From mboxrd@z Thu Jan 1 00:00:00 1970 From: robherring2@gmail.com (Rob Herring) Date: Tue, 6 May 2014 17:58:06 -0500 Subject: [PATCH 2/3] arm: add early_ioremap support In-Reply-To: <1399417087-24772-1-git-send-email-robherring2@gmail.com> References: <1399417087-24772-1-git-send-email-robherring2@gmail.com> Message-ID: <1399417087-24772-3-git-send-email-robherring2@gmail.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org From: Mark Salter 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 here: https://lkml.org/lkml/2013/10/3/279 Signed-off-by: Mark Salter Tested-by: Leif Lindholm Acked-by: Catalin Marinas [robh: minor re-work in prep for permanent mappings. Fix bug in page table allocation size. Rework CONFIG_MMU dependency.] Signed-off-by: Rob Herring --- arch/arm/Kconfig | 11 ++++++ arch/arm/include/asm/Kbuild | 1 + arch/arm/include/asm/fixmap.h | 21 ++++++++++ arch/arm/include/asm/io.h | 1 + arch/arm/kernel/setup.c | 2 + arch/arm/mm/Makefile | 2 + arch/arm/mm/early_ioremap.c | 90 +++++++++++++++++++++++++++++++++++++++++++ arch/arm/mm/mmu.c | 2 + 8 files changed, 130 insertions(+) create mode 100644 arch/arm/mm/early_ioremap.c diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index db3c541..b33c68b 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -1891,6 +1891,17 @@ 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 + bool "Provide early_ioremap() support for kernel initialization" + depends on MMU + 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 23e728e..ec64b55 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..e36020c 100644 --- a/arch/arm/include/asm/fixmap.h +++ b/arch/arm/include/asm/fixmap.h @@ -21,8 +21,29 @@ 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 - FIX_KMAP_BEGIN) +#define FIX_BTMAP_END FIX_KMAP_BEGIN +#define FIX_BTMAP_BEGIN (FIX_BTMAP_END + TOTAL_FIX_BTMAPS - 1) }; +#define FIXMAP_PAGE_COMMON (L_PTE_YOUNG | L_PTE_PRESENT | L_PTE_XN) + +#define FIXMAP_PAGE_NORMAL (FIXMAP_PAGE_COMMON | L_PTE_MT_WRITEBACK) +#define FIXMAP_PAGE_IO (FIXMAP_PAGE_COMMON | L_PTE_MT_DEV_SHARED | L_PTE_SHARED | L_PTE_DIRTY) +#define FIXMAP_PAGE_NOCACHE FIXMAP_PAGE_IO + +extern void __early_set_fixmap(enum fixed_addresses idx, + phys_addr_t phys, pgprot_t flags); + #include #endif diff --git a/arch/arm/include/asm/io.h b/arch/arm/include/asm/io.h index 8aa4cca..637e0cd 100644 --- a/arch/arm/include/asm/io.h +++ b/arch/arm/include/asm/io.h @@ -28,6 +28,7 @@ #include #include #include +#include #include /* diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c index 50e198c..7882f04 100644 --- a/arch/arm/kernel/setup.c +++ b/arch/arm/kernel/setup.c @@ -30,6 +30,7 @@ #include #include #include +#include #include #include @@ -883,6 +884,7 @@ void __init setup_arch(char **cmdline_p) const struct machine_desc *mdesc; setup_processor(); + early_ioremap_init(); mdesc = setup_machine_fdt(__atags_pointer); if (!mdesc) mdesc = setup_machine_tags(__atags_pointer, __machine_arch_type); diff --git a/arch/arm/mm/Makefile b/arch/arm/mm/Makefile index 7f39ce2..c6b7b5e 100644 --- a/arch/arm/mm/Makefile +++ b/arch/arm/mm/Makefile @@ -12,6 +12,8 @@ ifneq ($(CONFIG_MMU),y) obj-y += nommu.o endif +obj-$(CONFIG_EARLY_IOREMAP) += early_ioremap.o + obj-$(CONFIG_ARM_PTDUMP) += dump.o obj-$(CONFIG_MODULES) += proc-syms.o diff --git a/arch/arm/mm/early_ioremap.c b/arch/arm/mm/early_ioremap.c new file mode 100644 index 0000000..0258a20 --- /dev/null +++ b/arch/arm/mm/early_ioremap.c @@ -0,0 +1,90 @@ +/* + * early_ioremap() support for ARM + * + * Based on existing support in arch/x86/mm/ioremap.c + * + * Restrictions: currently only functional before paging_init() + */ + +#include +#include + +#include +#include +#include +#include + +#include + +static pte_t bm_pte[PTRS_PER_PTE + PTE_HWTABLE_PTRS] + __aligned(PTE_HWTABLE_OFF + 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); + + /* + * Make sure we don't span multiple pmds. + */ + BUILD_BUG_ON((__fix_to_virt(FIX_BTMAP_BEGIN) >> PMD_SHIFT) + != (__fix_to_virt(FIX_BTMAP_END) >> PMD_SHIFT)); + + 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_clear(early_ioremap_pmd(fix_to_virt(FIX_BTMAP_BEGIN))); +} diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c index b68c6b2..9576f87 100644 --- a/arch/arm/mm/mmu.c +++ b/arch/arm/mm/mmu.c @@ -35,6 +35,7 @@ #include #include #include +#include #include "mm.h" #include "tcm.h" @@ -1508,6 +1509,7 @@ void __init paging_init(const struct machine_desc *mdesc) prepare_page_table(); map_lowmem(); dma_contiguous_remap(); + early_ioremap_reset(); devicemaps_init(mdesc); kmap_init(); tcm_init(); -- 1.9.1