Re: [PATCH 1/4] Create generic early_ioremap() support

[Dave Young]

On 11/27/13 at 09:44pm, Mark Salter wrote:
> This patch copies generic bits of x86 early_ioremap() support
> into a library for potential use by other architectures.
> 
> Signed-off-by: Mark Salter <msalter@xxxxxxxxxx>
> CC: Arnd Bergmann <arnd@xxxxxxxx>
> CC: Ingo Molnar <mingo@xxxxxxxxxx>
> CC: linux-arch@xxxxxxxxxxxxxxx
> ---
>  include/asm-generic/early_ioremap.h |  40 ++++++
>  lib/Kconfig                         |   3 +
>  lib/Makefile                        |   1 +
>  lib/early_ioremap.c                 | 243 ++++++++++++++++++++++++++++++++++++

I do not understand why these should go to lib/, I feel it's slightly better
move them to mm/

ditto about lib/ioremap.c, ...

>  4 files changed, 287 insertions(+)
>  create mode 100644 include/asm-generic/early_ioremap.h
>  create mode 100644 lib/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..e26ce80
> --- /dev/null
> +++ b/include/asm-generic/early_ioremap.h
> @@ -0,0 +1,40 @@
> +#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 __iomem *early_memremap(resource_size_t phys_addr,
> +				    unsigned long size);
> +extern void early_iounmap(void __iomem *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/lib/Kconfig b/lib/Kconfig
> index 991c98b..5ebee09 100644
> --- a/lib/Kconfig
> +++ b/lib/Kconfig
> @@ -42,6 +42,9 @@ config GENERIC_IO
>  	boolean
>  	default n
>  
> +config GENERIC_EARLY_IOREMAP
> +	bool
> +
>  config STMP_DEVICE
>  	bool
>  
> diff --git a/lib/Makefile b/lib/Makefile
> index a459c31..2afe05d 100644
> --- a/lib/Makefile
> +++ b/lib/Makefile
> @@ -188,3 +188,4 @@ quiet_cmd_build_OID_registry = GEN     $@
>  clean-files	+= oid_registry_data.c
>  
>  obj-$(CONFIG_UCS2_STRING) += ucs2_string.o
> +obj-$(CONFIG_GENERIC_EARLY_IOREMAP) += early_ioremap.o
> diff --git a/lib/early_ioremap.c b/lib/early_ioremap.c
> new file mode 100644
> index 0000000..54623a7
> --- /dev/null
> +++ b/lib/early_ioremap.c
> @@ -0,0 +1,243 @@
> +/*
> + * 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 __iomem *
> +early_memremap(resource_size_t phys_addr, unsigned long size)
> +{
> +	return __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;
> +}
> -- 
> 1.8.3.1
> 
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