On 12/16/2015 09:02 AM, Michael Kerrisk (man-pages) wrote: > (Thanks, Carlos.) > >> Here is a patch for Linux man page. > > Thanks, H.J. I applied the patch and tweaked your text somewhat. > Does the following look okay? > > LD_PREFER_MAP_32BIT_EXEC > (x86-64 only)(glibc since 2.23) According to the Intel > Silvermont software optimization guide, for 64-bit appli‐ > cations, branch prediction performance can be negatively > impacted when the target of a branch is more than 4GB away > from the branch. If this environment variable is set (to > any value), ld.so will first try to map executable pages > using the mmap(2) MAP_32BIT flag, and fall back to mapping > without that flag if that attempt fails. NB: MAP_32BIT > will map to the low 2GB (not 2GB) of the address space. > Because MAP_32BIT reduces the address range available for > address space layout randomization (ASLR), LD_PRE‐ > FER_MAP_32BIT_EXEC is always disabled in secure-execution > mode. Looks great. Thanks for the quick turnaround Michael! Cheers, Carlos. -- To unsubscribe from this list: send the line "unsubscribe linux-man" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
