selftests/powerpc: ptrace-pkey: Update the test to mark an invalid pkey correctly

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200709032946.881753-22-aneesh.kumar@linux.ibm.com

diff --git a/tools/testing/selftests/powerpc/ptrace/ptrace-pkey.c b/tools/testing/selftests/powerpc/ptrace/ptrace-pkey.c
index a32a8034f95657314b9a2571070a336b94334219..80dc5085a412dfd15af8333e2d6563cdf203dd3f 100644 (file)
--- a/tools/testing/selftests/powerpc/ptrace/ptrace-pkey.c
+++ b/tools/testing/selftests/powerpc/ptrace/ptrace-pkey.c
@@ -66,11 +66,6 @@ static int sys_pkey_alloc(unsigned long flags, unsigned long init_access_rights)
        return syscall(__NR_pkey_alloc, flags, init_access_rights);
 }
 
-static int sys_pkey_free(int pkey)
-{
-       return syscall(__NR_pkey_free, pkey);
-}
-
 static int child(struct shared_info *info)
 {
        unsigned long reg;
@@ -100,7 +95,11 @@ static int child(struct shared_info *info)
 
        info->amr1 |= 3ul << pkeyshift(pkey1);
        info->amr2 |= 3ul << pkeyshift(pkey2);
-       info->invalid_amr |= info->amr2 | 3ul << pkeyshift(pkey3);
+       /*
+        * invalid amr value where we try to force write
+        * things which are deined by a uamor setting.
+        */
+       info->invalid_amr = info->amr2 | (~0x0UL & ~info->expected_uamor);
 
        if (disable_execute)
                info->expected_iamr |= 1ul << pkeyshift(pkey1);
@@ -111,17 +110,12 @@ static int child(struct shared_info *info)
 
        info->expected_uamor |= 3ul << pkeyshift(pkey1) |
                                3ul << pkeyshift(pkey2);
-       info->invalid_iamr |= 1ul << pkeyshift(pkey1) | 1ul << pkeyshift(pkey2);
-       info->invalid_uamor |= 3ul << pkeyshift(pkey1);
-
        /*
-        * We won't use pkey3. We just want a plausible but invalid key to test
-        * whether ptrace will let us write to AMR bits we are not supposed to.
-        *
-        * This also tests whether the kernel restores the UAMOR permissions
-        * after a key is freed.
+        * Create an IAMR value different from expected value.
+        * Kernel will reject an IAMR and UAMOR change.
         */
-       sys_pkey_free(pkey3);
+       info->invalid_iamr = info->expected_iamr | (1ul << pkeyshift(pkey1) | 1ul << pkeyshift(pkey2));
+       info->invalid_uamor = info->expected_uamor & ~(0x3ul << pkeyshift(pkey1));
 
        printf("%-30s AMR: %016lx pkey1: %d pkey2: %d pkey3: %d\n",
               user_write, info->amr1, pkey1, pkey2, pkey3);
@@ -196,9 +190,9 @@ static int parent(struct shared_info *info, pid_t pid)
        PARENT_SKIP_IF_UNSUPPORTED(ret, &info->child_sync);
        PARENT_FAIL_IF(ret, &info->child_sync);
 
-       info->amr1 = info->amr2 = info->invalid_amr = regs[0];
-       info->expected_iamr = info->invalid_iamr = regs[1];
-       info->expected_uamor = info->invalid_uamor = regs[2];
+       info->amr1 = info->amr2 = regs[0];
+       info->expected_iamr = regs[1];
+       info->expected_uamor = regs[2];
 
        /* Wake up child so that it can set itself up. */
        ret = prod_child(&info->child_sync);