xiaomi-sm8450/android_kernel_xiaomi_sm8450
1
0
Atdalīts 0
Kods Problēmas Izmaiņu pieprasījumi Darbības Pakotnes Projekti Laidieni Vikivietne Aktivitāte

ARM: net: support BPF_ALU | BPF_MOD instructions in the BPF JIT.

Pārlūkot izejas kodu 
For ARMv7 with UDIV instruction support, generate an UDIV instruction
followed by an MLS instruction.

For other ARM variants, generate code calling a C wrapper similar to
the jit_udiv() function used for BPF_ALU | BPF_DIV instructions.

Some performance numbers reported by the test_bpf module (the duration
per filter run is reported in nanoseconds, between "jitted:<x>" and
"PASS":

ARMv7 QEMU nojit:	test_bpf: #3 DIV_MOD_KX jited:0 2196 PASS
ARMv7 QEMU jit:		test_bpf: #3 DIV_MOD_KX jited:1 104 PASS
ARMv5 QEMU nojit:	test_bpf: #3 DIV_MOD_KX jited:0 2176 PASS
ARMv5 QEMU jit:		test_bpf: #3 DIV_MOD_KX jited:1 1104 PASS
ARMv5 kirkwood nojit:	test_bpf: #3 DIV_MOD_KX jited:0 1103 PASS
ARMv5 kirkwood jit:	test_bpf: #3 DIV_MOD_KX jited:1 311 PASS

Signed-off-by: Nicolas Schichan <nschichan@freebox.fr>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Šī revīzija ir iekļauta:
Nicolas Schichan
2015-10-02 17:06:47 +02:00
revīziju iesūtīja David S. Miller
vecāks df7b601542
revīzija 4560cdff03
2 mainīti faili ar 37 papildinājumiem un 6 dzēšanām
Lejupielādēt ielāpa failu Lejupielādēt izmaiņu failu Izvērst visus failus Savērst visus failus

38
arch/arm/net/bpf_jit_32.c
Parādīt failu

@@ -125,7 +125,7 @@ static u64 jit_get_skb_w(struct sk_buff *skb, int offset)
}
/*
* Wrapper that handles both OABI and EABI and assures Thumb2 interworking
* Wrappers which handle both OABI and EABI and assures Thumb2 interworking
* (where the assembly routines like __aeabi_uidiv could cause problems).
*/
static u32 jit_udiv(u32 dividend, u32 divisor)
@@ -133,6 +133,11 @@ static u32 jit_udiv(u32 dividend, u32 divisor)
return dividend / divisor;
}
static u32 jit_mod(u32 dividend, u32 divisor)
{
return dividend % divisor;
}
static inline void _emit(int cond, u32 inst, struct jit_ctx *ctx)
{
inst |= (cond << 28);
@@ -471,11 +476,17 @@ static inline void emit_blx_r(u8 tgt_reg, struct jit_ctx *ctx)
#endif
}
static inline void emit_udiv(u8 rd, u8 rm, u8 rn, struct jit_ctx *ctx)
static inline void emit_udivmod(u8 rd, u8 rm, u8 rn, struct jit_ctx *ctx,
int bpf_op)
{
#if __LINUX_ARM_ARCH__ == 7
if (elf_hwcap & HWCAP_IDIVA) {
emit(ARM_UDIV(rd, rm, rn), ctx);
if (bpf_op == BPF_DIV)
emit(ARM_UDIV(rd, rm, rn), ctx);
else {
emit(ARM_UDIV(ARM_R3, rm, rn), ctx);
emit(ARM_MLS(rd, rn, ARM_R3, rm), ctx);
}
return;
}
#endif
@@ -496,7 +507,8 @@ static inline void emit_udiv(u8 rd, u8 rm, u8 rn, struct jit_ctx *ctx)
emit(ARM_MOV_R(ARM_R0, rm), ctx);
ctx->seen |= SEEN_CALL;
emit_mov_i(ARM_R3, (u32)jit_udiv, ctx);
emit_mov_i(ARM_R3, bpf_op == BPF_DIV ? (u32)jit_udiv : (u32)jit_mod,
ctx);
emit_blx_r(ARM_R3, ctx);
if (rd != ARM_R0)
@@ -697,13 +709,27 @@ load_ind:
if (k == 1)
break;
emit_mov_i(r_scratch, k, ctx);
emit_udiv(r_A, r_A, r_scratch, ctx);
emit_udivmod(r_A, r_A, r_scratch, ctx, BPF_DIV);
break;
case BPF_ALU | BPF_DIV | BPF_X:
update_on_xread(ctx);
emit(ARM_CMP_I(r_X, 0), ctx);
emit_err_ret(ARM_COND_EQ, ctx);
emit_udiv(r_A, r_A, r_X, ctx);
emit_udivmod(r_A, r_A, r_X, ctx, BPF_DIV);
break;
case BPF_ALU | BPF_MOD | BPF_K:
if (k == 1) {
emit_mov_i(r_A, 0, ctx);
break;
}
emit_mov_i(r_scratch, k, ctx);
emit_udivmod(r_A, r_A, r_scratch, ctx, BPF_MOD);
break;
case BPF_ALU | BPF_MOD | BPF_X:
update_on_xread(ctx);
emit(ARM_CMP_I(r_X, 0), ctx);
emit_err_ret(ARM_COND_EQ, ctx);
emit_udivmod(r_A, r_A, r_X, ctx, BPF_MOD);
break;
case BPF_ALU | BPF_OR | BPF_K:
/* A |= K */