[PATCH v18 21/24] selftests/vm/pkeys: Test correct behaviour of pkey-0
From: Sandipan Das <hidden>
Date: 2020-01-30 06:38:21
Also in:
linux-arch, linux-kselftest, linux-mm
Subsystem:
kernel selftest framework, the rest · Maintainers:
Shuah Khan, Linus Torvalds
From: Ram Pai <redacted> Ensure that pkey-0 is allocated on start and that it can be attached dynamically in various modes, without failures. cc: Dave Hansen <redacted> cc: Florian Weimer <redacted> Signed-off-by: Ram Pai <redacted> Signed-off-by: Sandipan Das <redacted> --- tools/testing/selftests/vm/protection_keys.c | 53 ++++++++++++++++++++ 1 file changed, 53 insertions(+)
diff --git a/tools/testing/selftests/vm/protection_keys.c b/tools/testing/selftests/vm/protection_keys.c
index d4952b57cc90..a1cb9a71e77c 100644
--- a/tools/testing/selftests/vm/protection_keys.c
+++ b/tools/testing/selftests/vm/protection_keys.c@@ -964,6 +964,58 @@ __attribute__((noinline)) int read_ptr(int *ptr) return *ptr; } +void test_pkey_alloc_free_attach_pkey0(int *ptr, u16 pkey) +{ + int i, err; + int max_nr_pkey_allocs; + int alloced_pkeys[NR_PKEYS]; + int nr_alloced = 0; + long size; + + pkey_assert(pkey_last_malloc_record); + size = pkey_last_malloc_record->size; + /* + * This is a bit of a hack. But mprotect() requires + * huge-page-aligned sizes when operating on hugetlbfs. + * So, make sure that we use something that's a multiple + * of a huge page when we can. + */ + if (size >= HPAGE_SIZE) + size = HPAGE_SIZE; + + /* allocate every possible key and make sure key-0 never got allocated */ + max_nr_pkey_allocs = NR_PKEYS; + for (i = 0; i < max_nr_pkey_allocs; i++) { + int new_pkey = alloc_pkey(); + pkey_assert(new_pkey != 0); + + if (new_pkey < 0) + break; + alloced_pkeys[nr_alloced++] = new_pkey; + } + /* free all the allocated keys */ + for (i = 0; i < nr_alloced; i++) { + int free_ret; + + if (!alloced_pkeys[i]) + continue; + free_ret = sys_pkey_free(alloced_pkeys[i]); + pkey_assert(!free_ret); + } + + /* attach key-0 in various modes */ + err = sys_mprotect_pkey(ptr, size, PROT_READ, 0); + pkey_assert(!err); + err = sys_mprotect_pkey(ptr, size, PROT_WRITE, 0); + pkey_assert(!err); + err = sys_mprotect_pkey(ptr, size, PROT_EXEC, 0); + pkey_assert(!err); + err = sys_mprotect_pkey(ptr, size, PROT_READ|PROT_WRITE, 0); + pkey_assert(!err); + err = sys_mprotect_pkey(ptr, size, PROT_READ|PROT_WRITE|PROT_EXEC, 0); + pkey_assert(!err); +} + void test_read_of_write_disabled_region(int *ptr, u16 pkey) { int ptr_contents;
@@ -1448,6 +1500,7 @@ void (*pkey_tests[])(int *ptr, u16 pkey) = { test_pkey_syscalls_on_non_allocated_pkey, test_pkey_syscalls_bad_args, test_pkey_alloc_exhaust, + test_pkey_alloc_free_attach_pkey0, }; void run_tests_once(void)
--
2.17.1