VM: add "vm_brk()" helper function

[linux-flexiantxendom0-3.2.10.git] / fs / binfmt_elf.c

diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index f8ac425..0708a0b 100644 (file)
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -35,6 +35,7 @@
 #include <asm/uaccess.h>
 #include <asm/param.h>
 #include <asm/page.h>
+#include <asm/exec.h>
 
 static int load_elf_binary(struct linux_binprm *bprm, struct pt_regs *regs);
 static int load_elf_library(struct file *);
@@ -81,9 +82,7 @@ static int set_brk(unsigned long start, unsigned long end)
        end = ELF_PAGEALIGN(end);
        if (end > start) {
                unsigned long addr;
-               down_write(&current->mm->mmap_sem);
-               addr = do_brk(start, end - start);
-               up_write(&current->mm->mmap_sem);
+               addr = vm_brk(start, end - start);
                if (BAD_ADDR(addr))
                        return addr;
        }
@@ -513,9 +512,7 @@ static unsigned long load_elf_interp(struct elfhdr *interp_elf_ex,
                elf_bss = ELF_PAGESTART(elf_bss + ELF_MIN_ALIGN - 1);
 
                /* Map the last of the bss segment */
-               down_write(&current->mm->mmap_sem);
-               error = do_brk(elf_bss, last_bss - elf_bss);
-               up_write(&current->mm->mmap_sem);
+               error = vm_brk(elf_bss, last_bss - elf_bss);
                if (BAD_ADDR(error))
                        goto out_close;
        }
@@ -712,7 +709,6 @@ static int load_elf_binary(struct linux_binprm *bprm, struct pt_regs *regs)
                goto out_free_dentry;
 
        /* OK, This is the point of no return */
-       current->flags &= ~PF_FORKNOEXEC;
        current->mm->def_flags = def_flags;
 
        /* Do this immediately, since STACK_TOP as used in setup_arg_pages
@@ -934,7 +930,6 @@ static int load_elf_binary(struct linux_binprm *bprm, struct pt_regs *regs)
 #endif /* ARCH_HAS_SETUP_ADDITIONAL_PAGES */
 
        install_exec_creds(bprm);
-       current->flags &= ~PF_FORKNOEXEC;
        retval = create_elf_tables(bprm, &loc->elf_ex,
                          load_addr, interp_load_addr);
        if (retval < 0) {
@@ -1073,11 +1068,8 @@ static int load_elf_library(struct file *file)
        len = ELF_PAGESTART(eppnt->p_filesz + eppnt->p_vaddr +
                            ELF_MIN_ALIGN - 1);
        bss = eppnt->p_memsz + eppnt->p_vaddr;
-       if (bss > len) {
-               down_write(&current->mm->mmap_sem);
-               do_brk(len, bss - len);
-               up_write(&current->mm->mmap_sem);
-       }
+       if (bss > len)
+               vm_brk(len, bss - len);
        error = 0;
 
 out_free_ph:
@@ -1095,6 +1087,29 @@ out:
  */
 
 /*
+ * The purpose of always_dump_vma() is to make sure that special kernel mappings
+ * that are useful for post-mortem analysis are included in every core dump.
+ * In that way we ensure that the core dump is fully interpretable later
+ * without matching up the same kernel and hardware config to see what PC values
+ * meant. These special mappings include - vDSO, vsyscall, and other
+ * architecture specific mappings
+ */
+static bool always_dump_vma(struct vm_area_struct *vma)
+{
+       /* Any vsyscall mappings? */
+       if (vma == get_gate_vma(vma->vm_mm))
+               return true;
+       /*
+        * arch_vma_name() returns non-NULL for special architecture mappings,
+        * such as vDSO sections.
+        */
+       if (arch_vma_name(vma))
+               return true;
+
+       return false;
+}
+
+/*
  * Decide what to dump of a segment, part, all or none.
  */
 static unsigned long vma_dump_size(struct vm_area_struct *vma,
@@ -1102,10 +1117,13 @@ static unsigned long vma_dump_size(struct vm_area_struct *vma,
 {
 #define FILTER(type)   (mm_flags & (1UL << MMF_DUMP_##type))
 
-       /* The vma can be set up to tell us the answer directly.  */
-       if (vma->vm_flags & VM_ALWAYSDUMP)
+       /* always dump the vdso and vsyscall sections */
+       if (always_dump_vma(vma))
                goto whole;
 
+       if (vma->vm_flags & VM_NODUMP)
+               return 0;
+
        /* Hugetlb memory check */
        if (vma->vm_flags & VM_HUGETLB) {
                if ((vma->vm_flags & VM_SHARED) && FILTER(HUGETLB_SHARED))
@@ -1390,6 +1408,22 @@ static void do_thread_regset_writeback(struct task_struct *task,
                regset->writeback(task, regset, 1);
 }
 
+#ifndef PR_REG_SIZE
+#define PR_REG_SIZE(S) sizeof(S)
+#endif
+
+#ifndef PRSTATUS_SIZE
+#define PRSTATUS_SIZE(S) sizeof(S)
+#endif
+
+#ifndef PR_REG_PTR
+#define PR_REG_PTR(S) (&((S)->pr_reg))
+#endif
+
+#ifndef SET_PR_FPVALID
+#define SET_PR_FPVALID(S, V) ((S)->pr_fpvalid = (V))
+#endif
+
 static int fill_thread_core_info(struct elf_thread_core_info *t,
                                 const struct user_regset_view *view,
                                 long signr, size_t *total)
@@ -1404,11 +1438,11 @@ static int fill_thread_core_info(struct elf_thread_core_info *t,
         */
        fill_prstatus(&t->prstatus, t->task, signr);
        (void) view->regsets[0].get(t->task, &view->regsets[0],
-                                   0, sizeof(t->prstatus.pr_reg),
-                                   &t->prstatus.pr_reg, NULL);
+                                   0, PR_REG_SIZE(t->prstatus.pr_reg),
+                                   PR_REG_PTR(&t->prstatus), NULL);
 
        fill_note(&t->notes[0], "CORE", NT_PRSTATUS,
-                 sizeof(t->prstatus), &t->prstatus);
+                 PRSTATUS_SIZE(t->prstatus), &t->prstatus);
        *total += notesize(&t->notes[0]);
 
        do_thread_regset_writeback(t->task, &view->regsets[0]);
@@ -1438,7 +1472,7 @@ static int fill_thread_core_info(struct elf_thread_core_info *t,
                                                  regset->core_note_type,
                                                  size, data);
                                else {
-                                       t->prstatus.pr_fpvalid = 1;
+                                       SET_PR_FPVALID(&t->prstatus, 1);
                                        fill_note(&t->notes[i], "CORE",
                                                  NT_PRFPREG, size, data);
                                }