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SubjectWorkaround for 2.1.11 modules

Apologies if you've already seen the fix; I read linux-kernel off a
web page, and it seems to lag.

To fix modules, apply the patch (by David Miller?) that fixes the
checks on the return value from get_mod_name, and then apply this

What seems to be going on (at least on my system: gcc with -O6)
is that gcc is allocating %eax for %0 in __strncpy_from_user, when %al
is already being used. I don't know if this is a gcc bug. However,
changing "=r" to "=bcd" results in gcc error messages (too many
reloads, etc.). The gcc bug is that %ebp is not being used. Is there
some way to explicitly allow %ebp in a register constraint?

In any case, this code works by forcing res into %eax, shifting count
up into the high 24 bits of %eax, and then shifting it down again.
This means you can't copy strings longer than 16M. Also, would
somebody be so kind as to take a look at gcc and see if
a) there are some optimisation bugs?
(I stared at gcc ouput to find this bug, and I saw some sick things.)
b) there is maybe some way to exclude a register in a constraint?

Andrew Lewycky

Version: 3.1
GCS d+ s-:- a--- C++++$ UL++++ P- L+++>++++ E W+ N++ o+ K w-- O-- M- V--
PS+ PE- Y+ PGP t+@ 5- X- R- tv- b++ DI+ D+(---) G e- h! r--- !y

--- linux/include/asm/uaccess.h Tue Nov 19 17:43:10 1996
+++ linux/include/asm/uaccess.h Wed Nov 20 17:21:03 1996
@@ -399,7 +399,8 @@
" jz 1f\n" \
" decl %1\n" \
" jnz 0b\n" \
- "1: subl %1,%0\n" \
+ "1: shrl $8,%0\n" \
+ " subl %1,%0\n" \
"2:\n" \
".section .fixup,\"ax\"\n" \
"3: movl %2,%0\n" \
@@ -408,8 +409,8 @@
" .align 4\n" \
" .long 0b,3b\n" \
".text" \
- : "=r"(res), "=r"(count) \
- : "i"(-EFAULT), "0"(count), "1"(count), "S"(src), "D"(dst) \
+ : "=a"(res), "=r"(count) \
+ : "i"(-EFAULT), "0"(count<<8), "1"(count), "S"(src), "D"(dst) \
: "si", "di", "ax", "memory")

static inline long
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