On 02/13/2014 04:19 AM, Andy Lutomirski wrote:
On 02/12/2014 10:36 AM, Qiaowei Ren wrote:
An access to an invalid bound directory entry will cause a #BR
exception. This patch hook #BR exception handler to allocate
one bound table and bind it with that buond directory entry.
This will avoid the need of forwarding the #BR exception
to the user space when bound directory has invalid entry.
Signed-off-by: Qiaowei Ren <qiaowei....@intel.com>
---
+void do_mpx_bt_fault(struct xsave_struct *xsave_buf)
+{
+ unsigned long status;
+ unsigned long bd_entry, bd_base;
+ unsigned long bd_size = 1UL << (MPX_L1_BITS+MPX_L1_SHIFT);
+
+ bd_base = xsave_buf->bndcsr.cfg_reg_u & MPX_BNDCFG_ADDR_MASK;
+ status = xsave_buf->bndcsr.status_reg;
+
+ bd_entry = status & MPX_BNDSTA_ADDR_MASK;
+ if ((bd_entry >= bd_base) && (bd_entry < bd_base + bd_size))
+ allocate_bt(bd_entry);
+}
This still just loops on failure, right?
Seems like that SIGBUS should be raised if the allocation fail.
if (!do_mpx_bt_fault(xsave_buf))
force_sig(SIGBUS, tsk);
Thanks,
Qiaowei
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