Merge tag 'devmem-v4.11-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux (1882e562) · Commits · 戴 / test

arch/x86/mm/init.c

+30 −11

Original line number	Diff line number	Diff line
		@@ -643,23 +643,42 @@ void __init init_mem_mapping(void)
		* devmem_is_allowed() checks to see if /dev/mem access to a certain address
		* is valid. The argument is a physical page number.
		*
		*
		* On x86, access has to be given to the first megabyte of ram because that area
		* contains BIOS code and data regions used by X and dosemu and similar apps.
		* Access has to be given to non-kernel-ram areas as well, these contain the PCI
		* mmio resources as well as potential bios/acpi data regions.
		* On x86, access has to be given to the first megabyte of RAM because that
		* area traditionally contains BIOS code and data regions used by X, dosemu,
		* and similar apps. Since they map the entire memory range, the whole range
		* must be allowed (for mapping), but any areas that would otherwise be
		* disallowed are flagged as being "zero filled" instead of rejected.
		* Access has to be given to non-kernel-ram areas as well, these contain the
		* PCI mmio resources as well as potential bios/acpi data regions.
		*/
		int devmem_is_allowed(unsigned long pagenr)
		{
		if (page_is_ram(pagenr)) {
		/*
		* For disallowed memory regions in the low 1MB range,
		* request that the page be shown as all zeros.
		*/
		if (pagenr < 256)
		return 1;
		if (iomem_is_exclusive(pagenr << PAGE_SHIFT))
		return 2;

		return 0;
		if (!page_is_ram(pagenr))
		}

		/*
		* This must follow RAM test, since System RAM is considered a
		* restricted resource under CONFIG_STRICT_IOMEM.
		*/
		if (iomem_is_exclusive(pagenr << PAGE_SHIFT)) {
		/* Low 1MB bypasses iomem restrictions. */
		if (pagenr < 256)
		return 1;

		return 0;
		}

		return 1;
		}

		void free_init_pages(char *what, unsigned long begin, unsigned long end)
		{
		unsigned long begin_aligned, end_aligned;

drivers/char/mem.c

+52 −30

Original line number	Diff line number	Diff line
		@@ -60,6 +60,10 @@ static inline int valid_mmap_phys_addr_range(unsigned long pfn, size_t size)
		#endif

		#ifdef CONFIG_STRICT_DEVMEM
		static inline int page_is_allowed(unsigned long pfn)
		{
		return devmem_is_allowed(pfn);
		}
		static inline int range_is_allowed(unsigned long pfn, unsigned long size)
		{
		u64 from = ((u64)pfn) << PAGE_SHIFT;
		@@ -75,6 +79,10 @@ static inline int range_is_allowed(unsigned long pfn, unsigned long size)
		return 1;
		}
		#else
		static inline int page_is_allowed(unsigned long pfn)
		{
		return 1;
		}
		static inline int range_is_allowed(unsigned long pfn, unsigned long size)
		{
		return 1;
		@@ -122,23 +130,31 @@ static ssize_t read_mem(struct file file, char __user buf,

		while (count > 0) {
		unsigned long remaining;
		int allowed;

		sz = size_inside_page(p, count);

		if (!range_is_allowed(p >> PAGE_SHIFT, count))
		allowed = page_is_allowed(p >> PAGE_SHIFT);
		if (!allowed)
		return -EPERM;

		if (allowed == 2) {
		/* Show zeros for restricted memory. */
		remaining = clear_user(buf, sz);
		} else {
		/*
		* On ia64 if a page has been mapped somewhere as uncached, then
		* it must also be accessed uncached by the kernel or data
		* corruption may occur.
		* On ia64 if a page has been mapped somewhere as
		* uncached, then it must also be accessed uncached
		* by the kernel or data corruption may occur.
		*/
		ptr = xlate_dev_mem_ptr(p);
		if (!ptr)
		return -EFAULT;

		remaining = copy_to_user(buf, ptr, sz);

		unxlate_dev_mem_ptr(p, ptr);
		}

		if (remaining)
		return -EFAULT;

		@@ -181,15 +197,20 @@ static ssize_t write_mem(struct file file, const char __user buf,
		#endif

		while (count > 0) {
		int allowed;

		sz = size_inside_page(p, count);

		if (!range_is_allowed(p >> PAGE_SHIFT, sz))
		allowed = page_is_allowed(p >> PAGE_SHIFT);
		if (!allowed)
		return -EPERM;

		/* Skip actual writing when a page is marked as restricted. */
		if (allowed == 1) {
		/*
		* On ia64 if a page has been mapped somewhere as uncached, then
		* it must also be accessed uncached by the kernel or data
		* corruption may occur.
		* On ia64 if a page has been mapped somewhere as
		* uncached, then it must also be accessed uncached
		* by the kernel or data corruption may occur.
		*/
		ptr = xlate_dev_mem_ptr(p);
		if (!ptr) {
		@@ -206,6 +227,7 @@ static ssize_t write_mem(struct file file, const char __user buf,
		break;
		return -EFAULT;
		}
		}

		buf += sz;
		p += sz;

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