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Merge branch 'arm-bpf-fixes'

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Nicolas Schichan says:

====================
BPF JIT fixes for ARM

These patches are fixing bugs in the ARM JIT and should probably find
their way to a stable kernel. All 60 test_bpf tests in Linux 4.1 release
are now passing OK (was 54 out of 60 before).
====================

Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David S. Miller 2015-07-21 22:19:55 -07:00
commit 7c8cbacab1
1 changed files with 44 additions and 13 deletions
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57
arch/arm/net/bpf_jit_32.c
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@ -74,32 +74,52 @@ struct jit_ctx {
int bpf_jit_enable __read_mostly; int bpf_jit_enable __read_mostly;
static u64 jit_get_skb_b(struct sk_buff *skb, unsigned offset) static inline int call_neg_helper(struct sk_buff *skb, int offset, void *ret,
unsigned int size)
{
void *ptr = bpf_internal_load_pointer_neg_helper(skb, offset, size);
if (!ptr)
return -EFAULT;
memcpy(ret, ptr, size);
return 0;
}
static u64 jit_get_skb_b(struct sk_buff *skb, int offset)
{ {
u8 ret; u8 ret;
int err; int err;
err = skb_copy_bits(skb, offset, &ret, 1); if (offset < 0)
err = call_neg_helper(skb, offset, &ret, 1);
else
err = skb_copy_bits(skb, offset, &ret, 1);
return (u64)err << 32 | ret; return (u64)err << 32 | ret;
} }
static u64 jit_get_skb_h(struct sk_buff *skb, unsigned offset) static u64 jit_get_skb_h(struct sk_buff *skb, int offset)
{ {
u16 ret; u16 ret;
int err; int err;
err = skb_copy_bits(skb, offset, &ret, 2); if (offset < 0)
err = call_neg_helper(skb, offset, &ret, 2);
else
err = skb_copy_bits(skb, offset, &ret, 2);
return (u64)err << 32 | ntohs(ret); return (u64)err << 32 | ntohs(ret);
} }
static u64 jit_get_skb_w(struct sk_buff *skb, unsigned offset) static u64 jit_get_skb_w(struct sk_buff *skb, int offset)
{ {
u32 ret; u32 ret;
int err; int err;
err = skb_copy_bits(skb, offset, &ret, 4); if (offset < 0)
err = call_neg_helper(skb, offset, &ret, 4);
else
err = skb_copy_bits(skb, offset, &ret, 4);
return (u64)err << 32 | ntohl(ret); return (u64)err << 32 | ntohl(ret);
} }
@ -536,9 +556,6 @@ static int build_body(struct jit_ctx *ctx)
case BPF_LD | BPF_B | BPF_ABS: case BPF_LD | BPF_B | BPF_ABS:
load_order = 0; load_order = 0;
load: load:
/* the interpreter will deal with the negative K */
if ((int)k < 0)
return -ENOTSUPP;
emit_mov_i(r_off, k, ctx); emit_mov_i(r_off, k, ctx);
load_common: load_common:
ctx->seen |= SEEN_DATA | SEEN_CALL; ctx->seen |= SEEN_DATA | SEEN_CALL;
@ -547,12 +564,24 @@ load_common:
emit(ARM_SUB_I(r_scratch, r_skb_hl, emit(ARM_SUB_I(r_scratch, r_skb_hl,
1 << load_order), ctx); 1 << load_order), ctx);
emit(ARM_CMP_R(r_scratch, r_off), ctx); emit(ARM_CMP_R(r_scratch, r_off), ctx);
condt = ARM_COND_HS; condt = ARM_COND_GE;
} else { } else {
emit(ARM_CMP_R(r_skb_hl, r_off), ctx); emit(ARM_CMP_R(r_skb_hl, r_off), ctx);
condt = ARM_COND_HI; condt = ARM_COND_HI;
} }
/*
* test for negative offset, only if we are
* currently scheduled to take the fast
* path. this will update the flags so that
* the slowpath instruction are ignored if the
* offset is negative.
*
* for loard_order == 0 the HI condition will
* make loads at offset 0 take the slow path too.
*/
_emit(condt, ARM_CMP_I(r_off, 0), ctx);
_emit(condt, ARM_ADD_R(r_scratch, r_off, r_skb_data), _emit(condt, ARM_ADD_R(r_scratch, r_off, r_skb_data),
ctx); ctx);
@ -860,9 +889,11 @@ b_epilogue:
off = offsetof(struct sk_buff, vlan_tci); off = offsetof(struct sk_buff, vlan_tci);
emit(ARM_LDRH_I(r_A, r_skb, off), ctx); emit(ARM_LDRH_I(r_A, r_skb, off), ctx);
if (code == (BPF_ANC | SKF_AD_VLAN_TAG)) if (code == (BPF_ANC | SKF_AD_VLAN_TAG))
OP_IMM3(ARM_AND, r_A, r_A, VLAN_VID_MASK, ctx); OP_IMM3(ARM_AND, r_A, r_A, ~VLAN_TAG_PRESENT, ctx);
else else {
OP_IMM3(ARM_AND, r_A, r_A, VLAN_TAG_PRESENT, ctx); OP_IMM3(ARM_LSR, r_A, r_A, 12, ctx);
OP_IMM3(ARM_AND, r_A, r_A, 0x1, ctx);
}
break; break;
case BPF_ANC | SKF_AD_QUEUE: case BPF_ANC | SKF_AD_QUEUE:
ctx->seen |= SEEN_SKB; ctx->seen |= SEEN_SKB;