[PATCH bpf-next v3 0/9] arm32, bpf: add support for cpuv4 insns

Puranjay Mohan
2023-09-07T23:05:59Z

Changes in V2 -> V3
- Added comments at places where there could be confustion.
- In the patch for DIV64, fix the if-else case that would never run.
- In the same patch use a single instruction to POP caller saved regs.
- Add a patch to change maintainership of ARM32 BPF JIT.

Changes in V1 -> V2:
- Fix coding style issues.
- Don't use tmp variable for src in emit_ldsx_r() as it is redundant.
- Optimize emit_ldsx_r() when offset can fit in immediate.

Add the support for cpuv4 instructions for ARM32 BPF JIT. 64-bit division
was not supported earlier so this series adds 64-bit DIV, SDIV, MOD, SMOD
instructions as well.

This series needs any one of the patches from [1] to disable zero-extension
for BPF_MEMSX to support ldsx.

The relevant selftests have passed expect ldsx_insn which needs fentry:

Tested on BeagleBone Black (ARMv7-A):

[root@alarm del]# echo 1 > /proc/sys/net/core/bpf_jit_enable
[root@alarm del]# ./test_progs -a verifier_sdiv,verifier_movsx,verifier_ldsx,verifier_gotol,verifier_bswap
#337/1 verifier_bswap/BSWAP, 16:OK
#337/2 verifier_bswap/BSWAP, 16 @unpriv:OK
#337/3 verifier_bswap/BSWAP, 32:OK
#337/4 verifier_bswap/BSWAP, 32 @unpriv:OK
#337/5 verifier_bswap/BSWAP, 64:OK
#337/6 verifier_bswap/BSWAP, 64 @unpriv:OK
#337 verifier_bswap:OK
#351/1 verifier_gotol/gotol, small_imm:OK
#351/2 verifier_gotol/gotol, small_imm @unpriv:OK
#351 verifier_gotol:OK
#359/1 verifier_ldsx/LDSX, S8:OK
#359/2 verifier_ldsx/LDSX, S8 @unpriv:OK
#359/3 verifier_ldsx/LDSX, S16:OK
#359/4 verifier_ldsx/LDSX, S16 @unpriv:OK
#359/5 verifier_ldsx/LDSX, S32:OK
#359/6 verifier_ldsx/LDSX, S32 @unpriv:OK
#359/7 verifier_ldsx/LDSX, S8 range checking, privileged:OK
#359/8 verifier_ldsx/LDSX, S16 range checking:OK
#359/9 verifier_ldsx/LDSX, S16 range checking @unpriv:OK
#359/10 verifier_ldsx/LDSX, S32 range checking:OK
#359/11 verifier_ldsx/LDSX, S32 range checking @unpriv:OK
#359 verifier_ldsx:OK
#370/1 verifier_movsx/MOV32SX, S8:OK
#370/2 verifier_movsx/MOV32SX, S8 @unpriv:OK
#370/3 verifier_movsx/MOV32SX, S16:OK
#370/4 verifier_movsx/MOV32SX, S16 @unpriv:OK
#370/5 verifier_movsx/MOV64SX, S8:OK
#370/6 verifier_movsx/MOV64SX, S8 @unpriv:OK
#370/7 verifier_movsx/MOV64SX, S16:OK
#370/8 verifier_movsx/MOV64SX, S16 @unpriv:OK
#370/9 verifier_movsx/MOV64SX, S32:OK
#370/10 verifier_movsx/MOV64SX, S32 @unpriv:OK
#370/11 verifier_movsx/MOV32SX, S8, range_check:OK
#370/12 verifier_movsx/MOV32SX, S8, range_check @unpriv:OK
#370/13 verifier_movsx/MOV32SX, S16, range_check:OK
#370/14 verifier_movsx/MOV32SX, S16, range_check @unpriv:OK
#370/15 verifier_movsx/MOV32SX, S16, range_check 2:OK
#370/16 verifier_movsx/MOV32SX, S16, range_check 2 @unpriv:OK
#370/17 verifier_movsx/MOV64SX, S8, range_check:OK
#370/18 verifier_movsx/MOV64SX, S8, range_check @unpriv:OK
#370/19 verifier_movsx/MOV64SX, S16, range_check:OK
#370/20 verifier_movsx/MOV64SX, S16, range_check @unpriv:OK
#370/21 verifier_movsx/MOV64SX, S32, range_check:OK
#370/22 verifier_movsx/MOV64SX, S32, range_check @unpriv:OK
#370/23 verifier_movsx/MOV64SX, S16, R10 Sign Extension:OK
#370/24 verifier_movsx/MOV64SX, S16, R10 Sign Extension @unpriv:OK
#370 verifier_movsx:OK
#382/1 verifier_sdiv/SDIV32, non-zero imm divisor, check 1:OK
#382/2 verifier_sdiv/SDIV32, non-zero imm divisor, check 1 @unpriv:OK
#382/3 verifier_sdiv/SDIV32, non-zero imm divisor, check 2:OK
#382/4 verifier_sdiv/SDIV32, non-zero imm divisor, check 2 @unpriv:OK
#382/5 verifier_sdiv/SDIV32, non-zero imm divisor, check 3:OK
#382/6 verifier_sdiv/SDIV32, non-zero imm divisor, check 3 @unpriv:OK
#382/7 verifier_sdiv/SDIV32, non-zero imm divisor, check 4:OK
#382/8 verifier_sdiv/SDIV32, non-zero imm divisor, check 4 @unpriv:OK
#382/9 verifier_sdiv/SDIV32, non-zero imm divisor, check 5:OK
#382/10 verifier_sdiv/SDIV32, non-zero imm divisor, check 5 @unpriv:OK
#382/11 verifier_sdiv/SDIV32, non-zero imm divisor, check 6:OK
#382/12 verifier_sdiv/SDIV32, non-zero imm divisor, check 6 @unpriv:OK
#382/13 verifier_sdiv/SDIV32, non-zero imm divisor, check 7:OK
#382/14 verifier_sdiv/SDIV32, non-zero imm divisor, check 7 @unpriv:OK
#382/15 verifier_sdiv/SDIV32, non-zero imm divisor, check 8:OK
#382/16 verifier_sdiv/SDIV32, non-zero imm divisor, check 8 @unpriv:OK
#382/17 verifier_sdiv/SDIV32, non-zero reg divisor, check 1:OK
#382/18 verifier_sdiv/SDIV32, non-zero reg divisor, check 1 @unpriv:OK
#382/19 verifier_sdiv/SDIV32, non-zero reg divisor, check 2:OK
#382/20 verifier_sdiv/SDIV32, non-zero reg divisor, check 2 @unpriv:OK
#382/21 verifier_sdiv/SDIV32, non-zero reg divisor, check 3:OK
#382/22 verifier_sdiv/SDIV32, non-zero reg divisor, check 3 @unpriv:OK
#382/23 verifier_sdiv/SDIV32, non-zero reg divisor, check 4:OK
#382/24 verifier_sdiv/SDIV32, non-zero reg divisor, check 4 @unpriv:OK
#382/25 verifier_sdiv/SDIV32, non-zero reg divisor, check 5:OK
#382/26 verifier_sdiv/SDIV32, non-zero reg divisor, check 5 @unpriv:OK
#382/27 verifier_sdiv/SDIV32, non-zero reg divisor, check 6:OK
#382/28 verifier_sdiv/SDIV32, non-zero reg divisor, check 6 @unpriv:OK
#382/29 verifier_sdiv/SDIV32, non-zero reg divisor, check 7:OK
#382/30 verifier_sdiv/SDIV32, non-zero reg divisor, check 7 @unpriv:OK
#382/31 verifier_sdiv/SDIV32, non-zero reg divisor, check 8:OK
#382/32 verifier_sdiv/SDIV32, non-zero reg divisor, check 8 @unpriv:OK
#382/33 verifier_sdiv/SDIV64, non-zero imm divisor, check 1:OK
#382/34 verifier_sdiv/SDIV64, non-zero imm divisor, check 1 @unpriv:OK
#382/35 verifier_sdiv/SDIV64, non-zero imm divisor, check 2:OK
#382/36 verifier_sdiv/SDIV64, non-zero imm divisor, check 2 @unpriv:OK
#382/37 verifier_sdiv/SDIV64, non-zero imm divisor, check 3:OK
#382/38 verifier_sdiv/SDIV64, non-zero imm divisor, check 3 @unpriv:OK
#382/39 verifier_sdiv/SDIV64, non-zero imm divisor, check 4:OK
#382/40 verifier_sdiv/SDIV64, non-zero imm divisor, check 4 @unpriv:OK
#382/41 verifier_sdiv/SDIV64, non-zero imm divisor, check 5:OK
#382/42 verifier_sdiv/SDIV64, non-zero imm divisor, check 5 @unpriv:OK
#382/43 verifier_sdiv/SDIV64, non-zero imm divisor, check 6:OK
#382/44 verifier_sdiv/SDIV64, non-zero imm divisor, check 6 @unpriv:OK
#382/45 verifier_sdiv/SDIV64, non-zero reg divisor, check 1:OK
#382/46 verifier_sdiv/SDIV64, non-zero reg divisor, check 1 @unpriv:OK
#382/47 verifier_sdiv/SDIV64, non-zero reg divisor, check 2:OK
#382/48 verifier_sdiv/SDIV64, non-zero reg divisor, check 2 @unpriv:OK
#382/49 verifier_sdiv/SDIV64, non-zero reg divisor, check 3:OK
#382/50 verifier_sdiv/SDIV64, non-zero reg divisor, check 3 @unpriv:OK
#382/51 verifier_sdiv/SDIV64, non-zero reg divisor, check 4:OK
#382/52 verifier_sdiv/SDIV64, non-zero reg divisor, check 4 @unpriv:OK
#382/53 verifier_sdiv/SDIV64, non-zero reg divisor, check 5:OK
#382/54 verifier_sdiv/SDIV64, non-zero reg divisor, check 5 @unpriv:OK
#382/55 verifier_sdiv/SDIV64, non-zero reg divisor, check 6:OK
#382/56 verifier_sdiv/SDIV64, non-zero reg divisor, check 6 @unpriv:OK
#382/57 verifier_sdiv/SMOD32, non-zero imm divisor, check 1:OK
#382/58 verifier_sdiv/SMOD32, non-zero imm divisor, check 1 @unpriv:OK
#382/59 verifier_sdiv/SMOD32, non-zero imm divisor, check 2:OK
#382/60 verifier_sdiv/SMOD32, non-zero imm divisor, check 2 @unpriv:OK
#382/61 verifier_sdiv/SMOD32, non-zero imm divisor, check 3:OK
#382/62 verifier_sdiv/SMOD32, non-zero imm divisor, check 3 @unpriv:OK
#382/63 verifier_sdiv/SMOD32, non-zero imm divisor, check 4:OK
#382/64 verifier_sdiv/SMOD32, non-zero imm divisor, check 4 @unpriv:OK
#382/65 verifier_sdiv/SMOD32, non-zero imm divisor, check 5:OK
#382/66 verifier_sdiv/SMOD32, non-zero imm divisor, check 5 @unpriv:OK
#382/67 verifier_sdiv/SMOD32, non-zero imm divisor, check 6:OK
#382/68 verifier_sdiv/SMOD32, non-zero imm divisor, check 6 @unpriv:OK
#382/69 verifier_sdiv/SMOD32, non-zero reg divisor, check 1:OK
#382/70 verifier_sdiv/SMOD32, non-zero reg divisor, check 1 @unpriv:OK
#382/71 verifier_sdiv/SMOD32, non-zero reg divisor, check 2:OK
#382/72 verifier_sdiv/SMOD32, non-zero reg divisor, check 2 @unpriv:OK
#382/73 verifier_sdiv/SMOD32, non-zero reg divisor, check 3:OK
#382/74 verifier_sdiv/SMOD32, non-zero reg divisor, check 3 @unpriv:OK
#382/75 verifier_sdiv/SMOD32, non-zero reg divisor, check 4:OK
#382/76 verifier_sdiv/SMOD32, non-zero reg divisor, check 4 @unpriv:OK
#382/77 verifier_sdiv/SMOD32, non-zero reg divisor, check 5:OK
#382/78 verifier_sdiv/SMOD32, non-zero reg divisor, check 5 @unpriv:OK
#382/79 verifier_sdiv/SMOD32, non-zero reg divisor, check 6:OK
#382/80 verifier_sdiv/SMOD32, non-zero reg divisor, check 6 @unpriv:OK
#382/81 verifier_sdiv/SMOD64, non-zero imm divisor, check 1:OK
#382/82 verifier_sdiv/SMOD64, non-zero imm divisor, check 1 @unpriv:OK
#382/83 verifier_sdiv/SMOD64, non-zero imm divisor, check 2:OK
#382/84 verifier_sdiv/SMOD64, non-zero imm divisor, check 2 @unpriv:OK
#382/85 verifier_sdiv/SMOD64, non-zero imm divisor, check 3:OK
#382/86 verifier_sdiv/SMOD64, non-zero imm divisor, check 3 @unpriv:OK
#382/87 verifier_sdiv/SMOD64, non-zero imm divisor, check 4:OK
#382/88 verifier_sdiv/SMOD64, non-zero imm divisor, check 4 @unpriv:OK
#382/89 verifier_sdiv/SMOD64, non-zero imm divisor, check 5:OK
#382/90 verifier_sdiv/SMOD64, non-zero imm divisor, check 5 @unpriv:OK
#382/91 verifier_sdiv/SMOD64, non-zero imm divisor, check 6:OK
#382/92 verifier_sdiv/SMOD64, non-zero imm divisor, check 6 @unpriv:OK
#382/93 verifier_sdiv/SMOD64, non-zero imm divisor, check 7:OK
#382/94 verifier_sdiv/SMOD64, non-zero imm divisor, check 7 @unpriv:OK
#382/95 verifier_sdiv/SMOD64, non-zero imm divisor, check 8:OK
#382/96 verifier_sdiv/SMOD64, non-zero imm divisor, check 8 @unpriv:OK
#382/97 verifier_sdiv/SMOD64, non-zero reg divisor, check 1:OK
#382/98 verifier_sdiv/SMOD64, non-zero reg divisor, check 1 @unpriv:OK
#382/99 verifier_sdiv/SMOD64, non-zero reg divisor, check 2:OK
#382/100 verifier_sdiv/SMOD64, non-zero reg divisor, check 2 @unpriv:OK
#382/101 verifier_sdiv/SMOD64, non-zero reg divisor, check 3:OK
#382/102 verifier_sdiv/SMOD64, non-zero reg divisor, check 3 @unpriv:OK
#382/103 verifier_sdiv/SMOD64, non-zero reg divisor, check 4:OK
#382/104 verifier_sdiv/SMOD64, non-zero reg divisor, check 4 @unpriv:OK
#382/105 verifier_sdiv/SMOD64, non-zero reg divisor, check 5:OK
#382/106 verifier_sdiv/SMOD64, non-zero reg divisor, check 5 @unpriv:OK
#382/107 verifier_sdiv/SMOD64, non-zero reg divisor, check 6:OK
#382/108 verifier_sdiv/SMOD64, non-zero reg divisor, check 6 @unpriv:OK
#382/109 verifier_sdiv/SMOD64, non-zero reg divisor, check 7:OK
#382/110 verifier_sdiv/SMOD64, non-zero reg divisor, check 7 @unpriv:OK
#382/111 verifier_sdiv/SMOD64, non-zero reg divisor, check 8:OK
#382/112 verifier_sdiv/SMOD64, non-zero reg divisor, check 8 @unpriv:OK
#382/113 verifier_sdiv/SDIV32, zero divisor:OK
#382/114 verifier_sdiv/SDIV32, zero divisor @unpriv:OK
#382/115 verifier_sdiv/SDIV64, zero divisor:OK
#382/116 verifier_sdiv/SDIV64, zero divisor @unpriv:OK
#382/117 verifier_sdiv/SMOD32, zero divisor:OK
#382/118 verifier_sdiv/SMOD32, zero divisor @unpriv:OK
#382/119 verifier_sdiv/SMOD64, zero divisor:OK
#382/120 verifier_sdiv/SMOD64, zero divisor @unpriv:OK
#382 verifier_sdiv:OK
Summary: 5/163 PASSED, 0 SKIPPED, 0 FAILED

As the selftests don't compile for 32-bit architectures without
modifications due to long being 32-bit,
I have added new tests to lib/test_bpf.c for cpuv4 insns, all are passing:

test_bpf: Summary: 1052 PASSED, 0 FAILED, [891/1040 JIT'ed]
test_bpf: test_tail_calls: Summary: 10 PASSED, 0 FAILED, [10/10 JIT'ed]
test_bpf: test_skb_segment: Summary: 2 PASSED, 0 FAILED

[1] https://lore.kernel.org/all/mb61p5y4u3ptd.fsf@amazon.com/

Puranjay Mohan (9):
arm32, bpf: add support for 32-bit offset jmp instruction
arm32, bpf: add support for sign-extension load instruction
arm32, bpf: add support for sign-extension mov instruction
arm32, bpf: add support for unconditional bswap instruction
arm32, bpf: add support for 32-bit signed division
arm32, bpf: add support for 64 bit division instruction
selftest, bpf: enable cpu v4 tests for arm32
bpf/tests: add tests for cpuv4 instructions
MAINTAINERS: Add myself for ARM32 BPF JIT maintainer.

MAINTAINERS | 5 +-
arch/arm/net/bpf_jit_32.c | 280 ++++++++++++-
arch/arm/net/bpf_jit_32.h | 4 +
include/linux/filter.h | 50 ++-
lib/test_bpf.c | 371 ++++++++++++++++++
.../selftests/bpf/progs/verifier_bswap.c | 3 +-
.../selftests/bpf/progs/verifier_gotol.c | 3 +-
.../selftests/bpf/progs/verifier_ldsx.c | 3 +-
.../selftests/bpf/progs/verifier_movsx.c | 3 +-
.../selftests/bpf/progs/verifier_sdiv.c | 3 +-
10 files changed, 694 insertions(+), 31 deletions(-)

--
2.39.2