On Wed, Nov 19, 2014 at 05:02:40PM +0100, Ard Biesheuvel wrote: > On 19 November 2014 16:52, Konstantin Khlebnikov <koc...@gmail.com> wrote: > > Do you mean ldr pc, =symbol ? > > > > In this case I get this error: > > > > /tmp/ccAHtONU.s: Assembler messages: > > /tmp/ccAHtONU.s:220: Error: invalid literal constant: pool needs to be > > closer > > > > Probably constant pool doesn't work well in inline assembly. > > > > > > Something like this seems work: > > > > add lr, pc, #4 > > ldr pc, [pc, #-4] > > .long symbol > > > > You can add a '.ltorg' instruction which tells the assembler to dump > the literal pool, but you still need to jump over it, i.e., > > adr lr, 0f > ldr pc, =symbol > .ltorg > 0:
Which is not a good idea either, because the compiler needs to know how far away its own manually generated literal pool is from the instructions which reference it. The .ltorg statement can end up emitting any number of literals at that point, which makes it indeterminant how many words are contained within the asm() statement. Yes, it isn't desirable to waste an entire data cache line per indirect call like the original quote above, but I don't see a practical alternative. -- FTTC broadband for 0.8mile line: currently at 9.5Mbps down 400kbps up according to speedtest.net. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
