svn commit: r328130 - head/sys/arm64/arm64

[Ruslan Bukin]

Author: br
Date: Thu Jan 18 16:20:09 2018
New Revision: 328130
URL: https://svnweb.freebsd.org/changeset/base/328130

Log:
  Set the base address of translation table 0.
  
  This fixes operation on Qualcomm Snapdragon and some other platforms.
  
  During boot time on subsystems initialization we have some amount of
  kernel threads created, then scheduler gives CPU time to each thread.
  Eventually scheduler returns CPU execution back to thread 0. In this
  case writing zero to ttbr0 in cpu_switch leads Qualcomm board to
  reboot (asynchronously, CPU continues execution).
  
  Similar to other kernel threads install a valid physical address
  (kernel pmap) to user page table base register ttbr0.
  
  Reviewed by:	andrew
  Sponsored by:	DARPA, AFRL
  Differential Revision:	https://reviews.freebsd.org/D13536

Modified:
  head/sys/arm64/arm64/machdep.c

Modified: head/sys/arm64/arm64/machdep.c
==============================================================================
--- head/sys/arm64/arm64/machdep.c	Thu Jan 18 15:28:49 2018	(r328129)
+++ head/sys/arm64/arm64/machdep.c	Thu Jan 18 16:20:09 2018	(r328130)
@@ -715,6 +715,9 @@ init_proc0(vm_offset_t kstack)
 	thread0.td_pcb->pcb_vfpcpu = UINT_MAX;
 	thread0.td_frame = &proc0_tf;
 	pcpup->pc_curpcb = thread0.td_pcb;
+
+	/* Set the base address of translation table 0. */
+	thread0.td_proc->p_md.md_l0addr = READ_SPECIALREG(ttbr0_el1);
 }
 
 typedef struct {