On Fri, 2014-01-10 at 10:11 -0600, Rob Herring wrote:
> On Thu, Jan 9, 2014 at 9:50 PM, Mark Salter <msal...@redhat.com> wrote:
> > +config EARLY_IOREMAP
> > + depends on MMU
>
> Is it possible to implement a !MMU version of early_ioremap that
> simply returns the phys address rather than have this dependency?
I don't think that would be too hard to do.
>
> > + bool "Provide early_ioremap() support for kernel initialization."
> > + select GENERIC_EARLY_IOREMAP
> > + help
> > + Provide a mechanism for kernel initialisation code to temporarily
> > + map, in a highmem-agnostic way, memory pages in before ioremap()
> > + and friends are available (before paging_init() has run). It uses
> > + the same virtual memory range as kmap so all early mappings must
> > + be unapped before paging_init() is called.
> > +
> > config SECCOMP
> > bool
> > prompt "Enable seccomp to safely compute untrusted bytecode"
> > diff --git a/arch/arm/include/asm/Kbuild b/arch/arm/include/asm/Kbuild
> > index c38b58c..49ec506 100644
> > --- a/arch/arm/include/asm/Kbuild
> > +++ b/arch/arm/include/asm/Kbuild
> > @@ -4,6 +4,7 @@ generic-y += auxvec.h
> > generic-y += bitsperlong.h
> > generic-y += cputime.h
> > generic-y += current.h
> > +generic-y += early_ioremap.h
> > generic-y += emergency-restart.h
> > generic-y += errno.h
> > generic-y += exec.h
> > diff --git a/arch/arm/include/asm/fixmap.h b/arch/arm/include/asm/fixmap.h
> > index 68ea615..e92b7a4 100644
> > --- a/arch/arm/include/asm/fixmap.h
> > +++ b/arch/arm/include/asm/fixmap.h
> > @@ -21,8 +21,26 @@ enum fixed_addresses {
> > FIX_KMAP_BEGIN,
> > FIX_KMAP_END = (FIXADDR_TOP - FIXADDR_START) >> PAGE_SHIFT,
> > __end_of_fixed_addresses
> > +/*
> > + * 224 temporary boot-time mappings, used by early_ioremap(),
> > + * before ioremap() is functional.
> > + *
> > + * (P)re-using the FIXADDR region, which is used for highmem
> > + * later on, and statically aligned to 1MB.
> > + */
> > +#define NR_FIX_BTMAPS 32
> > +#define FIX_BTMAPS_SLOTS 7
> > +#define TOTAL_FIX_BTMAPS (NR_FIX_BTMAPS * FIX_BTMAPS_SLOTS)
> > +#define FIX_BTMAP_END FIX_KMAP_BEGIN
> > +#define FIX_BTMAP_BEGIN (FIX_BTMAP_END + TOTAL_FIX_BTMAPS -
> > 1)
> > };
> >
> > +#define FIXMAP_PAGE_NORMAL (L_PTE_MT_WRITEBACK | L_PTE_YOUNG |
> > L_PTE_PRESENT)
> > +#define FIXMAP_PAGE_IO (L_PTE_MT_DEV_NONSHARED | L_PTE_YOUNG |
> > L_PTE_PRESENT)
> > +
> > +extern void __early_set_fixmap(enum fixed_addresses idx,
> > + phys_addr_t phys, pgprot_t flags);
> > +
> > #include <asm-generic/fixmap.h>
> >
> > #endif
> > diff --git a/arch/arm/include/asm/io.h b/arch/arm/include/asm/io.h
> > index fbeb39c..6b2cc53 100644
> > --- a/arch/arm/include/asm/io.h
> > +++ b/arch/arm/include/asm/io.h
> > @@ -28,6 +28,7 @@
> > #include <asm/byteorder.h>
> > #include <asm/memory.h>
> > #include <asm-generic/pci_iomap.h>
> > +#include <asm/early_ioremap.h>
> > #include <xen/xen.h>
> >
> > /*
> > diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c
> > index 987a7f5..038fb75 100644
> > --- a/arch/arm/kernel/setup.c
> > +++ b/arch/arm/kernel/setup.c
> > @@ -36,6 +36,7 @@
> > #include <asm/cpu.h>
> > #include <asm/cputype.h>
> > #include <asm/elf.h>
> > +#include <asm/io.h>
>
> Use linux/io.h?
Yes.
>
> > #include <asm/procinfo.h>
> > #include <asm/psci.h>
> > #include <asm/sections.h>
> > @@ -887,6 +888,8 @@ void __init setup_arch(char **cmdline_p)
> >
> > parse_early_param();
> >
> > + early_ioremap_init();
> > +
>
> This call would need to be before parse_early_param for the earlycon to work.
Yes, like arm64 does it.
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