These changes are the raw update to linux-4.4.6-rt14. Kernel sources

[kvmfornfv.git] / kernel / fs / binfmt_elf_fdpic.c

diff --git a/kernel/fs/binfmt_elf_fdpic.c b/kernel/fs/binfmt_elf_fdpic.c
index d3634bf..b1adb92 100644 (file)
--- a/kernel/fs/binfmt_elf_fdpic.c
+++ b/kernel/fs/binfmt_elf_fdpic.c
@@ -35,6 +35,7 @@
 #include <linux/elf-fdpic.h>
 #include <linux/elfcore.h>
 #include <linux/coredump.h>
+#include <linux/dax.h>
 
 #include <asm/uaccess.h>
 #include <asm/param.h>
@@ -103,19 +104,36 @@ static void __exit exit_elf_fdpic_binfmt(void)
 core_initcall(init_elf_fdpic_binfmt);
 module_exit(exit_elf_fdpic_binfmt);
 
-static int is_elf_fdpic(struct elfhdr *hdr, struct file *file)
+static int is_elf(struct elfhdr *hdr, struct file *file)
 {
        if (memcmp(hdr->e_ident, ELFMAG, SELFMAG) != 0)
                return 0;
        if (hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN)
                return 0;
-       if (!elf_check_arch(hdr) || !elf_check_fdpic(hdr))
+       if (!elf_check_arch(hdr))
                return 0;
        if (!file->f_op->mmap)
                return 0;
        return 1;
 }
 
+#ifndef elf_check_fdpic
+#define elf_check_fdpic(x) 0
+#endif
+
+#ifndef elf_check_const_displacement
+#define elf_check_const_displacement(x) 0
+#endif
+
+static int is_constdisp(struct elfhdr *hdr)
+{
+       if (!elf_check_fdpic(hdr))
+               return 1;
+       if (elf_check_const_displacement(hdr))
+               return 1;
+       return 0;
+}
+
 /*****************************************************************************/
 /*
  * read the program headers table into memory
@@ -191,8 +209,18 @@ static int load_elf_fdpic_binary(struct linux_binprm *bprm)
 
        /* check that this is a binary we know how to deal with */
        retval = -ENOEXEC;
-       if (!is_elf_fdpic(&exec_params.hdr, bprm->file))
+       if (!is_elf(&exec_params.hdr, bprm->file))
+               goto error;
+       if (!elf_check_fdpic(&exec_params.hdr)) {
+#ifdef CONFIG_MMU
+               /* binfmt_elf handles non-fdpic elf except on nommu */
                goto error;
+#else
+               /* nommu can only load ET_DYN (PIE) ELF */
+               if (exec_params.hdr.e_type != ET_DYN)
+                       goto error;
+#endif
+       }
 
        /* read the program header table */
        retval = elf_fdpic_fetch_phdrs(&exec_params, bprm->file);
@@ -269,13 +297,13 @@ static int load_elf_fdpic_binary(struct linux_binprm *bprm)
 
        }
 
-       if (elf_check_const_displacement(&exec_params.hdr))
+       if (is_constdisp(&exec_params.hdr))
                exec_params.flags |= ELF_FDPIC_FLAG_CONSTDISP;
 
        /* perform insanity checks on the interpreter */
        if (interpreter_name) {
                retval = -ELIBBAD;
-               if (!is_elf_fdpic(&interp_params.hdr, interpreter))
+               if (!is_elf(&interp_params.hdr, interpreter))
                        goto error;
 
                interp_params.flags = ELF_FDPIC_FLAG_PRESENT;
@@ -306,9 +334,9 @@ static int load_elf_fdpic_binary(struct linux_binprm *bprm)
 
        retval = -ENOEXEC;
        if (stack_size == 0)
-               goto error;
+               stack_size = 131072UL; /* same as exec.c's default commit */
 
-       if (elf_check_const_displacement(&interp_params.hdr))
+       if (is_constdisp(&interp_params.hdr))
                interp_params.flags |= ELF_FDPIC_FLAG_CONSTDISP;
 
        /* flush all traces of the currently running executable */
@@ -319,7 +347,10 @@ static int load_elf_fdpic_binary(struct linux_binprm *bprm)
        /* there's now no turning back... the old userspace image is dead,
         * defunct, deceased, etc.
         */
-       set_personality(PER_LINUX_FDPIC);
+       if (elf_check_fdpic(&exec_params.hdr))
+               set_personality(PER_LINUX_FDPIC);
+       else
+               set_personality(PER_LINUX);
        if (elf_read_implies_exec(&exec_params.hdr, executable_stack))
                current->personality |= READ_IMPLIES_EXEC;
 
@@ -374,10 +405,7 @@ static int load_elf_fdpic_binary(struct linux_binprm *bprm)
                PAGE_ALIGN(current->mm->start_brk);
 
 #else
-       /* create a stack and brk area big enough for everyone
-        * - the brk heap starts at the bottom and works up
-        * - the stack starts at the top and works down
-        */
+       /* create a stack area and zero-size brk area */
        stack_size = (stack_size + PAGE_SIZE - 1) & PAGE_MASK;
        if (stack_size < PAGE_SIZE * 2)
                stack_size = PAGE_SIZE * 2;
@@ -400,8 +428,6 @@ static int load_elf_fdpic_binary(struct linux_binprm *bprm)
 
        current->mm->brk = current->mm->start_brk;
        current->mm->context.end_brk = current->mm->start_brk;
-       current->mm->context.end_brk +=
-               (stack_size > PAGE_SIZE) ? (stack_size - PAGE_SIZE) : 0;
        current->mm->start_stack = current->mm->start_brk + stack_size;
 #endif
 
@@ -1206,6 +1232,20 @@ static int maydump(struct vm_area_struct *vma, unsigned long mm_flags)
                return 0;
        }
 
+       /* support for DAX */
+       if (vma_is_dax(vma)) {
+               if (vma->vm_flags & VM_SHARED) {
+                       dump_ok = test_bit(MMF_DUMP_DAX_SHARED, &mm_flags);
+                       kdcore("%08lx: %08lx: %s (DAX shared)", vma->vm_start,
+                              vma->vm_flags, dump_ok ? "yes" : "no");
+               } else {
+                       dump_ok = test_bit(MMF_DUMP_DAX_PRIVATE, &mm_flags);
+                       kdcore("%08lx: %08lx: %s (DAX private)", vma->vm_start,
+                              vma->vm_flags, dump_ok ? "yes" : "no");
+               }
+               return dump_ok;
+       }
+
        /* By default, dump shared memory if mapped from an anonymous file. */
        if (vma->vm_flags & VM_SHARED) {
                if (file_inode(vma->vm_file)->i_nlink == 0) {