[POWERPC] PS3: Bootwrapper improvements
Improve the debugging support of the PS3 bootwraper code:
o Increase the size of the PS3 bootwrapper overlay from 256 to 512 bytes to
allow for more debugging code in the overlay.
o Use the dot symbol to set the size of __system_reset_overlay. The
assembler will then emit an error if the overlay code is too big.
o Remove some unused instructions.
o Update the text describing the PS3 bootwrapper overlay.
o Add a check for null pointer writes.
o Change hcall return value from s64.
Signed-off-by: Geoff Levand <geoffrey.levand@am.sony.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
diff --git a/arch/powerpc/boot/ps3-head.S b/arch/powerpc/boot/ps3-head.S
index a55c273..b6fcbaf 100644
--- a/arch/powerpc/boot/ps3-head.S
+++ b/arch/powerpc/boot/ps3-head.S
@@ -27,8 +27,9 @@
/*
* __system_reset_overlay - The PS3 first stage entry.
*
- * The bootwraper build script copies the 0x100 bytes at symbol
- * __system_reset_overlay to offset 0x100 of the rom image.
+ * The bootwraper build script copies the 512 bytes at symbol
+ * __system_reset_overlay to offset 0x100 of the rom image. This symbol
+ * must occupy 512 or less bytes.
*
* The PS3 has a single processor with two threads.
*/
@@ -47,8 +48,6 @@
mfspr r3, 0x88
cntlzw. r3, r3
- li r4, 0
- li r5, 0
beq 1f
/* Secondary goes to __secondary_hold in kernel. */
@@ -57,8 +56,14 @@
mtctr r4
bctr
- /* Primary delays then goes to _zimage_start in wrapper. */
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 */
or 31, 31, 31 /* db16cyc */
@@ -67,16 +72,18 @@
mtctr r4
bctr
+ . = __system_reset_overlay + 512
+
/*
* __system_reset_kernel - Place holder for the kernel reset vector.
*
- * The bootwrapper build script copies 0x100 bytes from offset 0x100
+ * The bootwrapper build script copies 512 bytes from offset 0x100
* of the rom image to the symbol __system_reset_kernel. At runtime
- * the bootwrapper program copies the 0x100 bytes at __system_reset_kernel
- * to ram address 0x100. This symbol must occupy 0x100 bytes.
+ * the bootwrapper program copies the 512 bytes at __system_reset_kernel
+ * to ram address 0x100. This symbol must occupy 512 bytes.
*/
.globl __system_reset_kernel
__system_reset_kernel:
- . = __system_reset_kernel + 0x100
+ . = __system_reset_kernel + 512