H. Peter Anvin 706276543b x86, extable: Switch to relative exception table entries ... Switch to using relative exception table entries on x86. On i386, this has the advantage that the exception table entries don't need to be relocated; on x86-64 this means the exception table entries take up only half the space. In either case, a 32-bit delta is sufficient, as the range of kernel code addresses is limited. Since part of the goal is to avoid needing to adjust the entries when the kernel is relocated, the old trick of using addresses in the NULL pointer range to indicate uaccess_err no longer works (and unlike RISC architectures we can't use a flag bit); instead use an delta just below +2G to indicate these special entries. The reach is still limited to a single instruction. Signed-off-by: H. Peter Anvin <hpa@zytor.com> Cc: David Daney <david.daney@cavium.com> Link: http://lkml.kernel.org/r/CA%2B55aFyijf43qSu3N9nWHEBwaGbb7T2Oq9A=9EyR=Jtyqfq_cQ@mail.gmail.com		2012-04-20 17:22:34 -07:00
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asm	x86, extable: Switch to relative exception table entries	2012-04-20 17:22:34 -07:00