On 7/17/24 17:27, Ryan Roberts wrote:
On 17/07/2024 12:10, Dev Jain wrote:
Post my improvement of the test:
https://lore.kernel.org/all/[email protected]/
The test begins to fail on 4k and 16k pages, on non-LPA2 systems. To
reduce noise in the CI systems, let us skip the test when higher address
space is not implemented.
Signed-off-by: Dev Jain <[email protected]>
---
The patch applies on linux-next.
tools/testing/selftests/mm/va_high_addr_switch.c | 14 +++++++++++++-
1 file changed, 13 insertions(+), 1 deletion(-)
diff --git a/tools/testing/selftests/mm/va_high_addr_switch.c
b/tools/testing/selftests/mm/va_high_addr_switch.c
index fa7eabfaf841..c6040e1d6e53 100644
--- a/tools/testing/selftests/mm/va_high_addr_switch.c
+++ b/tools/testing/selftests/mm/va_high_addr_switch.c
@@ -293,6 +293,18 @@ static int run_test(struct testcase *test, int count)
return ret;
}
+/* Check if userspace VA > 48 bits */
+static int high_address_present(void)
+{
+ void *ptr = mmap((void *)(1UL << 50), 1, PROT_READ | PROT_WRITE,
+ MAP_PRIVATE | MAP_ANONYMOUS | MAP_FIXED, -1, 0);
I think there is (very unlikely) possibility that something is already mapped at
this address so it will be replaced due to MAP_FIXED. That could break the test.
But the only way something could be already mapped is if ARM64_FORCE_52BIT is
set and in that case, the test will fail anyway, right? So I think this is fine.
The testcases already assume that high addresses must be empty. Yes, FORCE_52BIT
is the only way something could already be mapped at high addresses, but in that
case the test fails trivially.
+ if (ptr == MAP_FAILED)
+ return 0;
+
+ munmap(ptr, 1);
+ return 1;
+}
I'm guessing this will cause a function-not-used warning on arches other than
arm64? Perhaps wrap it in `#ifdef __aarch64__`?
Ah yes, I just checked and that is true. I shall post v2 in some time, shall
wait if any more comments are there.
Thanks,
Ryan
+
static int supported_arch(void)
{
#if defined(__powerpc64__)
@@ -300,7 +312,7 @@ static int supported_arch(void)
#elif defined(__x86_64__)
return 1;
#elif defined(__aarch64__)
- return 1;
+ return high_address_present();
#else
return 0;
#endif
