This is a note to let you know that I've just added the patch titled
sparc: bpf_jit: fix support for ldx/stx mem and SKF_AD_VLAN_TAG
to the 3.16-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
sparc-bpf_jit-fix-support-for-ldx-stx-mem-and-skf_ad_vlan_tag.patch
and it can be found in the queue-3.16 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From foo@baz Tue Oct 28 11:19:22 CST 2014
From: Alexei Starovoitov <ast@xxxxxxxxxxxx>
Date: Tue, 16 Sep 2014 18:32:58 -0700
Subject: sparc: bpf_jit: fix support for ldx/stx mem and SKF_AD_VLAN_TAG
From: Alexei Starovoitov <ast@xxxxxxxxxxxx>
[ Upstream commit f6f2332dce0efeea8c5653b6e9d1e8c379ace65c ]
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: 2809a2087cc4 ("net: filter: Just In Time compiler for sparc")
Signed-off-by: Alexei Starovoitov <ast@xxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/sparc/net/bpf_jit_comp.c | 25 ++++++++++++++++++-------
1 file changed, 18 insertions(+), 7 deletions(-)
--- a/arch/sparc/net/bpf_jit_comp.c
+++ b/arch/sparc/net/bpf_jit_comp.c
@@ -234,12 +234,18 @@ do { BUILD_BUG_ON(FIELD_SIZEOF(STRUCT, F
__emit_load8(BASE, STRUCT, FIELD, DEST); \
} while (0)
-#define emit_ldmem(OFF, DEST) \
-do { *prog++ = LD32I | RS1(FP) | S13(-(OFF)) | RD(DEST); \
+#ifdef CONFIG_SPARC64
+#define BIAS (STACK_BIAS - 4)
+#else
+#define BIAS (-4)
+#endif
+
+#define emit_ldmem(OFF, DEST) \
+do { *prog++ = LD32I | RS1(SP) | S13(BIAS - (OFF)) | RD(DEST); \
} while (0)
-#define emit_stmem(OFF, SRC) \
-do { *prog++ = LD32I | RS1(FP) | S13(-(OFF)) | RD(SRC); \
+#define emit_stmem(OFF, SRC) \
+do { *prog++ = ST32I | RS1(SP) | S13(BIAS - (OFF)) | RD(SRC); \
} while (0)
#ifdef CONFIG_SMP
@@ -615,10 +621,11 @@ void bpf_jit_compile(struct sk_filter *f
case BPF_ANC | SKF_AD_VLAN_TAG:
case BPF_ANC | SKF_AD_VLAN_TAG_PRESENT:
emit_skb_load16(vlan_tci, r_A);
- if (code == (BPF_ANC | SKF_AD_VLAN_TAG)) {
- emit_andi(r_A, VLAN_VID_MASK, r_A);
+ if (code != (BPF_ANC | SKF_AD_VLAN_TAG)) {
+ emit_alu_K(SRL, 12);
+ emit_andi(r_A, 1, r_A);
} else {
- emit_loadimm(VLAN_TAG_PRESENT, r_TMP);
+ emit_loadimm(~VLAN_TAG_PRESENT, r_TMP);
emit_and(r_A, r_TMP, r_A);
}
break;
@@ -630,15 +637,19 @@ void bpf_jit_compile(struct sk_filter *f
emit_loadimm(K, r_X);
break;
case BPF_LD | BPF_MEM:
+ seen |= SEEN_MEM;
emit_ldmem(K * 4, r_A);
break;
case BPF_LDX | BPF_MEM:
+ seen |= SEEN_MEM | SEEN_XREG;
emit_ldmem(K * 4, r_X);
break;
case BPF_ST:
+ seen |= SEEN_MEM;
emit_stmem(K * 4, r_A);
break;
case BPF_STX:
+ seen |= SEEN_MEM | SEEN_XREG;
emit_stmem(K * 4, r_X);
break;
Patches currently in stable-queue which might be from ast@xxxxxxxxxxxx are
queue-3.16/sparc-bpf_jit-fix-support-for-ldx-stx-mem-and-skf_ad_vlan_tag.patch
queue-3.16/sparc-bpf_jit-fix-loads-from-negative-offsets.patch
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