Subject: + vmcore-introduce-remap_oldmem_pfn_range.patch added to -mm tree To: holzheu@xxxxxxxxxxxxxxxxxx,d.hatayama@xxxxxxxxxxxxxx,vgoyal@xxxxxxxxxx,willeke@xxxxxxxxxx From: akpm@xxxxxxxxxxxxxxxxxxxx Date: Fri, 26 Jul 2013 13:20:55 -0700 The patch titled Subject: vmcore: introduce remap_oldmem_pfn_range() has been added to the -mm tree. Its filename is vmcore-introduce-remap_oldmem_pfn_range.patch This patch should soon appear at http://ozlabs.org/~akpm/mmots/broken-out/vmcore-introduce-remap_oldmem_pfn_range.patch and later at http://ozlabs.org/~akpm/mmotm/broken-out/vmcore-introduce-remap_oldmem_pfn_range.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: Michael Holzheu <holzheu@xxxxxxxxxxxxxxxxxx> Subject: vmcore: introduce remap_oldmem_pfn_range() For zfcpdump we can't map the HSA storage because it is only available via a read interface. Therefore, for the new vmcore mmap feature we have introduce a new mechanism to create mappings on demand. This patch introduces a new architecture function remap_oldmem_pfn_range() that should be used to create mappings with remap_pfn_range() for oldmem areas that can be directly mapped. For zfcpdump this is everything besides of the HSA memory. For the areas that are not mapped by remap_oldmem_pfn_range() a generic vmcore a new generic vmcore fault handler mmap_vmcore_fault() is called. This handler works as follows: * Get already available or new page from page cache (find_or_create_page) * Check if /proc/vmcore page is filled with data (PageUptodate) * If yes: Return that page * If no: Fill page using __vmcore_read(), set PageUptodate, and return page Signed-off-by: Michael Holzheu <holzheu@xxxxxxxxxxxxxxxxxx> Acked-by: Vivek Goyal <vgoyal@xxxxxxxxxx> Cc: HATAYAMA Daisuke <d.hatayama@xxxxxxxxxxxxxx> Cc: Jan Willeke <willeke@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- fs/proc/vmcore.c | 91 +++++++++++++++++++++++++++++++---- include/linux/crash_dump.h | 3 + 2 files changed, 86 insertions(+), 8 deletions(-) diff -puN fs/proc/vmcore.c~vmcore-introduce-remap_oldmem_pfn_range fs/proc/vmcore.c --- a/fs/proc/vmcore.c~vmcore-introduce-remap_oldmem_pfn_range +++ a/fs/proc/vmcore.c @@ -21,6 +21,7 @@ #include <linux/crash_dump.h> #include <linux/list.h> #include <linux/vmalloc.h> +#include <linux/pagemap.h> #include <asm/uaccess.h> #include <asm/io.h> #include "internal.h" @@ -153,11 +154,35 @@ ssize_t __weak elfcorehdr_read_notes(cha return read_from_oldmem(buf, count, ppos, 0); } +/* + * Architectures may override this function to map oldmem + */ +int __weak remap_oldmem_pfn_range(struct vm_area_struct *vma, + unsigned long from, unsigned long pfn, + unsigned long size, pgprot_t prot) +{ + return remap_pfn_range(vma, from, pfn, size, prot); +} + +/* + * Copy to either kernel or user space + */ +static int copy_to(void *target, void *src, size_t size, int userbuf) +{ + if (userbuf) { + if (copy_to_user(target, src, size)) + return -EFAULT; + } else { + memcpy(target, src, size); + } + return 0; +} + /* Read from the ELF header and then the crash dump. On error, negative value is * returned otherwise number of bytes read are returned. */ -static ssize_t read_vmcore(struct file *file, char __user *buffer, - size_t buflen, loff_t *fpos) +static ssize_t __read_vmcore(char *buffer, size_t buflen, loff_t *fpos, + int userbuf) { ssize_t acc = 0, tmp; size_t tsz; @@ -174,7 +199,7 @@ static ssize_t read_vmcore(struct file * /* Read ELF core header */ if (*fpos < elfcorebuf_sz) { tsz = min(elfcorebuf_sz - (size_t)*fpos, buflen); - if (copy_to_user(buffer, elfcorebuf + *fpos, tsz)) + if (copy_to(buffer, elfcorebuf + *fpos, tsz, userbuf)) return -EFAULT; buflen -= tsz; *fpos += tsz; @@ -192,7 +217,7 @@ static ssize_t read_vmcore(struct file * tsz = min(elfcorebuf_sz + elfnotes_sz - (size_t)*fpos, buflen); kaddr = elfnotes_buf + *fpos - elfcorebuf_sz; - if (copy_to_user(buffer, kaddr, tsz)) + if (copy_to(buffer, kaddr, tsz, userbuf)) return -EFAULT; buflen -= tsz; *fpos += tsz; @@ -208,7 +233,7 @@ static ssize_t read_vmcore(struct file * if (*fpos < m->offset + m->size) { tsz = min_t(size_t, m->offset + m->size - *fpos, buflen); start = m->paddr + *fpos - m->offset; - tmp = read_from_oldmem(buffer, tsz, &start, 1); + tmp = read_from_oldmem(buffer, tsz, &start, userbuf); if (tmp < 0) return tmp; buflen -= tsz; @@ -225,6 +250,55 @@ static ssize_t read_vmcore(struct file * return acc; } +static ssize_t read_vmcore(struct file *file, char __user *buffer, + size_t buflen, loff_t *fpos) +{ + return __read_vmcore(buffer, buflen, fpos, 1); +} + +/* + * The vmcore fault handler uses the page cache and fills data using the + * standard __vmcore_read() function. + * + * On s390 the fault handler is used for memory regions that can't be mapped + * directly with remap_pfn_range(). + */ +static int mmap_vmcore_fault(struct vm_area_struct *vma, struct vm_fault *vmf) +{ +#ifdef CONFIG_S390 + struct address_space *mapping = vma->vm_file->f_mapping; + pgoff_t index = vmf->pgoff; + struct page *page; + loff_t offset; + char *buf; + int rc; + + page = find_or_create_page(mapping, index, GFP_KERNEL); + if (!page) + return VM_FAULT_OOM; + if (!PageUptodate(page)) { + offset = (loff_t) index << PAGE_CACHE_SHIFT; + buf = __va((page_to_pfn(page) << PAGE_SHIFT)); + rc = __read_vmcore(buf, PAGE_SIZE, &offset, 0); + if (rc < 0) { + unlock_page(page); + page_cache_release(page); + return (rc == -ENOMEM) ? VM_FAULT_OOM : VM_FAULT_SIGBUS; + } + SetPageUptodate(page); + } + unlock_page(page); + vmf->page = page; + return 0; +#else + return VM_FAULT_SIGBUS; +#endif +} + +static const struct vm_operations_struct vmcore_mmap_ops = { + .fault = mmap_vmcore_fault, +}; + /** * alloc_elfnotes_buf - allocate buffer for ELF note segment in * vmalloc memory @@ -271,6 +345,7 @@ static int mmap_vmcore(struct file *file vma->vm_flags &= ~(VM_MAYWRITE | VM_MAYEXEC); vma->vm_flags |= VM_MIXEDMAP; + vma->vm_ops = &vmcore_mmap_ops; len = 0; @@ -312,9 +387,9 @@ static int mmap_vmcore(struct file *file tsz = min_t(size_t, m->offset + m->size - start, size); paddr = m->paddr + start - m->offset; - if (remap_pfn_range(vma, vma->vm_start + len, - paddr >> PAGE_SHIFT, tsz, - vma->vm_page_prot)) + if (remap_oldmem_pfn_range(vma, vma->vm_start + len, + paddr >> PAGE_SHIFT, tsz, + vma->vm_page_prot)) goto fail; size -= tsz; start += tsz; diff -puN include/linux/crash_dump.h~vmcore-introduce-remap_oldmem_pfn_range include/linux/crash_dump.h --- a/include/linux/crash_dump.h~vmcore-introduce-remap_oldmem_pfn_range +++ a/include/linux/crash_dump.h @@ -17,6 +17,9 @@ extern int __weak elfcorehdr_alloc(unsig extern void __weak elfcorehdr_free(unsigned long long addr); extern ssize_t __weak elfcorehdr_read(char *buf, size_t count, u64 *ppos); extern ssize_t __weak elfcorehdr_read_notes(char *buf, size_t count, u64 *ppos); +extern int __weak remap_oldmem_pfn_range(struct vm_area_struct *vma, + unsigned long from, unsigned long pfn, + unsigned long size, pgprot_t prot); extern ssize_t copy_oldmem_page(unsigned long, char *, size_t, unsigned long, int); _ Patches currently in -mm which might be from holzheu@xxxxxxxxxxxxxxxxxx are vmcore-introduce-elf-header-in-new-memory-feature.patch s390-vmcore-use-elf-header-in-new-memory-feature.patch vmcore-introduce-remap_oldmem_pfn_range.patch s390-vmcore-implement-remap_oldmem_pfn_range-for-s390.patch vmcore-enable-proc-vmcore-mmap-for-s390.patch s390-vmcore-use-vmcore-for-zfcpdump.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html