From mboxrd@z Thu Jan 1 00:00:00 1970 From: julien.grall@arm.com (Julien Grall) Date: Mon, 16 Jan 2017 12:43:58 +0000 Subject: [PATCH v3 4/5] Xen: Select correct dom0 console In-Reply-To: <20170103172859.GC14183@leverpostej> References: <20161215122718.21422-1-andre.przywara@arm.com> <20161215122718.21422-5-andre.przywara@arm.com> <20170103172859.GC14183@leverpostej> Message-ID: <063e6a8d-2d1e-d88e-7a38-a2f9d992813e@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi Mark, On 03/01/17 17:29, Mark Rutland wrote: > On Thu, Dec 15, 2016 at 12:27:17PM +0000, Andre Przywara wrote: >> From: Ian Campbell >> >> If Xen is enabled, tell Dom0 to use the 'hvc0' console, and fall back to >> the usual ttyAMA0 otherwise. >> >> Signed-off-by: Ian Campbell >> Signed-off-by: Christoffer Dall >> Signed-off-by: Andre Przywara >> Reviewed-by: Julien Grall >> Tested-by: Konrad Rzeszutek Wilk >> --- >> configure.ac | 3 ++- >> 1 file changed, 2 insertions(+), 1 deletion(-) >> >> diff --git a/configure.ac b/configure.ac >> index ea02dca..d23cced 100644 >> --- a/configure.ac >> +++ b/configure.ac >> @@ -105,7 +105,8 @@ AC_ARG_WITH([initrd], >> AC_SUBST([FILESYSTEM], [$USE_INITRD]) >> AM_CONDITIONAL([INITRD], [test "x$USE_INITRD" != "x"]) >> >> -C_CMDLINE="console=ttyAMA0 earlyprintk=pl011,0x1c090000" >> +AS_IF([test "x$X_IMAGE" = "x"],[C_CONSOLE="ttyAMA0"],[C_CONSOLE="hvc0"]) >> +C_CMDLINE="console=$C_CONSOLE earlyprintk=pl011,0x1c090000" > > Just to check: what happesns if Dom0 tries to write to 0x1c090000? Xen is emulating a simple UART (only write is supported) replacing the real UART for DOM0. So character will be printed on the console when the domain is writing to 0x1c090000. > > Shouldn't we override/delete earlyprintk/earlycon here too? The ideal would be to use xen console for the earlyprintk/earlycon, but it seems that it has not been wired for ARM. So for now, I would keep the earlyprintk options to help developer debugging early crash. > I've applied this as-is, so if we do need to, I'll need a fixup patch. Thank you for pushing the series. Cheers, -- Julien Grall