[PATCH x86_64]: Setup PER_LINUX32 on x86_64

[PATCH x86_64]: Setup PER_LINUX32 on x86_64

[Jin, Gordon]

On x86_64, PER_LINUX32 is not setup but used by syscall personality and uname.
This patch sets PER_LINUX32 when x86 binary loaded so it can be used correctly.
- Set personality to PER_LINUX32 when x86 binary loaded.
- Set personality to PER_LINUX when x86_64 binary loaded.
- Use sys32_personality instead of sys_personality.
- Add sys32_newuname() for syscall newuname.
- Remove the unnecessary check for PER_LINUX32 in sys_uname().

Signed-off-by: Gordon Jin <gordon.jin@intel.com>

Index: linux-2.6.9/arch/x86_64/kernel/process.c
===================================================================
--- linux-2.6.9/arch/x86_64/kernel/process.c	(revision 1)
+++ linux-2.6.9/arch/x86_64/kernel/process.c	(revision 3)
@@ -550,7 +550,7 @@ long sys_execve(char __user *name, char 
 
 void set_personality_64bit(void)
 {
-	/* inherit personality from parent */
+	set_personality(PER_LINUX);
 
 	/* Make sure to be in 64bit mode */
 	clear_thread_flag(TIF_IA32); 
Index: linux-2.6.9/arch/x86_64/kernel/sys_x86_64.c
===================================================================
--- linux-2.6.9/arch/x86_64/kernel/sys_x86_64.c	(revision 1)
+++ linux-2.6.9/arch/x86_64/kernel/sys_x86_64.c	(revision 3)
@@ -148,8 +148,6 @@ asmlinkage long sys_uname(struct new_uts
 	down_read(&uts_sem);
 	err = copy_to_user(name, &system_utsname, sizeof (*name));
 	up_read(&uts_sem);
-	if (personality(current->personality) == PER_LINUX32) 
-		err |= copy_to_user(&name->machine, "i686", 5); 		
 	return err ? -EFAULT : 0;
 }
 
Index: linux-2.6.9/arch/x86_64/ia32/ia32entry.S
===================================================================
--- linux-2.6.9/arch/x86_64/ia32/ia32entry.S	(revision 1)
+++ linux-2.6.9/arch/x86_64/ia32/ia32entry.S	(revision 3)
@@ -424,7 +424,7 @@ ia32_sys_call_table:
 	.quad stub32_sigreturn
 	.quad stub32_clone		/* 120 */
 	.quad sys_setdomainname
-	.quad sys_uname
+	.quad sys32_newuname
 	.quad sys_modify_ldt
 	.quad sys32_adjtimex
 	.quad sys32_mprotect		/* 125 */
@@ -438,7 +438,7 @@ ia32_sys_call_table:
 	.quad sys_fchdir
 	.quad quiet_ni_syscall	/* bdflush */
 	.quad sys_sysfs		/* 135 */
-	.quad sys_personality
+	.quad sys32_personality
 	.quad quiet_ni_syscall	/* for afs_syscall */
 	.quad sys_setfsuid16
 	.quad sys_setfsgid16
Index: linux-2.6.9/arch/x86_64/ia32/ia32_aout.c
===================================================================
--- linux-2.6.9/arch/x86_64/ia32/ia32_aout.c	(revision 1)
+++ linux-2.6.9/arch/x86_64/ia32/ia32_aout.c	(revision 3)
@@ -297,7 +297,7 @@ static int load_aout_binary(struct linux
 		regs->r13 = regs->r14 = regs->r15 = 0;
 
 	/* OK, This is the point of no return */
-	set_personality(PER_LINUX);
+	set_personality(PER_LINUX32);
 	set_thread_flag(TIF_IA32); 
 	clear_thread_flag(TIF_ABI_PENDING);
 
Index: linux-2.6.9/arch/x86_64/ia32/sys_ia32.c
===================================================================
--- linux-2.6.9/arch/x86_64/ia32/sys_ia32.c	(revision 1)
+++ linux-2.6.9/arch/x86_64/ia32/sys_ia32.c	(revision 3)
@@ -1103,6 +1103,16 @@ long sys32_uname(struct old_utsname __us
 	return err?-EFAULT:0;
 }
 
+asmlinkage long sys32_newuname (struct new_utsname __user *name)
+{
+	int ret = sys_newuname(name);
+
+	if (!ret)
+		if (copy_to_user(name->machine, "i686", 5))
+			ret = -EFAULT;
+	return ret;
+}
+
 long sys32_ustat(unsigned dev, struct ustat32 __user *u32p)
 {
 	struct ustat u;
Index: linux-2.6.9/arch/x86_64/ia32/ia32_binfmt.c
===================================================================
--- linux-2.6.9/arch/x86_64/ia32/ia32_binfmt.c	(revision 1)
+++ linux-2.6.9/arch/x86_64/ia32/ia32_binfmt.c	(revision 3)
@@ -254,8 +254,10 @@ elf_core_copy_task_xfpregs(struct task_s
 #define SET_PERSONALITY(ex, ibcs2)			\
 do {							\
 	unsigned long new_flags = 0;				\
-	if ((ex).e_ident[EI_CLASS] == ELFCLASS32)		\
+	if ((ex).e_ident[EI_CLASS] == ELFCLASS32) {		\
+		set_personality(PER_LINUX32);			\
 		new_flags = _TIF_IA32;				\
+	}							\
 	if ((current_thread_info()->flags & _TIF_IA32)		\
 	    != new_flags)					\
 		set_thread_flag(TIF_ABI_PENDING);		\

Thanks,
Gordon 

Re: [discuss] [PATCH x86_64]: Setup PER_LINUX32 on x86_64

[Arnd Bergmann]

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On Dinsdag 02 November 2004 09:47, Jin, Gordon wrote:
> On x86_64, PER_LINUX32 is not setup but used by syscall personality and uname.
> This patch sets PER_LINUX32 when x86 binary loaded so it can be used correctly.
> - Set personality to PER_LINUX32 when x86 binary loaded.
> - Set personality to PER_LINUX when x86_64 binary loaded.
> - Use sys32_personality instead of sys_personality.
> - Add sys32_newuname() for syscall newuname.
> - Remove the unnecessary check for PER_LINUX32 in sys_uname().

That behavior would be significantly different from the current one,
which is also used on all other biarch architectures. This probably
breaks lots of user setups.

I also think the current behavior is the right one. For things like
configure, you need a way to set the uname independent of the binary
format of your shell. Another example is building rpm packages
on a mixed system, where should be able to set the personality
to decide which target architecture to build for.

	Arnd <><



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Re: [PATCH x86_64]: Setup PER_LINUX32 on x86_64

[Andi Kleen]

"Jin, Gordon" <gordon.jin@intel.com> writes:

> On x86_64, PER_LINUX32 is not setup but used by syscall personality and uname.
> This patch sets PER_LINUX32 when x86 binary loaded so it can be used correctly.
> - Set personality to PER_LINUX32 when x86 binary loaded.
> - Set personality to PER_LINUX when x86_64 binary loaded.
> - Use sys32_personality instead of sys_personality.
> - Add sys32_newuname() for syscall newuname.
> - Remove the unnecessary check for PER_LINUX32 in sys_uname().

Rejected. This was separated intentionally. Otherwise 
e.g. you can never get x86_64 out of uname with a 32bit uname.

-Andi

 

RE: [PATCH x86_64]: Setup PER_LINUX32 on x86_64

[Jin, Gordon]

Jin, Gordon <> wrote on Tuesday, November 02, 2004 4:48 PM:

> On x86_64, PER_LINUX32 is not setup but used by syscall personality
> and uname. This patch sets PER_LINUX32 when x86 binary loaded so it
> can be used correctly. 
> - Set personality to PER_LINUX32 when x86 binary loaded.
> - Set personality to PER_LINUX when x86_64 binary loaded.
> - Use sys32_personality instead of sys_personality.
> - Add sys32_newuname() for syscall newuname.
> - Remove the unnecessary check for PER_LINUX32 in sys_uname().
> 
A side question is:
To distinguish 32-bit and native 64-bit app on x86-64(and some other archs),
somewhere PER_LINUX32 is used, while somewhere TIF_IA32 is used.
So both of them need maintained, respectively in task_struct and thread_info.
Is it redundant? Can we do away TIF_IA32?

Thanks,
Gordon