From mboxrd@z Thu Jan 1 00:00:00 1970 From: dave.martin@linaro.org (Dave Martin) Date: Mon, 16 May 2011 17:31:26 +0100 Subject: [PATCH 0/1] ARM: thumb: Fix thumb mode compilation problems. In-Reply-To: References: <20110513195845.2FFE540CD1@eskimo.mtv.corp.google.com> <20110516103835.GA6955@arm.com> Message-ID: <20110516163126.GB22931@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Mon, May 16, 2011 at 09:06:26AM -0700, Colin Cross wrote: > On Mon, May 16, 2011 at 3:38 AM, Dave Martin wrote: > > On Fri, May 13, 2011 at 12:58:45PM -0700, Vadim Bendebury wrote: > >> > >> This patch won't necessarily apply as it has not been verified on > >> a real hardware, so this is more of an RFC. > >> > >> Vadim Bendebury (1): > >> ? ARM: thumb: Fix thumb mode compilation problems. > >> > >> ?arch/arm/kernel/fiq.c ? ? ? ? | ? 34 ++++++++++++++++++++++++++-------- > >> ?arch/arm/mach-tegra/headsmp.S | ? ?3 ++- > >> ?2 files changed, 28 insertions(+), 9 deletions(-) > >> > >> -- > >> 1.7.3.1 > >> > >> > >> _______________________________________________ > >> linux-arm-kernel mailing list > >> linux-arm-kernel at lists.infradead.org > >> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel > > > > A different patch for this has already been discussed: > > > > http://thread.gmane.org/gmane.linux.ports.arm.kernel/112864 > > > > It's a bit stalled on my side because I don't have a suitable platform > > to test it on. ?As some have suggested, in my case (imx51) the inclusion > > of code was inherited from from an older subarch tree and is no longer > > appropriate -- so my problem is actually solved just by not building > > this code. > > > > If the code is really used in your kernel (not just built) it would > > be really useful if you could test this patch. > > > > However you should definitely check whether the code is really used at > > all on tegra. > > > > There's a fair chance that it's not used: FIQ is not much used by linux > > on armv7 and above: unless you make use of cache+TLB lockdown / SRAM etc., > > FIQ is unlikely to be significantly faster than IRQ on recent CPUs. ?FIQ > > may also get reserved for use by TrustZone on some platforms, complicating > > the picture further. > > Most Android kernels, including on Tegra, use the FIQ handler for a > simple debugger on the serial console. Sending a break will enter > debugger mode, which can dump backtraces from FIQ context, even if the > CPU is stuck in an IRQ, or with IRQs off. > > We've never used a Thumb2 kernel though. Fair enough -- in that case I guess it may be needed. Sounds like entering the debugger will help in testing this; I don't have the board myself though. ---Dave