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authorRussell King <rmk+kernel@armlinux.org.uk>2018-07-11 10:31:36 +0100
committerDaniel Borkmann <daniel@iogearbox.net>2018-07-12 20:45:22 +0200
commita8ef95a034233190b1dd73ff03472ff0f7f4fbdf (patch)
tree195d4fd69d71ea07bbc5fcc063723605a6312f67
parentd449ceb11b3884770c06e71cf15edc9f3b4c9b05 (diff)
ARM: net: bpf: provide load/store ops with negative immediates
Provide a set of load/store opcode generators that work with negative immediates as well as positive ones. Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
-rw-r--r--arch/arm/net/bpf_jit_32.c28
-rw-r--r--arch/arm/net/bpf_jit_32.h35
2 files changed, 41 insertions, 22 deletions
diff --git a/arch/arm/net/bpf_jit_32.c b/arch/arm/net/bpf_jit_32.c
index f2e6ffe57788..c81da1a50834 100644
--- a/arch/arm/net/bpf_jit_32.c
+++ b/arch/arm/net/bpf_jit_32.c
@@ -239,6 +239,34 @@ static int16_t imm8m(u32 x)
return -1;
}
+static u32 arm_bpf_ldst_imm12(u32 op, u8 rt, u8 rn, s16 imm12)
+{
+ op |= rt << 12 | rn << 16;
+ if (imm12 >= 0)
+ op |= ARM_INST_LDST__U;
+ else
+ imm12 = -imm12;
+ return op | (imm12 & 0xfff);
+}
+
+static u32 arm_bpf_ldst_imm8(u32 op, u8 rt, u8 rn, s16 imm8)
+{
+ op |= rt << 12 | rn << 16;
+ if (imm8 >= 0)
+ op |= ARM_INST_LDST__U;
+ else
+ imm8 = -imm8;
+ return op | (imm8 & 0xf0) << 4 | (imm8 & 0x0f);
+}
+
+#define ARM_LDR_I(rt, rn, off) arm_bpf_ldst_imm12(ARM_INST_LDR_I, rt, rn, off)
+#define ARM_LDRB_I(rt, rn, off) arm_bpf_ldst_imm12(ARM_INST_LDRB_I, rt, rn, off)
+#define ARM_LDRH_I(rt, rn, off) arm_bpf_ldst_imm8(ARM_INST_LDRH_I, rt, rn, off)
+
+#define ARM_STR_I(rt, rn, off) arm_bpf_ldst_imm12(ARM_INST_STR_I, rt, rn, off)
+#define ARM_STRB_I(rt, rn, off) arm_bpf_ldst_imm12(ARM_INST_STRB_I, rt, rn, off)
+#define ARM_STRH_I(rt, rn, off) arm_bpf_ldst_imm8(ARM_INST_STRH_I, rt, rn, off)
+
/*
* Initializes the JIT space with undefined instructions.
*/
diff --git a/arch/arm/net/bpf_jit_32.h b/arch/arm/net/bpf_jit_32.h
index d5cf5f6208aa..c55bc39d3e22 100644
--- a/arch/arm/net/bpf_jit_32.h
+++ b/arch/arm/net/bpf_jit_32.h
@@ -77,11 +77,12 @@
#define ARM_INST_EOR_R 0x00200000
#define ARM_INST_EOR_I 0x02200000
-#define ARM_INST_LDRB_I 0x05d00000
+#define ARM_INST_LDST__U 0x00800000
+#define ARM_INST_LDRB_I 0x05500000
#define ARM_INST_LDRB_R 0x07d00000
-#define ARM_INST_LDRH_I 0x01d000b0
+#define ARM_INST_LDRH_I 0x015000b0
#define ARM_INST_LDRH_R 0x019000b0
-#define ARM_INST_LDR_I 0x05900000
+#define ARM_INST_LDR_I 0x05100000
#define ARM_INST_LDR_R 0x07900000
#define ARM_INST_LDM 0x08900000
@@ -124,9 +125,9 @@
#define ARM_INST_SBC_R 0x00c00000
#define ARM_INST_SBCS_R 0x00d00000
-#define ARM_INST_STR_I 0x05800000
-#define ARM_INST_STRB_I 0x05c00000
-#define ARM_INST_STRH_I 0x01c000b0
+#define ARM_INST_STR_I 0x05000000
+#define ARM_INST_STRB_I 0x05400000
+#define ARM_INST_STRH_I 0x014000b0
#define ARM_INST_TST_R 0x01100000
#define ARM_INST_TST_I 0x03100000
@@ -183,17 +184,14 @@
#define ARM_EOR_R(rd, rn, rm) _AL3_R(ARM_INST_EOR, rd, rn, rm)
#define ARM_EOR_I(rd, rn, imm) _AL3_I(ARM_INST_EOR, rd, rn, imm)
-#define ARM_LDR_I(rt, rn, off) (ARM_INST_LDR_I | (rt) << 12 | (rn) << 16 \
- | ((off) & 0xfff))
-#define ARM_LDR_R(rt, rn, rm) (ARM_INST_LDR_R | (rt) << 12 | (rn) << 16 \
+#define ARM_LDR_R(rt, rn, rm) (ARM_INST_LDR_R | ARM_INST_LDST__U \
+ | (rt) << 12 | (rn) << 16 \
| (rm))
-#define ARM_LDRB_I(rt, rn, off) (ARM_INST_LDRB_I | (rt) << 12 | (rn) << 16 \
- | (off))
-#define ARM_LDRB_R(rt, rn, rm) (ARM_INST_LDRB_R | (rt) << 12 | (rn) << 16 \
+#define ARM_LDRB_R(rt, rn, rm) (ARM_INST_LDRB_R | ARM_INST_LDST__U \
+ | (rt) << 12 | (rn) << 16 \
| (rm))
-#define ARM_LDRH_I(rt, rn, off) (ARM_INST_LDRH_I | (rt) << 12 | (rn) << 16 \
- | (((off) & 0xf0) << 4) | ((off) & 0xf))
-#define ARM_LDRH_R(rt, rn, rm) (ARM_INST_LDRH_R | (rt) << 12 | (rn) << 16 \
+#define ARM_LDRH_R(rt, rn, rm) (ARM_INST_LDRH_R | ARM_INST_LDST__U \
+ | (rt) << 12 | (rn) << 16 \
| (rm))
#define ARM_LDM(rn, regs) (ARM_INST_LDM | (rn) << 16 | (regs))
@@ -254,13 +252,6 @@
#define ARM_SUBS_I(rd, rn, imm) _AL3_I(ARM_INST_SUBS, rd, rn, imm)
#define ARM_SBC_I(rd, rn, imm) _AL3_I(ARM_INST_SBC, rd, rn, imm)
-#define ARM_STR_I(rt, rn, off) (ARM_INST_STR_I | (rt) << 12 | (rn) << 16 \
- | ((off) & 0xfff))
-#define ARM_STRH_I(rt, rn, off) (ARM_INST_STRH_I | (rt) << 12 | (rn) << 16 \
- | (((off) & 0xf0) << 4) | ((off) & 0xf))
-#define ARM_STRB_I(rt, rn, off) (ARM_INST_STRB_I | (rt) << 12 | (rn) << 16 \
- | (((off) & 0xf0) << 4) | ((off) & 0xf))
-
#define ARM_TST_R(rn, rm) _AL3_R(ARM_INST_TST, 0, rn, rm)
#define ARM_TST_I(rn, imm) _AL3_I(ARM_INST_TST, 0, rn, imm)