[IA64] Simulator bootloader fails with gcc 4

After building a fresh tree with gcc 4 I can't boot the simulator as
the bootloader loader dies with

loading /home/ianw/kerntest/kerncomp//build/sim_defconfig/vmlinux...
failed to read phdr

After some investigation I believe this is do with differences between
the alignment of variables on the stack between gcc 3 and 4 and the
ski simulator.  If you trace through with the simulator you can see
that the disk_stat structure value returned from the SSC_WAIT_COMPLETION
call seems to be only half loaded.  I guess it doesn't like the alignment
of the input.

Signed-off-by: Ian Wienand <ianw@gelato.unsw.edu.au>
Signed-off-by: Tony Luck <tony.luck@intel.com>

diff --git a/arch/ia64/hp/sim/boot/bootloader.c b/arch/ia64/hp/sim/boot/bootloader.c
index 51a7b7b..a7bed60 100644 (file)
--- a/arch/ia64/hp/sim/boot/bootloader.c
+++ b/arch/ia64/hp/sim/boot/bootloader.c
@@ -30,10 +30,14 @@ struct disk_req {
        unsigned len;
 };
 
+/* SSC_WAIT_COMPLETION appears to want this large alignment.  gcc < 4
+ * seems to give it by default, however gcc > 4 is smarter and may
+ * not.
+ */
 struct disk_stat {
        int fd;
        unsigned count;
-};
+} __attribute__ ((aligned (16)));
 
 extern void jmp_to_kernel (unsigned long bp, unsigned long e_entry);
 extern struct ia64_boot_param *sys_fw_init (const char *args, int arglen);