| From e85871218513c54f7dfdb6009043cb638f2fecbe Mon Sep 17 00:00:00 2001 |
| From: Heiko Carstens <heiko.carstens@de.ibm.com> |
| Date: Wed, 8 Aug 2012 09:32:20 +0200 |
| Subject: s390/compat: fix mmap compat system calls |
| |
| From: Heiko Carstens <heiko.carstens@de.ibm.com> |
| |
| commit e85871218513c54f7dfdb6009043cb638f2fecbe upstream. |
| |
| The native 31 bit and the compat behaviour for the mmap system calls differ: |
| |
| In native 31 bit mode the passed in address for the mmap system call will be |
| unmodified passed to sys_mmap_pgoff(). |
| In compat mode however the passed in address will be modified with |
| compat_ptr() which masks out the most significant bit. |
| |
| The result is that in native 31 bit mode each mmap request (with MAP_FIXED) |
| will fail where the most significat bit is set, while in compat mode it |
| may succeed. |
| |
| This odd behaviour was introduced with d3815898 "[S390] mmap: add missing |
| compat_ptr conversion to both mmap compat syscalls". |
| |
| To restore a consistent behaviour accross native and compat mode this |
| patch functionally reverts the above mentioned commit. |
| |
| Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> |
| Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| arch/s390/kernel/compat_linux.c | 2 -- |
| 1 file changed, 2 deletions(-) |
| |
| --- a/arch/s390/kernel/compat_linux.c |
| +++ b/arch/s390/kernel/compat_linux.c |
| @@ -612,7 +612,6 @@ asmlinkage unsigned long old32_mmap(stru |
| return -EFAULT; |
| if (a.offset & ~PAGE_MASK) |
| return -EINVAL; |
| - a.addr = (unsigned long) compat_ptr(a.addr); |
| return sys_mmap_pgoff(a.addr, a.len, a.prot, a.flags, a.fd, |
| a.offset >> PAGE_SHIFT); |
| } |
| @@ -623,7 +622,6 @@ asmlinkage long sys32_mmap2(struct mmap_ |
| |
| if (copy_from_user(&a, arg, sizeof(a))) |
| return -EFAULT; |
| - a.addr = (unsigned long) compat_ptr(a.addr); |
| return sys_mmap_pgoff(a.addr, a.len, a.prot, a.flags, a.fd, a.offset); |
| } |
| |
