| Message ID | 1404898792-4201-3-git-send-email-leif.lindholm@linaro.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Wed, Jul 09, 2014 at 10:39:52AM +0100, Leif Lindholm wrote: > +config EARLY_IOREMAP > + depends on MMU > + bool "Provide early_ioremap() support for kernel initialization." > + select GENERIC_EARLY_IOREMAP Nit: please order as bool, then depends, then select. > diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c > index 8a16ee5..aa2621a 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> Please always use linux/io.h in preference to asm/io.h. > +static inline pmd_t * __init early_ioremap_pmd(unsigned long addr) > +{ > + unsigned int index = pgd_index(addr); > + pgd_t *pgd = cpu_get_pgd() + index; What is the reasoning for using cpu_get_pgd() ? Is there some specific reason you want to read from the hardware register rather than using the pgd_offset_k() macro here? > +void __init > +early_ioremap_shutdown(void) Nit: should be a single line. The rest of the patch looks fine, thanks.
Hi Leif, On 09.07.2014 11:39, Leif Lindholm wrote: > From: Mark Salter <msalter@redhat.com> > > This patch uses the generic early_ioremap code to implement > early_ioremap for ARM. The ARM-specific bits come mostly from > an earlier patch from Leif Lindholm <leif.lindholm@linaro.org> > here: > > https://lkml.org/lkml/2013/10/3/279 [snip] > diff --git a/arch/arm/mm/early_ioremap.c b/arch/arm/mm/early_ioremap.c > new file mode 100644 > index 0000000..1013109 > --- /dev/null > +++ b/arch/arm/mm/early_ioremap.c > @@ -0,0 +1,86 @@ > +/* > + * early_ioremap() support for ARM > + * > + * Based on existing support in arch/x86/mm/ioremap.c > + * > + * Restrictions: currently only functional before paging_init() Uhm, that's bad... This would explain why my earlycon code generates a fault as soon as something prints after paging_init(). I'd say this feature would be much more useful if mappings were carried over paging_init(), so that mapped devices are available later as well. I'll see if I can code this on top of your patch, but unfortunately it might end up with -ENOTIME. Best regards, Tomasz
On Tue, Jul 22, 2014 at 11:48 AM, Tomasz Figa <t.figa@samsung.com> wrote: > Hi Leif, > > On 09.07.2014 11:39, Leif Lindholm wrote: >> From: Mark Salter <msalter@redhat.com> >> >> This patch uses the generic early_ioremap code to implement >> early_ioremap for ARM. The ARM-specific bits come mostly from >> an earlier patch from Leif Lindholm <leif.lindholm@linaro.org> >> here: >> >> https://lkml.org/lkml/2013/10/3/279 > > [snip] > >> diff --git a/arch/arm/mm/early_ioremap.c b/arch/arm/mm/early_ioremap.c >> new file mode 100644 >> index 0000000..1013109 >> --- /dev/null >> +++ b/arch/arm/mm/early_ioremap.c >> @@ -0,0 +1,86 @@ >> +/* >> + * early_ioremap() support for ARM >> + * >> + * Based on existing support in arch/x86/mm/ioremap.c >> + * >> + * Restrictions: currently only functional before paging_init() > > Uhm, that's bad... This would explain why my earlycon code generates a > fault as soon as something prints after paging_init(). I'd say this > feature would be much more useful if mappings were carried over > paging_init(), so that mapped devices are available later as well. > > I'll see if I can code this on top of your patch, but unfortunately it > might end up with -ENOTIME. I have fixmap support that's needed for earlycon. Here is the branch: git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux.git fixmap It is based on an earlier version of patchset and not on the latest version from Leif. Unfortunately, I don't have more time to spend on it ATM. Rob
On 22.07.2014 19:11, Rob Herring wrote: > On Tue, Jul 22, 2014 at 11:48 AM, Tomasz Figa <t.figa@samsung.com> wrote: >> Hi Leif, >> >> On 09.07.2014 11:39, Leif Lindholm wrote: >>> From: Mark Salter <msalter@redhat.com> >>> >>> This patch uses the generic early_ioremap code to implement >>> early_ioremap for ARM. The ARM-specific bits come mostly from >>> an earlier patch from Leif Lindholm <leif.lindholm@linaro.org> >>> here: >>> >>> https://lkml.org/lkml/2013/10/3/279 >> >> [snip] >> >>> diff --git a/arch/arm/mm/early_ioremap.c b/arch/arm/mm/early_ioremap.c >>> new file mode 100644 >>> index 0000000..1013109 >>> --- /dev/null >>> +++ b/arch/arm/mm/early_ioremap.c >>> @@ -0,0 +1,86 @@ >>> +/* >>> + * early_ioremap() support for ARM >>> + * >>> + * Based on existing support in arch/x86/mm/ioremap.c >>> + * >>> + * Restrictions: currently only functional before paging_init() >> >> Uhm, that's bad... This would explain why my earlycon code generates a >> fault as soon as something prints after paging_init(). I'd say this >> feature would be much more useful if mappings were carried over >> paging_init(), so that mapped devices are available later as well. >> >> I'll see if I can code this on top of your patch, but unfortunately it >> might end up with -ENOTIME. > > I have fixmap support that's needed for earlycon. Here is the branch: > > git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux.git fixmap > > It is based on an earlier version of patchset and not on the latest > version from Leif. Unfortunately, I don't have more time to spend on > it ATM. Thanks Rob. I'll give it a try. Best regards, Tomasz
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index 245058b..04b8f8a 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -1800,6 +1800,17 @@ config UACCESS_WITH_MEMCPY However, if the CPU data cache is using a write-allocate mode, this option is unlikely to provide any performance gain. +config EARLY_IOREMAP + depends on MMU + 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 unmapped 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 f5a3576..0bc5a02 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/io.h b/arch/arm/include/asm/io.h index 3d23418..7b8a981 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 8a16ee5..aa2621a 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> #include <asm/procinfo.h> #include <asm/psci.h> #include <asm/sections.h> @@ -894,6 +895,8 @@ void __init setup_arch(char **cmdline_p) parse_early_param(); + early_ioremap_init(); + early_paging_init(mdesc, lookup_processor_type(read_cpuid_id())); setup_dma_zone(mdesc); sanity_check_meminfo(); diff --git a/arch/arm/mm/Makefile b/arch/arm/mm/Makefile index 91da64d..1c8ce752 100644 --- a/arch/arm/mm/Makefile +++ b/arch/arm/mm/Makefile @@ -16,6 +16,7 @@ obj-$(CONFIG_ARM_PTDUMP) += dump.o obj-$(CONFIG_MODULES) += proc-syms.o obj-$(CONFIG_ALIGNMENT_TRAP) += alignment.o +obj-$(CONFIG_EARLY_IOREMAP) += early_ioremap.o obj-$(CONFIG_HIGHMEM) += highmem.o obj-$(CONFIG_HUGETLB_PAGE) += hugetlbpage.o diff --git a/arch/arm/mm/early_ioremap.c b/arch/arm/mm/early_ioremap.c new file mode 100644 index 0000000..1013109 --- /dev/null +++ b/arch/arm/mm/early_ioremap.c @@ -0,0 +1,86 @@ +/* + * early_ioremap() support for ARM + * + * Based on existing support in arch/x86/mm/ioremap.c + * + * Restrictions: currently only functional before paging_init() + */ + +#include <linux/init.h> +#include <linux/io.h> + +#include <asm/fixmap.h> +#include <asm/pgalloc.h> +#include <asm/pgtable.h> +#include <asm/tlbflush.h> + +#include <asm/mach/map.h> + +static pte_t bm_pte[PTRS_PER_PTE] __aligned(PTE_HWTABLE_SIZE) __initdata; + +static inline pmd_t * __init early_ioremap_pmd(unsigned long addr) +{ + unsigned int index = pgd_index(addr); + pgd_t *pgd = cpu_get_pgd() + index; + pud_t *pud = pud_offset(pgd, addr); + pmd_t *pmd = pmd_offset(pud, addr); + + return pmd; +} + +static inline pte_t * __init early_ioremap_pte(unsigned long addr) +{ + return &bm_pte[pte_index(addr)]; +} + +void __init early_ioremap_init(void) +{ + pmd_t *pmd; + + pmd = early_ioremap_pmd(fix_to_virt(FIX_BTMAP_BEGIN)); + pmd_populate_kernel(NULL, pmd, bm_pte); + + if (pmd != early_ioremap_pmd(fix_to_virt(FIX_BTMAP_END))) { + WARN_ON(1); + pr_warn("pmd %p != %p\n", + pmd, early_ioremap_pmd(fix_to_virt(FIX_BTMAP_END))); + pr_warn("fix_to_virt(FIX_BTMAP_BEGIN): %08lx\n", + fix_to_virt(FIX_BTMAP_BEGIN)); + pr_warn("fix_to_virt(FIX_BTMAP_END): %08lx\n", + fix_to_virt(FIX_BTMAP_END)); + pr_warn("FIX_BTMAP_END: %d\n", FIX_BTMAP_END); + pr_warn("FIX_BTMAP_BEGIN: %d\n", FIX_BTMAP_BEGIN); + } + + early_ioremap_setup(); +} + +void __init __early_set_fixmap(enum fixed_addresses idx, + phys_addr_t phys, pgprot_t flags) +{ + unsigned long addr = __fix_to_virt(idx); + pte_t *pte; + u64 desc; + + if (idx > FIX_KMAP_END) { + BUG(); + return; + } + pte = early_ioremap_pte(addr); + + if (pgprot_val(flags)) + set_pte_at(NULL, addr, pte, + pfn_pte(phys >> PAGE_SHIFT, flags)); + else + pte_clear(NULL, addr, pte); + flush_tlb_kernel_range(addr, addr + PAGE_SIZE); + desc = *pte; +} + +void __init +early_ioremap_shutdown(void) +{ + pmd_t *pmd = early_ioremap_pmd(fix_to_virt(FIX_BTMAP_BEGIN)); + + pmd_clear(pmd); +} diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c index ab14b79..608dc36 100644 --- a/arch/arm/mm/mmu.c +++ b/arch/arm/mm/mmu.c @@ -36,6 +36,7 @@ #include <asm/mach/map.h> #include <asm/mach/pci.h> #include <asm/fixmap.h> +#include <asm/early_ioremap.h> #include "mm.h" #include "tcm.h" @@ -1474,6 +1475,7 @@ void __init paging_init(const struct machine_desc *mdesc) { void *zero_page; + early_ioremap_reset(); build_mem_type_table(); prepare_page_table(); map_lowmem();