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| author | Thomas Gleixner <tglx@linutronix.de> | 2020-03-09 22:47:17 +0100 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2020-05-19 15:47:20 +0200 |
| commit | 6553896666433e7efec589838b400a2a652b3ffa (patch) | |
| tree | c9dfa95f4349ad1e6cbc42f5e9e824c63e8c3011 /scripts/mod/modpost.c | |
| parent | 2ef96a5bb12be62ef75b5828c0aab838ebb29cb8 (diff) | |
| download | linux-6553896666433e7efec589838b400a2a652b3ffa.tar.bz2 | |
vmlinux.lds.h: Create section for protection against instrumentation
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
Diffstat (limited to 'scripts/mod/modpost.c')
| -rw-r--r-- | scripts/mod/modpost.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 5c3c50c5ec52..0053d4fea847 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -948,7 +948,7 @@ static void check_section(const char *modname, struct elf_info *elf, #define DATA_SECTIONS ".data", ".data.rel" #define TEXT_SECTIONS ".text", ".text.unlikely", ".sched.text", \ - ".kprobes.text", ".cpuidle.text" + ".kprobes.text", ".cpuidle.text", ".noinstr.text" #define OTHER_TEXT_SECTIONS ".ref.text", ".head.text", ".spinlock.text", \ ".fixup", ".entry.text", ".exception.text", ".text.*", \ ".coldtext" |