target/linux/pxa/patches-2.6.21/032-misalignment-handling.patch

   1 Change the default alingment handling to not be silent failure
   2 --- a/arch/arm/mm/alignment.c
   3 +++ b/arch/arm/mm/alignment.c
   4 @@ -797,6 +797,8 @@ static int __init alignment_init(void)
   5         res->write_proc = proc_alignment_write;
   6  #endif
   7
   8 +       ai_usermode = CONFIG_ALIGNMENT_HANDLING;
   9 +
  10         hook_fault_code(1, do_alignment, SIGILL, "alignment exception");
  11         hook_fault_code(3, do_alignment, SIGILL, "alignment exception");
  12
  13 --- a/arch/arm/Kconfig
  14 +++ b/arch/arm/Kconfig
  15 @@ -709,6 +709,19 @@ config ALIGNMENT_TRAP
  16           correct operation of some network protocols. With an IP-only
  17           configuration it is safe to say N, otherwise say Y.
  18
  19 +config ALIGNMENT_HANDLING
  20 +       hex "Userspace alignment trap handling"
  21 +       default "0x3"
  22 +       depends on ALIGNMENT_TRAP
  23 +       help
  24 +         How should we handle alignment errors in userspace by default?  This is a bitfield where:
  25 +         0 - silently ignore alignment errors (will lead to unexpected results)
  26 +         1 - report alignment errors through printk (will lead to unexpected results, but you'll know about them)
  27 +         2 - fix the alignment and make things work properly (performance degradation for un-aligned code)
  28 +         4 - raise SIGBUS on alignment traps
  29 +         A good number to choose is probably either 3 (work slowly but log message) or 5 (log message and SIGBUS).
  30 +         You can change the behavior at runtime through /proc/cpu/alignment if you have PROC_FS enabled.
  31 +
  32  endmenu
  33
  34  menu "Boot options"