[PATCH bpf-next 0/4] Add ftrace direct call for arm64

From: Xu Kuohai
Date: Tue Sep 13 2022 - 02:24:21 EST


From: Xu Kuohai <xukuohai@xxxxxxxxxx>

This series adds ftrace direct call for arm64, which is required to attach
bpf trampoline to fentry.

Although there is no agreement on how to support ftrace direct call on arm64,
no patch has been posted except the one I posted in [1], so this series
continues the work of [1] with the addition of long jump support. Now ftrace
direct call works regardless of the distance between the callsite and custom
trampoline.

[1] https://lore.kernel.org/bpf/20220518131638.3401509-2-xukuohai@xxxxxxxxxx/

Xu Kuohai (4):
ftrace: Allow users to disable ftrace direct call
arm64: ftrace: Support long jump for ftrace direct call
arm64: ftrace: Add ftrace direct call support
ftrace: Fix dead loop caused by direct call in ftrace selftest

arch/arm64/Kconfig | 2 +
arch/arm64/Makefile | 4 +
arch/arm64/include/asm/ftrace.h | 35 ++++--
arch/arm64/include/asm/patching.h | 2 +
arch/arm64/include/asm/ptrace.h | 6 +-
arch/arm64/kernel/asm-offsets.c | 1 +
arch/arm64/kernel/entry-ftrace.S | 39 ++++--
arch/arm64/kernel/ftrace.c | 198 ++++++++++++++++++++++++++++--
arch/arm64/kernel/patching.c | 14 +++
arch/arm64/net/bpf_jit_comp.c | 4 +
kernel/trace/Kconfig | 7 +-
kernel/trace/ftrace.c | 10 +-
kernel/trace/trace_selftest.c | 2 +
13 files changed, 295 insertions(+), 29 deletions(-)

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2.30.2