This patch creates a generic implementation of early_ioremap() support based on the existing x86 implementation. early_ioremp() is useful for early boot code which needs to temporarily map I/O or memory regions before normal mapping functions such as ioremap() are available. There is one difference from the existing x86 implementation which should be noted. The generic early_memremap() function does not return an __iomem pointer and a new early_memunmap() function has been added to act as a wrapper for early_iounmap() but with a non __iomem pointer passed in. This is in line with the first patch of this series: https://lkml.org/lkml/2013/12/22/69 Signed-off-by: Mark Salter <msalter@xxxxxxxxxx> CC: x86@xxxxxxxxxx CC: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx CC: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> CC: Arnd Bergmann <arnd@xxxxxxxx> CC: Ingo Molnar <mingo@xxxxxxxxxx> CC: Thomas Gleixner <tglx@xxxxxxxxxxxxx> CC: "H. Peter Anvin" <hpa@xxxxxxxxx> CC: Russell King <linux@xxxxxxxxxxxxxxxx> CC: Catalin Marinas <catalin.marinas@xxxxxxx> CC: Will Deacon <will.deacon@xxxxxxx> --- include/asm-generic/early_ioremap.h | 41 ++++++ mm/Kconfig | 3 + mm/Makefile | 1 + mm/early_ioremap.c | 249 ++++++++++++++++++++++++++++++++++++ 4 files changed, 294 insertions(+) create mode 100644 include/asm-generic/early_ioremap.h create mode 100644 mm/early_ioremap.c diff --git a/include/asm-generic/early_ioremap.h b/include/asm-generic/early_ioremap.h new file mode 100644 index 0000000..d43e187 --- /dev/null +++ b/include/asm-generic/early_ioremap.h @@ -0,0 +1,41 @@ +#ifndef _ASM_EARLY_IOREMAP_H_ +#define _ASM_EARLY_IOREMAP_H_ + +#include <linux/types.h> + +#ifdef CONFIG_GENERIC_EARLY_IOREMAP +/* + * early_ioremap() and early_iounmap() are for temporary early boot-time + * mappings, before the real ioremap() is functional. + */ +extern void __iomem *early_ioremap(resource_size_t phys_addr, + unsigned long size); +extern void *early_memremap(resource_size_t phys_addr, + unsigned long size); +extern void early_iounmap(void __iomem *addr, unsigned long size); +extern void early_memunmap(void *addr, unsigned long size); + +/* Arch-specific initialization */ +extern void early_ioremap_init(void); + +/* Generic initialization called by architecture code */ +extern void early_ioremap_setup(void); + +/* + * Called as last step in paging_init() so library can act + * accordingly for subsequent map/unmap requests. + */ +extern void early_ioremap_reset(void); + +/* + * Weak function called by early_ioremap_reset(). It does nothing, but + * architectures may provide their own version to do any needed cleanups. + */ +extern void early_ioremap_shutdown(void); +#else +static inline void early_ioremap_init(void) { } +static inline void early_ioremap_setup(void) { } +static inline void early_ioremap_reset(void) { } +#endif + +#endif /* _ASM_EARLY_IOREMAP_H_ */ diff --git a/mm/Kconfig b/mm/Kconfig index 723bbe0..0dcebf2a 100644 --- a/mm/Kconfig +++ b/mm/Kconfig @@ -552,3 +552,6 @@ config MEM_SOFT_DIRTY it can be cleared by hands. See Documentation/vm/soft-dirty.txt for more details. + +config GENERIC_EARLY_IOREMAP + bool diff --git a/mm/Makefile b/mm/Makefile index 305d10a..4e102e9 100644 --- a/mm/Makefile +++ b/mm/Makefile @@ -60,3 +60,4 @@ obj-$(CONFIG_DEBUG_KMEMLEAK_TEST) += kmemleak-test.o obj-$(CONFIG_CLEANCACHE) += cleancache.o obj-$(CONFIG_MEMORY_ISOLATION) += page_isolation.o obj-$(CONFIG_ZBUD) += zbud.o +obj-$(CONFIG_GENERIC_EARLY_IOREMAP) += early_ioremap.o diff --git a/mm/early_ioremap.c b/mm/early_ioremap.c new file mode 100644 index 0000000..8c1ac48 --- /dev/null +++ b/mm/early_ioremap.c @@ -0,0 +1,249 @@ +/* + * Provide common bits of early_ioremap() support for architectures needing + * temporary mappings during boot before ioremap() is available. + * + * This is mostly a direct copy of the x86 early_ioremap implementation. + * + * (C) Copyright 1995 1996 Linus Torvalds + * + */ +#include <linux/init.h> +#include <linux/io.h> +#include <linux/module.h> +#include <linux/slab.h> +#include <linux/mm.h> +#include <linux/vmalloc.h> +#include <asm/fixmap.h> + +static int early_ioremap_debug __initdata; + +static int __init early_ioremap_debug_setup(char *str) +{ + early_ioremap_debug = 1; + + return 0; +} +early_param("early_ioremap_debug", early_ioremap_debug_setup); + +static int after_paging_init __initdata; + +void __init __attribute__((weak)) early_ioremap_shutdown(void) +{ +} + +void __init early_ioremap_reset(void) +{ + early_ioremap_shutdown(); + after_paging_init = 1; +} + +/* + * Generally, ioremap() is available after paging_init() has been called. + * Architectures wanting to allow early_ioremap after paging_init() can + * define __late_set_fixmap and __late_clear_fixmap to do the right thing. + */ +#ifndef __late_set_fixmap +static inline void __init __late_set_fixmap(enum fixed_addresses idx, + phys_addr_t phys, pgprot_t prot) +{ + BUG(); +} +#endif + +#ifndef __late_clear_fixmap +static inline void __init __late_clear_fixmap(enum fixed_addresses idx) +{ + BUG(); +} +#endif + +static void __iomem *prev_map[FIX_BTMAPS_SLOTS] __initdata; +static unsigned long prev_size[FIX_BTMAPS_SLOTS] __initdata; +static unsigned long slot_virt[FIX_BTMAPS_SLOTS] __initdata; + +void __init early_ioremap_setup(void) +{ + int i; + + for (i = 0; i < FIX_BTMAPS_SLOTS; i++) { + if (prev_map[i]) { + WARN_ON(1); + break; + } + } + + for (i = 0; i < FIX_BTMAPS_SLOTS; i++) + slot_virt[i] = __fix_to_virt(FIX_BTMAP_BEGIN - NR_FIX_BTMAPS*i); +} + +static int __init check_early_ioremap_leak(void) +{ + int count = 0; + int i; + + for (i = 0; i < FIX_BTMAPS_SLOTS; i++) + if (prev_map[i]) + count++; + + if (!count) + return 0; + WARN(1, KERN_WARNING + "Debug warning: early ioremap leak of %d areas detected.\n", + count); + pr_warn("please boot with early_ioremap_debug and report the dmesg.\n"); + + return 1; +} +late_initcall(check_early_ioremap_leak); + +static void __init __iomem * +__early_ioremap(resource_size_t phys_addr, unsigned long size, pgprot_t prot) +{ + unsigned long offset; + resource_size_t last_addr; + unsigned int nrpages; + enum fixed_addresses idx; + int i, slot; + + WARN_ON(system_state != SYSTEM_BOOTING); + + slot = -1; + for (i = 0; i < FIX_BTMAPS_SLOTS; i++) { + if (!prev_map[i]) { + slot = i; + break; + } + } + + if (slot < 0) { + pr_info("%s(%08llx, %08lx) not found slot\n", + __func__, (u64)phys_addr, size); + WARN_ON(1); + return NULL; + } + + if (early_ioremap_debug) { + pr_info("%s(%08llx, %08lx) [%d] => ", + __func__, (u64)phys_addr, size, slot); + dump_stack(); + } + + /* Don't allow wraparound or zero size */ + last_addr = phys_addr + size - 1; + if (!size || last_addr < phys_addr) { + WARN_ON(1); + return NULL; + } + + prev_size[slot] = size; + /* + * Mappings have to be page-aligned + */ + offset = phys_addr & ~PAGE_MASK; + phys_addr &= PAGE_MASK; + size = PAGE_ALIGN(last_addr + 1) - phys_addr; + + /* + * Mappings have to fit in the FIX_BTMAP area. + */ + nrpages = size >> PAGE_SHIFT; + if (nrpages > NR_FIX_BTMAPS) { + WARN_ON(1); + return NULL; + } + + /* + * Ok, go for it.. + */ + idx = FIX_BTMAP_BEGIN - NR_FIX_BTMAPS*slot; + while (nrpages > 0) { + if (after_paging_init) + __late_set_fixmap(idx, phys_addr, prot); + else + __early_set_fixmap(idx, phys_addr, prot); + phys_addr += PAGE_SIZE; + --idx; + --nrpages; + } + if (early_ioremap_debug) + pr_cont("%08lx + %08lx\n", offset, slot_virt[slot]); + + prev_map[slot] = (void __iomem *)(offset + slot_virt[slot]); + return prev_map[slot]; +} + +/* Remap an IO device */ +void __init __iomem * +early_ioremap(resource_size_t phys_addr, unsigned long size) +{ + return __early_ioremap(phys_addr, size, FIXMAP_PAGE_IO); +} + +/* Remap memory */ +void __init * +early_memremap(resource_size_t phys_addr, unsigned long size) +{ + return (__force void *)__early_ioremap(phys_addr, size, + FIXMAP_PAGE_NORMAL); +} + +void __init early_iounmap(void __iomem *addr, unsigned long size) +{ + unsigned long virt_addr; + unsigned long offset; + unsigned int nrpages; + enum fixed_addresses idx; + int i, slot; + + slot = -1; + for (i = 0; i < FIX_BTMAPS_SLOTS; i++) { + if (prev_map[i] == addr) { + slot = i; + break; + } + } + + if (slot < 0) { + pr_info("early_iounmap(%p, %08lx) not found slot\n", + addr, size); + WARN_ON(1); + return; + } + + if (prev_size[slot] != size) { + pr_info("early_iounmap(%p, %08lx) [%d] size not consistent %08lx\n", + addr, size, slot, prev_size[slot]); + WARN_ON(1); + return; + } + + if (early_ioremap_debug) { + pr_info("early_iounmap(%p, %08lx) [%d]\n", addr, + size, slot); + dump_stack(); + } + + virt_addr = (unsigned long)addr; + if (virt_addr < fix_to_virt(FIX_BTMAP_BEGIN)) { + WARN_ON(1); + return; + } + offset = virt_addr & ~PAGE_MASK; + nrpages = PAGE_ALIGN(offset + size) >> PAGE_SHIFT; + + idx = FIX_BTMAP_BEGIN - NR_FIX_BTMAPS*slot; + while (nrpages > 0) { + if (after_paging_init) + __late_clear_fixmap(idx); + else + __early_set_fixmap(idx, 0, FIXMAP_PAGE_CLEAR); + --idx; + --nrpages; + } + prev_map[slot] = NULL; +} + +void __init early_memunmap(void *addr, unsigned long size) +{ + early_iounmap((__force void __iomem *)addr, size); +} -- 1.8.3.1 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. 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