[bpf-next,v8,0/2] Support kCFI + BPF on arm64

Message

Sami Tolvanen March 10, 2025, 10:29 p.m. UTC

Hi folks,

These patches add KCFI types to arm64 BPF JIT output. Puranjay and
Maxwell have been working on this for some time now, but I haven't
seen any progress since June 2024, so I decided to pick up the latest
version[1] posted by Maxwell and fix the few remaining issues I
noticed. I confirmed that with these patches applied, I no longer see
CFI failures when running BPF self-tests on arm64.

[1] https://lore.kernel.org/linux-arm-kernel/ptrugmna4xb5o5lo4xislf4rlz7avdmd4pfho5fjwtjj7v422u@iqrwfrbwuxrq/

Sami

---

v8:
- Changed DEFINE_CFI_TYPE to use .4byte to match __CFI_TYPE.
- Changed cfi_get_func_hash() to again use get_kernel_nofault().
- Fixed a panic in bpf_jit_free() by resetting prog->bpf_func before
  calling bpf_jit_binary_pack_hdr().

---

Mark Rutland (1):
  cfi: add C CFI type macro

Puranjay Mohan (1):
  arm64/cfi,bpf: Support kCFI + BPF on arm64

 arch/arm64/include/asm/cfi.h    | 23 ++++++++++++++++++++++
 arch/arm64/kernel/alternative.c | 25 +++++++++++++++++++++++
 arch/arm64/net/bpf_jit_comp.c   | 22 ++++++++++++++++++---
 arch/riscv/kernel/cfi.c         | 35 +++------------------------------
 arch/x86/kernel/alternative.c   | 35 +++------------------------------
 include/linux/cfi_types.h       | 23 ++++++++++++++++++++++
 6 files changed, 96 insertions(+), 67 deletions(-)
 create mode 100644 arch/arm64/include/asm/cfi.h