selftests/bpf: Add big-endian support to the ldsx test

Prepare the ldsx test to run on big-endian systems by adding the
necessary endianness checks around narrow memory accesses.
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Link: https://lore.kernel.org/r/20230919101336.2223655-4-iii@linux.ibm.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

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

@@ -104,7 +104,11 @@ int _tc(volatile struct __sk_buff *skb)
 		      "%[tmp_mark] = r1"
 		      : [tmp_mark]"=r"(tmp_mark)
 		      : [ctx]"r"(skb),
-			[off_mark]"i"(offsetof(struct __sk_buff, mark))
+			[off_mark]"i"(offsetof(struct __sk_buff, mark)
+#if __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
+			+ sizeof(skb->mark) - 1
+#endif
+			)
 		      : "r1");
 #else
 	tmp_mark = (char)skb->mark;

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

@@ -13,12 +13,16 @@ __description("LDSX, S8")
 __success __success_unpriv __retval(-2)
 __naked void ldsx_s8(void)
 {
-	asm volatile ("					\
-	r1 = 0x3fe;					\
-	*(u64 *)(r10 - 8) = r1;				\
-	r0 = *(s8 *)(r10 - 8);				\
-	exit;						\
-"	::: __clobber_all);
+	asm volatile (
+	"r1 = 0x3fe;"
+	"*(u64 *)(r10 - 8) = r1;"
+#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+	"r0 = *(s8 *)(r10 - 8);"
+#else
+	"r0 = *(s8 *)(r10 - 1);"
+#endif
+	"exit;"
+	::: __clobber_all);
 }
 
 SEC("socket")
@@ -26,12 +30,16 @@ __description("LDSX, S16")
 __success __success_unpriv __retval(-2)
 __naked void ldsx_s16(void)
 {
-	asm volatile ("					\
-	r1 = 0x3fffe;					\
-	*(u64 *)(r10 - 8) = r1;				\
-	r0 = *(s16 *)(r10 - 8);				\
-	exit;						\
-"	::: __clobber_all);
+	asm volatile (
+	"r1 = 0x3fffe;"
+	"*(u64 *)(r10 - 8) = r1;"
+#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+	"r0 = *(s16 *)(r10 - 8);"
+#else
+	"r0 = *(s16 *)(r10 - 2);"
+#endif
+	"exit;"
+	::: __clobber_all);
 }
 
 SEC("socket")
@@ -39,13 +47,17 @@ __description("LDSX, S32")
 __success __success_unpriv __retval(-1)
 __naked void ldsx_s32(void)
 {
-	asm volatile ("					\
-	r1 = 0xfffffffe;				\
-	*(u64 *)(r10 - 8) = r1;				\
-	r0 = *(s32 *)(r10 - 8);				\
-	r0 >>= 1;					\
-	exit;						\
-"	::: __clobber_all);
+	asm volatile (
+	"r1 = 0xfffffffe;"
+	"*(u64 *)(r10 - 8) = r1;"
+#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+	"r0 = *(s32 *)(r10 - 8);"
+#else
+	"r0 = *(s32 *)(r10 - 4);"
+#endif
+	"r0 >>= 1;"
+	"exit;"
+	::: __clobber_all);
 }
 
 SEC("socket")
@@ -54,20 +66,24 @@ __log_level(2) __success __retval(1)
 __msg("R1_w=scalar(smin=-128,smax=127)")
 __naked void ldsx_s8_range_priv(void)
 {
-	asm volatile ("					\
-	call %[bpf_get_prandom_u32];			\
-	*(u64 *)(r10 - 8) = r0;				\
-	r1 = *(s8 *)(r10 - 8);				\
-	/* r1 with s8 range */				\
-	if r1 s> 0x7f goto l0_%=;			\
-	if r1 s< -0x80 goto l0_%=;			\
-	r0 = 1;						\
-l1_%=:							\
-	exit;						\
-l0_%=:							\
-	r0 = 2;						\
-	goto l1_%=;					\
-"	:
+	asm volatile (
+	"call %[bpf_get_prandom_u32];"
+	"*(u64 *)(r10 - 8) = r0;"
+#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+	"r1 = *(s8 *)(r10 - 8);"
+#else
+	"r1 = *(s8 *)(r10 - 1);"
+#endif
+	/* r1 with s8 range */
+	"if r1 s> 0x7f goto l0_%=;"
+	"if r1 s< -0x80 goto l0_%=;"
+	"r0 = 1;"
+"l1_%=:"
+	"exit;"
+"l0_%=:"
+	"r0 = 2;"
+	"goto l1_%=;"
+	:
 	: __imm(bpf_get_prandom_u32)
 	: __clobber_all);
 }
@@ -77,20 +93,24 @@ __description("LDSX, S16 range checking")
 __success __success_unpriv __retval(1)
 __naked void ldsx_s16_range(void)
 {
-	asm volatile ("					\
-	call %[bpf_get_prandom_u32];			\
-	*(u64 *)(r10 - 8) = r0;				\
-	r1 = *(s16 *)(r10 - 8);				\
-	/* r1 with s16 range */				\
-	if r1 s> 0x7fff goto l0_%=;			\
-	if r1 s< -0x8000 goto l0_%=;			\
-	r0 = 1;						\
-l1_%=:							\
-	exit;						\
-l0_%=:							\
-	r0 = 2;						\
-	goto l1_%=;					\
-"	:
+	asm volatile (
+	"call %[bpf_get_prandom_u32];"
+	"*(u64 *)(r10 - 8) = r0;"
+#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+	"r1 = *(s16 *)(r10 - 8);"
+#else
+	"r1 = *(s16 *)(r10 - 2);"
+#endif
+	/* r1 with s16 range */
+	"if r1 s> 0x7fff goto l0_%=;"
+	"if r1 s< -0x8000 goto l0_%=;"
+	"r0 = 1;"
+"l1_%=:"
+	"exit;"
+"l0_%=:"
+	"r0 = 2;"
+	"goto l1_%=;"
+	:
 	: __imm(bpf_get_prandom_u32)
 	: __clobber_all);
 }
@@ -100,20 +120,24 @@ __description("LDSX, S32 range checking")
 __success __success_unpriv __retval(1)
 __naked void ldsx_s32_range(void)
 {
-	asm volatile ("					\
-	call %[bpf_get_prandom_u32];			\
-	*(u64 *)(r10 - 8) = r0;				\
-	r1 = *(s32 *)(r10 - 8);				\
-	/* r1 with s16 range */				\
-	if r1 s> 0x7fffFFFF goto l0_%=;			\
-	if r1 s< -0x80000000 goto l0_%=;		\
-	r0 = 1;						\
-l1_%=:							\
-	exit;						\
-l0_%=:							\
-	r0 = 2;						\
-	goto l1_%=;					\
-"	:
+	asm volatile (
+	"call %[bpf_get_prandom_u32];"
+	"*(u64 *)(r10 - 8) = r0;"
+#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+	"r1 = *(s32 *)(r10 - 8);"
+#else
+	"r1 = *(s32 *)(r10 - 4);"
+#endif
+	/* r1 with s16 range */
+	"if r1 s> 0x7fffFFFF goto l0_%=;"
+	"if r1 s< -0x80000000 goto l0_%=;"
+	"r0 = 1;"
+"l1_%=:"
+	"exit;"
+"l0_%=:"
+	"r0 = 2;"
+	"goto l1_%=;"
+	:
 	: __imm(bpf_get_prandom_u32)
 	: __clobber_all);
 }