The Power ISA mandates that all writes to the Authority Mask Register (AMR) must always be preceded as well as succeeded by a context synchronizing instruction.
This makes sure that the tests follow this requirement when attempting to update a pkey's access rights.
Signed-off-by: Sandipan Das sandipan@linux.ibm.com --- tools/testing/selftests/powerpc/include/reg.h | 6 ++++++ tools/testing/selftests/powerpc/ptrace/core-pkey.c | 2 +- tools/testing/selftests/powerpc/ptrace/ptrace-pkey.c | 2 +- 3 files changed, 8 insertions(+), 2 deletions(-)
diff --git a/tools/testing/selftests/powerpc/include/reg.h b/tools/testing/selftests/powerpc/include/reg.h index 022c5076b2c5..c0f2742a3a59 100644 --- a/tools/testing/selftests/powerpc/include/reg.h +++ b/tools/testing/selftests/powerpc/include/reg.h @@ -57,6 +57,12 @@ #define SPRN_PPR 896 /* Program Priority Register */ #define SPRN_AMR 13 /* Authority Mask Register - problem state */
+#define set_amr(v) asm volatile("isync;" \ + "mtspr " __stringify(SPRN_AMR) ",%0;" \ + "isync" : \ + : "r" ((unsigned long)(v)) \ + : "memory") + /* TEXASR register bits */ #define TEXASR_FC 0xFE00000000000000 #define TEXASR_FP 0x0100000000000000 diff --git a/tools/testing/selftests/powerpc/ptrace/core-pkey.c b/tools/testing/selftests/powerpc/ptrace/core-pkey.c index d5c64fee032d..bbc05ffc5860 100644 --- a/tools/testing/selftests/powerpc/ptrace/core-pkey.c +++ b/tools/testing/selftests/powerpc/ptrace/core-pkey.c @@ -150,7 +150,7 @@ static int child(struct shared_info *info) printf("%-30s AMR: %016lx pkey1: %d pkey2: %d pkey3: %d\n", user_write, info->amr, pkey1, pkey2, pkey3);
- mtspr(SPRN_AMR, info->amr); + set_amr(info->amr);
/* * We won't use pkey3. This tests whether the kernel restores the UAMOR diff --git a/tools/testing/selftests/powerpc/ptrace/ptrace-pkey.c b/tools/testing/selftests/powerpc/ptrace/ptrace-pkey.c index bdbbbe8431e0..904c04f8c919 100644 --- a/tools/testing/selftests/powerpc/ptrace/ptrace-pkey.c +++ b/tools/testing/selftests/powerpc/ptrace/ptrace-pkey.c @@ -126,7 +126,7 @@ static int child(struct shared_info *info) printf("%-30s AMR: %016lx pkey1: %d pkey2: %d pkey3: %d\n", user_write, info->amr1, pkey1, pkey2, pkey3);
- mtspr(SPRN_AMR, info->amr1); + set_amr(info->amr1);
/* Wait for parent to read our AMR value and write a new one. */ ret = prod_parent(&info->child_sync);