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Commit 90d304b7 authored by Daniel Borkmann's avatar Daniel Borkmann
Browse files

Merge branch 'bpf-riscv-jit' 



Björn Töpel says:

====================
This v2 series adds an RV64G BPF JIT to the kernel.

At the moment the RISC-V Linux port does not support
CONFIG_HAVE_KPROBES (Patrick Stählin sent out an RFC last year), which
means that CONFIG_BPF_EVENTS is not supported. Thus, no tests
involving BPF_PROG_TYPE_TRACEPOINT, BPF_PROG_TYPE_PERF_EVENT,
BPF_PROG_TYPE_KPROBE and BPF_PROG_TYPE_RAW_TRACEPOINT passes.

The implementation does not support "far branching" (>4KiB).

Test results:
  # modprobe test_bpf
  test_bpf: Summary: 378 PASSED, 0 FAILED, [366/366 JIT'ed]

  # echo 1 > /proc/sys/kernel/unprivileged_bpf_disabled
  # ./test_verifier
  ...
  Summary: 761 PASSED, 507 SKIPPED, 2 FAILED

Note that "test_verifier" was run with one build with
CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS=y and one without, otherwise
many of the the tests that require unaligned access were skipped.

CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS=y:
  # echo 1 > /proc/sys/kernel/unprivileged_bpf_disabled
  # ./test_verifier | grep -c 'NOTE.*unknown align'
  0

No CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS:
  # echo 1 > /proc/sys/kernel/unprivileged_bpf_disabled
  # ./test_verifier | grep -c 'NOTE.*unknown align'
  59

The two failing test_verifier tests are:
  "ld_abs: vlan + abs, test 1"
  "ld_abs: jump around ld_abs"

This is due to that "far branching" involved in those tests.
All tests where done on QEMU emulator version 3.1.50
(v3.1.0-688-g8ae951fbc106). I'll test it on real hardware, when I get
access to it.

I'm routing this patch via bpf-next/netdev mailing list (after a
conversation with Palmer at FOSDEM), mainly because the other JITs
went that path.

Again, thanks for all the comments!

Cheers,
Björn

v1 -> v2:
* Added JMP32 support. (Daniel)
* Add RISC-V to Documentation/sysctl/net.txt. (Daniel)
* Fixed seen_call() asymmetry. (Daniel)
* Fixed broken bpf_flush_icache() range. (Daniel)
* Added alignment annotations to some selftests.

RFCv1 -> v1:
* Cleaned up the Kconfig and net/Makefile. (Christoph)
* Removed the entry-stub and squashed the build/config changes to be
  part of the JIT implementation. (Christoph)
* Simplified the register tracking code. (Daniel)
* Removed unused macros. (Daniel)
* Added myself as maintainer and updated documentation. (Daniel)
* Removed HAVE_EFFICIENT_UNALIGNED_ACCESS. (Christoph, Palmer)
* Added tail-calls and cleaned up the code.
====================

Acked-by: default avatarDavid S. Miller <davem@davemloft.net>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
parents 31de3897 e2c6f50e

Documentation/networking/filter.txt

+9 −7
Original line number Diff line number Diff line
@@ -464,10 +464,11 @@ breakpoints: 0 1 
JIT compiler

------------



The Linux kernel has a built-in BPF JIT compiler for x86_64, SPARC, PowerPC,

ARM, ARM64, MIPS and s390 and can be enabled through CONFIG_BPF_JIT. The JIT

compiler is transparently invoked for each attached filter from user space

or for internal kernel users if it has been previously enabled by root:

The Linux kernel has a built-in BPF JIT compiler for x86_64, SPARC,

PowerPC, ARM, ARM64, MIPS, RISC-V and s390 and can be enabled through

CONFIG_BPF_JIT. The JIT compiler is transparently invoked for each

attached filter from user space or for internal kernel users if it has

been previously enabled by root:



  echo 1 > /proc/sys/net/core/bpf_jit_enable
@@ -603,9 +604,10 @@ got from bpf_prog_create(), and 'ctx' the given context (e.g. 
skb pointer). All constraints and restrictions from bpf_check_classic() apply

before a conversion to the new layout is being done behind the scenes!



Currently, the classic BPF format is being used for JITing on most 32-bit

architectures, whereas x86-64, aarch64, s390x, powerpc64, sparc64, arm32 perform

JIT compilation from eBPF instruction set.

Currently, the classic BPF format is being used for JITing on most

32-bit architectures, whereas x86-64, aarch64, s390x, powerpc64,

sparc64, arm32, riscv (RV64G) perform JIT compilation from eBPF

instruction set.



Some core changes of the new internal format:

Documentation/sysctl/net.txt

+1 −0
Original line number Diff line number Diff line
@@ -52,6 +52,7 @@ two flavors of JITs, the newer eBPF JIT currently supported on: 
  - sparc64

  - mips64

  - s390x

  - riscv



And the older cBPF JIT supported on the following archs:

  - mips

MAINTAINERS

+6 −0
Original line number Diff line number Diff line
@@ -2907,6 +2907,12 @@ L: netdev@vger.kernel.org 
S:	Maintained

F:	arch/powerpc/net/



BPF JIT for RISC-V (RV64G)

M:	Björn Töpel <bjorn.topel@gmail.com>

L:	netdev@vger.kernel.org

S:	Maintained

F:	arch/riscv/net/



BPF JIT for S390

M:	Martin Schwidefsky <schwidefsky@de.ibm.com>

M:	Heiko Carstens <heiko.carstens@de.ibm.com>

arch/riscv/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -49,6 +49,7 @@ config RISCV 
	select RISCV_TIMER

	select GENERIC_IRQ_MULTI_HANDLER

	select ARCH_HAS_PTE_SPECIAL

	select HAVE_EBPF_JIT if 64BIT



config MMU

	def_bool y

arch/riscv/Makefile

+1 −1
Original line number Diff line number Diff line
@@ -77,7 +77,7 @@ KBUILD_IMAGE := $(boot)/Image.gz 


head-y := arch/riscv/kernel/head.o



core-y += arch/riscv/kernel/ arch/riscv/mm/

core-y += arch/riscv/kernel/ arch/riscv/mm/ arch/riscv/net/



libs-y += arch/riscv/lib/