[PATCH v8 7/9] vmcore: Allow user process to remap ELF note segment buffer

[HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>]

Now ELF note segment has been copied in the buffer on vmalloc
memory. To allow user process to remap the ELF note segment buffer
with remap_vmalloc_page, the corresponding VM area object has to have
VM_USERMAP flag set.

Signed-off-by: HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>
---

 fs/proc/vmcore.c |   14 ++++++++++++++
 1 files changed, 14 insertions(+), 0 deletions(-)

diff --git a/fs/proc/vmcore.c b/fs/proc/vmcore.c
index 937709d..9de4d91 100644
--- a/fs/proc/vmcore.c
+++ b/fs/proc/vmcore.c
@@ -375,6 +375,7 @@ static int __init merge_note_headers_elf64(char *elfptr, size_t *elfsz,
 	Elf64_Ehdr *ehdr_ptr;
 	Elf64_Phdr phdr;
 	u64 phdr_sz = 0, note_off;
+	struct vm_struct *vm;
 
 	ehdr_ptr = (Elf64_Ehdr *)elfptr;
 
@@ -391,6 +392,12 @@ static int __init merge_note_headers_elf64(char *elfptr, size_t *elfsz,
 	if (!*notes_buf)
 		return -ENOMEM;
 
+	/* Allow users to remap ELF note segment buffer on vmalloc
+	 * memory using remap_vmalloc_range. */
+	vm = find_vm_area(*notes_buf);
+	BUG_ON(!vm);
+	vm->flags |= VM_USERMAP;
+
 	rc = copy_notes_elf64(ehdr_ptr, *notes_buf);
 	if (rc < 0)
 		return rc;
@@ -554,6 +561,7 @@ static int __init merge_note_headers_elf32(char *elfptr, size_t *elfsz,
 	Elf32_Ehdr *ehdr_ptr;
 	Elf32_Phdr phdr;
 	u64 phdr_sz = 0, note_off;
+	struct vm_struct *vm;
 
 	ehdr_ptr = (Elf32_Ehdr *)elfptr;
 
@@ -570,6 +578,12 @@ static int __init merge_note_headers_elf32(char *elfptr, size_t *elfsz,
 	if (!*notes_buf)
 		return -ENOMEM;
 
+	/* Allow users to remap ELF note segment buffer on vmalloc
+	 * memory using remap_vmalloc_range. */
+	vm = find_vm_area(*notes_buf);
+	BUG_ON(!vm);
+	vm->flags |= VM_USERMAP;
+
 	rc = copy_notes_elf32(ehdr_ptr, *notes_buf);
 	if (rc < 0)
 		return rc;

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