selftests/powerpc: Remove powerpc special cases from stack expansion test

Now that the powerpc code behaves the same as other architectures we
can drop the special cases we had.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200724092528.1578671-5-mpe@ellerman.id.au

tools/testing/selftests/powerpc/mm/stack_expansion_ldst.c

@@ -56,13 +56,7 @@ int consume_stack(unsigned long target_sp, unsigned long stack_high, int delta,
 #else
 		asm volatile ("mov %%rsp, %[sp]" : [sp] "=r" (stack_top_sp));
 #endif
-
-		// Kludge, delta < 0 indicates relative to SP
-		if (delta < 0)
-			target = stack_top_sp + delta;
-		else
-			target = stack_high - delta + 1;
-
+		target = stack_high - delta + 1;
 		volatile char *p = (char *)target;
 
 		if (type == STORE)
@@ -162,41 +156,16 @@ static int test_one(unsigned int stack_used, int delta, enum access_type type)
 
 static void test_one_type(enum access_type type, unsigned long page_size, unsigned long rlim_cur)
 {
-	assert(test_one(DEFAULT_SIZE, 512 * _KB, type) == 0);
+	unsigned long delta;
 
-	// powerpc has a special case to allow up to 1MB
-	assert(test_one(DEFAULT_SIZE, 1 * _MB, type) == 0);
-
-#ifdef __powerpc__
-	// This fails on powerpc because it's > 1MB and is not a stdu &
-	// not close to r1
-	assert(test_one(DEFAULT_SIZE, 1 * _MB + 8, type) != 0);
-#else
-	assert(test_one(DEFAULT_SIZE, 1 * _MB + 8, type) == 0);
-#endif
-
-#ifdef __powerpc__
-	// Accessing way past the stack pointer is not allowed on powerpc
-	assert(test_one(DEFAULT_SIZE, rlim_cur, type) != 0);
-#else
 	// We should be able to access anywhere within the rlimit
+	for (delta = page_size; delta <= rlim_cur; delta += page_size)
+		assert(test_one(DEFAULT_SIZE, delta, type) == 0);
+
 	assert(test_one(DEFAULT_SIZE, rlim_cur, type) == 0);
-#endif
 
 	// But if we go past the rlimit it should fail
 	assert(test_one(DEFAULT_SIZE, rlim_cur + 1, type) != 0);
-
-	// Above 1MB powerpc only allows accesses within 4224 bytes of
-	// r1 for accesses that aren't stdu
-	assert(test_one(1 * _MB + page_size - 128, -4224, type) == 0);
-#ifdef __powerpc__
-	assert(test_one(1 * _MB + page_size - 128, -4225, type) != 0);
-#else
-	assert(test_one(1 * _MB + page_size - 128, -4225, type) == 0);
-#endif
-
-	// By consuming 2MB of stack we test the stdu case
-	assert(test_one(2 * _MB + page_size - 128, -4224, type) == 0);
 }
 
 static int test(void)