From f774b7d10e2155e52b92dfce2f8cb099a6d6d0e6 Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Mon, 28 Apr 2014 19:50:06 +0100 Subject: arm64: fixmap: fix missing sub-page offset for earlyprintk Commit d57c33c5daa4 (add generic fixmap.h) added (among other similar things) set_fixmap_io to deal with early ioremap of devices. More recently, commit bf4b558eba92 (arm64: add early_ioremap support) converted the arm64 earlyprintk to use set_fixmap_io. A side effect of this conversion is that my virtual machines have stopped booting when I pass "earlyprintk=uart8250-8bit,0x3f8" to the guest kernel. Turns out that the new earlyprintk code doesn't care at all about sub-page offsets, and just assumes that the earlyprintk device will be page-aligned. Obviously, that doesn't play well with the above example. Further investigation shows that set_fixmap_io uses __set_fixmap instead of __set_fixmap_offset. A fix is to introduce a set_fixmap_offset_io that uses the latter, and to remove the superflous call to fix_to_virt (which only returns the value that set_fixmap_io has already given us). With this applied, my VMs are back in business. Tested on a Cortex-A57 platform with kvmtool as platform emulation. Cc: Will Deacon Acked-by: Mark Salter Acked-by: Arnd Bergmann Signed-off-by: Marc Zyngier Signed-off-by: Catalin Marinas --- arch/arm64/kernel/early_printk.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) (limited to 'arch/arm64/kernel') diff --git a/arch/arm64/kernel/early_printk.c b/arch/arm64/kernel/early_printk.c index ffbbdde7aba..2dc36d00add 100644 --- a/arch/arm64/kernel/early_printk.c +++ b/arch/arm64/kernel/early_printk.c @@ -143,10 +143,8 @@ static int __init setup_early_printk(char *buf) } /* no options parsing yet */ - if (paddr) { - set_fixmap_io(FIX_EARLYCON_MEM_BASE, paddr); - early_base = (void __iomem *)fix_to_virt(FIX_EARLYCON_MEM_BASE); - } + if (paddr) + early_base = (void __iomem *)set_fixmap_offset_io(FIX_EARLYCON_MEM_BASE, paddr); printch = match->printch; early_console = &early_console_dev; -- cgit v1.2.3