FAILED: patch "[PATCH] bpf, arm64: Use emit_addr_mov_i64() for BPF_PSEUDO_FUNC" failed to apply to 5.15-stable tree

The patch below does not apply to the 5.15-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From e4a41c2c1fa916547e63440c73a51a5eb06247af Mon Sep 17 00:00:00 2001
From: Hou Tao <[email protected]>
Date: Fri, 31 Dec 2021 23:10:18 +0800
Subject: [PATCH] bpf, arm64: Use emit_addr_mov_i64() for BPF_PSEUDO_FUNC

The following error is reported when running "./test_progs -t for_each" under arm64:

bpf_jit: multi-func JIT bug 58 != 56
[...]
JIT doesn't support bpf-to-bpf calls

The root cause is the size of BPF_PSEUDO_FUNC instruction increases from 2 to 3 after the address of called bpf-function is settled and there are two bpf-to-bpf calls in test_pkt_access. The generated instructions are shown below:

  0x48:  21 00 C0 D2    movz x1, #0x1, lsl #32
  0x4c:  21 00 80 F2    movk x1, #0x1

  0x48:  E1 3F C0 92    movn x1, #0x1ff, lsl #32
  0x4c:  41 FE A2 F2    movk x1, #0x17f2, lsl #16
  0x50:  81 70 9F F2    movk x1, #0xfb84

Fixing it by using emit_addr_mov_i64() for BPF_PSEUDO_FUNC, so the size of jited image will not change.

index 07aad85848fa..e96d4d87291f 100644
@@ -792,7 +792,10 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx,
 		u64 imm64;
 
 		imm64 = (u64)insn1.imm << 32 | (u32)imm;
-		emit_a64_mov_i64(dst, imm64, ctx);
+		if (bpf_pseudo_func(insn))
+			emit_addr_mov_i64(dst, imm64, ctx);
+		else
+			emit_a64_mov_i64(dst, imm64, ctx);
 
 		return 1;
 	}