Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf

Alexei Starovoitov says:

====================
pull-request: bpf 2020-04-24

The following pull-request contains BPF updates for your *net* tree.

We've added 17 non-merge commits during the last 5 day(s) which contain
a total of 19 files changed, 203 insertions(+), 85 deletions(-).

The main changes are:

1) link_update fix, from Andrii.

2) libbpf get_xdp_id fix, from David.

3) xadd verifier fix, from Jann.

4) x86-32 JIT fixes, from Luke and Wang.

5) test_btf fix, from Stanislav.

6) freplace verifier fix, from Toke.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 15 insertions, 3 deletions

diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c
index 5ea7c2cf7ab4..42b6709e6dc7 100644
--- a/arch/x86/net/bpf_jit_comp.c
+++ b/arch/x86/net/bpf_jit_comp.c
@@ -158,6 +158,19 @@ static bool is_ereg(u32 reg)
 			     BIT(BPF_REG_AX));
 }
 
+/*
+ * is_ereg_8l() == true if BPF register 'reg' is mapped to access x86-64
+ * lower 8-bit registers dil,sil,bpl,spl,r8b..r15b, which need extra byte
+ * of encoding. al,cl,dl,bl have simpler encoding.
+ */
+static bool is_ereg_8l(u32 reg)
+{
+	return is_ereg(reg) ||
+	    (1 << reg) & (BIT(BPF_REG_1) |
+			  BIT(BPF_REG_2) |
+			  BIT(BPF_REG_FP));
+}
+
 static bool is_axreg(u32 reg)
 {
 	return reg == BPF_REG_0;
@@ -598,9 +611,8 @@ static void emit_stx(u8 **pprog, u32 size, u32 dst_reg, u32 src_reg, int off)
 	switch (size) {
 	case BPF_B:
 		/* Emit 'mov byte ptr [rax + off], al' */
-		if (is_ereg(dst_reg) || is_ereg(src_reg) ||
-		    /* We have to add extra byte for x86 SIL, DIL regs */
-		    src_reg == BPF_REG_1 || src_reg == BPF_REG_2)
+		if (is_ereg(dst_reg) || is_ereg_8l(src_reg))
+			/* Add extra byte for eregs or SIL,DIL,BPL in src_reg */
 			EMIT2(add_2mod(0x40, dst_reg, src_reg), 0x88);
 		else
 			EMIT1(0x88);