selftests/bpf: Fix SPEC_V1/V4 for other archs

Currently, SPEC_V1/V4 is not defined for architectures except x86/arm64
even though bpf_jit_bypass_spec_v1/v4 is usually false (the default)
there.

To avoid triggering tests failures on these other archs when adding the
missing SPEC_V1-ifdefs, set it there (and on all other archs) to put it
in sync with bpf_jit_bypass_spec_v1/v4.

For PowerPC, setting the value correctly is complicated because it
depends on the exact CPU and security config. Instead, skip unpriv tests
there.

Signed-off-by: Luis Gerhorst <[email protected]>

Author: luisgerhorst

tools/testing/selftests/bpf/progs/bpf_misc.h

@@ -258,11 +258,15 @@
 #define CAN_USE_LOAD_ACQ_STORE_REL
 #endif
 
-#if defined(__TARGET_ARCH_arm64) || defined(__TARGET_ARCH_x86)
+/* Add architectures that always set bpf_jit_bypass_spec_v1/v4 here. If the
+ * value is determined at runtime, it is best to skip unpriv tests by adding a
+ * case for your architecture in get_mitigations_off().
+ */
+#if !defined(__TARGET_ARCH_loongarch)
 #define SPEC_V1
 #endif
 
-#if defined(__TARGET_ARCH_x86)
+#if !defined(__TARGET_ARCH_arm64) && !defined(__TARGET_ARCH_loongarch)
 #define SPEC_V4
 #endif
 

tools/testing/selftests/bpf/unpriv_helpers.c

@@ -100,6 +100,12 @@ static bool cmdline_contains(const char *pat)
 
 static int get_mitigations_off(void)
 {
+#if defined(__TARGET_ARCH_powerpc)
+	/* Unknown, depends on return value of PowerPC's
+	 * bpf_jit_bypass_spec_v1/v4(). For simplicity, skip unpriv tests.
+	 */
+	return -1;
+#else
 	int enabled_in_config;
 
 	if (cmdline_contains("mitigations=off"))
@@ -108,6 +114,7 @@ static int get_mitigations_off(void)
 	if (enabled_in_config < 0)
 		return -1;
 	return !enabled_in_config;
+#endif
 }
 
 bool get_unpriv_disabled(void)