[PATCH 3.16 063/370] powerpc/ps3: Fix system hang with GCC 5 builds

Ben Hutchings
2017-03-10T14:23:06Z

From: Geoff Levand <geoff@infradead.org>

commit 6dff5b67054e17c91bd630bcdda17cfca5aa4215 upstream.

GCC 5 generates different code for this bootwrapper null check that
causes the PS3 to hang very early in its bootup. This check is of
limited value, so just get rid of it.

Signed-off-by: Geoff Levand <geoff@infradead.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
arch/powerpc/boot/ps3-head.S | 5 -----
arch/powerpc/boot/ps3.c | 8 +-------
2 files changed, 1 insertion(+), 12 deletions(-)

--- a/arch/powerpc/boot/ps3-head.S
+++ b/arch/powerpc/boot/ps3-head.S
@@ -57,11 +57,6 @@ __system_reset_overlay:
bctr

1:
- /* Save the value at addr zero for a null pointer write check later. */
-
- li r4, 0
- lwz r3, 0(r4)
-
/* Primary delays then goes to _zimage_start in wrapper. */

or 31, 31, 31 /* db16cyc */
--- a/arch/powerpc/boot/ps3.c
+++ b/arch/powerpc/boot/ps3.c
@@ -119,13 +119,12 @@ void ps3_copy_vectors(void)
flush_cache((void *)0x100, 512);
}

-void platform_init(unsigned long null_check)
+void platform_init(void)
{
const u32 heapsize = 0x1000000 - (u32)_end; /* 16MiB */
void *chosen;
unsigned long ft_addr;
u64 rm_size;
- unsigned long val;

console_ops.write = ps3_console_write;
platform_ops.exit = ps3_exit;
@@ -153,11 +152,6 @@ void platform_init(unsigned long null_ch

printf(" flat tree at 0x%lx\n\r", ft_addr);

- val = *(unsigned long *)0;
-
- if (val != null_check)
- printf("null check failed: %lx != %lx\n\r", val, null_check);
-
((kernel_entry_t)0)(ft_addr, 0, NULL);

ps3_exit();