diff options
| author | Markos Chandras | 2014-06-23 10:38:56 +0100 |
|---|---|---|
| committer | Ralf Baechle | 2014-06-26 10:48:22 +0100 |
| commit | e5bb48b0553d75918094c5a6f7b60a4359887218 (patch) | |
| tree | 77ac48000e90b3dc10e1ada667c17d500ff15502 /arch | |
| parent | 10c4d614d2ffcfc17add01f9648c3e530fb308d1 (diff) | |
MIPS: bpf: Drop update_on_xread and always initialize the X register
Previously, update_on_xread() only set the reset flag if SEEN_X hasn't
been set already. However, SEEN_X is used to indicate that X is used
as destination or source register so there are some cases where X
is only used as source register and we really need to make sure that it
has been initialized in time. As a result of which, drop this function and
always set X to zero if it's used in any of the opcodes.
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Daniel Borkmann <dborkman@redhat.com>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: netdev@vger.kernel.org
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/7133/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/mips/net/bpf_jit.c | 22 |
1 files changed, 1 insertions, 21 deletions
diff --git a/arch/mips/net/bpf_jit.c b/arch/mips/net/bpf_jit.c index 00c4c83972bb..1bcd599d9971 100644 --- a/arch/mips/net/bpf_jit.c +++ b/arch/mips/net/bpf_jit.c @@ -119,8 +119,6 @@ /* Arguments used by JIT */ #define ARGS_USED_BY_JIT 2 /* only applicable to 64-bit */ -#define FLAG_NEED_X_RESET (1 << 0) - #define SBIT(x) (1 << (x)) /* Signed version of BIT() */ /** @@ -549,14 +547,6 @@ static inline u16 align_sp(unsigned int num) return num; } -static inline void update_on_xread(struct jit_ctx *ctx) -{ - if (!(ctx->flags & SEEN_X)) - ctx->flags |= FLAG_NEED_X_RESET; - - ctx->flags |= SEEN_X; -} - static bool is_load_to_a(u16 inst) { switch (inst) { @@ -701,7 +691,7 @@ static void build_prologue(struct jit_ctx *ctx) if (ctx->flags & SEEN_SKB) emit_reg_move(r_skb, MIPS_R_A0, ctx); - if (ctx->flags & FLAG_NEED_X_RESET) + if (ctx->flags & SEEN_X) emit_jit_reg_move(r_X, r_zero, ctx); /* Do not leak kernel data to userspace */ @@ -876,7 +866,6 @@ load_common: /* A <- P[X + k:1] */ load_order = 0; load_ind: - update_on_xread(ctx); ctx->flags |= SEEN_OFF | SEEN_X; emit_addiu(r_off, r_X, k, ctx); goto load_common; @@ -972,7 +961,6 @@ load_ind: break; case BPF_ALU | BPF_MUL | BPF_X: /* A *= X */ - update_on_xread(ctx); ctx->flags |= SEEN_A | SEEN_X; emit_mul(r_A, r_A, r_X, ctx); break; @@ -1002,7 +990,6 @@ load_ind: break; case BPF_ALU | BPF_DIV | BPF_X: /* A /= X */ - update_on_xread(ctx); ctx->flags |= SEEN_X | SEEN_A; /* Check if r_X is zero */ emit_bcond(MIPS_COND_EQ, r_X, r_zero, @@ -1012,7 +999,6 @@ load_ind: break; case BPF_ALU | BPF_MOD | BPF_X: /* A %= X */ - update_on_xread(ctx); ctx->flags |= SEEN_X | SEEN_A; /* Check if r_X is zero */ emit_bcond(MIPS_COND_EQ, r_X, r_zero, @@ -1027,7 +1013,6 @@ load_ind: break; case BPF_ALU | BPF_OR | BPF_X: /* A |= X */ - update_on_xread(ctx); ctx->flags |= SEEN_A; emit_ori(r_A, r_A, r_X, ctx); break; @@ -1039,7 +1024,6 @@ load_ind: case BPF_ANC | SKF_AD_ALU_XOR_X: case BPF_ALU | BPF_XOR | BPF_X: /* A ^= X */ - update_on_xread(ctx); ctx->flags |= SEEN_A; emit_xor(r_A, r_A, r_X, ctx); break; @@ -1050,7 +1034,6 @@ load_ind: break; case BPF_ALU | BPF_AND | BPF_X: /* A &= X */ - update_on_xread(ctx); ctx->flags |= SEEN_A | SEEN_X; emit_and(r_A, r_A, r_X, ctx); break; @@ -1062,7 +1045,6 @@ load_ind: case BPF_ALU | BPF_LSH | BPF_X: /* A <<= X */ ctx->flags |= SEEN_A | SEEN_X; - update_on_xread(ctx); emit_sllv(r_A, r_A, r_X, ctx); break; case BPF_ALU | BPF_RSH | BPF_K: @@ -1072,7 +1054,6 @@ load_ind: break; case BPF_ALU | BPF_RSH | BPF_X: ctx->flags |= SEEN_A | SEEN_X; - update_on_xread(ctx); emit_srlv(r_A, r_A, r_X, ctx); break; case BPF_ALU | BPF_NEG: @@ -1243,7 +1224,6 @@ jmp_cmp: case BPF_MISC | BPF_TXA: /* A = X */ ctx->flags |= SEEN_A | SEEN_X; - update_on_xread(ctx); emit_jit_reg_move(r_A, r_X, ctx); break; /* AUX */ |