linux/tools
Puranjay Mohan 4ea43a4355 bpftool: Enable aarch64 ISA extensions for JIT disassembly
The LLVM disassembler needs ISA extension features enabled to correctly
decode instructions from those extensions. On aarch64, without these
features, instructions like LSE atomics (e.g. ldaddal) are silently
decoded as incorrect instructions and disassembly is truncated.

Use LLVMCreateDisasmCPUFeatures() with "+all" features for aarch64
targets so that the disassembler can handle any instruction the kernel
JIT might emit.

Before:

int bench_trigger_uprobe(void * ctx):
bpf_prog_538c6a43d1c6b84c_bench_trigger_uprobe:
; int cpu = bpf_get_smp_processor_id();
   0:   mov     x9, x30
   4:   nop
   8:   stp     x29, x30, [sp, #-16]!
   c:   mov     x29, sp
  10:   stp     xzr, x26, [sp, #-16]!
  14:   mov     x26, sp
  18:   mrs     x10, SP_EL0
  1c:   ldr     w7, [x10, #16]
; __sync_add_and_fetch(&hits[cpu & CPU_MASK].value, 1);
  20:   and     w7, w7, #0xff
; __sync_add_and_fetch(&hits[cpu & CPU_MASK].value, 1);
  24:   lsl     x7, x7, #7
  28:   mov     x0, #-281474976710656
  2c:   movk    x0, #32768, lsl #32
  30:   movk    x0, #35407, lsl #16
  34:   add     x0, x0, x7
  38:   mov     x1, #1
; __sync_add_and_fetch(&hits[cpu & CPU_MASK].value, 1);
  3c:   mov     x1, #1

After:

int bench_trigger_uprobe(void * ctx):
bpf_prog_538c6a43d1c6b84c_bench_trigger_uprobe:
; int cpu = bpf_get_smp_processor_id();
   0:   mov     x9, x30
   4:   nop
   8:   stp     x29, x30, [sp, #-16]!
   c:   mov     x29, sp
  10:   stp     xzr, x26, [sp, #-16]!
  14:   mov     x26, sp
  18:   mrs     x10, SP_EL0
  1c:   ldr     w7, [x10, #16]
; __sync_add_and_fetch(&hits[cpu & CPU_MASK].value, 1);
  20:   and     w7, w7, #0xff
; __sync_add_and_fetch(&hits[cpu & CPU_MASK].value, 1);
  24:   lsl     x7, x7, #7
  28:   mov     x0, #-281474976710656
  2c:   movk    x0, #32768, lsl #32
  30:   movk    x0, #35407, lsl #16
  34:   add     x0, x0, x7
  38:   mov     x1, #1
; __sync_add_and_fetch(&hits[cpu & CPU_MASK].value, 1);
  3c:   ldaddal x1, x1, [x0]
; return 0;
  40:   mov     w7, #0
  44:   ldp     xzr, x26, [sp], #16
  48:   ldp     x29, x30, [sp], #16
  4c:   mov     x0, x7
  50:   ret
  54:   nop
  58:   ldr     x10, #8
  5c:   br      x10

Signed-off-by: Puranjay Mohan <puranjay@kernel.org>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Acked-by: Leon Hwang <leon.hwang@linux.dev>
Acked-by: Quentin Monnet <qmo@kernel.org>
Reviewed-by: Emil Tsalapatis <emil@etsalapatis.com>
Link: https://lore.kernel.org/r/20260318172259.2882792-1-puranjay@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-03-24 08:44:29 -07:00
..
accounting delayacct: fix build regression on accounting tool 2026-02-12 15:45:56 -08:00
arch tools headers UAPI: Update tools' copy of linux/coresight-pmu.h 2026-03-05 17:28:44 -03:00
bootconfig tools/bootconfig: fix fd leak in load_xbc_file() on fstat failure 2026-03-19 08:43:06 +09:00
bpf bpftool: Enable aarch64 ISA extensions for JIT disassembly 2026-03-24 08:44:29 -07:00
build tools build: Fix rust cross compilation 2026-03-04 11:37:30 -03:00
certs
cgroup
counter
crypto
debugging kernel-chktaint: add reporting for tainted modules 2026-01-26 19:07:15 -08:00
dma
docs tools: sphinx-build-wrapper: improve its help message 2026-02-02 09:57:46 -07:00
firewire
firmware
gpio
hv
iio
include perf tools fixes for v7.0: 2026-03-13 14:24:15 -07:00
kvm/kvm_stat
laptop
leds
lib libbpf: Introduce bpf_program__clone() 2026-03-21 13:17:13 -07:00
memory-model
mm
net NFSD 7.0 Release Notes 2026-02-12 08:23:53 -08:00
objtool objtool: Fix Clang jump table detection 2026-03-16 15:31:25 -07:00
pcmcia
perf perf synthetic-events: Fix stale build ID in module MMAP2 records 2026-03-11 17:47:42 -03:00
power cpupower: Add intel_pstate turbo boost support for Intel platforms 2026-03-03 11:18:53 -07:00
rcu
sched
sched_ext tools/sched_ext: Add -fms-extensions to bpf build flags 2026-03-02 22:00:23 -10:00
scripts tools headers: Update the syscall tables and unistd.h, to support the new 'rseq_slice_yield' syscall 2026-03-05 17:20:23 -03:00
sound
spi spi: tools: Add include folder to .gitignore 2026-02-09 12:27:31 +00:00
testing selftests/bpf: Improve connect_force_port test reliability 2026-03-23 11:37:34 -07:00
thermal
time
tracing
usb tools: usb: usbip: remove dead-link from README 2026-01-23 17:16:42 +01:00
verification
virtio
wmi
workqueue
writeback
Makefile