sparc: bpf_jit: fix support for ldx/stx mem and SKF_AD_VLAN_TAG
fix several issues in sparc BPF JIT compiler.
ldx/stx related:
. classic BPF instructions that access mem[] slots were not setting
SEEN_MEM flag, so stack wasn't allocated. Fix that by advertising
correct flags
. LDX/STX instructions were missing SEEN_XREG, so register value
could have leaked to user space. Fix it.
. since stack for mem[] slots is allocated with 'sub %sp' instead
of 'save %sp', use %sp as base register instead of %fp.
. ldx mem[0] means first slot in classic BPF which should have
-4 offset instead of 0.
. sparc64 needs 2047 stack bias as per ABI to access stack
. emit_stmem() was using LD32I macro instead of ST32I
SKF_AD_VLAN_TAG* related:
. SKF_AD_VLAN_TAG_PRESENT must return 1 or 0 instead of '> 0' or 0
as per classic BPF de facto standard
. SKF_AD_VLAN_TAG needs to mask the field correctly
Fixes: 2809a2087c
("net: filter: Just In Time compiler for sparc")
Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
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@ -234,12 +234,18 @@ do { BUILD_BUG_ON(FIELD_SIZEOF(STRUCT, FIELD) != sizeof(u8)); \
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__emit_load8(BASE, STRUCT, FIELD, DEST); \
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} while (0)
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#define emit_ldmem(OFF, DEST) \
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do { *prog++ = LD32I | RS1(FP) | S13(-(OFF)) | RD(DEST); \
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#ifdef CONFIG_SPARC64
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#define BIAS (STACK_BIAS - 4)
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#else
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#define BIAS (-4)
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#endif
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#define emit_ldmem(OFF, DEST) \
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do { *prog++ = LD32I | RS1(SP) | S13(BIAS - (OFF)) | RD(DEST); \
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} while (0)
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#define emit_stmem(OFF, SRC) \
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do { *prog++ = LD32I | RS1(FP) | S13(-(OFF)) | RD(SRC); \
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#define emit_stmem(OFF, SRC) \
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do { *prog++ = ST32I | RS1(SP) | S13(BIAS - (OFF)) | RD(SRC); \
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} while (0)
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#ifdef CONFIG_SMP
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@ -615,10 +621,11 @@ void bpf_jit_compile(struct bpf_prog *fp)
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case BPF_ANC | SKF_AD_VLAN_TAG:
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case BPF_ANC | SKF_AD_VLAN_TAG_PRESENT:
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emit_skb_load16(vlan_tci, r_A);
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if (code == (BPF_ANC | SKF_AD_VLAN_TAG)) {
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emit_andi(r_A, VLAN_VID_MASK, r_A);
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if (code != (BPF_ANC | SKF_AD_VLAN_TAG)) {
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emit_alu_K(SRL, 12);
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emit_andi(r_A, 1, r_A);
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} else {
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emit_loadimm(VLAN_TAG_PRESENT, r_TMP);
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emit_loadimm(~VLAN_TAG_PRESENT, r_TMP);
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emit_and(r_A, r_TMP, r_A);
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}
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break;
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@ -630,15 +637,19 @@ void bpf_jit_compile(struct bpf_prog *fp)
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emit_loadimm(K, r_X);
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break;
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case BPF_LD | BPF_MEM:
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seen |= SEEN_MEM;
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emit_ldmem(K * 4, r_A);
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break;
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case BPF_LDX | BPF_MEM:
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seen |= SEEN_MEM | SEEN_XREG;
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emit_ldmem(K * 4, r_X);
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break;
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case BPF_ST:
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seen |= SEEN_MEM;
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emit_stmem(K * 4, r_A);
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break;
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case BPF_STX:
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seen |= SEEN_MEM | SEEN_XREG;
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emit_stmem(K * 4, r_X);
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break;
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