"Aneesh Kumar K.V" <aneesh.kumar@xxxxxxxxxxxxxxxxxx> writes:
> mmap(-1,..) is expected to search from max supported VA top down. It should find
> an address above ADDR_SWITCH_HINT. Explicitly check for this.
>
> Also derefer the address even if we failed the addr check.
>
> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
One issue I noticed is how to make this conditional so that we can still
run the test on x86 with 4 level page table?
> ---
> tools/testing/selftests/vm/va_128TBswitch.c | 27 ++++++++++++++++++++-------
> 1 file changed, 20 insertions(+), 7 deletions(-)
>
> diff --git a/tools/testing/selftests/vm/va_128TBswitch.c b/tools/testing/selftests/vm/va_128TBswitch.c
> index e7fe734c374f..f68fa4bd8179 100644
> --- a/tools/testing/selftests/vm/va_128TBswitch.c
> +++ b/tools/testing/selftests/vm/va_128TBswitch.c
> @@ -44,6 +44,7 @@ struct testcase {
> unsigned long flags;
> const char *msg;
> unsigned int low_addr_required:1;
> + unsigned int high_addr_required:1;
> unsigned int keep_mapped:1;
> };
>
> @@ -108,6 +109,7 @@ static struct testcase testcases[] = {
> .flags = MAP_PRIVATE | MAP_ANONYMOUS,
> .msg = "mmap(HIGH_ADDR)",
> .keep_mapped = 1,
> + .high_addr_required = 1,
> },
> {
> .addr = HIGH_ADDR,
> @@ -115,12 +117,14 @@ static struct testcase testcases[] = {
> .flags = MAP_PRIVATE | MAP_ANONYMOUS,
> .msg = "mmap(HIGH_ADDR) again",
> .keep_mapped = 1,
> + .high_addr_required = 1,
> },
> {
> .addr = HIGH_ADDR,
> .size = 2 * PAGE_SIZE,
> .flags = MAP_PRIVATE | MAP_ANONYMOUS | MAP_FIXED,
> .msg = "mmap(HIGH_ADDR, MAP_FIXED)",
> + .high_addr_required = 1,
> },
> {
> .addr = (void *) -1,
> @@ -128,12 +132,14 @@ static struct testcase testcases[] = {
> .flags = MAP_PRIVATE | MAP_ANONYMOUS,
> .msg = "mmap(-1)",
> .keep_mapped = 1,
> + .high_addr_required = 1,
> },
> {
> .addr = (void *) -1,
> .size = 2 * PAGE_SIZE,
> .flags = MAP_PRIVATE | MAP_ANONYMOUS,
> .msg = "mmap(-1) again",
> + .high_addr_required = 1,
> },
> {
> .addr = ((void *)(ADDR_SWITCH_HINT - PAGE_SIZE)),
> @@ -193,6 +199,7 @@ static struct testcase hugetlb_testcases[] = {
> .flags = MAP_HUGETLB | MAP_PRIVATE | MAP_ANONYMOUS,
> .msg = "mmap(HIGH_ADDR, MAP_HUGETLB)",
> .keep_mapped = 1,
> + .high_addr_required = 1,
> },
> {
> .addr = HIGH_ADDR,
> @@ -200,12 +207,14 @@ static struct testcase hugetlb_testcases[] = {
> .flags = MAP_HUGETLB | MAP_PRIVATE | MAP_ANONYMOUS,
> .msg = "mmap(HIGH_ADDR, MAP_HUGETLB) again",
> .keep_mapped = 1,
> + .high_addr_required = 1,
> },
> {
> .addr = HIGH_ADDR,
> .size = HUGETLB_SIZE,
> .flags = MAP_HUGETLB | MAP_PRIVATE | MAP_ANONYMOUS | MAP_FIXED,
> .msg = "mmap(HIGH_ADDR, MAP_FIXED | MAP_HUGETLB)",
> + .high_addr_required = 1,
> },
> {
> .addr = (void *) -1,
> @@ -213,12 +222,14 @@ static struct testcase hugetlb_testcases[] = {
> .flags = MAP_HUGETLB | MAP_PRIVATE | MAP_ANONYMOUS,
> .msg = "mmap(-1, MAP_HUGETLB)",
> .keep_mapped = 1,
> + .high_addr_required = 1,
> },
> {
> .addr = (void *) -1,
> .size = HUGETLB_SIZE,
> .flags = MAP_HUGETLB | MAP_PRIVATE | MAP_ANONYMOUS,
> .msg = "mmap(-1, MAP_HUGETLB) again",
> + .high_addr_required = 1,
> },
> {
> .addr = (void *)(ADDR_SWITCH_HINT - PAGE_SIZE),
> @@ -257,14 +268,16 @@ static int run_test(struct testcase *test, int count)
> if (t->low_addr_required && p >= (void *)(ADDR_SWITCH_HINT)) {
> printf("FAILED\n");
> ret = 1;
> - } else {
> - /*
> - * Do a dereference of the address returned so that we catch
> - * bugs in page fault handling
> - */
> - memset(p, 0, t->size);
> + } else if (t->high_addr_required && p < (void *)(ADDR_SWITCH_HINT)) {
> + printf("FAILED\n");
> + ret = 1;
> + } else
> printf("OK\n");
> - }
> + /*
> + * Do a dereference of the address returned so that we catch
> + * bugs in page fault handling
> + */
> + memset(p, 0, t->size);
> if (!t->keep_mapped)
> munmap(p, t->size);
> }
> --
> 2.14.3
>
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