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Based on 1 normalized pattern(s):
this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation either version 2 of the license or at
your option any later version
extracted by the scancode license scanner the SPDX license identifier
GPL-2.0-or-later
has been chosen to replace the boilerplate/reference in 3029 file(s).
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Currently, we expect to be able to reach ftrace_caller() from all
ftrace-enabled functions through a single relative branch. With large
kernel configs, we see functions outside of 32MB of ftrace_caller()
causing ftrace_init() to bail.
In such configurations, gcc/ld emits two types of trampolines for mcount():
1. A long_branch, which has a single branch to mcount() for functions that
are one hop away from mcount():
c0000000019e8544 <00031b56.long_branch._mcount>:
c0000000019e8544: 4a 69 3f ac b c00000000007c4f0 <._mcount>
2. A plt_branch, for functions that are farther away from mcount():
c0000000051f33f8 <0008ba04.plt_branch._mcount>:
c0000000051f33f8: 3d 82 ff a4 addis r12,r2,-92
c0000000051f33fc: e9 8c 04 20 ld r12,1056(r12)
c0000000051f3400: 7d 89 03 a6 mtctr r12
c0000000051f3404: 4e 80 04 20 bctr
We can reuse those trampolines for ftrace if we can have those
trampolines go to ftrace_caller() instead. However, with ABIv2, we
cannot depend on r2 being valid. As such, we use only the long_branch
trampolines by patching those to instead branch to ftrace_caller or
ftrace_regs_caller.
In addition, we add additional trampolines around .text and .init.text
to catch locations that are covered by the plt branches. This allows
ftrace to work with most large kernel configurations.
For now, we always patch the trampolines to go to ftrace_regs_caller,
which is slightly inefficient. This can be optimized further at a later
point.
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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We've had dynamic ftrace support for over 9 years since Steve first
wrote it, all the distros use dynamic, and static is basically
untested these days, so drop support for static ftrace.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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Split ftrace_64.S further retaining the core ftrace 64-bit aspects
in ftrace_64.S and moving ftrace_caller() and ftrace_graph_caller() into
separate files based on -mprofile-kernel. The livepatch routines are all
now contained within the mprofile file.
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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entry_*.S now includes a lot more than just kernel entry/exit code. As a
first step at cleaning this up, let's split out the ftrace bits into
separate files. Also move all related tracing code into a new trace/
subdirectory.
No functional changes.
Suggested-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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