tags 349765 patch thanks On Sat, Jan 28, 2006 at 01:48:21AM -0500, Kyle McMartin wrote: > > After changing addr to value, compiles fine; prctl -q runs ok now, prctl > > --unaligned=signal doesn't have any effect. You say that it's going to be > > the prctl() function in the kernel that needs further tweaks?
> I suspect this is the problem: > (linux/prctl.h) > # define PR_UNALIGN_NOPRINT 1 /* silently fix up unaligned user > accesses */ > # define PR_UNALIGN_SIGBUS 2 /* generate SIGBUS on unaligned user > access */ > (asm-parisc/processor.h & asm-ia64/processor.h) > #define PARISC_UAC_NOPRINT (1UL << 0) /* see prctl and unaligned.c */ > #define PARISC_UAC_SIGBUS (1UL << 1) > IE, NOPRINT is set by 1, and SIGBUS set by 2. > on alpha, because it's reusing the OSF/1 crap, the order is > NOPRINT, NOFIX, SIGNAL, ie: 1, 2, 4. > I don't know what the best way to fix this is, but something like > this patch will probably help, As discussed, I think it's more appropriate to fix this in the kernel, so that the syscall behavior actually matches what's documented in linux/prctl.h. :) So here's a tested patch which does this. Ugly as sin, but I'm at a loss for how you'd make this pretty... -- Steve Langasek Give me a lever long enough and a Free OS Debian Developer to set it on, and I can move the world. [EMAIL PROTECTED] http://www.debian.org/
diff --git a/include/asm-alpha/thread_info.h b/include/asm-alpha/thread_info.h
index 69ffd93..011daaf 100644
--- a/include/asm-alpha/thread_info.h
+++ b/include/asm-alpha/thread_info.h
@@ -92,5 +92,27 @@ register struct thread_info *__current_t
#define _TIF_ALLWORK_MASK (_TIF_WORK_MASK \
| _TIF_SYSCALL_TRACE)
+#define ALPHA_UAC_SHIFT 6
+#define ALPHA_UAC_MASK (1 << TIF_UAC_NOPRINT | 1 << TIF_UAC_NOFIX | \
+ 1 << TIF_UAC_SIGBUS)
+
+#define SET_UNALIGN_CTL(task,value) ({ \
+ (task)->thread_info->flags = (((task)->thread_info->flags & \
+ ~ALPHA_UAC_MASK) \
+ | (((value) << ALPHA_UAC_SHIFT) & (1 << TIF_UAC_NOPRINT)) \
+ | (((value) << ALPHA_UAC_SHIFT + 1) & (1 << TIF_UAC_SIGBUS)) \
+ | (((value) << ALPHA_UAC_SHIFT - 1) & (1 << TIF_UAC_NOFIX)));\
+ 0; })
+
+#define GET_UNALIGN_CTL(task,value) ({ \
+ put_user(((task)->thread_info->flags & (1 << TIF_UAC_NOPRINT)) \
+ >> ALPHA_UAC_SHIFT \
+ | ((task)->thread_info->flags & (1 << TIF_UAC_SIGBUS)) \
+ >> ALPHA_UAC_SHIFT + 1 \
+ | ((task)->thread_info->flags & (1 << TIF_UAC_NOFIX)) \
+ >> ALPHA_UAC_SHIFT - 1, \
+ (int __user *)(value)); \
+ })
+
#endif /* __KERNEL__ */
#endif /* _ALPHA_THREAD_INFO_H */
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