On Fri, Jan 14, 2011 at 11:43 AM, Russell King - ARM Linux <linux@xxxxxxxxxxxxxxxx> wrote: > On Fri, Jan 14, 2011 at 11:15:19AM -0600, Dave Martin wrote: >> There's another problem which I hadn't spotted before: >> >> In the Thumb case, we risk violating the alignment constraints of the >> code which gets copied (actually, this is also true of the ARM case, >> but less likely to bite). This matters because the code may contain >> literals and other data words -- quite likely given the requirement >> for self-containedness. > > There's a solution to this - require that the thumb function is > preceded by a .align 3 (which according to the GAS documentation I > have means for ARM, it aligns the PC to 1 << 3 not 3 bytes.) > > Also require 8-byte alignment from the allocation function, and make > fncpy() bug if the destination isn't 8-byte aligned. Same for the > source function argument (but ignoring bit 0 of course.) > > We don't then have to mess with rounding allocation sizes up, nor worry > about aligning the destination according to the source or any other > games like that. > > The down-side is wastage of maybe 7 bytes a function, but that's > probably going to happen anyway. > OK, that sounds like a practical compromise. I'll roll this in and repost the patch. Cheers ---Dave -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
