Hi Michael,
On 26/05/20 6:05 pm, Michael Ellerman wrote:
[...]
+/* Override definitions as they might be inconsistent */ +#undef PKEY_DISABLE_ACCESS +#define PKEY_DISABLE_ACCESS 0x3
Why would they be inconsistent?
The definition in sys/mman.h still uses the value specific to Intel's implementation i.e. 1, when this should have been 3 for powerpc. I have seen this on Ubuntu 18.04 and 20.04.
+/* Older distros might not define this */ +#ifndef SEGV_PKUERR +#define SEGV_PKUERR 4 +#endif
...
- /* Restore permissions in order to continue */
- switch (fcode) {
- case SEGV_ACCERR:
if (mprotect(insns, pgsize, PROT_READ | PROT_WRITE)) {perror("mprotect");goto fail;}break;- case SEGV_PKUERR:
if (sinfo->si_pkey != fpkey)goto fail;This doesn't compile on older distros, eg Ubuntu 16.04:
pkey_exec_prot.c: In function 'segv_handler': pkey_exec_prot.c:121:12: error: 'siginfo_t {aka struct <anonymous>}' has no member named 'si_pkey' if (sinfo->si_pkey != fpkey) ^ pkey_exec_prot.c:151:24: error: 'siginfo_t {aka struct <anonymous>}' has no member named 'si_pkey' pkey_set_rights(sinfo->si_pkey, 0); ^ ../../lib.mk:142: recipe for target '/output/kselftest/powerpc/mm/pkey_exec_prot' failed
Thanks for reporting this.
I think a reasonable solution is to use the absence of SEGV_PKUERR to basically turn the whole test into a nop at build time, eg:
diff --git a/tools/testing/selftests/powerpc/mm/pkey_exec_prot.c b/tools/testing/selftests/powerpc/mm/pkey_exec_prot.c index b346ad205e68..218257b89fbb 100644 --- a/tools/testing/selftests/powerpc/mm/pkey_exec_prot.c +++ b/tools/testing/selftests/powerpc/mm/pkey_exec_prot.c @@ -30,9 +30,7 @@ #define PKEY_DISABLE_EXECUTE 0x4
/* Older distros might not define this */ -#ifndef SEGV_PKUERR -#define SEGV_PKUERR 4 -#endif +#ifdef SEGV_PKUERR
#define SYS_pkey_mprotect 386 #define SYS_pkey_alloc 384 @@ -319,6 +317,13 @@ static int test(void)
return 0;} +#else +static int test(void) +{
printf("Test built with old libc lacking pkey support.\n");SKIP_IF(true);+} +#endif /* SEGV_PKUERR */
int main(void) {
Or can I use this from the pkey tests under selftests/vm?
static inline u32 *siginfo_get_pkey_ptr(siginfo_t *si) { #ifdef si_pkey return &si->si_pkey; #else return (u32 *)(((u8 *)si) + si_pkey_offset); #endif }
Where si_pkey_offset is 0x20 for powerpc.
- Sandipan