[PATCH 0/2] s390/ftrace: implement hotpatching

From: Ilya Leoshkevich
Date: Wed Jul 28 2021 - 17:26:30 EST


Hello,

This series implements the stop_machine()-less ftrace code patching
for s390. It's trickier than that of e.g. Intel, because the only
on-the-fly code patching allowed by s390 is changing a mask of a
conditional branch instruction. Patch 1 contains a new common code hook
that we need for that, patch 2 contains the actual implementation as
well as explanation of all the small details.

We would like to take this series through the s390 tree, and we need a
review on the patch 1 for that. Could you please take a look?

Best regards,
Ilya

Ilya Leoshkevich (2):
ftrace: Introduce ftrace_need_init_nop()
s390/ftrace: implement hotpatching

arch/s390/include/asm/ftrace.h | 46 +------
arch/s390/include/asm/ftrace.lds.h | 21 +++
arch/s390/include/asm/module.h | 8 ++
arch/s390/kernel/ftrace.c | 207 ++++++++++++++++++++++++++---
arch/s390/kernel/ftrace.h | 24 ++++
arch/s390/kernel/module.c | 45 +++++++
arch/s390/kernel/vmlinux.lds.S | 2 +
include/linux/ftrace.h | 16 +++
kernel/trace/ftrace.c | 4 +-
9 files changed, 314 insertions(+), 59 deletions(-)
create mode 100644 arch/s390/include/asm/ftrace.lds.h
create mode 100644 arch/s390/kernel/ftrace.h

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2.31.1