[PATCHv5 OPTIONAL 13/13] selftests/x86/lam: Add tests cases for LAM_U48
From: Kirill A. Shutemov
Date: Tue Jul 12 2022 - 19:14:16 EST
From: Weihong Zhang <weihong.zhang@xxxxxxxxx>
LAM supports configurations that differ regarding which pointer bits are masked.
With LAM_U48, bits 62:48 in pointers can be masked as metadata bits, the width
of LAM is 15.
Add test cases in existed test scenarios:
MALLOC:
- Enable LAM_U48, masks bits 48:62 of user pointers as metadata, the
process can dereference these pointers.
MMAP:
- Enable LAM_U48, mmaping with high address (above bits 47) have to be
failed, which lead to trigger SIGSEGV.
- LAM_U48 can't be enabled if there is a mmaping with high
address(above bits 47) before enable LAM_U48.
SYSCALL:
- LAM supports set metadata in high bits 62:48 (LAM48) of user process,
pass these pointers to SYSCALL, SYSCALL can dereference pointers and
return correct result.
IO_URING:
- Add LAM_U48 test on IO_URING, Enable LAM_U48, set metadata in bits
62:48 of buffers, IO_URING can handle these buffers well.
FORK/EXEC:
- Add LAM_U48 test cases in inherit scenarios. these cases should same
as LAM_U57;
Signed-off-by: Weihong Zhang <weihong.zhang@xxxxxxxxx>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
---
tools/testing/selftests/x86/lam.c | 67 ++++++++++++++++++++++++++++++-
1 file changed, 66 insertions(+), 1 deletion(-)
diff --git a/tools/testing/selftests/x86/lam.c b/tools/testing/selftests/x86/lam.c
index fcac5feb47d0..b354e57bf072 100644
--- a/tools/testing/selftests/x86/lam.c
+++ b/tools/testing/selftests/x86/lam.c
@@ -24,6 +24,7 @@
/* LAM modes, these definitions were copied from kernel code */
#define LAM_NONE 0
#define LAM_U57_BITS 6
+#define LAM_U48_BITS 15
/* arch prctl for LAM */
#define ARCH_GET_UNTAG_MASK 0x4001
#define ARCH_ENABLE_TAGGED_ADDR 0x4002
@@ -126,7 +127,7 @@ static int set_lam(unsigned long lam)
int ret = 0;
uint64_t ptr = 0;
- if (lam != LAM_U57_BITS && lam != LAM_NONE)
+ if (lam != LAM_U48_BITS && lam != LAM_U57_BITS && lam != LAM_NONE)
return -1;
/* Skip check return */
@@ -138,6 +139,8 @@ static int set_lam(unsigned long lam)
/* Check mask returned is expected */
if (lam == LAM_U57_BITS)
ret = (ptr != ~(0x3fULL << 57));
+ else if (lam == LAM_U48_BITS)
+ ret = (ptr != ~(0x7fffULL << 48));
else if (lam == LAM_NONE)
ret = (ptr != -1ULL);
@@ -161,6 +164,8 @@ static int get_lam(void)
ret = LAM_U57_BITS;
else if (ptr == -1ULL)
ret = LAM_NONE;
+ else if (ptr == ~(0x7fffULL << 48))
+ ret = LAM_U48_BITS;
return ret;
@@ -176,6 +181,9 @@ static uint64_t get_metadata(uint64_t src, unsigned long lam)
metadata = rand();
switch (lam) {
+ case LAM_U48_BITS: /* Set metadata in bits 62:48 */
+ metadata = (src & ~(0x7fffULL << 48)) | ((metadata & 0x7fff) << 48);
+ break;
case LAM_U57_BITS: /* Set metadata in bits 62:57 */
metadata = (src & ~(0x3fULL << 57)) | ((metadata & 0x3f) << 57);
break;
@@ -552,6 +560,9 @@ int do_uring(unsigned long lam)
uint64_t addr = ((uint64_t)fi->iovecs[i].iov_base);
switch (lam) {
+ case LAM_U48_BITS: /* Clear bits 62:48 */
+ addr = (addr & ~(0x7fffULL << 48));
+ break;
case LAM_U57_BITS: /* Clear bits 62:57 */
addr = (addr & ~(0x3fULL << 57));
break;
@@ -696,6 +707,12 @@ static struct testcases uring_cases[] = {
.test_func = handle_uring,
.msg = "URING: LAM_U57. Dereferencing pointer with metadata\n",
},
+ {
+ .later = 0,
+ .lam = LAM_U48_BITS,
+ .test_func = handle_uring,
+ .msg = "URING: LAM_U48. Dereferencing pointer with metadata.\n",
+ },
{
.later = 1,
.expected = 1,
@@ -712,6 +729,12 @@ static struct testcases malloc_cases[] = {
.test_func = handle_malloc,
.msg = "MALLOC: LAM_U57. Dereferencing pointer with metadata\n",
},
+ {
+ .later = 0,
+ .lam = LAM_U48_BITS,
+ .test_func = handle_malloc,
+ .msg = "MALLOC: LAM_U48. Dereferencing pointer with metadata.\n",
+ },
{
.later = 1,
.expected = 2,
@@ -728,6 +751,12 @@ static struct testcases syscall_cases[] = {
.test_func = handle_syscall,
.msg = "SYSCALL: LAM_U57. syscall with metadata\n",
},
+ {
+ .later = 0,
+ .lam = LAM_U48_BITS,
+ .test_func = handle_syscall,
+ .msg = "SYSCALL: LAM_U48. syscall with metadata\n",
+ },
{
.later = 1,
.expected = 1,
@@ -738,6 +767,14 @@ static struct testcases syscall_cases[] = {
};
static struct testcases mmap_cases[] = {
+ {
+ .later = 0,
+ .expected = 2,
+ .lam = LAM_U48_BITS,
+ .addr = HIGH_ADDR,
+ .test_func = handle_mmap,
+ .msg = "MMAP: [Negtive] First LAM_U48, then High address.\n",
+ },
{
.later = 1,
.expected = 0,
@@ -746,6 +783,14 @@ static struct testcases mmap_cases[] = {
.test_func = handle_mmap,
.msg = "MMAP: First mmap high address, then set LAM_U57.\n",
},
+ {
+ .later = 1,
+ .expected = 1,
+ .lam = LAM_U48_BITS,
+ .addr = HIGH_ADDR,
+ .test_func = handle_mmap,
+ .msg = "MMAP: [Negtive] First mmap high address, then set LAM_U48.\n",
+ },
{
.later = 0,
.expected = 0,
@@ -762,6 +807,14 @@ static struct testcases mmap_cases[] = {
.test_func = handle_mmap,
.msg = "MMAP: First LAM_U57, then Low address.\n",
},
+ {
+ .later = 0,
+ .expected = 0,
+ .lam = LAM_U48_BITS,
+ .addr = LOW_ADDR,
+ .test_func = handle_mmap,
+ .msg = "MMAP: First LAM_U48, then low address.\n",
+ },
};
static struct testcases inheritance_cases[] = {
@@ -771,12 +824,24 @@ static struct testcases inheritance_cases[] = {
.test_func = handle_inheritance,
.msg = "FORK: LAM_U57, child process should get LAM mode same as parent\n",
},
+ {
+ .expected = 0,
+ .lam = LAM_U48_BITS,
+ .test_func = handle_inheritance,
+ .msg = "FORK: LAM_U48, child process should get LAM mode same as parent\n",
+ },
{
.expected = 0,
.lam = LAM_U57_BITS,
.test_func = handle_execve,
.msg = "EXECVE: LAM_U57, child process should get disabled LAM mode\n",
},
+ {
+ .expected = 0,
+ .lam = LAM_U48_BITS,
+ .test_func = handle_execve,
+ .msg = "EXECVE: LAM_U48, child process should get disabled LAM mode\n",
+ },
};
static void cmd_help(void)
--
2.35.1