selftests/bpf: Avoid passing out-of-range values to __retval()

Currently, we pass 0x1234567890abcdef to __retval() for the following
two tests:

  verifier_load_acquire/load_acquire_64
  verifier_store_release/store_release_64

However, the upper 32 bits of that value are being ignored, since
__retval() expects an int.  Actually, the tests would still pass even if
I change '__retval(0x1234567890abcdef)' to e.g. '__retval(0x90abcdef)'.

Restructure the tests a bit to test the entire 64-bit values properly.
Do the same to their 8-, 16- and 32-bit variants as well to keep the
style consistent.

Fixes: ff3afe5 ("selftests/bpf: Add selftests for load-acquire and store-release instructions")
Signed-off-by: Peilin Ye <[email protected]>

Author: peilin-ye

tools/testing/selftests/bpf/progs/verifier_load_acquire.c

@@ -10,65 +10,81 @@
 
 SEC("socket")
 __description("load-acquire, 8-bit")
-__success __success_unpriv __retval(0x12)
+__success __success_unpriv __retval(0)
 __naked void load_acquire_8(void)
 {
 	asm volatile (
+	"r0 = 0;"
 	"w1 = 0x12;"
 	"*(u8 *)(r10 - 1) = w1;"
-	".8byte %[load_acquire_insn];" // w0 = load_acquire((u8 *)(r10 - 1));
+	".8byte %[load_acquire_insn];" // w2 = load_acquire((u8 *)(r10 - 1));
+	"if r2 == r1 goto 1f;"
+	"r0 = 1;"
+"1:"
 	"exit;"
 	:
 	: __imm_insn(load_acquire_insn,
-		     BPF_ATOMIC_OP(BPF_B, BPF_LOAD_ACQ, BPF_REG_0, BPF_REG_10, -1))
+		     BPF_ATOMIC_OP(BPF_B, BPF_LOAD_ACQ, BPF_REG_2, BPF_REG_10, -1))
 	: __clobber_all);
 }
 
 SEC("socket")
 __description("load-acquire, 16-bit")
-__success __success_unpriv __retval(0x1234)
+__success __success_unpriv __retval(0)
 __naked void load_acquire_16(void)
 {
 	asm volatile (
+	"r0 = 0;"
 	"w1 = 0x1234;"
 	"*(u16 *)(r10 - 2) = w1;"
-	".8byte %[load_acquire_insn];" // w0 = load_acquire((u16 *)(r10 - 2));
+	".8byte %[load_acquire_insn];" // w2 = load_acquire((u16 *)(r10 - 2));
+	"if r2 == r1 goto 1f;"
+	"r0 = 1;"
+"1:"
 	"exit;"
 	:
 	: __imm_insn(load_acquire_insn,
-		     BPF_ATOMIC_OP(BPF_H, BPF_LOAD_ACQ, BPF_REG_0, BPF_REG_10, -2))
+		     BPF_ATOMIC_OP(BPF_H, BPF_LOAD_ACQ, BPF_REG_2, BPF_REG_10, -2))
 	: __clobber_all);
 }
 
 SEC("socket")
 __description("load-acquire, 32-bit")
-__success __success_unpriv __retval(0x12345678)
+__success __success_unpriv __retval(0)
 __naked void load_acquire_32(void)
 {
 	asm volatile (
+	"r0 = 0;"
 	"w1 = 0x12345678;"
 	"*(u32 *)(r10 - 4) = w1;"
-	".8byte %[load_acquire_insn];" // w0 = load_acquire((u32 *)(r10 - 4));
+	".8byte %[load_acquire_insn];" // w2 = load_acquire((u32 *)(r10 - 4));
+	"if r2 == r1 goto 1f;"
+	"r0 = 1;"
+"1:"
 	"exit;"
 	:
 	: __imm_insn(load_acquire_insn,
-		     BPF_ATOMIC_OP(BPF_W, BPF_LOAD_ACQ, BPF_REG_0, BPF_REG_10, -4))
+		     BPF_ATOMIC_OP(BPF_W, BPF_LOAD_ACQ, BPF_REG_2, BPF_REG_10, -4))
 	: __clobber_all);
 }
 
 SEC("socket")
 __description("load-acquire, 64-bit")
-__success __success_unpriv __retval(0x1234567890abcdef)
+__success __success_unpriv __retval(0)
 __naked void load_acquire_64(void)
 {
 	asm volatile (
+	"r0 = 0;"
 	"r1 = 0x1234567890abcdef ll;"
 	"*(u64 *)(r10 - 8) = r1;"
-	".8byte %[load_acquire_insn];" // r0 = load_acquire((u64 *)(r10 - 8));
+	".8byte %[load_acquire_insn];" // r2 = load_acquire((u64 *)(r10 - 8));
+	"if r2 == r1 goto 1f;"
+	"r0 = 1;"
+"1:"
 	"exit;"
 	:
 	: __imm_insn(load_acquire_insn,
-		     BPF_ATOMIC_OP(BPF_DW, BPF_LOAD_ACQ, BPF_REG_0, BPF_REG_10, -8))
+		     BPF_ATOMIC_OP(BPF_DW, BPF_LOAD_ACQ, BPF_REG_2, BPF_REG_10, -8))
 	: __clobber_all);
 }
 

tools/testing/selftests/bpf/progs/verifier_store_release.c

@@ -10,13 +10,17 @@
 
 SEC("socket")
 __description("store-release, 8-bit")
-__success __success_unpriv __retval(0x12)
+__success __success_unpriv __retval(0)
 __naked void store_release_8(void)
 {
 	asm volatile (
+	"r0 = 0;"
 	"w1 = 0x12;"
 	".8byte %[store_release_insn];" // store_release((u8 *)(r10 - 1), w1);
-	"w0 = *(u8 *)(r10 - 1);"
+	"w2 = *(u8 *)(r10 - 1);"
+	"if r2 == r1 goto 1f;"
+	"r0 = 1;"
+"1:"
 	"exit;"
 	:
 	: __imm_insn(store_release_insn,
@@ -26,13 +30,17 @@ __naked void store_release_8(void)
 
 SEC("socket")
 __description("store-release, 16-bit")
-__success __success_unpriv __retval(0x1234)
+__success __success_unpriv __retval(0)
 __naked void store_release_16(void)
 {
 	asm volatile (
+	"r0 = 0;"
 	"w1 = 0x1234;"
 	".8byte %[store_release_insn];" // store_release((u16 *)(r10 - 2), w1);
-	"w0 = *(u16 *)(r10 - 2);"
+	"w2 = *(u16 *)(r10 - 2);"
+	"if r2 == r1 goto 1f;"
+	"r0 = 1;"
+"1:"
 	"exit;"
 	:
 	: __imm_insn(store_release_insn,
@@ -42,13 +50,17 @@ __naked void store_release_16(void)
 
 SEC("socket")
 __description("store-release, 32-bit")
-__success __success_unpriv __retval(0x12345678)
+__success __success_unpriv __retval(0)
 __naked void store_release_32(void)
 {
 	asm volatile (
+	"r0 = 0;"
 	"w1 = 0x12345678;"
 	".8byte %[store_release_insn];" // store_release((u32 *)(r10 - 4), w1);
-	"w0 = *(u32 *)(r10 - 4);"
+	"w2 = *(u32 *)(r10 - 4);"
+	"if r2 == r1 goto 1f;"
+	"r0 = 1;"
+"1:"
 	"exit;"
 	:
 	: __imm_insn(store_release_insn,
@@ -58,13 +70,17 @@ __naked void store_release_32(void)
 
 SEC("socket")
 __description("store-release, 64-bit")
-__success __success_unpriv __retval(0x1234567890abcdef)
+__success __success_unpriv __retval(0)
 __naked void store_release_64(void)
 {
 	asm volatile (
+	"r0 = 0;"
 	"r1 = 0x1234567890abcdef ll;"
 	".8byte %[store_release_insn];" // store_release((u64 *)(r10 - 8), r1);
-	"r0 = *(u64 *)(r10 - 8);"
+	"r2 = *(u64 *)(r10 - 8);"
+	"if r2 == r1 goto 1f;"
+	"r0 = 1;"
+"1:"
 	"exit;"
 	:
 	: __imm_insn(store_release_insn,