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UML - Tidy ptrace interface

PATCH In review Jeff Dike 2 participants 4 messages Apr 25, 2008 – Apr 29, 2008

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User-mode Linux (UML) ptrace support
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Jeff Dike

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#0 lore raw

PATCH 9/19 UML - Tidy ptrace interface

Tidy the ptrace interface code. Removed a bunch of unused macros. Started converting register sets from arrays of longs to structures.

Signed-off-by Jeff Dike <[email protected]>
---
 arch/um/include/sysdep-i386/ptrace_user.h   |   30 ----------------------------
 arch/um/include/sysdep-x86_64/ptrace_user.h |   17 +++------------
 arch/um/os-Linux/sys-i386/registers.c       |    5 ++--
 arch/um/sys-i386/ptrace.c                   |   30 +++++++++++++---------------
 arch/um/sys-i386/user-offsets.c             |    2 -
 arch/um/sys-x86_64/user-offsets.c           |    1 
 6 files changed, 23 insertions(+), 62 deletions(-)
arch/um/include/sysdep-i386/ptrace_user.h +1 -29
Index: linux-2.6-git/arch/um/include/sysdep-i386/ptrace_user.h
===================================================================
@@ -41,38 +41,10 @@
 #define PT_SP_OFFSET PT_OFFSET(UESP)
 #define PT_SP(regs) ((regs)[UESP])
 
-#define FP_SIZE ((HOST_XFP_SIZE > HOST_FP_SIZE) ? HOST_XFP_SIZE : HOST_FP_SIZE)
+#define FP_SIZE ((HOST_FPX_SIZE > HOST_FP_SIZE) ? HOST_FPX_SIZE : HOST_FP_SIZE)
 
 #ifndef FRAME_SIZE
 #define FRAME_SIZE (17)
 #endif
-#define FRAME_SIZE_OFFSET (FRAME_SIZE * sizeof(unsigned long))
-
-#define FP_FRAME_SIZE (27)
-#define FPX_FRAME_SIZE (128)
-
-#ifdef PTRACE_GETREGS
-#define UM_HAVE_GETREGS
-#endif
-
-#ifdef PTRACE_SETREGS
-#define UM_HAVE_SETREGS
-#endif
-
-#ifdef PTRACE_GETFPREGS
-#define UM_HAVE_GETFPREGS
-#endif
-
-#ifdef PTRACE_SETFPREGS
-#define UM_HAVE_SETFPREGS
-#endif
-
-#ifdef PTRACE_GETFPXREGS
-#define UM_HAVE_GETFPXREGS
-#endif
-
-#ifdef PTRACE_SETFPXREGS
-#define UM_HAVE_SETFPXREGS
-#endif
 
 #endif
arch/um/include/sysdep-x86_64/ptrace_user.h +4 -13
Index: linux-2.6-git/arch/um/include/sysdep-x86_64/ptrace_user.h
===================================================================
@@ -48,7 +48,8 @@
 #define PT_ORIG_RAX_OFFSET (ORIG_RAX)
 #define PT_ORIG_RAX(regs) ((regs)[PT_INDEX(ORIG_RAX)])
 
-/* x86_64 FC3 doesn't define this in /usr/include/linux/ptrace.h even though
+/*
+ * x86_64 FC3 doesn't define this in /usr/include/linux/ptrace.h even though
  * it's defined in the kernel's include/linux/ptrace.h. Additionally, use the
  * 2.4 name and value for 2.4 host compatibility.
  */

@@ -56,7 +57,8 @@
 #define PTRACE_OLDSETOPTIONS 21
 #endif
 
-/* These are before the system call, so the system call number is RAX
+/*
+ * These are before the system call, so the system call number is RAX
  * rather than ORIG_RAX, and arg4 is R10 rather than RCX
  */
 #define REGS_SYSCALL_NR PT_INDEX(RAX)

@@ -73,14 +75,3 @@
 #define FP_SIZE (HOST_FP_SIZE)
 
 #endif
-
-/*
- * Overrides for Emacs so that we follow Linus's tabbing style.
- * Emacs will notice this stuff at the end of the file and automatically
- * adjust the settings for this buffer only.  This must remain at the end
- * of the file.
- * ---------------------------------------------------------------------------
- * Local variables:
- * c-file-style: "linux"
- * End:
- */
arch/um/sys-i386/ptrace.c +14 -16
Index: linux-2.6-git/arch/um/sys-i386/ptrace.c
===================================================================
@@ -148,14 +148,13 @@ int peek_user(struct task_struct *child,
 int get_fpregs(struct user_i387_struct __user *buf, struct task_struct *child)
 {
 	int err, n, cpu = ((struct thread_info *) child->stack)->cpu;
-	long fpregs[HOST_FP_SIZE];
+	struct user_i387_struct fpregs;
 
-	BUG_ON(sizeof(*buf) != sizeof(fpregs));
-	err = save_fp_registers(userspace_pid[cpu], fpregs);
+	err = save_fp_registers(userspace_pid[cpu], (unsigned long *) &fpregs);
 	if (err)
 		return err;
 
-	n = copy_to_user(buf, fpregs, sizeof(fpregs));
+	n = copy_to_user(buf, &fpregs, sizeof(fpregs));
 	if(n > 0)
 		return -EFAULT;
 

@@ -165,27 +164,26 @@ int get_fpregs(struct user_i387_struct _
 int set_fpregs(struct user_i387_struct __user *buf, struct task_struct *child)
 {
 	int n, cpu = ((struct thread_info *) child->stack)->cpu;
-	long fpregs[HOST_FP_SIZE];
+	struct user_i387_struct fpregs;
 
-	BUG_ON(sizeof(*buf) != sizeof(fpregs));
-	n = copy_from_user(fpregs, buf, sizeof(fpregs));
+	n = copy_from_user(&fpregs, buf, sizeof(fpregs));
 	if (n > 0)
 		return -EFAULT;
 
-	return restore_fp_registers(userspace_pid[cpu], fpregs);
+	return restore_fp_registers(userspace_pid[cpu],
+				    (unsigned long *) &fpregs);
 }
 
 int get_fpxregs(struct user_fxsr_struct __user *buf, struct task_struct *child)
 {
 	int err, n, cpu = ((struct thread_info *) child->stack)->cpu;
-	long fpregs[HOST_XFP_SIZE];
+	struct user_fxsr_struct fpregs;
 
-	BUG_ON(sizeof(*buf) != sizeof(fpregs));
-	err = save_fpx_registers(userspace_pid[cpu], fpregs);
+	err = save_fpx_registers(userspace_pid[cpu], (unsigned long *) &fpregs);
 	if (err)
 		return err;
 
-	n = copy_to_user(buf, fpregs, sizeof(fpregs));
+	n = copy_to_user(buf, &fpregs, sizeof(fpregs));
 	if(n > 0)
 		return -EFAULT;
 

@@ -195,14 +193,14 @@ int get_fpxregs(struct user_fxsr_struct 
 int set_fpxregs(struct user_fxsr_struct __user *buf, struct task_struct *child)
 {
 	int n, cpu = ((struct thread_info *) child->stack)->cpu;
-	long fpregs[HOST_XFP_SIZE];
+	struct user_fxsr_struct fpregs;
 
-	BUG_ON(sizeof(*buf) != sizeof(fpregs));
-	n = copy_from_user(fpregs, buf, sizeof(fpregs));
+	n = copy_from_user(&fpregs, buf, sizeof(fpregs));
 	if (n > 0)
 		return -EFAULT;
 
-	return restore_fpx_registers(userspace_pid[cpu], fpregs);
+	return restore_fpx_registers(userspace_pid[cpu],
+				     (unsigned long *) &fpregs);
 }
 
 long subarch_ptrace(struct task_struct *child, long request, long addr,
arch/um/os-Linux/sys-i386/registers.c +3 -2
Index: linux-2.6-git/arch/um/os-Linux/sys-i386/registers.c
===================================================================
@@ -5,6 +5,7 @@
  */
 
 #include <errno.h>
+#include <asm/user.h>
 #include "kern_constants.h"
 #include "longjmp.h"
 #include "user.h"

@@ -74,10 +75,10 @@ int put_fp_registers(int pid, unsigned l
 
 void arch_init_registers(int pid)
 {
-	unsigned long fpx_regs[HOST_XFP_SIZE];
+	struct user_fxsr_struct fpx_regs;
 	int err;
 
-	err = ptrace(PTRACE_GETFPXREGS, pid, 0, fpx_regs);
+	err = ptrace(PTRACE_GETFPXREGS, pid, 0, &fpx_regs);
 	if (!err)
 		return;
arch/um/sys-i386/user-offsets.c +1 -1
Index: linux-2.6-git/arch/um/sys-i386/user-offsets.c
===================================================================
@@ -22,7 +22,7 @@ void foo(void)
 	OFFSET(HOST_SC_CR2, sigcontext, cr2);
 
 	DEFINE_LONGS(HOST_FP_SIZE, sizeof(struct user_fpregs_struct));
-	DEFINE_LONGS(HOST_XFP_SIZE, sizeof(struct user_fpxregs_struct));
+	DEFINE_LONGS(HOST_FPX_SIZE, sizeof(struct user_fpxregs_struct));
 
 	DEFINE(HOST_IP, EIP);
 	DEFINE(HOST_SP, UESP);
arch/um/sys-x86_64/user-offsets.c +0 -1
Index: linux-2.6-git/arch/um/sys-x86_64/user-offsets.c
===================================================================
@@ -24,7 +24,6 @@ void foo(void)
 	OFFSET(HOST_SC_TRAPNO, sigcontext, trapno);
 
 	DEFINE(HOST_FP_SIZE, sizeof(struct _fpstate) / sizeof(unsigned long));
-	DEFINE(HOST_XFP_SIZE, 0);
 	DEFINE_LONGS(HOST_RBX, RBX);
 	DEFINE_LONGS(HOST_RCX, RCX);
 	DEFINE_LONGS(HOST_RDI, RDI);

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#1 lore raw

From: Jeff Dike <[email protected]>
Date: Fri, 25 Apr 2008 13:56:10 -0400

Quoted 2 lines

Tidy the ptrace interface code. Removed a bunch of unused macros. Started converting register sets from arrays of longs to structures.

Could you please explain a bit why do this? I think long arrary is OK.

Thanks.

Cong

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author
#2 lore raw
Quoted 6 lines · WANG Cong

From: Jeff Dike <[email protected]>
Date: Fri, 25 Apr 2008 13:56:10 -0400

Quoted 2 lines

Tidy the ptrace interface code. Removed a bunch of unused macros. Started converting register sets from arrays of longs to structures.

Could you please explain a bit why do this? I think long arrary is OK.

It's wrong on x86_64. There, FRAME_SIZE is 168 -

     #define FRAME_SIZE 
and SS is the last register defined -
    #define SS 160
but there are a number of registers beyond that in the user_regs_struct:
	unsigned long	ss;
	unsigned long	fs_base;
	unsigned long	gs_base;
	unsigned long	ds;
	unsigned long	es;
	unsigned long	fs;
	unsigned long	gs;

The effect of GETREGS into a long[FRAME_SIZE] will be stack corruption.

Jeff

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Work email - jdike at linux dot intel dot com

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#3 lore raw
Quoted 21 lines · Jeff Dike
Quoted 6 lines · WANG Cong

From: Jeff Dike <[email protected]>
Date: Fri, 25 Apr 2008 13:56:10 -0400

Quoted 2 lines

Tidy the ptrace interface code. Removed a bunch of unused macros. Started converting register sets from arrays of longs to structures.

Could you please explain a bit why do this? I think long arrary is OK.

It's wrong on x86_64. There, FRAME_SIZE is 168 -

    #define FRAME_SIZE 
and SS is the last register defined -
   #define SS 160
but there are a number of registers beyond that in the user_regs_struct:
	unsigned long	ss;
	unsigned long	fs_base;
	unsigned long	gs_base;
	unsigned long	ds;
	unsigned long	es;
	unsigned long	fs;
	unsigned long	gs;
Quoted 2 lines

The effect of GETREGS into a long[FRAME_SIZE] will be stack corruption.

Thanks for teaching this. ;-)

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