[PATCH] alpha: bootp fixes

- redefine "printk" as "srm_printk" for bootstrappers;
- fix stack corruption problem with bootp/bootpz loaders and older
  SRM consoles.

arch/alpha/boot/bootloader.lds

 OUTPUT_FORMAT("elf64-alpha")
 ENTRY(__start)
+printk = srm_printk;
 SECTIONS
 {
   . = 0x20000000;

arch/alpha/boot/bootp.c

@@ -26,6 +26,8 @@ extern unsigned long switch_to_osf_pal(unsigned long nr,
 	struct pcb_struct * pcb_va, struct pcb_struct * pcb_pa,
 	unsigned long *vptb);
 
+extern void move_stack(unsigned long new_stack);
+
 struct hwrpb_struct *hwrpb = INIT_HWRPB;
 static struct pcb_struct pcb_va[1];
 
@@ -118,12 +120,10 @@ static inline void
 runkernel(void)
 {
 	__asm__ __volatile__(
-		"bis %1,%1,$30\n\t"
 		"bis %0,%0,$27\n\t"
 		"jmp ($27)"
 		: /* no outputs: it doesn't even return */
-		: "r" (START_ADDR),
-		  "r" (PAGE_SIZE + INIT_STACK));
+		: "r" (START_ADDR));
 }
 
 extern char _end;
@@ -147,9 +147,7 @@ start_kernel(void)
 	 */
 	static long nbytes;
 	static char envval[256] __attribute__((aligned(8)));
-#ifdef INITRD_IMAGE_SIZE
 	static unsigned long initrd_start;
-#endif
 
 	srm_printk("Linux/AXP bootp loader for Linux " UTS_RELEASE "\n");
 	if (INIT_HWRPB->pagesize != 8192) {
@@ -164,13 +162,20 @@ start_kernel(void)
 	}
 	pal_init();
 
-#ifdef INITRD_IMAGE_SIZE
 	/* The initrd must be page-aligned.  See below for the 
 	   cause of the magic number 5.  */
-	initrd_start = ((START_ADDR + 5*KERNEL_SIZE) | (PAGE_SIZE-1)) + 1;
+	initrd_start = ((START_ADDR + 5*KERNEL_SIZE + PAGE_SIZE) |
+			(PAGE_SIZE-1)) + 1;
+#ifdef INITRD_IMAGE_SIZE
 	srm_printk("Initrd positioned at %#lx\n", initrd_start);
 #endif
 
+	/*
+	 * Move the stack to a safe place to ensure it won't be
+	 * overwritten by kernel image.
+	 */
+	move_stack(initrd_start - PAGE_SIZE);
+
 	nbytes = callback_getenv(ENV_BOOTED_OSFLAGS, envval, sizeof(envval));
 	if (nbytes < 0 || nbytes >= sizeof(envval)) {
 		nbytes = 0;

arch/alpha/boot/bootpz.c

@@ -41,9 +41,6 @@
 #undef DEBUG_ADDRESSES
 #undef DEBUG_LAST_STEPS
 
-#define DEBUG_SP(x) \
-    {register long sp asm("30"); srm_printk("%s (sp=%lx)\n", x, sp);}
-
 extern unsigned long switch_to_osf_pal(unsigned long nr,
 	struct pcb_struct * pcb_va, struct pcb_struct * pcb_pa,
 	unsigned long *vptb);
@@ -51,6 +48,8 @@ extern unsigned long switch_to_osf_pal(unsigned long nr,
 extern int decompress_kernel(void* destination, void *source,
 			     size_t ksize, size_t kzsize);
 
+extern void move_stack(unsigned long new_stack);
+
 struct hwrpb_struct *hwrpb = INIT_HWRPB;
 static struct pcb_struct pcb_va[1];
 
@@ -163,12 +162,10 @@ static inline void
 runkernel(void)
 {
 	__asm__ __volatile__(
-		"bis %1,%1,$30\n\t"
 		"bis %0,%0,$27\n\t"
 		"jmp ($27)"
 		: /* no outputs: it doesn't even return */
-		: "r" (START_ADDR),
-		  "r" (PAGE_SIZE + INIT_STACK));
+		: "r" (START_ADDR));
 }
 
 /* Must record the SP (it is virtual) on entry, so we can make sure
@@ -253,7 +250,9 @@ extern char _end;
    for "bootmem" anyway.
 */
 #define K_COPY_IMAGE_START	NEXT_PAGE(K_KERNEL_IMAGE_END)
-#define K_INITRD_START		NEXT_PAGE(K_COPY_IMAGE_START + KERNEL_SIZE)
+/* Reserve one page below INITRD for the new stack. */
+#define K_INITRD_START \
+    NEXT_PAGE(K_COPY_IMAGE_START + KERNEL_SIZE + PAGE_SIZE)
 #define K_COPY_IMAGE_END \
     (K_INITRD_START + REAL_INITRD_SIZE + MALLOC_AREA_SIZE)
 #define K_COPY_IMAGE_SIZE \
@@ -419,8 +418,7 @@ start_kernel(void)
 		   initrd_image_start,
 		   INITRD_IMAGE_SIZE);
 #endif
-	memcpy((void *)initrd_image_start,
-	       (void *)V_INITRD_START,
+	memcpy((void *)initrd_image_start, (void *)V_INITRD_START,
 	       INITRD_IMAGE_SIZE);
 
 #endif /* INITRD_IMAGE_SIZE */
@@ -436,9 +434,14 @@ start_kernel(void)
 			   K_KERNEL_IMAGE_START,
 			   (unsigned)KERNEL_SIZE);
 #endif
+		/*
+		 * Move the stack to a safe place to ensure it won't be
+		 * overwritten by kernel image.
+		 */
+		move_stack(initrd_image_start - PAGE_SIZE);
+
 		memcpy((void *)K_KERNEL_IMAGE_START,
-		       (void *)uncompressed_image_start,
-		       KERNEL_SIZE);
+		       (void *)uncompressed_image_start, KERNEL_SIZE);
 	}
 	
 	/* Clear the zero page, then move the argument list in. */

arch/alpha/boot/head.S

@@ -100,3 +100,24 @@ halt:
 	.prologue 0
 	call_pal PAL_halt
 	.end halt
+
+/* $16 - new stack page */
+	.align 3
+	.globl	move_stack
+	.ent	move_stack
+move_stack:
+	.prologue 0
+	lda	$0, 0x1fff($31)
+	and	$0, $30, $1			/* Stack offset */
+	or	$1, $16, $16			/* New stack pointer */
+	mov	$30, $1
+	mov	$16, $2
+1:	ldq	$3, 0($1)			/* Move the stack */
+	addq	$1, 8, $1
+	stq	$3, 0($2)
+	and	$0, $1, $4
+	addq	$2, 8, $2
+	bne	$4, 1b
+	mov	$16, $30
+	ret	($26)
+	.end move_stack

arch/alpha/boot/misc.c

@@ -205,15 +205,3 @@ decompress_kernel(void *output_start,
 /*	puts(" done, booting the kernel.\n"); */
 	return output_ptr;
 }
-
-/* dummy-up printk */
-asmlinkage int printk(const char *fmt, ...)
-{
-        va_list args;
-	long ret;
-
-        va_start(args, fmt);
-        ret = srm_printk(fmt, args);
-        va_end(args);
-	return ret;
-}