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| author | Xu Kuohai <xukuohai@huawei.com> | 2023-08-15 18:41:52 +0300 |
|---|---|---|
| committer | Daniel Borkmann <daniel@iogearbox.net> | 2023-08-18 16:45:34 +0300 |
| commit | 6c9f86d3632c1abcbdaabeab1ee6d6de059b4ae7 (patch) | |
| tree | 313cbd0b01bda36bb00fec6498383fd5393aa6e1 /arch/arm64/lib | |
| parent | c2e5f4fd1148727801a63d938cec210f16b48864 (diff) | |
| download | linux-6c9f86d3632c1abcbdaabeab1ee6d6de059b4ae7.tar.xz | |
arm64: insn: Add encoders for LDRSB/LDRSH/LDRSW
To support BPF sign-extend load instructions, add encoders for
LDRSB/LDRSH/LDRSW.
LDRSB/LDRSH/LDRSW (immediate) is encoded as follows:
3 2 2 2 2 1 0 0
0 7 6 4 2 0 5 0
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| sz|1 1 1|0|0 1|opc| imm12 | Rn | Rt |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
LDRSB/LDRSH/LDRSW (register) is encoded as follows:
3 2 2 2 2 2 1 1 1 1 0 0
0 7 6 4 2 1 6 3 2 0 5 0
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| sz|1 1 1|0|0 0|opc|1| Rm | opt |S|1 0| Rn | Rt |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
where:
- sz
indicates whether 8-bit, 16-bit or 32-bit data is to be loaded
- opc
opc[1] (bit 23) is always 1 and opc[0] == 1 indicates regsize
is 32-bit. Since BPF signed load instructions always exend the
sign bit to bit 63 regardless of whether it loads an 8-bit,
16-bit or 32-bit data. So only 64-bit register size is required.
That is, it's sufficient to set field opc fixed to 0x2.
- opt
Indicates whether to sign extend the offset register Rm and the
effective bits of Rm. We set opt to 0x7 (SXTX) since we'll use
Rm as a sgined 64-bit value in BPF.
- S
Optional only when opt field is 0x3 (LSL)
In short, the above fields are encoded to the values listed below.
sz opc opt S
LDRSB (immediate) 0x0 0x2 na na
LDRSH (immediate) 0x1 0x2 na na
LDRSW (immediate) 0x2 0x2 na na
LDRSB (register) 0x0 0x2 0x7 0
LDRSH (register) 0x1 0x2 0x7 0
LDRSW (register) 0x2 0x2 0x7 0
Signed-off-by: Xu Kuohai <xukuohai@huawei.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Tested-by: Florent Revest <revest@chromium.org>
Acked-by: Florent Revest <revest@chromium.org>
Link: https://lore.kernel.org/bpf/20230815154158.717901-2-xukuohai@huaweicloud.com
Diffstat (limited to 'arch/arm64/lib')
| -rw-r--r-- | arch/arm64/lib/insn.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/arch/arm64/lib/insn.c b/arch/arm64/lib/insn.c index 924934cb85ee..a635ab83fee3 100644 --- a/arch/arm64/lib/insn.c +++ b/arch/arm64/lib/insn.c @@ -385,6 +385,9 @@ u32 aarch64_insn_gen_load_store_reg(enum aarch64_insn_register reg, case AARCH64_INSN_LDST_LOAD_REG_OFFSET: insn = aarch64_insn_get_ldr_reg_value(); break; + case AARCH64_INSN_LDST_SIGNED_LOAD_REG_OFFSET: + insn = aarch64_insn_get_signed_ldr_reg_value(); + break; case AARCH64_INSN_LDST_STORE_REG_OFFSET: insn = aarch64_insn_get_str_reg_value(); break; @@ -430,6 +433,9 @@ u32 aarch64_insn_gen_load_store_imm(enum aarch64_insn_register reg, case AARCH64_INSN_LDST_LOAD_IMM_OFFSET: insn = aarch64_insn_get_ldr_imm_value(); break; + case AARCH64_INSN_LDST_SIGNED_LOAD_IMM_OFFSET: + insn = aarch64_insn_get_signed_load_imm_value(); + break; case AARCH64_INSN_LDST_STORE_IMM_OFFSET: insn = aarch64_insn_get_str_imm_value(); break; |