* Russell King - ARM Linux <linux@xxxxxxxxxxxxxxxx> [100319 01:49]: > On Thu, Mar 18, 2010 at 06:35:21PM -0700, Tony Lindgren wrote: > > -#if defined(CONFIG_HAS_TLS_REG) > > - mcr p15, 0, r3, c13, c0, 3 @ set TLS register > > -#elif !defined(CONFIG_TLS_REG_EMUL) > > - mov r4, #0xffff0fff > > - str r3, [r4, #-15] @ TLS val at 0xffff0ff0 > > +#if !defined(CONFIG_TLS_REG_EMUL) > > + ldr r4, =elf_hwcap > > + ldr r4, [r4, #0] > > + tst r4, #HWCAP_TLS @ hardware with TLS? > > This is really really inefficient. Both the second ldr and tst will stall > the pipeline because they need to wait for the result of the precending > ldr. Can we do better by re-ordering some instructions? Or set ifdef CONFIG_CPU_V6 and test for the cp15 id register every time.. > Also, the ifndef seems incorrect - if we have TLS_REG_EMUL we seem to omit > all this code. Is the current ifdef elif wrong? The current code does not seem to do anything if TLS_REG_EMUL is set and HAS_TLS_REG is not set. HAS_TLS_REG depends !TLS_REG_EMUL. Regards, Tony -- 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
