ -276,11 +363,54 @@ static struct testcases bits_cases[] = {
},
};

+static struct testcases syscall_cases[] = {
+ {
+ .later = 0,
+ .lam = LAM_U57_BITS,
+ .test_func = handle_syscall,
+ .msg = "SYSCALL: LAM_U57. syscall with metadata\n",
+ },
+ {
+ .later = 1,
+ .expected = 1,
+ .lam = LAM_U57_BITS,
+ .test_func = handle_syscall,
+ .msg = "SYSCALL:[Negative] Disable LAM. Dereferencing pointer with metadata.\n",
+ },
+};
+
+static struct testcases mmap_cases[] = {
+ {
+ .later = 1,
+ .expected = 0,
+ .lam = LAM_U57_BITS,
+ .addr = HIGH_ADDR,
+ .test_func = handle_mmap,
+ .msg = "MMAP: First mmap high address, then set LAM_U57.\n",
+ },
+ {
+ .later = 0,
+ .expected = 0,
+ .lam = LAM_U57_BITS,
+ .addr = HIGH_ADDR,
+ .test_func = handle_mmap,
+ .msg = "MMAP: First LAM_U57, then High address.\n",
+ },
+ {
+ .later = 0,
+ .expected = 0,
+ .lam = LAM_U57_BITS,
+ .addr = LOW_ADDR,
+ .test_func = handle_mmap,
+ .msg = "MMAP: First LAM_U57, then Low address.\n",
+ },
+};
+
static void cmd_help(void)
{
printf("usage: lam [-h] [-t test list]\n");
printf("\t-t test list: run tests specified in the test list, default:0x%x\n", TEST_MASK);
- printf("\t\t0x1:malloc; 0x2:max_bits;\n");
+ printf("\t\t0x1:malloc; 0x2:max_bits; 0x4:mmap; 0x8:syscall.\n");
printf("\t-h: help\n");
}

@@ -320,6 +450,12 @@ int main(int argc, char **argv)
if (tests & FUNC_BITS)
run_test(bits_cases, ARRAY_SIZE(bits_cases));

+ if (tests & FUNC_MMAP)
+ run_test(mmap_cases, ARRAY_SIZE(mmap_cases));
+
+ if (tests & FUNC_SYSCALL)
+ run_test(syscall_cases, ARRAY_SIZE(syscall_cases));
+
ksft_set_plan(tests_cnt);

return ksft_exit_pass();
--
2.38.0