[PATCH] powerpc: Merge kexec

This patch merges, to some extent, the PPC32 and PPC64 kexec implementations.

We adopt the PPC32 approach of having ppc_md callbacks for the kexec functions.
The current PPC64 implementation becomes the "default" implementation for PPC64
which platforms can select if they need no special treatment.

I've added these default callbacks to pseries/maple/cell/powermac, this means
iSeries no longer supports kexec - but it never worked anyway.

I've renamed PPC32's machine_kexec_simple to default_machine_kexec, inline with
PPC64. Judging by the comments it might be better named machine_kexec_non_of,
or something, but at the moment it's the only implementation for PPC32 so it's
the "default".

Kexec requires machine_shutdown(), which is in machine_kexec.c on PPC32, but we
already have in setup-common.c on powerpc. All this does is call
ppc_md.nvram_sync, which only powermac implements, so instead make
machine_shutdown a ppc_md member and have it call core99_nvram_sync directly
on powermac.

I've also stuck relocate_kernel.S into misc_32.S for powerpc.

Built for ARCH=ppc, and 32 & 64 bit ARCH=powerpc, with KEXEC=y/n. Booted on
P5 LPAR and successfully kexec'ed.

Should apply on top of 493f25e.

Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>

arch/powerpc/kernel/Makefile

@@ -65,8 +65,9 @@ pci64-$(CONFIG_PPC64)		+= pci_64.o pci_dn.o pci_iommu.o \
 				   pci_direct_iommu.o iomap.o
 obj-$(CONFIG_PCI)		+= $(pci64-y)
 
-kexec64-$(CONFIG_PPC64)		+= machine_kexec_64.o
-obj-$(CONFIG_KEXEC)		+= $(kexec64-y)
+kexec-$(CONFIG_PPC64)		:= machine_kexec_64.o
+kexec-$(CONFIG_PPC32)		:= machine_kexec_32.o
+obj-$(CONFIG_KEXEC)		+= machine_kexec.o $(kexec-y)
 
 ifeq ($(CONFIG_PPC_ISERIES),y)
 $(obj)/head_64.o: $(obj)/lparmap.s

arch/powerpc/kernel/machine_kexec.c

@@ -0,0 +1,67 @@
+/*
+ * Code to handle transition of Linux booting another kernel.
+ *
+ * Copyright (C) 2002-2003 Eric Biederman  <ebiederm@xmission.com>
+ * GameCube/ppc32 port Copyright (C) 2004 Albert Herranz
+ * Copyright (C) 2005 IBM Corporation.
+ *
+ * This source code is licensed under the GNU General Public License,
+ * Version 2.  See the file COPYING for more details.
+ */
+
+#include <linux/kexec.h>
+#include <linux/reboot.h>
+#include <linux/threads.h>
+#include <asm/machdep.h>
+
+/*
+ * Provide a dummy crash_notes definition until crash dump is implemented.
+ * This prevents breakage of crash_notes attribute in kernel/ksysfs.c.
+ */
+note_buf_t crash_notes[NR_CPUS];
+
+void machine_crash_shutdown(struct pt_regs *regs)
+{
+	if (ppc_md.machine_crash_shutdown)
+		ppc_md.machine_crash_shutdown();
+}
+
+/*
+ * Do what every setup is needed on image and the
+ * reboot code buffer to allow us to avoid allocations
+ * later.
+ */
+int machine_kexec_prepare(struct kimage *image)
+{
+	if (ppc_md.machine_kexec_prepare)
+		return ppc_md.machine_kexec_prepare(image);
+	/*
+	 * Fail if platform doesn't provide its own machine_kexec_prepare
+	 * implementation.
+	 */
+	return -ENOSYS;
+}
+
+void machine_kexec_cleanup(struct kimage *image)
+{
+	if (ppc_md.machine_kexec_cleanup)
+		ppc_md.machine_kexec_cleanup(image);
+}
+
+/*
+ * Do not allocate memory (or fail in any way) in machine_kexec().
+ * We are past the point of no return, committed to rebooting now.
+ */
+NORET_TYPE void machine_kexec(struct kimage *image)
+{
+	if (ppc_md.machine_kexec)
+		ppc_md.machine_kexec(image);
+	else {
+		/*
+		 * Fall back to normal restart if platform doesn't provide
+		 * its own kexec function, and user insist to kexec...
+		 */
+		machine_restart(NULL);
+	}
+	for(;;);
+}

arch/powerpc/kernel/machine_kexec_32.c

@@ -0,0 +1,65 @@
+/*
+ * PPC32 code to handle Linux booting another kernel.
+ *
+ * Copyright (C) 2002-2003 Eric Biederman  <ebiederm@xmission.com>
+ * GameCube/ppc32 port Copyright (C) 2004 Albert Herranz
+ * Copyright (C) 2005 IBM Corporation.
+ *
+ * This source code is licensed under the GNU General Public License,
+ * Version 2.  See the file COPYING for more details.
+ */
+
+#include <linux/kexec.h>
+#include <linux/mm.h>
+#include <linux/string.h>
+#include <asm/cacheflush.h>
+#include <asm/hw_irq.h>
+#include <asm/io.h>
+
+typedef NORET_TYPE void (*relocate_new_kernel_t)(
+				unsigned long indirection_page,
+				unsigned long reboot_code_buffer,
+				unsigned long start_address) ATTRIB_NORET;
+
+/*
+ * This is a generic machine_kexec function suitable at least for
+ * non-OpenFirmware embedded platforms.
+ * It merely copies the image relocation code to the control page and
+ * jumps to it.
+ * A platform specific function may just call this one.
+ */
+void default_machine_kexec(struct kimage *image)
+{
+	const extern unsigned char relocate_new_kernel[];
+	const extern unsigned int relocate_new_kernel_size;
+	unsigned long page_list;
+	unsigned long reboot_code_buffer, reboot_code_buffer_phys;
+	relocate_new_kernel_t rnk;
+
+	/* Interrupts aren't acceptable while we reboot */
+	local_irq_disable();
+
+	page_list = image->head;
+
+	/* we need both effective and real address here */
+	reboot_code_buffer =
+			(unsigned long)page_address(image->control_code_page);
+	reboot_code_buffer_phys = virt_to_phys((void *)reboot_code_buffer);
+
+	/* copy our kernel relocation code to the control code page */
+	memcpy((void *)reboot_code_buffer, relocate_new_kernel,
+						relocate_new_kernel_size);
+
+	flush_icache_range(reboot_code_buffer,
+				reboot_code_buffer + KEXEC_CONTROL_CODE_SIZE);
+	printk(KERN_INFO "Bye!\n");
+
+	/* now call it */
+	rnk = (relocate_new_kernel_t) reboot_code_buffer;
+	(*rnk)(page_list, reboot_code_buffer_phys, image->start);
+}
+
+int default_machine_kexec_prepare(struct kimage *image)
+{
+	return 0;
+}

arch/powerpc/kernel/machine_kexec_64.c

@@ -1,5 +1,5 @@
 /*
- * machine_kexec.c - handle transition of Linux booting another kernel
+ * PPC64 code to handle Linux booting another kernel.
  *
  * Copyright (C) 2004-2005, IBM Corp.
  *
@@ -28,21 +28,7 @@
 
 #define HASH_GROUP_SIZE 0x80	/* size of each hash group, asm/mmu.h */
 
-/* Have this around till we move it into crash specific file */
-note_buf_t crash_notes[NR_CPUS];
-
-/* Dummy for now. Not sure if we need to have a crash shutdown in here
- * and if what it will achieve. Letting it be now to compile the code
- * in generic kexec environment
- */
-void machine_crash_shutdown(struct pt_regs *regs)
-{
-	/* do nothing right now */
-	/* smp_relase_cpus() if we want smp on panic kernel */
-	/* cpu_irq_down to isolate us until we are ready */
-}
-
-int machine_kexec_prepare(struct kimage *image)
+int default_machine_kexec_prepare(struct kimage *image)
 {
 	int i;
 	unsigned long begin, end;	/* limits of segment */
@@ -111,11 +97,6 @@ int machine_kexec_prepare(struct kimage *image)
 	return 0;
 }
 
-void machine_kexec_cleanup(struct kimage *image)
-{
-	/* we do nothing in prepare that needs to be undone */
-}
-
 #define IND_FLAGS (IND_DESTINATION | IND_INDIRECTION | IND_DONE | IND_SOURCE)
 
 static void copy_segments(unsigned long ind)
@@ -283,7 +264,7 @@ extern NORET_TYPE void kexec_sequence(void *newstack, unsigned long start,
 					void (*clear_all)(void)) ATTRIB_NORET;
 
 /* too late to fail here */
-void machine_kexec(struct kimage *image)
+void default_machine_kexec(struct kimage *image)
 {
 
 	/* prepare control code if any */

arch/powerpc/kernel/misc_32.S

@@ -5,6 +5,10 @@
  * Largely rewritten by Cort Dougan (cort@cs.nmt.edu)
  * and Paul Mackerras.
  *
+ * kexec bits:
+ * Copyright (C) 2002-2003 Eric Biederman  <ebiederm@xmission.com>
+ * GameCube/ppc32 port Copyright (C) 2004 Albert Herranz
+ *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License
  * as published by the Free Software Foundation; either version
@@ -24,6 +28,8 @@
 #include <asm/ppc_asm.h>
 #include <asm/thread_info.h>
 #include <asm/asm-offsets.h>
+#include <asm/processor.h>
+#include <asm/kexec.h>
 
 	.text
 
@@ -1006,3 +1012,110 @@ _GLOBAL(execve)
  */
 _GLOBAL(__main)
 	blr
+
+#ifdef CONFIG_KEXEC
+	/*
+	 * Must be relocatable PIC code callable as a C function.
+	 */
+	.globl relocate_new_kernel
+relocate_new_kernel:
+	/* r3 = page_list   */
+	/* r4 = reboot_code_buffer */
+	/* r5 = start_address      */
+
+	li	r0, 0
+
+	/*
+	 * Set Machine Status Register to a known status,
+	 * switch the MMU off and jump to 1: in a single step.
+	 */
+
+	mr	r8, r0
+	ori     r8, r8, MSR_RI|MSR_ME
+	mtspr	SPRN_SRR1, r8
+	addi	r8, r4, 1f - relocate_new_kernel
+	mtspr	SPRN_SRR0, r8
+	sync
+	rfi
+
+1:
+	/* from this point address translation is turned off */
+	/* and interrupts are disabled */
+
+	/* set a new stack at the bottom of our page... */
+	/* (not really needed now) */
+	addi	r1, r4, KEXEC_CONTROL_CODE_SIZE - 8 /* for LR Save+Back Chain */
+	stw	r0, 0(r1)
+
+	/* Do the copies */
+	li	r6, 0 /* checksum */
+	mr	r0, r3
+	b	1f
+
+0:	/* top, read another word for the indirection page */
+	lwzu	r0, 4(r3)
+
+1:
+	/* is it a destination page? (r8) */
+	rlwinm.	r7, r0, 0, 31, 31 /* IND_DESTINATION (1<<0) */
+	beq	2f
+
+	rlwinm	r8, r0, 0, 0, 19 /* clear kexec flags, page align */
+	b	0b
+
+2:	/* is it an indirection page? (r3) */
+	rlwinm.	r7, r0, 0, 30, 30 /* IND_INDIRECTION (1<<1) */
+	beq	2f
+
+	rlwinm	r3, r0, 0, 0, 19 /* clear kexec flags, page align */
+	subi	r3, r3, 4
+	b	0b
+
+2:	/* are we done? */
+	rlwinm.	r7, r0, 0, 29, 29 /* IND_DONE (1<<2) */
+	beq	2f
+	b	3f
+
+2:	/* is it a source page? (r9) */
+	rlwinm.	r7, r0, 0, 28, 28 /* IND_SOURCE (1<<3) */
+	beq	0b
+
+	rlwinm	r9, r0, 0, 0, 19 /* clear kexec flags, page align */
+
+	li	r7, PAGE_SIZE / 4
+	mtctr   r7
+	subi    r9, r9, 4
+	subi    r8, r8, 4
+9:
+	lwzu    r0, 4(r9)  /* do the copy */
+	xor	r6, r6, r0
+	stwu    r0, 4(r8)
+	dcbst	0, r8
+	sync
+	icbi	0, r8
+	bdnz    9b
+
+	addi    r9, r9, 4
+	addi    r8, r8, 4
+	b	0b
+
+3:
+
+	/* To be certain of avoiding problems with self-modifying code
+	 * execute a serializing instruction here.
+	 */
+	isync
+	sync
+
+	/* jump to the entry point, usually the setup routine */
+	mtlr	r5
+	blrl
+
+1:	b	1b
+
+relocate_new_kernel_end:
+
+	.globl relocate_new_kernel_size
+relocate_new_kernel_size:
+	.long relocate_new_kernel_end - relocate_new_kernel
+#endif

arch/powerpc/kernel/setup-common.c

@@ -93,8 +93,8 @@ EXPORT_SYMBOL(ppc_do_canonicalize_irqs);
 /* also used by kexec */
 void machine_shutdown(void)
 {
-	if (ppc_md.nvram_sync)
-		ppc_md.nvram_sync();
+	if (ppc_md.machine_shutdown)
+		ppc_md.machine_shutdown();
 }
 
 void machine_restart(char *cmd)

arch/powerpc/platforms/cell/setup.c

@@ -33,6 +33,7 @@
 #include <asm/mmu.h>
 #include <asm/processor.h>
 #include <asm/io.h>
+#include <asm/kexec.h>
 #include <asm/pgtable.h>
 #include <asm/prom.h>
 #include <asm/rtas.h>
@@ -138,4 +139,8 @@ struct machdep_calls __initdata cell_md = {
 	.set_rtc_time		= rtas_set_rtc_time,
 	.calibrate_decr		= generic_calibrate_decr,
 	.progress		= cell_progress,
+#ifdef CONFIG_KEXEC
+	.machine_kexec		= default_machine_kexec,
+	.machine_kexec_prepare	= default_machine_kexec_prepare,
+#endif
 };

arch/powerpc/platforms/maple/setup.c

@@ -51,6 +51,7 @@
 #include <asm/pgtable.h>
 #include <asm/bitops.h>
 #include <asm/io.h>
+#include <asm/kexec.h>
 #include <asm/pci-bridge.h>
 #include <asm/iommu.h>
 #include <asm/machdep.h>
@@ -292,4 +293,8 @@ struct machdep_calls __initdata maple_md = {
       	.calibrate_decr		= generic_calibrate_decr,
 	.progress		= maple_progress,
 	.idle_loop		= native_idle,
+#ifdef CONFIG_KEXEC
+	.machine_kexec		= default_machine_kexec,
+	.machine_kexec_prepare	= default_machine_kexec_prepare,
+#endif
 };

arch/powerpc/platforms/powermac/nvram.c

@@ -549,6 +549,7 @@ static int __init core99_nvram_setup(struct device_node *dp)
 	ppc_md.nvram_write	= core99_nvram_write;
 	ppc_md.nvram_size	= core99_nvram_size;
 	ppc_md.nvram_sync	= core99_nvram_sync;
+	ppc_md.machine_shutdown	= core99_nvram_sync;
 	/* 
 	 * Maybe we could be smarter here though making an exclusive list
 	 * of known flash chips is a bit nasty as older OF didn't provide us