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| author |   Russell King <rmk+kernel@armlinux.org.uk> | 2018-07-11 10:31:36 +0100 |
|---|---|---|
| committer |   Daniel Borkmann <daniel@iogearbox.net> | 2018-07-12 20:45:22 +0200 |
| commit | a8ef95a034233190b1dd73ff03472ff0f7f4fbdf (patch) | |
| tree | 195d4fd69d71ea07bbc5fcc063723605a6312f67 /arch/arm/net/bpf_jit_32.c | |
| parent | ARM: net: bpf: enumerate the JIT scratch stack layout (diff) | |
| download | linux-dev-a8ef95a034233190b1dd73ff03472ff0f7f4fbdf.tar.xz linux-dev-a8ef95a034233190b1dd73ff03472ff0f7f4fbdf.zip | |
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>
Diffstat (limited to 'arch/arm/net/bpf_jit_32.c')
| -rw-r--r-- | arch/arm/net/bpf_jit_32.c | 28 |
1 files changed, 28 insertions, 0 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. */ |