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

   1 Change the default alingment handling to not be silent failure
   2 Index: linux-2.6.21.7/arch/arm/mm/alignment.c
   3 ===================================================================
   4 --- linux-2.6.21.7.orig/arch/arm/mm/alignment.c
   5 +++ linux-2.6.21.7/arch/arm/mm/alignment.c
   6 @@ -797,6 +797,8 @@ static int __init alignment_init(void)
   7         res->write_proc = proc_alignment_write;
   8  #endif
   9
  10 +       ai_usermode = CONFIG_ALIGNMENT_HANDLING;
  11 +
  12         hook_fault_code(1, do_alignment, SIGILL, "alignment exception");
  13         hook_fault_code(3, do_alignment, SIGILL, "alignment exception");
  14
  15 Index: linux-2.6.21.7/arch/arm/Kconfig
  16 ===================================================================
  17 --- linux-2.6.21.7.orig/arch/arm/Kconfig
  18 +++ linux-2.6.21.7/arch/arm/Kconfig
  19 @@ -709,6 +709,19 @@ config ALIGNMENT_TRAP
  20           correct operation of some network protocols. With an IP-only
  21           configuration it is safe to say N, otherwise say Y.
  22
  23 +config ALIGNMENT_HANDLING
  24 +       hex "Userspace alignment trap handling"
  25 +       default "0x3"
  26 +       depends on ALIGNMENT_TRAP
  27 +       help
  28 +         How should we handle alignment errors in userspace by default?  This is a bitfield where:
  29 +         0 - silently ignore alignment errors (will lead to unexpected results)
  30 +         1 - report alignment errors through printk (will lead to unexpected results, but you'll know about them)
  31 +         2 - fix the alignment and make things work properly (performance degradation for un-aligned code)
  32 +         4 - raise SIGBUS on alignment traps
  33 +         A good number to choose is probably either 3 (work slowly but log message) or 5 (log message and SIGBUS).
  34 +         You can change the behavior at runtime through /proc/cpu/alignment if you have PROC_FS enabled.
  35 +
  36  endmenu
  37
  38  menu "Boot options"