From ad1df95419cc46b4a832cbb537716e3da9a98881 Mon Sep 17 00:00:00 2001 From: Guoyun Sun Date: Wed, 15 Jan 2020 11:35:00 +0800 Subject: mips/vdso: Support mremap() for vDSO vDSO VMA address is saved in mm_context for the purpose of using restorer from vDSO page to return to userspace after signal handling. In Checkpoint Restore in Userspace (CRIU) project we place vDSO VMA on restore back to the place where it was on the dump. Make vDSO code track the VMA address by supplying .mremap() fops the same way it's done for x86 and arm by: commit b059a453b1cf ("x86/vdso: Add mremap hook to vm_special_mapping") commit 739586951b8a ("arm64/vdso: Support mremap() for vDSO"). Signed-off-by: Guoyun Sun Signed-off-by: Paul Burton Cc: Ralf Baechle Cc: Allison Randal Cc: Thomas Gleixner Cc: Greg Kroah-Hartman Cc: linux-mips@vger.kernel.org Cc: linux-kernel@vger.kernel.org --- arch/mips/vdso/genvdso.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) (limited to 'arch/mips/vdso') diff --git a/arch/mips/vdso/genvdso.c b/arch/mips/vdso/genvdso.c index b66b6b1c4aeb..be57b832bbe0 100644 --- a/arch/mips/vdso/genvdso.c +++ b/arch/mips/vdso/genvdso.c @@ -251,6 +251,18 @@ int main(int argc, char **argv) fprintf(out_file, "#include \n"); fprintf(out_file, "#include \n"); fprintf(out_file, "#include \n"); + fprintf(out_file, "static int vdso_mremap(\n"); + fprintf(out_file, " const struct vm_special_mapping *sm,\n"); + fprintf(out_file, " struct vm_area_struct *new_vma)\n"); + fprintf(out_file, "{\n"); + fprintf(out_file, " unsigned long new_size =\n"); + fprintf(out_file, " new_vma->vm_end - new_vma->vm_start;\n"); + fprintf(out_file, " if (vdso_image.size != new_size)\n"); + fprintf(out_file, " return -EINVAL;\n"); + fprintf(out_file, " current->mm->context.vdso =\n"); + fprintf(out_file, " (void __user *)(new_vma->vm_start);\n"); + fprintf(out_file, " return 0;\n"); + fprintf(out_file, "}\n"); /* Write out the stripped VDSO data. */ fprintf(out_file, @@ -275,6 +287,7 @@ int main(int argc, char **argv) fprintf(out_file, "\t.mapping = {\n"); fprintf(out_file, "\t\t.name = \"[vdso]\",\n"); fprintf(out_file, "\t\t.pages = vdso_pages,\n"); + fprintf(out_file, "\t\t.mremap = vdso_mremap,\n"); fprintf(out_file, "\t},\n"); /* Calculate and write symbol offsets to */ -- cgit v1.2.3