Subject: + vmcore-support-mmap-on-proc-vmcore.patch added to -mm tree To: d.hatayama@xxxxxxxxxxxxxx,kosaki.motohiro@xxxxxxxxxxxxxx,kumagai-atsushi@xxxxxxxxxxxxxxxxx,lisa.mitchell@xxxxxx,vgoyal@xxxxxxxxxx,zhangyanfei@xxxxxxxxxxxxxx From: akpm@xxxxxxxxxxxxxxxxxxxx Date: Thu, 23 May 2013 17:20:41 -0700 The patch titled Subject: vmcore: support mmap() on /proc/vmcore has been added to the -mm tree. Its filename is vmcore-support-mmap-on-proc-vmcore.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: HATAYAMA Daisuke <d.hatayama@xxxxxxxxxxxxxx> Subject: vmcore: support mmap() on /proc/vmcore This patch introduces mmap_vmcore(). Don't permit writable nor executable mapping even with mprotect() because this mmap() is aimed at reading crash dump memory. Non-writable mapping is also requirement of remap_pfn_range() when mapping linear pages on non-consecutive physical pages; see is_cow_mapping(). Set VM_MIXEDMAP flag to remap memory by remap_pfn_range and by remap_vmalloc_range_pertial at the same time for a single vma. do_munmap() can correctly clean partially remapped vma with two functions in abnormal case. See zap_pte_range(), vm_normal_page() and their comments for details. On x86-32 PAE kernels, mmap() supports at most 16TB memory only. This limitation comes from the fact that the third argument of remap_pfn_range(), pfn, is of 32-bit length on x86-32: unsigned long. Signed-off-by: HATAYAMA Daisuke <d.hatayama@xxxxxxxxxxxxxx> Acked-by: Vivek Goyal <vgoyal@xxxxxxxxxx> Cc: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx> Cc: Atsushi Kumagai <kumagai-atsushi@xxxxxxxxxxxxxxxxx> Cc: Lisa Mitchell <lisa.mitchell@xxxxxx> Cc: Zhang Yanfei <zhangyanfei@xxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- fs/proc/vmcore.c | 86 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 86 insertions(+) diff -puN fs/proc/vmcore.c~vmcore-support-mmap-on-proc-vmcore fs/proc/vmcore.c --- a/fs/proc/vmcore.c~vmcore-support-mmap-on-proc-vmcore +++ a/fs/proc/vmcore.c @@ -20,6 +20,7 @@ #include <linux/init.h> #include <linux/crash_dump.h> #include <linux/list.h> +#include <linux/vmalloc.h> #include <asm/uaccess.h> #include <asm/io.h> #include "internal.h" @@ -194,9 +195,94 @@ static ssize_t read_vmcore(struct file * return acc; } +static int mmap_vmcore(struct file *file, struct vm_area_struct *vma) +{ + size_t size = vma->vm_end - vma->vm_start; + u64 start, end, len, tsz; + struct vmcore *m; + + start = (u64)vma->vm_pgoff << PAGE_SHIFT; + end = start + size; + + if (size > vmcore_size || end > vmcore_size) + return -EINVAL; + + if (vma->vm_flags & (VM_WRITE | VM_EXEC)) + return -EPERM; + + vma->vm_flags &= ~(VM_MAYWRITE | VM_MAYEXEC); + vma->vm_flags |= VM_MIXEDMAP; + + len = 0; + + if (start < elfcorebuf_sz) { + u64 pfn; + + tsz = elfcorebuf_sz - start; + if (size < tsz) + tsz = size; + pfn = __pa(elfcorebuf + start) >> PAGE_SHIFT; + if (remap_pfn_range(vma, vma->vm_start, pfn, tsz, + vma->vm_page_prot)) + return -EAGAIN; + size -= tsz; + start += tsz; + len += tsz; + + if (size == 0) + return 0; + } + + if (start < elfcorebuf_sz + elfnotes_sz) { + void *kaddr; + + tsz = elfcorebuf_sz + elfnotes_sz - start; + if (size < tsz) + tsz = size; + kaddr = elfnotes_buf + start - elfcorebuf_sz; + if (remap_vmalloc_range_partial(vma, vma->vm_start + len, + kaddr, tsz)) { + do_munmap(vma->vm_mm, vma->vm_start, len); + return -EAGAIN; + } + size -= tsz; + start += tsz; + len += tsz; + + if (size == 0) + return 0; + } + + list_for_each_entry(m, &vmcore_list, list) { + if (start < m->offset + m->size) { + u64 paddr = 0; + + tsz = m->offset + m->size - start; + if (size < tsz) + tsz = size; + paddr = m->paddr + start - m->offset; + if (remap_pfn_range(vma, vma->vm_start + len, + paddr >> PAGE_SHIFT, tsz, + vma->vm_page_prot)) { + do_munmap(vma->vm_mm, vma->vm_start, len); + return -EAGAIN; + } + size -= tsz; + start += tsz; + len += tsz; + + if (size == 0) + return 0; + } + } + + return 0; +} + static const struct file_operations proc_vmcore_operations = { .read = read_vmcore, .llseek = default_llseek, + .mmap = mmap_vmcore, }; static struct vmcore* __init get_new_element(void) _ Patches currently in -mm which might be from d.hatayama@xxxxxxxxxxxxxx are include-linux-mmh-add-page_aligned-helper.patch vmcore-clean-up-read_vmcore.patch vmcore-allocate-buffer-for-elf-headers-on-page-size-alignment.patch vmcore-allocate-buffer-for-elf-headers-on-page-size-alignment-fix.patch vmcore-treat-memory-chunks-referenced-by-pt_load-program-header-entries-in-page-size-boundary-in-vmcore_list.patch vmalloc-make-find_vm_area-check-in-range.patch vmalloc-introduce-remap_vmalloc_range_partial.patch vmalloc-introduce-remap_vmalloc_range_partial-fix.patch vmcore-allocate-elf-note-segment-in-the-2nd-kernel-vmalloc-memory.patch vmcore-allocate-elf-note-segment-in-the-2nd-kernel-vmalloc-memory-fix.patch vmcore-allow-user-process-to-remap-elf-note-segment-buffer.patch vmcore-allow-user-process-to-remap-elf-note-segment-buffer-fix.patch vmcore-calculate-vmcore-file-size-from-buffer-size-and-total-size-of-vmcore-objects.patch vmcore-support-mmap-on-proc-vmcore.patch vmcore-support-mmap-on-proc-vmcore-fix.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