svn commit: r296908 - in head/sys: amd64/amd64 i386/i386

[Konstantin Belousov]

Author: kib
Date: Tue Mar 15 15:42:53 2016
New Revision: 296908
URL: https://svnweb.freebsd.org/changeset/base/296908

Log:
  The PKRU state size is 4 bytes, its support makes the XSAVE area size
  non-multiple of 64 bytes.  Thereafter, the user state save area is
  misaligned, which triggers assertion in the debugging kernels, or
  segmentation violation on accesses for non-debugging configs.
  
  Force the desired alignment of the user save area as the fix
  (workaround is to disable bit 9 in the hw.xsave_mask loader tunable).
  This correction is required for booting on the upcoming Intel' Purley
  platform.
  
  Reported and tested by:	"Pieper, Jeffrey E" <jeffrey.e.pieper at intel.com>,
  	jimharris
  Sponsored by:	The FreeBSD Foundation
  MFC after:	3 days

Modified:
  head/sys/amd64/amd64/vm_machdep.c
  head/sys/i386/i386/vm_machdep.c

Modified: head/sys/amd64/amd64/vm_machdep.c
==============================================================================
--- head/sys/amd64/amd64/vm_machdep.c	Tue Mar 15 15:31:17 2016	(r296907)
+++ head/sys/amd64/amd64/vm_machdep.c	Tue Mar 15 15:42:53 2016	(r296908)
@@ -102,8 +102,8 @@ get_pcb_user_save_td(struct thread *td)
 	vm_offset_t p;
 
 	p = td->td_kstack + td->td_kstack_pages * PAGE_SIZE -
-	    cpu_max_ext_state_size;
-	KASSERT((p % 64) == 0, ("Unaligned pcb_user_save area"));
+	    roundup2(cpu_max_ext_state_size, XSAVE_AREA_ALIGN);
+	KASSERT((p % XSAVE_AREA_ALIGN) == 0, ("Unaligned pcb_user_save area"));
 	return ((struct savefpu *)p);
 }
 
@@ -122,7 +122,8 @@ get_pcb_td(struct thread *td)
 	vm_offset_t p;
 
 	p = td->td_kstack + td->td_kstack_pages * PAGE_SIZE -
-	    cpu_max_ext_state_size - sizeof(struct pcb);
+	    roundup2(cpu_max_ext_state_size, XSAVE_AREA_ALIGN) -
+	    sizeof(struct pcb);
 	return ((struct pcb *)p);
 }
 

Modified: head/sys/i386/i386/vm_machdep.c
==============================================================================
--- head/sys/i386/i386/vm_machdep.c	Tue Mar 15 15:31:17 2016	(r296907)
+++ head/sys/i386/i386/vm_machdep.c	Tue Mar 15 15:42:53 2016	(r296908)
@@ -127,8 +127,8 @@ get_pcb_user_save_td(struct thread *td)
 	vm_offset_t p;
 
 	p = td->td_kstack + td->td_kstack_pages * PAGE_SIZE -
-	    cpu_max_ext_state_size;
-	KASSERT((p % 64) == 0, ("Unaligned pcb_user_save area"));
+	    roundup2(cpu_max_ext_state_size, XSAVE_AREA_ALIGN);
+	KASSERT((p % XSAVE_AREA_ALIGN) == 0, ("Unaligned pcb_user_save area"));
 	return ((union savefpu *)p);
 }
 
@@ -147,7 +147,8 @@ get_pcb_td(struct thread *td)
 	vm_offset_t p;
 
 	p = td->td_kstack + td->td_kstack_pages * PAGE_SIZE -
-	    cpu_max_ext_state_size - sizeof(struct pcb);
+	    roundup2(cpu_max_ext_state_size, XSAVE_AREA_ALIGN) -
+	    sizeof(struct pcb);
 	return ((struct pcb *)p);
 }