Nicolas Boichat c0387536ed vmlinux.lds.h: Create section for protection against instrumentation ... From: Thomas Gleixner <tglx@linutronix.de> commit 6553896666 upstream. Some code pathes, especially the low level entry code, must be protected against instrumentation for various reasons: - Low level entry code can be a fragile beast, especially on x86. - With NO_HZ_FULL RCU state needs to be established before using it. Having a dedicated section for such code allows to validate with tooling that no unsafe functions are invoked. Add the .noinstr.text section and the noinstr attribute to mark functions. noinstr implies notrace. Kprobes will gain a section check later. Provide also a set of markers: instrumentation_begin()/end() These are used to mark code inside a noinstr function which calls into regular instrumentable text section as safe. The instrumentation markers are only active when CONFIG_DEBUG_ENTRY is enabled as the end marker emits a NOP to prevent the compiler from merging the annotation points. This means the objtool verification requires a kernel compiled with this option. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com> Acked-by: Peter Zijlstra <peterz@infradead.org> Link: https://lkml.kernel.org/r/20200505134100.075416272@linutronix.de [Nicolas: Guard noinstr macro in include/linux/compiler_types.h in __KERNEL__ && !__ASSEMBLY__, otherwise noinstr is expanded in the linker script construct. Upstream does not have this problem as many macros were moved by commit 71391bdd2e ("include/linux/compiler_types.h: don't pollute userspace with macro definitions"). We take the minimal approach here and just guard the new macro. Minor context conflicts in: arch/powerpc/kernel/vmlinux.lds.S include/asm-generic/vmlinux.lds.h include/linux/compiler.h] Signed-off-by: Nicolas Boichat <drinkcat@chromium.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2021-03-24 11:07:31 +01:00
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.gitignore	kbuild: trivial - remove trailing empty lines	2014-06-10 00:04:06 +02:00
devicetable-offsets.c	usb: typec: Bus type for alternate modes	2018-07-02 17:42:36 +02:00
empty.c
file2alias.c	modpost: file2alias: check prototype of handler	2019-04-27 09:36:39 +02:00
Makefile	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
mk_elfconfig.c	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
modpost.c	vmlinux.lds.h: Create section for protection against instrumentation	2021-03-24 11:07:31 +01:00
modpost.h	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
sumversion.c	modpost: delete stale comment	2018-05-03 01:17:44 +09:00