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authorDavidlohr Bueso <dave@stgolabs.net>2015-02-25 13:58:35 -0800
committerChris Metcalf <cmetcalf@ezchip.com>2015-04-17 12:58:31 -0400
commit5a3b4e8000c1ce476f5e8babd62c580457561f34 (patch)
tree9ee106a764964508ce11beff4b06b9727a7e8381 /arch/tile/mm
parent89067c2daf3d9e0ce51c768589e79e845e6fda42 (diff)
downloadlinux-5a3b4e8000c1ce476f5e8babd62c580457561f34.tar.bz2
tile/elf: reorganize notify_exec()
In the future mm->exe_file will be done without mmap_sem serialization, thus isolate and reorganize the tile elf code to make the transition easier. Good users will, make use of the more standard get_mm_exe_file(), requiring only holding the mmap_sem to read the value, and relying on reference counting to make sure that the exe file won't dissappear underneath us. The visible effects of this patch are: o We now take and drop the mmap_sem more often. Instead of just in arch_setup_additional_pages(), we also do it in: 1) get_mm_exe_file() 2) to get the mm->vm_file and notify the simulator. [Note that 1) will disappear once we change the locking rules for exe_file.] o We avoid getting a free page and doing d_path() while holding the mmap_sem. This requires reordering the checks. Signed-off-by: Davidlohr Bueso <dbueso@suse.de> Signed-off-by: Chris Metcalf <cmetcalf@ezchip.com>
Diffstat (limited to 'arch/tile/mm')
-rw-r--r--arch/tile/mm/elf.c47
1 files changed, 29 insertions, 18 deletions
diff --git a/arch/tile/mm/elf.c b/arch/tile/mm/elf.c
index 23f044e8a7ab..f7ddae3725a4 100644
--- a/arch/tile/mm/elf.c
+++ b/arch/tile/mm/elf.c
@@ -17,6 +17,7 @@
#include <linux/binfmts.h>
#include <linux/compat.h>
#include <linux/mman.h>
+#include <linux/file.h>
#include <linux/elf.h>
#include <asm/pgtable.h>
#include <asm/pgalloc.h>
@@ -39,30 +40,34 @@ static void sim_notify_exec(const char *binary_name)
static int notify_exec(struct mm_struct *mm)
{
+ int ret = 0;
char *buf, *path;
struct vm_area_struct *vma;
+ struct file *exe_file;
if (!sim_is_simulator())
return 1;
- if (mm->exe_file == NULL)
- return 0;
-
- for (vma = current->mm->mmap; ; vma = vma->vm_next) {
- if (vma == NULL)
- return 0;
- if (vma->vm_file == mm->exe_file)
- break;
- }
-
buf = (char *) __get_free_page(GFP_KERNEL);
if (buf == NULL)
return 0;
- path = d_path(&mm->exe_file->f_path, buf, PAGE_SIZE);
- if (IS_ERR(path)) {
- free_page((unsigned long)buf);
- return 0;
+ exe_file = get_mm_exe_file(mm);
+ if (exe_file == NULL)
+ goto done_free;
+
+ path = d_path(&exe_file->f_path, buf, PAGE_SIZE);
+ if (IS_ERR(path))
+ goto done_put;
+
+ down_read(&mm->mmap_sem);
+ for (vma = current->mm->mmap; ; vma = vma->vm_next) {
+ if (vma == NULL) {
+ up_read(&mm->mmap_sem);
+ goto done_put;
+ }
+ if (vma->vm_file == exe_file)
+ break;
}
/*
@@ -80,14 +85,20 @@ static int notify_exec(struct mm_struct *mm)
__insn_mtspr(SPR_SIM_CONTROL,
(SIM_CONTROL_DLOPEN
| (c << _SIM_CONTROL_OPERATOR_BITS)));
- if (c == '\0')
+ if (c == '\0') {
+ ret = 1; /* success */
break;
+ }
}
}
+ up_read(&mm->mmap_sem);
sim_notify_exec(path);
+done_put:
+ fput(exe_file);
+done_free:
free_page((unsigned long)buf);
- return 1;
+ return ret;
}
/* Notify a running simulator, if any, that we loaded an interpreter. */
@@ -109,8 +120,6 @@ int arch_setup_additional_pages(struct linux_binprm *bprm,
struct mm_struct *mm = current->mm;
int retval = 0;
- down_write(&mm->mmap_sem);
-
/*
* Notify the simulator that an exec just occurred.
* If we can't find the filename of the mapping, just use
@@ -119,6 +128,8 @@ int arch_setup_additional_pages(struct linux_binprm *bprm,
if (!notify_exec(mm))
sim_notify_exec(bprm->filename);
+ down_write(&mm->mmap_sem);
+
retval = setup_vdso_pages();
#ifndef __tilegx__