> I'll build alpha toolchain / qemu root and will try to cook > nicer patch with compile-time safety checks. Sent reworked patch: http://marc.info/?l=linux-alpha&m=131318270531656&w=2 Yelling at the header I've found minor nit: ... #define SET_UNALIGN_CTL(task,value) ({ \ task_thread_info(task)->flags = ((task_thread_info(task)->flags & \ ~ALPHA_UAC_MASK) | (((value) << ALPHA_UAC_SHIFT) & (1<<TIF_UAC_NOPRINT))\ | (((value) << (ALPHA_UAC_SHIFT + 1)) & (1<<TIF_UAC_SIGBUS)) \ | (((value) << (ALPHA_UAC_SHIFT - 1)) & (1<<TIF_UAC_NOFIX)));\ 0; }) #define GET_UNALIGN_CTL(task,value) ({ \ put_user((task_thread_info(task)->flags & (1 << TIF_UAC_NOPRINT))\ >> ALPHA_UAC_SHIFT \ | (task_thread_info(task)->flags & (1 << TIF_UAC_SIGBUS))\ >> (ALPHA_UAC_SHIFT + 1) \ | (task_thread_info(task)->flags & (1 << TIF_UAC_NOFIX))\ >> (ALPHA_UAC_SHIFT - 1), \ (int __user *)(value)); \ }) The macros SET_UNALIGN_CTL/GET_UNALIGN_CTL are used only in kernel/sys.c:prctl syscall. > | (((value) << ALPHA_UAC_SHIFT) & (1<<TIF_UAC_NOPRINT)) prctl.h: # define PR_UNALIGN_NOPRINT 1 > | (((value) << (ALPHA_UAC_SHIFT + 1)) & (1<<TIF_UAC_SIGBUS)) prctl.h: # define PR_UNALIGN_SIGBUS 2 > | (((value) << (ALPHA_UAC_SHIFT - 1)) & (1<<TIF_UAC_NOFIX))); prctl.h: no '4' value Do you think it's worth adding to userspace interface or should one just remove it from handled by prctl flags [ABI change]? Thanks! diff --git a/include/linux/prctl.h b/include/linux/prctl.h index a3baeb2..f66539a 100644 --- a/include/linux/prctl.h +++ b/include/linux/prctl.h @@ -15,6 +15,7 @@ #define PR_SET_UNALIGN 6 # define PR_UNALIGN_NOPRINT 1 /* silently fix up unaligned user accesses */ # define PR_UNALIGN_SIGBUS 2 /* generate SIGBUS on unaligned user access */ +# define PR_UNALIGN_NOFIX 4 /* skip offending instruction and do nothing */ /* Get/set whether or not to drop capabilities on setuid() away from * uid 0 (as per security/commoncap.c) */ -- Sergei
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