On 17/07/2024 13:11, Dev Jain wrote: > > 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/20240522070435.773918-3-dev.jain@xxxxxxx/ >>> 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 <dev.jain@xxxxxxx> >>> --- >>> 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. agreed. > >> >>> + 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. With this fixup: Reviewed-by: Ryan Roberts <ryan.roberts@xxxxxxx> > >> >> 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
