There's currently only one usage of this but implementation of
atomic_sub add another.
Signed-off-by: Brendan Jackman <jackmanb@xxxxxxxxxx>
---
arch/x86/net/bpf_jit_comp.c | 23 ++++++++++++++++++-----
1 file changed, 18 insertions(+), 5 deletions(-)
diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c
index a839c1a54276..49dea0c1a130 100644
--- a/arch/x86/net/bpf_jit_comp.c
+++ b/arch/x86/net/bpf_jit_comp.c
@@ -783,6 +783,22 @@ static void emit_stx(u8 **pprog, u32 size, u32 dst_reg, u32 src_reg, int off)
*pprog = prog;
}
+
+static void emit_neg(u8 **pprog, u32 reg, bool is64)
+{
+ u8 *prog = *pprog;
+ int cnt = 0;
+
+ /* Emit REX byte if necessary */
+ if (is64)
+ EMIT1(add_1mod(0x48, reg));
+ else if (is_ereg(reg))
+ EMIT1(add_1mod(0x40, reg));
+
+ EMIT2(0xF7, add_1reg(0xD8, reg)); /* x86 NEG */
+ *pprog = prog;
+}
+
static bool ex_handler_bpf(const struct exception_table_entry *x,
struct pt_regs *regs, int trapnr,
unsigned long error_code, unsigned long fault_addr)
@@ -884,11 +900,8 @@ static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image,
/* neg dst */
case BPF_ALU | BPF_NEG:
case BPF_ALU64 | BPF_NEG:
- if (BPF_CLASS(insn->code) == BPF_ALU64)
- EMIT1(add_1mod(0x48, dst_reg));
- else if (is_ereg(dst_reg))
- EMIT1(add_1mod(0x40, dst_reg));
- EMIT2(0xF7, add_1reg(0xD8, dst_reg));
+ emit_neg(&prog, dst_reg,
+ BPF_CLASS(insn->code) == BPF_ALU64);
break;
case BPF_ALU | BPF_ADD | BPF_K:
--
2.29.2.454.gaff20da3a2-goog
