Commit Graph

2 Commits

Author SHA1 Message Date
Tony Luck 548acf1923 x86/mm: Expand the exception table logic to allow new handling options
Huge amounts of help from  Andy Lutomirski and Borislav Petkov to
produce this. Andy provided the inspiration to add classes to the
exception table with a clever bit-squeezing trick, Boris pointed
out how much cleaner it would all be if we just had a new field.

Linus Torvalds blessed the expansion with:

  ' I'd rather not be clever in order to save just a tiny amount of space
    in the exception table, which isn't really criticial for anybody. '

The third field is another relative function pointer, this one to a
handler that executes the actions.

We start out with three handlers:

 1: Legacy - just jumps the to fixup IP
 2: Fault - provide the trap number in %ax to the fixup code
 3: Cleaned up legacy for the uaccess error hack

Signed-off-by: Tony Luck <tony.luck@intel.com>
Reviewed-by: Borislav Petkov <bp@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/f6af78fcbd348cf4939875cfda9c19689b5e50b8.1455732970.git.tony.luck@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-02-18 09:21:46 +01:00
Amerigo Wang c368b4921b Doc: move Documentation/exception.txt into x86 subdir
exception.txt only explains the code on x86, so it's better to
move it into Documentation/x86 directory.

And also rename it to exception-tables.txt which looks much
more reasonable.

This patch is on top of the previous one.

Signed-off-by: WANG Cong <amwang@redhat.com>
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-07-10 19:10:32 -07:00