010e593b14
I was writing some MPX test programs and realized that the
current design makes it tricky. I did something like:
bndcfgu |= bnd_dir | BNDCFGU_ENABLE;
xrstor();
printf("xrstor done");
// #BR bounds exception here
prctl(MPX_ENABLE_MANAGEMENT);
and then compiled the app with "-fcheck-pointer-bounds -mmpx"
to enable MPX instrumentation.
The problem is that there is MPX instrumentation inserted in
to the area of the printf(). The kernel gets a bounds exception
and since management isn't yet enabled, it SIGSEGV's.
Add a bit to the documentation to explain a way around this and
where apps need to be careful.
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Dave Hansen <dave@sr71.net>
Link: http://lkml.kernel.org/r/20141212183835.8C581B3E@viggo.jf.intel.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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|---|---|---|
| .. | ||
| i386 | ||
| x86_64 | ||
| 00-INDEX | ||
| boot.txt | ||
| early-microcode.txt | ||
| earlyprintk.txt | ||
| entry_64.txt | ||
| exception-tables.txt | ||
| intel_mpx.txt | ||
| mtrr.txt | ||
| pat.txt | ||
| tlb.txt | ||
| usb-legacy-support.txt | ||
| zero-page.txt | ||