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s390: do not clobber personality flags in sys_32_personality()

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There are multiple errors in how sys_32_personality() handles personality
flags stored in top three bytes.

- directly comparing current->personality against PER_LINUX32 doesn't work
  in cases when any of the personality flags stored in the top three bytes
  are used.
- directly forcefully setting personality to PER_LINUX32 or PER_LINUX
  discards any flags stored in the top three bytes

Fix the first one by properly using personality() macro to compare only
PER_MASK bytes.
Fix the second one by setting only the bits that should be set, instead of
overwriting the whole value.

Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
Jiri Kosina 2012-08-02 09:11:23 +02:00 committed by Martin Schwidefsky
parent c63cb468f3
commit 5ab37e1b22
1 changed files with 5 additions and 4 deletions
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9
arch/s390/kernel/sys_s390.c
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@ -81,11 +81,12 @@ SYSCALL_DEFINE1(s390_personality, unsigned int, personality)
{
unsigned int ret;
if (current->personality == PER_LINUX32 && personality == PER_LINUX)
personality = PER_LINUX32;
if (personality(current->personality) == PER_LINUX32 &&
personality(personality) == PER_LINUX)
personality |= PER_LINUX32;
ret = sys_personality(personality);
if (ret == PER_LINUX32)
ret = PER_LINUX;
if (personality(ret) == PER_LINUX32)
ret &= ~PER_LINUX32;
return ret;
}