On Thu, 3 Dec 2015, Dave Hansen wrote: > vma->vm_flags is an 'unsigned long', so has space for 32 flags > on 32-bit architectures. The high 32 bits are unused on 64-bit > platforms. We've steered away from using the unused high VMA > bits for things because we would have difficulty supporting it > on 32-bit. > > Protection Keys are not available in 32-bit mode, so there is > no concern about supporting this feature in 32-bit mode or on > 32-bit CPUs. > > This patch carves out 4 bits from the high half of > vma->vm_flags and allows architectures to set config option > to make them available. > > Sparse complains about these constants unless we explicitly > call them "UL". > > Signed-off-by: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx> Reviewed-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>