On 2/27/24 13:59, Kevin Brodsky wrote:
On 23/02/2024 12:07, Chaitanya S Prakash wrote:
From: Amit Daniel Kachhap amit.kachhap@arm.com
Morello uses a compressed capability format which makes it difficult to represent bounds with arbitrary precision. As the corresponding address range of a given memory mapping may not be exactly representable as valid capability bounds, a test to verify that the PCuABI kernel is able to mmap/munmap those addresses has been added.
Signed-off-by: Amit Daniel Kachhap amit.kachhap@arm.com Signed-off-by: Chaitanya S Prakash ChaitanyaS.Prakash@arm.com
Assuming you wrote / modified part of this patch, you should add your Co-developed-by, above your Signed-off-by.
tools/testing/selftests/arm64/morello/mmap.c | 45 ++++++++++++++++++++ 1 file changed, 45 insertions(+)
diff --git a/tools/testing/selftests/arm64/morello/mmap.c b/tools/testing/selftests/arm64/morello/mmap.c index 8dc4e1dedef3..936e64fe8708 100644 --- a/tools/testing/selftests/arm64/morello/mmap.c +++ b/tools/testing/selftests/arm64/morello/mmap.c @@ -563,6 +563,50 @@ TEST(test_brk_check) EXPECT_EQ(retval, -ENOSYS); } +/* test to verify the CHERI unrepresentable address/length */ +TEST(test_cheri_unrepresentability) +{
- void *ptr1, *ptr2;
- int retval;
- int count = 0;
- int prot = PROT_READ | PROT_WRITE;
- int flags = MAP_PRIVATE | MAP_ANONYMOUS;
- size_t len, representable_base;
- /* Use pageshift 16 for 64K pages so as to use as mmap fixed address */
- unsigned long pageshift = 16;
- /* Generate an unrepresentable length/address */
- do {
len = (1 << (pageshift++)) + ((count++ % pagesize) * pagesize);Is there a particular rationale for the added multiplier (count++ % pagesize)? Does that yield an unrepresentable length faster?
Kevin
It was done to randomize the generation of the unrepresentable length/address.
- } while (len == cheri_representable_length(len));
- /* Create a memory mapping with reserved memory at the end */
- ptr1 = mmap(NULL, len, prot, flags, -1, 0);
- ASSERT_FALSE(IS_ERR_VALUE(ptr1));
- EXPECT_EQ(1, cheri_tag_get(ptr1));
- EXPECT_EQ(cheri_length_get(ptr1), cheri_representable_length(len));
- representable_base = (cheri_address_get(ptr1) & cheri_representable_alignment_mask(len));
- EXPECT_EQ(representable_base, cheri_base_get(ptr1));
- EXPECT_EQ(0, probe_mem_range(ptr1, len, PROBE_MODE_TOUCH | PROBE_MODE_VERIFY));
- /* Create a memory mapping with reserved memory at the front */
- ptr2 = mmap((void *)(uintcap_t)len, len, prot, flags, -1, 0);
- ASSERT_FALSE(IS_ERR_VALUE(ptr2));
- EXPECT_EQ(1, cheri_tag_get(ptr2));
- EXPECT_EQ(cheri_length_get(ptr2), cheri_representable_length(len));
- representable_base = (cheri_address_get(ptr2) & cheri_representable_alignment_mask(len));
- EXPECT_EQ(representable_base, cheri_base_get(ptr2));
- ASSERT_EQ(len, cheri_address_get(ptr2));
- EXPECT_EQ(0, probe_mem_range(ptr2, len, PROBE_MODE_TOUCH | PROBE_MODE_VERIFY));
- retval = munmap(ptr1, len);
- ASSERT_EQ(retval, 0);
- retval = munmap(ptr2, len);
- ASSERT_EQ(retval, 0);
+}
- int main(int argc __maybe_unused, char **argv __maybe_unused, char **envp __maybe_unused, struct morello_auxv *auxv) {
@@ -577,5 +621,6 @@ int main(int argc __maybe_unused, char **argv __maybe_unused, char **envp __mayb test_check_mremap_reservation(); test_permissions(); test_brk_check();
- test_cheri_unrepresentability(); return 0; }