| Message ID | 1398711006-14943-1-git-send-email-marc.zyngier@arm.com |
|---|---|
| State | Accepted |
| Commit | f774b7d10e2155e52b92dfce2f8cb099a6d6d0e6 |
| Headers | show |
On Mon, 2014-04-28 at 19:50 +0100, Marc Zyngier wrote: > 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: Mark Salter <msalter@redhat.com> > Cc: Catalin Marinas <catalin.marinas@arm.com> > Cc: Will Deacon <will.deacon@arm.com> > Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> > --- Acked-by: Mark Salter <msalter@redhat.com> -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
On Mon, Apr 28, 2014 at 1:50 PM, Marc Zyngier <marc.zyngier@arm.com> wrote: > 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: Mark Salter <msalter@redhat.com> > Cc: Catalin Marinas <catalin.marinas@arm.com> > Cc: Will Deacon <will.deacon@arm.com> > Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> > --- > arch/arm64/kernel/early_printk.c | 6 ++---- > include/asm-generic/fixmap.h | 3 +++ > 2 files changed, 5 insertions(+), 4 deletions(-) This will be fixed already in 3.16 with my earlycon series[1] if this is not taken for 3.15. Probably still a good addition for fixmap. Rob [1] https://lkml.org/lkml/2014/4/18/573 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
On Tue, Apr 29, 2014 at 12:51:18AM +0100, Rob Herring wrote: > On Mon, Apr 28, 2014 at 1:50 PM, Marc Zyngier <marc.zyngier@arm.com> wrote: > > 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: Mark Salter <msalter@redhat.com> > > Cc: Catalin Marinas <catalin.marinas@arm.com> > > Cc: Will Deacon <will.deacon@arm.com> > > Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> > > --- > > arch/arm64/kernel/early_printk.c | 6 ++---- > > include/asm-generic/fixmap.h | 3 +++ > > 2 files changed, 5 insertions(+), 4 deletions(-) > > This will be fixed already in 3.16 with my earlycon series[1] if this > is not taken for 3.15. I'd like to take this for 3.15 as it's currently broken. I just need another ack from Arnd on the generic header change.
diff --git a/arch/arm64/kernel/early_printk.c b/arch/arm64/kernel/early_printk.c index ffbbdde..2dc36d0 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; diff --git a/include/asm-generic/fixmap.h b/include/asm-generic/fixmap.h index 5a64ca4..f23174f 100644 --- a/include/asm-generic/fixmap.h +++ b/include/asm-generic/fixmap.h @@ -93,5 +93,8 @@ static inline unsigned long virt_to_fix(const unsigned long vaddr) #define set_fixmap_io(idx, phys) \ __set_fixmap(idx, phys, FIXMAP_PAGE_IO) +#define set_fixmap_offset_io(idx, phys) \ + __set_fixmap_offset(idx, phys, FIXMAP_PAGE_IO) + #endif /* __ASSEMBLY__ */ #endif /* __ASM_GENERIC_FIXMAP_H */
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: Mark Salter <msalter@redhat.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> --- arch/arm64/kernel/early_printk.c | 6 ++---- include/asm-generic/fixmap.h | 3 +++ 2 files changed, 5 insertions(+), 4 deletions(-)