[PATCH] gcc-4.1.0 is bust
Keith says
Compiling 2.6.19-rc6 with gcc version 4.1.0 (SUSE Linux), wait_hpet_tick is
optimized away to a never ending loop and the kernel hangs on boot in timer
setup.
0000001a <wait_hpet_tick>:
1a: 55 push %ebp
1b: 89 e5 mov %esp,%ebp
1d: eb fe jmp 1d <wait_hpet_tick+0x3>
This is not a problem with gcc 3.3.5. Adding barrier() calls to
wait_hpet_tick does not help, making the variables volatile does.
And the consensus is that gcc-4.1.0 is busted. Suse went and shipped
gcc-4.1.0 so we cannot ban it. Add a warning.
Cc: Keith Owens <kaos@ocs.com.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/init/main.c b/init/main.c
index 36f608a..4650830 100644
--- a/init/main.c
+++ b/init/main.c
@@ -73,6 +73,10 @@
#error Sorry, your GCC is too old. It builds incorrect kernels.
#endif
+#if __GNUC__ == 4 && __GNUC_MINOR__ == 1 && __GNUC_PATCHLEVEL__ == 0
+#warning gcc-4.1.0 is known to miscompile the kernel. A different compiler version is recommended.
+#endif
+
static int init(void *);
extern void init_IRQ(void);