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arm32, bpf: add support for cpuv4 insns #5621

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arm32, bpf: add support for cpuv4 insns #5621

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Pull request for series with
subject: arm32, bpf: add support for cpuv4 insns
version: 1
url: https://patchwork.kernel.org/project/netdevbpf/list/?series=781824

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Upstream branch: 2e29df8
series: https://patchwork.kernel.org/project/netdevbpf/list/?series=781824
version: 1

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Upstream branch: 7e117de
series: https://patchwork.kernel.org/project/netdevbpf/list/?series=781824
version: 1

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At least one diff in series https://patchwork.kernel.org/project/netdevbpf/list/?series=781824 expired. Closing PR.

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Upstream branch: 23d9204
series: https://patchwork.kernel.org/project/netdevbpf/list/?series=782066
version: 2

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Upstream branch: 831c4b3
series: https://patchwork.kernel.org/project/netdevbpf/list/?series=782066
version: 2

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Upstream branch: 831c4b3
series: https://patchwork.kernel.org/project/netdevbpf/list/?series=782358
version: 3

@kernel-patches-daemon-bpf kernel-patches-daemon-bpf bot added V3 and removed V2 labels Sep 7, 2023
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Upstream branch: 9bc8692
series: https://patchwork.kernel.org/project/netdevbpf/list/?series=782358
version: 3

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Upstream branch: 234b977
series: https://patchwork.kernel.org/project/netdevbpf/list/?series=782358
version: 3

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Upstream branch: 5c04433
series: https://patchwork.kernel.org/project/netdevbpf/list/?series=782358
version: 3

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Upstream branch: d609f3d
series: https://patchwork.kernel.org/project/netdevbpf/list/?series=782358
version: 3

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Upstream branch: 45ee73a
series: https://patchwork.kernel.org/project/netdevbpf/list/?series=782358
version: 3

@puranjaymohan
arm32, bpf: add support for 32-bit offset jmp instruction
02125f8 
The cpuv4 adds unconditional jump with 32-bit offset where the immediate
field of the instruction is to be used to calculate the jump offset.

BPF_JA | BPF_K | BPF_JMP32 => gotol +imm => PC += imm.

Signed-off-by: Puranjay Mohan <puranjay12@gmail.com>
Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
@puranjaymohan
arm32, bpf: add support for sign-extension load instruction
56ed891 
The cpuv4 added the support of an instruction that is similar to load
but also sign-extends the result after the load.

BPF_MEMSX | <size> | BPF_LDX means dst = *(signed size *) (src + offset)
here <size> can be one of BPF_B, BPF_H, BPF_W.

ARM32 has instructions to load a byte or a half word with sign
extension into a 32bit register. As the JIT uses two 32 bit registers
to simulate a 64-bit BPF register, an extra instruction is emitted to
sign-extent the result up to the second register.

Signed-off-by: Puranjay Mohan <puranjay12@gmail.com>
Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
@puranjaymohan
arm32, bpf: add support for sign-extension mov instruction
fd6170a 
The cpuv4 added a new BPF_MOVSX instruction that sign extends the src
before moving it to the destination.

BPF_ALU | BPF_MOVSX sign extends 8-bit and 16-bit operands into 32-bit
operands, and zeroes the remaining upper 32 bits.

BPF_ALU64 | BPF_MOVSX sign extends 8-bit, 16-bit, and 32-bit  operands
into 64-bit operands.

The offset field of the instruction is used to tell the number of bit to
use for sign-extension. BPF_MOV and BPF_MOVSX have the same code but the
former sets offset to 0 and the later one sets the offset to 8, 16 or 32

The behaviour of this instruction is dst = (s8,s16,s32)src

On ARM32 the implementation uses LSH and ARSH to extend the 8/16 bits to
a 32-bit register and then it is sign extended to the upper 32-bit
register using ARSH. For 32-bit we just move it to the destination
register and use ARSH to extend it to the upper 32-bit register.

Signed-off-by: Puranjay Mohan <puranjay12@gmail.com>
Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
@puranjaymohan
arm32, bpf: add support for unconditional bswap instruction
0304359 
The cpuv4 added a new unconditional bswap instruction with following
behaviour:

BPF_ALU64 | BPF_TO_LE | BPF_END with imm = 16/32/64 means:
dst = bswap16(dst)
dst = bswap32(dst)
dst = bswap64(dst)

As we already support converting to big-endian from little-endian we can
use the same for unconditional bswap. just treat the unconditional scenario
the same as big-endian conversion.

Signed-off-by: Puranjay Mohan <puranjay12@gmail.com>
Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
@puranjaymohan
arm32, bpf: add support for 32-bit signed division
4a66110 
The cpuv4 added a new BPF_SDIV instruction that does signed division.
The encoding is similar to BPF_DIV but BPF_SDIV sets offset=1.

ARM32 already supports 32-bit BPF_DIV which can be easily extended to
support BPF_SDIV as ARM32 has the SDIV instruction. When the CPU is not
ARM-v7, we implement that SDIV/SMOD with the function call similar to
the implementation of DIV/MOD.

Signed-off-by: Puranjay Mohan <puranjay12@gmail.com>
Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
@puranjaymohan
arm32, bpf: add support for 64 bit division instruction
cc1dbc8 
ARM32 doesn't have instructions to do 64-bit/64-bit divisions. So, to
implement the following instructions:
BPF_ALU64 | BPF_DIV
BPF_ALU64 | BPF_MOD
BPF_ALU64 | BPF_SDIV
BPF_ALU64 | BPF_SMOD

We implement the above instructions by doing function calls to div64_u64()
and div64_u64_rem() for unsigned division/mod and calls to div64_s64()
for signed division/mod.

Signed-off-by: Puranjay Mohan <puranjay12@gmail.com>
Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
@puranjaymohan
selftest, bpf: enable cpu v4 tests for arm32
21e20ff 
Now that all the cpuv4 instructions are supported by the arm32 JIT,
enable the selftests for arm32.

Signed-off-by: Puranjay Mohan <puranjay12@gmail.com>
@puranjaymohan
bpf/tests: add tests for cpuv4 instructions
3cf825d 
The BPF JITs now support cpuv4 instructions. Add tests for these new
instructions to the test suite:

1. Sign extended Load
2. Sign extended Mov
3. Unconditional byte swap
4. Unconditional jump with 32-bit offset
5. Signed division and modulo

Signed-off-by: Puranjay Mohan <puranjay12@gmail.com>
@puranjaymohan
MAINTAINERS: Add myself for ARM32 BPF JIT maintainer.
d35004b 
As Shubham has been inactive since 2017, Add myself for ARM32 BPF JIT.

Signed-off-by: Puranjay Mohan <puranjay12@gmail.com>
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Upstream branch: 9b2b863
series: https://patchwork.kernel.org/project/netdevbpf/list/?series=782358
version: 3

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At least one diff in series https://patchwork.kernel.org/project/netdevbpf/list/?series=782358 irrelevant now. Closing PR.

@kernel-patches-daemon-bpf kernel-patches-daemon-bpf bot deleted the series/781824=>bpf-next branch September 16, 2023 00:24
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