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Message-ID: <36375e1f113abf53ebfcac87a4275a5efd9d8057.1394573469.git.josh@joshtriplett.org>
Date: Tue, 11 Mar 2014 14:41:41 -0700
From: Josh Triplett <josh@...htriplett.org>
To: Andrew Morton <akpm@...ux-foundation.org>,
Alexander van Heukelum <heukelum@...tmail.fm>,
Alok Kataria <akataria@...are.com>,
Boris Ostrovsky <boris.ostrovsky@...cle.com>,
Chris Wright <chrisw@...s-sol.org>,
David Vrabel <david.vrabel@...rix.com>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
"H. Peter Anvin" <hpa@...or.com>, Ingo Molnar <mingo@...hat.com>,
Jeremy Fitzhardinge <jeremy@...p.org>,
Jiri Slaby <jslaby@...e.cz>, Kees Cook <keescook@...omium.org>,
Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>,
Rusty Russell <rusty@...tcorp.com.au>,
Thomas Gleixner <tglx@...utronix.de>,
linux-kernel@...r.kernel.org,
virtualization@...ts.linux-foundation.org, x86@...nel.org,
xen-devel@...ts.xenproject.org
Subject: [PATCHv2 1/3] x86: process: Unify 32-bit and 64-bit copy_thread I/O
bitmap handling
The 32-bit and 64-bit versions of copy_thread have functionally
identical handling for copying the I/O bitmap, modulo differences in
error handling. Clean up the error paths in both by moving the copy of
the I/O bitmap to the end, to eliminate the need to free it if
subsequent copy steps fail; move the resulting identical code to a
static inline in a common header.
Signed-off-by: Josh Triplett <josh@...htriplett.org>
Acked-by: Kees Cook <keescook@...omium.org>
---
v2: Rebased and updated for changes to copy_thread; no other changes in
patch 1/3.
arch/x86/kernel/process-io.h | 22 ++++++++++++++++++++++
arch/x86/kernel/process_32.c | 28 ++++++++--------------------
arch/x86/kernel/process_64.c | 25 +++++--------------------
3 files changed, 35 insertions(+), 40 deletions(-)
create mode 100644 arch/x86/kernel/process-io.h
diff --git a/arch/x86/kernel/process-io.h b/arch/x86/kernel/process-io.h
new file mode 100644
index 0000000..d884444
--- /dev/null
+++ b/arch/x86/kernel/process-io.h
@@ -0,0 +1,22 @@
+#ifndef _X86_KERNEL_PROCESS_IO_H
+#define _X86_KERNEL_PROCESS_IO_H
+
+static inline int copy_io_bitmap(struct task_struct *me,
+ struct task_struct *p)
+{
+ if (unlikely(test_tsk_thread_flag(me, TIF_IO_BITMAP))) {
+ p->thread.io_bitmap_ptr = kmemdup(me->thread.io_bitmap_ptr,
+ IO_BITMAP_BYTES, GFP_KERNEL);
+ if (!p->thread.io_bitmap_ptr) {
+ p->thread.io_bitmap_max = 0;
+ return -ENOMEM;
+ }
+ set_tsk_thread_flag(p, TIF_IO_BITMAP);
+ } else {
+ p->thread.io_bitmap_ptr = NULL;
+ }
+
+ return 0;
+}
+
+#endif /* _X86_KERNEL_PROCESS_IO_H */
diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c
index 0de43e9..73a38c8 100644
--- a/arch/x86/kernel/process_32.c
+++ b/arch/x86/kernel/process_32.c
@@ -55,6 +55,8 @@
#include <asm/debugreg.h>
#include <asm/switch_to.h>
+#include "process-io.h"
+
asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
asmlinkage void ret_from_kernel_thread(void) __asm__("ret_from_kernel_thread");
@@ -134,7 +136,6 @@ int copy_thread(unsigned long clone_flags, unsigned long sp,
{
struct pt_regs *childregs = task_pt_regs(p);
struct task_struct *tsk;
- int err;
p->thread.sp = (unsigned long) childregs;
p->thread.sp0 = (unsigned long) (childregs+1);
@@ -168,34 +169,21 @@ int copy_thread(unsigned long clone_flags, unsigned long sp,
p->thread.fpu_counter = 0;
p->thread.io_bitmap_ptr = NULL;
tsk = current;
- err = -ENOMEM;
memset(p->thread.ptrace_bps, 0, sizeof(p->thread.ptrace_bps));
- if (unlikely(test_tsk_thread_flag(tsk, TIF_IO_BITMAP))) {
- p->thread.io_bitmap_ptr = kmemdup(tsk->thread.io_bitmap_ptr,
- IO_BITMAP_BYTES, GFP_KERNEL);
- if (!p->thread.io_bitmap_ptr) {
- p->thread.io_bitmap_max = 0;
- return -ENOMEM;
- }
- set_tsk_thread_flag(p, TIF_IO_BITMAP);
- }
-
- err = 0;
-
/*
* Set a new TLS for the child thread?
*/
- if (clone_flags & CLONE_SETTLS)
+ if (clone_flags & CLONE_SETTLS) {
+ int err;
err = do_set_thread_area(p, -1,
(struct user_desc __user *)childregs->si, 0);
-
- if (err && p->thread.io_bitmap_ptr) {
- kfree(p->thread.io_bitmap_ptr);
- p->thread.io_bitmap_max = 0;
+ if(err)
+ return err;
}
- return err;
+
+ return copy_io_bitmap(tsk, p);
}
void
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index 9c0280f..3b8f17c 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -50,6 +50,8 @@
#include <asm/debugreg.h>
#include <asm/switch_to.h>
+#include "process-io.h"
+
asmlinkage extern void ret_from_fork(void);
asmlinkage DEFINE_PER_CPU(unsigned long, old_rsp);
@@ -154,7 +156,6 @@ static inline u32 read_32bit_tls(struct task_struct *t, int tls)
int copy_thread(unsigned long clone_flags, unsigned long sp,
unsigned long arg, struct task_struct *p)
{
- int err;
struct pt_regs *childregs;
struct task_struct *me = current;
@@ -192,23 +193,13 @@ int copy_thread(unsigned long clone_flags, unsigned long sp,
if (sp)
childregs->sp = sp;
- err = -ENOMEM;
memset(p->thread.ptrace_bps, 0, sizeof(p->thread.ptrace_bps));
- if (unlikely(test_tsk_thread_flag(me, TIF_IO_BITMAP))) {
- p->thread.io_bitmap_ptr = kmemdup(me->thread.io_bitmap_ptr,
- IO_BITMAP_BYTES, GFP_KERNEL);
- if (!p->thread.io_bitmap_ptr) {
- p->thread.io_bitmap_max = 0;
- return -ENOMEM;
- }
- set_tsk_thread_flag(p, TIF_IO_BITMAP);
- }
-
/*
* Set a new TLS for the child thread?
*/
if (clone_flags & CLONE_SETTLS) {
+ int err;
#ifdef CONFIG_IA32_EMULATION
if (test_thread_flag(TIF_IA32))
err = do_set_thread_area(p, -1,
@@ -217,16 +208,10 @@ int copy_thread(unsigned long clone_flags, unsigned long sp,
#endif
err = do_arch_prctl(p, ARCH_SET_FS, childregs->r8);
if (err)
- goto out;
- }
- err = 0;
-out:
- if (err && p->thread.io_bitmap_ptr) {
- kfree(p->thread.io_bitmap_ptr);
- p->thread.io_bitmap_max = 0;
+ return err;
}
- return err;
+ return copy_io_bitmap(me, p);
}
static void
--
1.9.0
--
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