On Wed, 2 Nov 2005, David Daney wrote:
__get_user() is unhappy, with tpyes that are "const". It uses __typeof()
to create a local variable that it wants to write to. I've intended to
have offer up a patch by now, but, too many unexpected thing have happened
in the firs thalf of this week.
I shamed myself into sitting down and doing this. 8-)
The attached patch seems to work, or at least doesn't seem to cause
things to blow up. An o32 userspace on a 64-bit kernel comes up
multi-user and can build a kernel, and run a quick subset of LTP.
There was a comment on IRC that there was a register allocation issue which
lead to the current code. I'm not sure of the exact details, but I _think_
this change ends up being equivilent to the code it replaces.
Stuart
Stuart R. Anderson anderson@xxxxxxxxxxxx
Network & Software Engineering http://www.netsweng.com/
1024D/37A79149: 0791 D3B8 9A4C 2CDC A31F
BD03 0A62 E534 37A7 9149Index: uaccess.h
===================================================================
--- uaccess.h (revision 84)
+++ uaccess.h (working copy)
@@ -210,17 +210,35 @@
#define __get_user_nocheck(x,ptr,size) \
({ \
- __typeof(*(ptr)) __gu_val = (__typeof(*(ptr))) 0; \
long __gu_err = 0; \
\
switch (size) { \
- case 1: __get_user_asm("lb", ptr); break; \
- case 2: __get_user_asm("lh", ptr); break; \
- case 4: __get_user_asm("lw", ptr); break; \
- case 8: __GET_USER_DW(ptr); break; \
+ case 1: { \
+ s8 __gu_val = (s8) 0; \
+ __get_user_asm("lb", ptr); \
+ (x) = (__typeof__(*(ptr))) __gu_val; \
+ break; \
+ } \
+ case 2: { \
+ s16 __gu_val = (s16) 0; \
+ __get_user_asm("lh", ptr); \
+ (x) = (__typeof__(*(ptr))) __gu_val; \
+ break; \
+ } \
+ case 4: { \
+ s32 __gu_val = (s32) 0; \
+ __get_user_asm("lw", ptr); \
+ (x) = (__typeof__(*(ptr))) __gu_val; \
+ break; \
+ } \
+ case 8: { \
+ s64 __gu_val = (s64) 0; \
+ __GET_USER_DW(ptr); \
+ (x) = (__typeof__(*(ptr))) __gu_val; \
+ break; \
+ } \
default: __get_user_unknown(); break; \
} \
- (x) = (__typeof__(*(ptr))) __gu_val; \
__gu_err; \
})
