Re: [PATCH 1/2] arm: Replace CONFIG_HAS_TLS_REG with HWCAP_TLS and check for it on V6

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Li Li wrote:
> Nicolas,
> 
> Thanks for the explanation. :)
> 
> I noticed what you mentioned. Actually, Kconfig says TLS EMU might be
> used in some "old" (e.g. pre-armv6) SMP platforms without TLS
> register. In such a case, could we still ensure it's SMP safe by a
> single ldr?

In that case, the hardware TLS 'mcr' is used, which traps and is
emulated by the undefined instruction handler.  It's not fast but
presumably those platforms don't really matter.

See CONFIG_TLS_REG_EMUL in arch/arm/kernel/traps.c, and 'tls_emu'.

'tls_emu' is a constant, so if a kernel built for TLS emulation is run
on something which has the TLS register, it will not work properly.

-- JAmie
--
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


[Index of Archives]     [Linux Arm (vger)]     [ARM Kernel]     [ARM MSM]     [Linux Tegra]     [Linux WPAN Networking]     [Linux Wireless Networking]     [Maemo Users]     [Linux USB Devel]     [Video for Linux]     [Linux Audio Users]     [Yosemite Trails]     [Linux Kernel]     [Linux SCSI]

  Powered by Linux