From: Nick Desaulniers <ndesaulniers@google.com>
To: tglx@linutronix.de, mingo@redhat.com, bp@alien8.de
Cc: peterz@infradead.org, clang-built-linux@googlegroups.com,
linux-kernel@vger.kernel.org, yamada.masahiro@socionext.com,
Nick Desaulniers <ndesaulniers@google.com>
Subject: [PATCH v3 0/2] Support kexec/kdump for clang built kernel
Date: Tue, 23 Jul 2019 14:24:12 -0700 [thread overview]
Message-ID: <20190723212418.36379-3-ndesaulniers@google.com> (raw)
In-Reply-To: <20190723212418.36379-1-ndesaulniers@google.com>
1. Reuse the implementation of memcpy and memset instead of relying on
__builtin_memcpy and __builtin_memset as it causes infinite recursion
in Clang (at any opt level) or GCC at -O2.
2. Don't reset KBUILD_CFLAGS, rather filter CONFIG_FUNCTION_TRACER,
CONFIG_STACKPROTECTOR, and CONFIG_STACKPROTECTOR_STRONG flags via
`CFLAGS_REMOVE_<file>.o'
A good test of this series (besides boot testing a kexec kernel):
* There should be no undefined symbols in arch/x86/purgatory/purgatory.ro:
$ nm arch/x86/purgatory/purgatory.ro
particularly `warn`, `bcmp`, `__stack_chk_fail`, `memcpy` or `memset`.
* `-pg`, `-fstack-protector`, `-fstack-protector-strong` should not be
added to the command line for the c source files under arch/x86/purgatory/
when compiling with CONFIG_FUNCTION_TRACER=y, CONFIG_STACKPROTECTOR=y,
and CONFIG_STACKPROTECTOR_STRONG=y.
V3 of: https://groups.google.com/forum/#!msg/clang-built-linux/GzThkAkZqqI/J727I6vpBwAJ
Nick Desaulniers (2):
x86/purgatory: do not use __builtin_memcpy and __builtin_memset
x86/purgatory: use CFLAGS_REMOVE rather than reset KBUILD_CFLAGS
arch/x86/boot/string.c | 7 +++++++
arch/x86/purgatory/Makefile | 29 ++++++++++++++++++++++++-----
arch/x86/purgatory/purgatory.c | 6 ++++++
arch/x86/purgatory/string.c | 23 -----------------------
4 files changed, 37 insertions(+), 28 deletions(-)
delete mode 100644 arch/x86/purgatory/string.c
--
2.22.0.709.g102302147b-goog
next prev parent reply other threads:[~2019-07-23 21:24 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-23 21:24 [PATCH v3 1/2] x86/purgatory: do not use __builtin_memcpy and __builtin_memset Nick Desaulniers
2019-07-23 21:24 ` [PATCH v3 2/2] x86/purgatory: use CFLAGS_REMOVE rather than reset KBUILD_CFLAGS Nick Desaulniers
2019-07-24 10:35 ` Thomas Gleixner
2019-07-24 23:49 ` Vaibhav Rustagi
2019-07-23 21:24 ` Nick Desaulniers [this message]
2019-07-24 10:33 ` [PATCH v3 1/2] x86/purgatory: do not use __builtin_memcpy and __builtin_memset Thomas Gleixner
2019-07-24 20:55 ` Vaibhav Rustagi
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