On 01/26/2014 12:22 PM, David Rientjes wrote:
On Sun, 26 Jan 2014, Qiaowei Ren wrote:
This patch adds new fields about bound violation into siginfo
structure. si_lower and si_upper are respectively lower bound
and upper bound when bound violation is caused.
These fields will be set in #BR exception handler by decoding
the user instruction and constructing the faulting pointer.
A userspace application can get violation address, lower bound
and upper bound for bound violation from this new siginfo structure.
Signed-off-by: Qiaowei Ren <qiaowei....@intel.com>
Same 32-bit warnings I reported for v2:
arch/x86/kernel/mpx.c: In function ‘do_mpx_bounds’:
arch/x86/kernel/mpx.c:407:3: warning: cast to pointer from integer of different
size [-Wint-to-pointer-cast]
arch/x86/kernel/mpx.c:409:3: warning: cast to pointer from integer of different
size [-Wint-to-pointer-cast]
and the documentation says you explicitly want to support this config.
These types of warnings are usually indicative of real problems when
you're storing upper and lower bits in 32-bit fields after casting them
from 64-bit values.
I'm also not sure if the added fields to the generic struct siginfo can be
justified for this.
According to MPX spec, for 32-bit case, the upper 32-bits of 64-bits
bound register are ignored, and so casting to pointer from 64-bit values
should be not produce any problems.
Thanks,
Qiaowei
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