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Subject[PATCH v10 15/24] selftests/vm: powerpc implementation to check support for pkey
Date
pkey subsystem is supported if the hardware and kernel has support.
We determine that by checking if allocation of a key succeeds or not.

Signed-off-by: Ram Pai <linuxram@us.ibm.com>
---
tools/testing/selftests/vm/pkey-helpers.h | 22 ++++++++++++++++------
tools/testing/selftests/vm/protection_keys.c | 9 +++++----
2 files changed, 21 insertions(+), 10 deletions(-)

diff --git a/tools/testing/selftests/vm/pkey-helpers.h b/tools/testing/selftests/vm/pkey-helpers.h
index cfc1a18..3559527 100644
--- a/tools/testing/selftests/vm/pkey-helpers.h
+++ b/tools/testing/selftests/vm/pkey-helpers.h
@@ -261,7 +261,7 @@ static inline void __cpuid(unsigned int *eax, unsigned int *ebx,
#define X86_FEATURE_PKU (1<<3) /* Protection Keys for Userspace */
#define X86_FEATURE_OSPKE (1<<4) /* OS Protection Keys Enable */

-static inline int cpu_has_pku(void)
+static inline bool is_pkey_supported(void)
{
unsigned int eax;
unsigned int ebx;
@@ -274,13 +274,13 @@ static inline int cpu_has_pku(void)

if (!(ecx & X86_FEATURE_PKU)) {
dprintf2("cpu does not have PKU\n");
- return 0;
+ return false;
}
if (!(ecx & X86_FEATURE_OSPKE)) {
dprintf2("cpu does not have OSPKE\n");
- return 0;
+ return false;
}
- return 1;
+ return true;
}

#define XSTATE_PKEY_BIT (9)
@@ -326,9 +326,19 @@ static inline void __page_o_noops(void)
#elif __powerpc64__ /* arch */

#define PAGE_SIZE (0x1UL << 16)
-static inline int cpu_has_pku(void)
+static inline bool is_pkey_supported(void)
{
- return 1;
+ /*
+ * No simple way to determine this.
+ * lets try allocating a key and see if it succeeds.
+ */
+ int ret = sys_pkey_alloc(0, 0);
+
+ if (ret > 0) {
+ sys_pkey_free(ret);
+ return true;
+ }
+ return false;
}

/* 8-bytes of instruction * 16384bytes = 1 page */
diff --git a/tools/testing/selftests/vm/protection_keys.c b/tools/testing/selftests/vm/protection_keys.c
index d1cbdfe..65e6dd6 100644
--- a/tools/testing/selftests/vm/protection_keys.c
+++ b/tools/testing/selftests/vm/protection_keys.c
@@ -1299,8 +1299,8 @@ void test_mprotect_pkey_on_unsupported_cpu(int *ptr, u16 pkey)
int size = PAGE_SIZE;
int sret;

- if (cpu_has_pku()) {
- dprintf1("SKIP: %s: no CPU support\n", __func__);
+ if (is_pkey_supported()) {
+ dprintf1("SKIP: %s: no CPU/kernel support\n", __func__);
return;
}

@@ -1362,12 +1362,13 @@ void run_tests_once(void)
int main(void)
{
int nr_iterations = 22;
+ int pkey_supported = is_pkey_supported();

setup_handlers();

- printf("has pkey: %d\n", cpu_has_pku());
+ printf("has pkey: %s\n", pkey_supported ? "Yes" : "No");

- if (!cpu_has_pku()) {
+ if (!pkey_supported) {
int size = PAGE_SIZE;
int *ptr;

--
1.7.1
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