1 files changed, 20 insertions, 26 deletions

diff --git a/arch/s390/net/bpf_jit_comp.c b/arch/s390/net/bpf_jit_comp.c
index b418333bb08635..5af0402e94b88c 100644
--- a/arch/s390/net/bpf_jit_comp.c
+++ b/arch/s390/net/bpf_jit_comp.c
@@ -516,11 +516,12 @@ static void bpf_skip(struct bpf_jit *jit, int size)
  * PLT for hotpatchable calls. The calling convention is the same as for the
  * ftrace hotpatch trampolines: %r0 is return address, %r1 is clobbered.
  */
-extern const char bpf_plt[];
-extern const char bpf_plt_ret[];
-extern const char bpf_plt_target[];
-extern const char bpf_plt_end[];
-#define BPF_PLT_SIZE 32
+struct bpf_plt {
+	char code[16];
+	void *ret;
+	void *target;
+} __packed;
+extern const struct bpf_plt bpf_plt;
 asm(
 	".pushsection .rodata\n"
 	"	.balign 8\n"
@@ -531,15 +532,14 @@ asm(
 	"	.balign 8\n"
 	"bpf_plt_ret: .quad 0\n"
 	"bpf_plt_target: .quad 0\n"
-	"bpf_plt_end:\n"
 	"	.popsection\n"
 );
 
-static void bpf_jit_plt(void *plt, void *ret, void *target)
+static void bpf_jit_plt(struct bpf_plt *plt, void *ret, void *target)
 {
-	memcpy(plt, bpf_plt, BPF_PLT_SIZE);
-	*(void **)((char *)plt + (bpf_plt_ret - bpf_plt)) = ret;
-	*(void **)((char *)plt + (bpf_plt_target - bpf_plt)) = target ?: ret;
+	memcpy(plt, &bpf_plt, sizeof(*plt));
+	plt->ret = ret;
+	plt->target = target;
 }
 
 /*
@@ -662,9 +662,9 @@ static void bpf_jit_epilogue(struct bpf_jit *jit, u32 stack_depth)
 	jit->prg = ALIGN(jit->prg, 8);
 	jit->prologue_plt = jit->prg;
 	if (jit->prg_buf)
-		bpf_jit_plt(jit->prg_buf + jit->prg,
+		bpf_jit_plt((struct bpf_plt *)(jit->prg_buf + jit->prg),
 			    jit->prg_buf + jit->prologue_plt_ret, NULL);
-	jit->prg += BPF_PLT_SIZE;
+	jit->prg += sizeof(struct bpf_plt);
 }
 
 static int get_probe_mem_regno(const u8 *insn)
@@ -2040,9 +2040,6 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *fp)
 	struct bpf_jit jit;
 	int pass;
 
-	if (WARN_ON_ONCE(bpf_plt_end - bpf_plt != BPF_PLT_SIZE))
-		return orig_fp;
-
 	if (!fp->jit_requested)
 		return orig_fp;
 
@@ -2148,14 +2145,11 @@ bool bpf_jit_supports_far_kfunc_call(void)
 int bpf_arch_text_poke(void *ip, enum bpf_text_poke_type t,
 		       void *old_addr, void *new_addr)
 {
+	struct bpf_plt expected_plt, current_plt, new_plt, *plt;
 	struct {
 		u16 opc;
 		s32 disp;
 	} __packed insn;
-	char expected_plt[BPF_PLT_SIZE];
-	char current_plt[BPF_PLT_SIZE];
-	char new_plt[BPF_PLT_SIZE];
-	char *plt;
 	char *ret;
 	int err;
 
@@ -2174,18 +2168,18 @@ int bpf_arch_text_poke(void *ip, enum bpf_text_poke_type t,
 		 */
 	} else {
 		/* Verify the PLT. */
-		plt = (char *)ip + (insn.disp << 1);
-		err = copy_from_kernel_nofault(current_plt, plt, BPF_PLT_SIZE);
+		plt = ip + (insn.disp << 1);
+		err = copy_from_kernel_nofault(&current_plt, plt,
+					       sizeof(current_plt));
 		if (err < 0)
 			return err;
 		ret = (char *)ip + 6;
-		bpf_jit_plt(expected_plt, ret, old_addr);
-		if (memcmp(current_plt, expected_plt, BPF_PLT_SIZE))
+		bpf_jit_plt(&expected_plt, ret, old_addr);
+		if (memcmp(&current_plt, &expected_plt, sizeof(current_plt)))
 			return -EINVAL;
 		/* Adjust the call address. */
-		bpf_jit_plt(new_plt, ret, new_addr);
-		s390_kernel_write(plt + (bpf_plt_target - bpf_plt),
-				  new_plt + (bpf_plt_target - bpf_plt),
+		bpf_jit_plt(&new_plt, ret, new_addr);
+		s390_kernel_write(&plt->target, &new_plt.target,
 				  sizeof(void *));
 	}