[PATCH] ppc64: Fix PER_LINUX32 behaviour

This patch fixes some bugs in the ppc64 PER_LINUX32 implementation,
noted by Juergen Kreileder:

* uname(2) doesn't respect PER_LINUX32, it returns 'ppc64' instead of 'ppc'
* Child processes of a PER_LINUX32 process don't inherit PER_LINUX32

Along the way I took the opportunity to move things around so that
sys_ppc32.c only has 32-bit syscall emulation functions and to remove
the obsolete "fakeppc" command line option.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

4 files changed, 56 insertions, 53 deletions

diff --git a/arch/ppc64/kernel/misc.S b/arch/ppc64/kernel/misc.S
index b944717c1dbd..e3c73b3425dc 100644
--- a/arch/ppc64/kernel/misc.S
+++ b/arch/ppc64/kernel/misc.S
@@ -792,7 +792,7 @@ _GLOBAL(sys_call_table32)
         .llong .compat_sys_newstat
         .llong .compat_sys_newlstat
         .llong .compat_sys_newfstat
-        .llong .sys_uname
+        .llong .sys32_uname
         .llong .sys_ni_syscall          /* 110 old iopl syscall */
         .llong .sys_vhangup
         .llong .sys_ni_syscall          /* old idle syscall */
diff --git a/arch/ppc64/kernel/sys_ppc32.c b/arch/ppc64/kernel/sys_ppc32.c
index 7cf7a9600025..9c8e317c598d 100644
--- a/arch/ppc64/kernel/sys_ppc32.c
+++ b/arch/ppc64/kernel/sys_ppc32.c
@@ -791,31 +791,6 @@ asmlinkage int sys32_pciconfig_iobase(u32 which, u32 in_bus, u32 in_devfn)
 }
 
 
-asmlinkage int ppc64_newuname(struct new_utsname __user * name)
-{
-        int errno = sys_newuname(name);
-
-        if (current->personality == PER_LINUX32 && !errno) {
-                if(copy_to_user(name->machine, "ppc\0\0", 8)) {
-                        errno = -EFAULT;
-                }
-        }
-        return errno;
-}
-
-asmlinkage int ppc64_personality(unsigned long personality)
-{
-        int ret;
-        if (current->personality == PER_LINUX32 && personality == PER_LINUX)
-                personality = PER_LINUX32;
-        ret = sys_personality(personality);
-        if (ret == PER_LINUX32)
-                ret = PER_LINUX;
-        return ret;
-}
-
-
-
 /* Note: it is necessary to treat mode as an unsigned int,
  * with the corresponding cast to a signed int to insure that the 
  * proper conversion (sign extension) between the register representation of a signed int (msr in 32-bit mode)
@@ -1158,26 +1133,47 @@ asmlinkage long sys32_sysctl(struct __sysctl_args32 __user *args)
 }
 #endif
 
+asmlinkage int sys32_uname(struct old_utsname __user * name)
+{
+        int err = 0;
+        
+        down_read(&uts_sem);
+        if (copy_to_user(name, &system_utsname, sizeof(*name)))
+                err = -EFAULT;
+        up_read(&uts_sem);
+        if (!err && personality(current->personality) == PER_LINUX32) {
+                /* change "ppc64" to "ppc" */
+                if (__put_user(0, name->machine + 3)
+                    || __put_user(0, name->machine + 4))
+                        err = -EFAULT;
+        }
+        return err;
+}
+
 asmlinkage int sys32_olduname(struct oldold_utsname __user * name)
 {
         int error;
-        
-        if (!name)
-                return -EFAULT;
+
         if (!access_ok(VERIFY_WRITE,name,sizeof(struct oldold_utsname)))
                 return -EFAULT;
   
         down_read(&uts_sem);
         error = __copy_to_user(&name->sysname,&system_utsname.sysname,__OLD_UTS_LEN);
-        error -= __put_user(0,name->sysname+__OLD_UTS_LEN);
-        error -= __copy_to_user(&name->nodename,&system_utsname.nodename,__OLD_UTS_LEN);
-        error -= __put_user(0,name->nodename+__OLD_UTS_LEN);
-        error -= __copy_to_user(&name->release,&system_utsname.release,__OLD_UTS_LEN);
-        error -= __put_user(0,name->release+__OLD_UTS_LEN);
-        error -= __copy_to_user(&name->version,&system_utsname.version,__OLD_UTS_LEN);
-        error -= __put_user(0,name->version+__OLD_UTS_LEN);
-        error -= __copy_to_user(&name->machine,&system_utsname.machine,__OLD_UTS_LEN);
-        error = __put_user(0,name->machine+__OLD_UTS_LEN);
+        error |= __put_user(0,name->sysname+__OLD_UTS_LEN);
+        error |= __copy_to_user(&name->nodename,&system_utsname.nodename,__OLD_UTS_LEN);
+        error |= __put_user(0,name->nodename+__OLD_UTS_LEN);
+        error |= __copy_to_user(&name->release,&system_utsname.release,__OLD_UTS_LEN);
+        error |= __put_user(0,name->release+__OLD_UTS_LEN);
+        error |= __copy_to_user(&name->version,&system_utsname.version,__OLD_UTS_LEN);
+        error |= __put_user(0,name->version+__OLD_UTS_LEN);
+        error |= __copy_to_user(&name->machine,&system_utsname.machine,__OLD_UTS_LEN);
+        error |= __put_user(0,name->machine+__OLD_UTS_LEN);
+        if (personality(current->personality) == PER_LINUX32) {
+                /* change "ppc64" to "ppc" */
+                error |= __put_user(0, name->machine + 3);
+                error |= __put_user(0, name->machine + 4);
+        }
+        
         up_read(&uts_sem);
 
         error = error ? -EFAULT : 0;
diff --git a/arch/ppc64/kernel/syscalls.c b/arch/ppc64/kernel/syscalls.c
index f2865ff8d2f9..a8cbb202b8cd 100644
--- a/arch/ppc64/kernel/syscalls.c
+++ b/arch/ppc64/kernel/syscalls.c
@@ -199,24 +199,33 @@ out:
         return ret;
 }
 
-static int __init set_fakeppc(char *str)
+long ppc64_personality(unsigned long personality)
 {
-        if (*str)
-                return 0;
-        init_task.personality = PER_LINUX32;
-        return 1;
+        long ret;
+
+        if (personality(current->personality) == PER_LINUX32
+            && personality == PER_LINUX)
+                personality = PER_LINUX32;
+        ret = sys_personality(personality);
+        if (ret == PER_LINUX32)
+                ret = PER_LINUX;
+        return ret;
 }
-__setup("fakeppc", set_fakeppc);
 
-asmlinkage int sys_uname(struct old_utsname __user * name)
+long ppc64_newuname(struct new_utsname __user * name)
 {
-        int err = -EFAULT;
-        
+        int err = 0;
+
         down_read(&uts_sem);
-        if (name && !copy_to_user(name, &system_utsname, sizeof (*name)))
-                err = 0;
+        if (copy_to_user(name, &system_utsname, sizeof(*name)))
+                err = -EFAULT;
         up_read(&uts_sem);
-        
+        if (!err && personality(current->personality) == PER_LINUX32) {
+                /* change ppc64 to ppc */
+                if (__put_user(0, name->machine + 3)
+                    || __put_user(0, name->machine + 4))
+                        err = -EFAULT;
+        }
         return err;
 }
 
diff --git a/include/asm-ppc64/elf.h b/include/asm-ppc64/elf.h
index 6c42d61bedd1..085eedb956fe 100644
--- a/include/asm-ppc64/elf.h
+++ b/include/asm-ppc64/elf.h
@@ -221,9 +221,7 @@ do {								\
                 set_thread_flag(TIF_ABI_PENDING);               \
         else                                                    \
                 clear_thread_flag(TIF_ABI_PENDING);             \
-        if (ibcs2)                                              \
-                set_personality(PER_SVR4);                      \
-        else if (current->personality != PER_LINUX32)           \
+        if (personality(current->personality) != PER_LINUX32)   \
                 set_personality(PER_LINUX);                     \
 } while (0)