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authorSergei Trofimovich <slyfox@gentoo.org>2011-08-25 15:59:02 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2011-08-25 16:25:33 -0700
commit2df7a7d1cd07626dd235ca102830ebfc6c01a09e (patch)
treedb226e5a1728f600e8f711400e97098023f3c2f4 /arch/alpha
parent06ed4625fdfffee1251708cd30de276186d5fdcf (diff)
downloadlinux-2df7a7d1cd07626dd235ca102830ebfc6c01a09e.tar.bz2
alpha: unbreak osf_setsysinfo(SSI_NVPAIRS, [SSIN_UACPROC, UAC_SIGBUS])
The bug was accidentally found by the following program: #include <asm/sysinfo.h> #include <asm/unistd.h> #include <sys/syscall.h> static int setsysinfo(unsigned long op, void *buffer, unsigned long size, int *start, void *arg, unsigned long flag) { return syscall(__NR_osf_setsysinfo, op, buffer, size, start, arg, flag); } int main(int argc, char **argv) { short x[10]; unsigned int buf[2] = { SSIN_UACPROC, UAC_SIGBUS, }; setsysinfo(SSI_NVPAIRS, buf, 1, 0, 0, 0); int *y = (int*) (x+1); *y = 0; return 0; } The program shoud fail on SIGBUS, but didn't. The patch is a second part of userspace flag fix (commit 745dd2405e28 "Alpha: Rearrange thread info flags fixing two regressions"). Deleted outdated out-of-sync 'UAC_SHIFT' (the cause of bug) in favour of 'ALPHA_UAC_SHIFT'. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Sergei Trofimovich <slyfox@gentoo.org> Acked-by: Michael Cree <mcree@orcon.net.nz> Cc: Richard Henderson <rth@twiddle.net> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Matt Turner <mattst88@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch/alpha')
-rw-r--r--arch/alpha/include/asm/sysinfo.h9
-rw-r--r--arch/alpha/include/asm/thread_info.h8
-rw-r--r--arch/alpha/kernel/osf_sys.c12
3 files changed, 11 insertions, 18 deletions
diff --git a/arch/alpha/include/asm/sysinfo.h b/arch/alpha/include/asm/sysinfo.h
index 086aba284df2..e77d77cd07b8 100644
--- a/arch/alpha/include/asm/sysinfo.h
+++ b/arch/alpha/include/asm/sysinfo.h
@@ -27,13 +27,4 @@
#define UAC_NOFIX 2
#define UAC_SIGBUS 4
-
-#ifdef __KERNEL__
-
-/* This is the shift that is applied to the UAC bits as stored in the
- per-thread flags. See thread_info.h. */
-#define UAC_SHIFT 6
-
-#endif
-
#endif /* __ASM_ALPHA_SYSINFO_H */
diff --git a/arch/alpha/include/asm/thread_info.h b/arch/alpha/include/asm/thread_info.h
index 6f32f9c84a2d..ff73db022342 100644
--- a/arch/alpha/include/asm/thread_info.h
+++ b/arch/alpha/include/asm/thread_info.h
@@ -74,9 +74,9 @@ register struct thread_info *__current_thread_info __asm__("$8");
#define TIF_NEED_RESCHED 3 /* rescheduling necessary */
#define TIF_POLLING_NRFLAG 8 /* poll_idle is polling NEED_RESCHED */
#define TIF_DIE_IF_KERNEL 9 /* dik recursion lock */
-#define TIF_UAC_NOPRINT 10 /* see sysinfo.h */
-#define TIF_UAC_NOFIX 11
-#define TIF_UAC_SIGBUS 12
+#define TIF_UAC_NOPRINT 10 /* ! Preserve sequence of following */
+#define TIF_UAC_NOFIX 11 /* ! flags as they match */
+#define TIF_UAC_SIGBUS 12 /* ! userspace part of 'osf_sysinfo' */
#define TIF_MEMDIE 13 /* is terminating due to OOM killer */
#define TIF_RESTORE_SIGMASK 14 /* restore signal mask in do_signal */
#define TIF_FREEZE 16 /* is freezing for suspend */
@@ -97,7 +97,7 @@ register struct thread_info *__current_thread_info __asm__("$8");
#define _TIF_ALLWORK_MASK (_TIF_WORK_MASK \
| _TIF_SYSCALL_TRACE)
-#define ALPHA_UAC_SHIFT 10
+#define ALPHA_UAC_SHIFT TIF_UAC_NOPRINT
#define ALPHA_UAC_MASK (1 << TIF_UAC_NOPRINT | 1 << TIF_UAC_NOFIX | \
1 << TIF_UAC_SIGBUS)
diff --git a/arch/alpha/kernel/osf_sys.c b/arch/alpha/kernel/osf_sys.c
index 326f0a2d56e5..01e8715e26d9 100644
--- a/arch/alpha/kernel/osf_sys.c
+++ b/arch/alpha/kernel/osf_sys.c
@@ -42,6 +42,7 @@
#include <asm/uaccess.h>
#include <asm/system.h>
#include <asm/sysinfo.h>
+#include <asm/thread_info.h>
#include <asm/hwrpb.h>
#include <asm/processor.h>
@@ -633,9 +634,10 @@ SYSCALL_DEFINE5(osf_getsysinfo, unsigned long, op, void __user *, buffer,
case GSI_UACPROC:
if (nbytes < sizeof(unsigned int))
return -EINVAL;
- w = (current_thread_info()->flags >> UAC_SHIFT) & UAC_BITMASK;
- if (put_user(w, (unsigned int __user *)buffer))
- return -EFAULT;
+ w = (current_thread_info()->flags >> ALPHA_UAC_SHIFT) &
+ UAC_BITMASK;
+ if (put_user(w, (unsigned int __user *)buffer))
+ return -EFAULT;
return 1;
case GSI_PROC_TYPE:
@@ -756,8 +758,8 @@ SYSCALL_DEFINE5(osf_setsysinfo, unsigned long, op, void __user *, buffer,
case SSIN_UACPROC:
again:
old = current_thread_info()->flags;
- new = old & ~(UAC_BITMASK << UAC_SHIFT);
- new = new | (w & UAC_BITMASK) << UAC_SHIFT;
+ new = old & ~(UAC_BITMASK << ALPHA_UAC_SHIFT);
+ new = new | (w & UAC_BITMASK) << ALPHA_UAC_SHIFT;
if (cmpxchg(&current_thread_info()->flags,
old, new) != old)
goto again;