svn commit: r290413 - in stable: 10/gnu/usr.bin/gdb/kgdb 9/gnu/usr.bin/gdb/kgdb

[John Baldwin]

Author: jhb
Date: Thu Nov  5 21:22:23 2015
New Revision: 290413
URL: https://svnweb.freebsd.org/changeset/base/290413

Log:
  MFC 288371:
  When XSAVE support was added on amd64, the FPU save area was moved
  out of 'struct pcb' and into a variable-sized region after the
  structure.  The kgdb code currently only reads the pcb.  It does not
  read in the FPU save area but instead passes stack garbage as the
  FPU's saved context.  Fixing this would mean determining the proper
  size of the area and fetching it.  However, this state is not saved
  for running CPUs in stoppcbs[], so the callback would also have to
  know to ignore those pcbs.  Instead, just remove the call since it is
  of limited usefulness.  It results in kgdb reporting the state of the
  FPU/SIMD registers in userland, not their current values in the kernel.
  In particular, it does not report the correct state for any code in
  the kernel which does use the FPU and would report incorrect values
  in that case.

Modified:
  stable/9/gnu/usr.bin/gdb/kgdb/trgt_amd64.c
Directory Properties:
  stable/9/gnu/usr.bin/gdb/kgdb/   (props changed)

Changes in other areas also in this revision:
Modified:
  stable/10/gnu/usr.bin/gdb/kgdb/trgt_amd64.c
Directory Properties:
  stable/10/   (props changed)

Modified: stable/9/gnu/usr.bin/gdb/kgdb/trgt_amd64.c
==============================================================================
--- stable/9/gnu/usr.bin/gdb/kgdb/trgt_amd64.c	Thu Nov  5 20:24:56 2015	(r290412)
+++ stable/9/gnu/usr.bin/gdb/kgdb/trgt_amd64.c	Thu Nov  5 21:22:23 2015	(r290413)
@@ -66,7 +66,6 @@ kgdb_trgt_fetch_registers(int regno __un
 	supply_register(AMD64_R8_REGNUM + 6, (char *)&pcb.pcb_r14);
 	supply_register(AMD64_R15_REGNUM, (char *)&pcb.pcb_r15);
 	supply_register(AMD64_RIP_REGNUM, (char *)&pcb.pcb_rip);
-	amd64_supply_fxsave(current_regcache, -1, (struct fpusave *)(&pcb + 1));
 }
 
 void