ppc64 kdump purgatory backup support

This patch implements the purgatory support to take backup
of the first 32KB of the first kernel
- Modified the v2wrap code to make the secondary cpus spin
directly in the v2wrap after pulling them out of kexec_wait
- Use the elf_rel function support to set the various
symbols used in purgatory
- load device-tree as a separate segment
- other miscellaneous compiler warnings cleanup
- add purgatory code support for backup
- build purgatory as relocatable for ppc64

Signed-off-by: R Sharada <sharada@in.ibm.com>
Signed-off-by: Mohan Kumar M <mohan@in.ibm.com>
Signed-off-by: Maneesh Soni <maneesh@in.ibm.com>

7 files changed, 178 insertions, 55 deletions

diff --git a/purgatory/Makefile b/purgatory/Makefile
index 5dd03e71..50ce99fe 100644
--- a/purgatory/Makefile
+++ b/purgatory/Makefile
@@ -21,13 +21,11 @@ PCFLAGS += $(call cc-option, -fnobuiltin)
 PCFLAGS += $(call cc-option, -fnostdinc)
 PCFLAGS += $(call cc-option, -fno-zero-initialized-in-bss)
 
-PURGATORY_C_SRCS:= 
-ifneq ($(ARCH),ppc64)
+PURGATORY_C_SRCS:=
 PURGATORY_C_SRCS += purgatory/purgatory.c
 PURGATORY_C_SRCS += purgatory/printf.c
 PURGATORY_C_SRCS += purgatory/string.c
-endif
-PURGATORY_S_OBJS:= 
+PURGATORY_S_OBJS:=
 
 include purgatory/arch/$(ARCH)/Makefile
 
@@ -61,12 +59,7 @@ $(PURGATORY_S_OBJS): $(OBJDIR)/%.o: %.S $(OBJDIR)/%.d
 
 $(PURGATORY): $(PURGATORY_OBJS) $(UTIL_LIB)
 	$(MKDIR) -p $(@D)
-ifneq ($(ARCH),ppc64)
 	$(LD) $(LDFLAGS) --no-undefined -e purgatory_start -r -o $@ $(PURGATORY_OBJS) $(UTIL_LIB)
-else
-	$(LD) -Ttext=0 -e 0 -o $(OBJDIR)/purgatory/v2wrap.elf $(PURGATORY_OBJS)
-	objcopy -O binary $(OBJDIR)/purgatory/v2wrap.elf $@
-endif
 
 echo::
 	@echo "PURGATORY_C_SRCS $(PURGATORY_C_SRCS)"
diff --git a/purgatory/arch/ppc64/Makefile b/purgatory/arch/ppc64/Makefile
index 6916c5fc..82b16543 100644
--- a/purgatory/arch/ppc64/Makefile
+++ b/purgatory/arch/ppc64/Makefile
@@ -2,6 +2,7 @@
 # Purgatory ppc
 #
 
-PURGATORY_C_SRCS+=
 PURGATORY_S_SRCS+= purgatory/arch/ppc64/v2wrap.S
-
+PURGATORY_C_SRCS += purgatory/arch/ppc64/purgatory-ppc64.c
+PURGATORY_C_SRCS += purgatory/arch/ppc64/console-ppc64.c
+PURGATORY_C_SRCS += purgatory/arch/ppc64/crashdump_backup.c
diff --git a/purgatory/arch/ppc64/console-ppc64.c b/purgatory/arch/ppc64/console-ppc64.c
new file mode 100644
index 00000000..d6da7b37
--- /dev/null
+++ b/purgatory/arch/ppc64/console-ppc64.c
@@ -0,0 +1,27 @@
+/*
+ * kexec: Linux boots Linux
+ *
+ * Created by: Mohan Kumar M (mohan@in.ibm.com)
+ *
+ * Copyright (C) IBM Corporation, 2005. All rights reserved
+ *
+ * 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 (version 2 of the License).
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <purgatory.h>
+
+void putchar(int c)
+{
+	return;
+}
diff --git a/purgatory/arch/ppc64/crashdump_backup.c b/purgatory/arch/ppc64/crashdump_backup.c
new file mode 100644
index 00000000..07f7847e
--- /dev/null
+++ b/purgatory/arch/ppc64/crashdump_backup.c
@@ -0,0 +1,41 @@
+/*
+ * kexec: Linux boots Linux
+ *
+ * Created by: Mohan Kumar M (mohan@in.ibm.com)
+ *
+ * Copyright (C) IBM Corporation, 2005. All rights reserved
+ *
+ * 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 (version 2 of the License).
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <stdint.h>
+#include <string.h>
+
+#define BACKUP_REGION_SOURCE 0x0
+#define BACKUP_REGION_SIZE 32*1024
+
+extern unsigned long backup_start;
+
+/* Backup first 32KB of memory to backup region reserved by kexec */
+void crashdump_backup_memory(void)
+{
+	void *dest, *src;
+
+	src = (void *)BACKUP_REGION_SOURCE;
+
+	if (backup_start) {
+		dest = (void *)(backup_start);
+		memcpy(dest, src, BACKUP_REGION_SIZE);
+	}
+}
diff --git a/purgatory/arch/ppc64/purgatory-ppc64.c b/purgatory/arch/ppc64/purgatory-ppc64.c
new file mode 100644
index 00000000..93f28d2e
--- /dev/null
+++ b/purgatory/arch/ppc64/purgatory-ppc64.c
@@ -0,0 +1,41 @@
+/*
+ * kexec: Linux boots Linux
+ *
+ * Created by: Mohan Kumar M (mohan@in.ibm.com)
+ *
+ * Copyright (C) IBM Corporation, 2005. All rights reserved
+ *
+ * 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 (version 2 of the License).
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <purgatory.h>
+#include "purgatory-ppc64.h"
+
+unsigned int panic_kernel = 0;
+unsigned long backup_start = 0;
+unsigned long stack = 0;
+unsigned long dt_offset = 0;
+unsigned long my_toc = 0;
+unsigned long kernel = 0;
+
+void setup_arch(void)
+{
+	return;
+}
+
+void post_verification_setup_arch(void)
+{
+	if (panic_kernel)
+		crashdump_backup_memory();
+}
diff --git a/purgatory/arch/ppc64/purgatory-ppc64.h b/purgatory/arch/ppc64/purgatory-ppc64.h
new file mode 100644
index 00000000..52eaf439
--- /dev/null
+++ b/purgatory/arch/ppc64/purgatory-ppc64.h
@@ -0,0 +1,6 @@
+#ifndef PURGATORY_PPC64_H
+#define PURGATORY_PPC64_H
+
+void crashdump_backup_memory(void);
+
+#endif /* PURGATORY_PPC64_H */
diff --git a/purgatory/arch/ppc64/v2wrap.S b/purgatory/arch/ppc64/v2wrap.S
index 6e5cdcea..7514d686 100644
--- a/purgatory/arch/ppc64/v2wrap.S
+++ b/purgatory/arch/ppc64/v2wrap.S
@@ -2,6 +2,7 @@
 #  kexec: Linux boots Linux
 #
 #  Copyright (C) 2004 - 2005, Milton D Miller II, IBM Corporation
+#  Copyright (C) 2006, Mohan Kumar M (mohan@in.ibm.com), IBM Corporation
 #
 #  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
@@ -18,14 +19,17 @@
 #
 
 # v2wrap.S
-# a wrapper to place in front of a v2 device tree
-# to call a ppc64 kernel with the expected arguments
+# a wrapper to call purgatory code to backup first
+# 32kB of first kernel into the backup region
+# reserved by kexec-tools.
+# Invokes ppc64 kernel with the expected arguments
 # of kernel(device-tree, phys-offset, 0)
+
 #
 # calling convention:
 #   r3 = physical number of this cpu (all cpus)
 #   r4 = address of this chunk (master only)
-# master enters at start (aka first byte of this chunk)
+# master enters at purgatory_start (aka first byte of this chunk)
 # slaves (additional cpus), if any, enter a copy of the
 # first 0x100 bytes of this code relocated to 0x0
 #
@@ -34,50 +38,50 @@
 #   and the slaves are sent to address 0x60
 #   with r3 = their physical cpu number.
 
+#define LOADADDR(rn,name) \
+	lis     rn,name##@highest;      \
+	ori     rn,rn,name##@higher;    \
+	rldicr  rn,rn,32,31;            \
+	oris    rn,rn,name##@h;         \
+	ori     rn,rn,name##@l
 
 # look a bit like a Linux kernel here ...
 	.machine ppc64
-	.org 0
-start:	b	master
+	.globl purgatory_start
+purgatory_start:	b	master
 	tweq	0,0
-secondary_hold:
-	.llong	0
-
-	.org 0x20	# need a bit more space than after slave,
 master:
-	std	4,secondary_hold@l(0)	# bring slaves up here to this copy
-	sync			# try to get the slaves to see this
 	or	1,1,1		# low priority to let other thread catchup
 	isync
-	mr	5,3		# save cpu id to r5
-	addi	3,4,0x100	# r3 = boot param block
-	lwz	6,20(3)		# fetch version number
-	cmpwi	0,6,2		# v2 ?
-	blt	80f
-	stw	5,28(3)		# save my cpu number as boot_cpu_phys
-80:	b	81f
-
-	.org 0x60		# ABI: slaves start at 60 with r3=phys
-slave:	ld	4,secondary_hold@l(0);
-	cmpdi	0,4,0
-	beq	slave
-
-	# ahh, master told us where he is running from
-	# jump into our copy of the code up there so this code can change
-	addi	5,4,1f-start
-	mtctr	5
-	bctr
+	mr      17,3            # save cpu id to r17
+	mr      15,4            # save physical address in reg15
+
+	LOADADDR(6,my_toc)
+	ld      2,0(6)          #setup toc
 
-	# ok, now wait for the master to tell is to go back to the new block
-1:	ld	5,copied@l(4)
-	cmpdi	0,5,0
-	beq	1b
-	ba	0x60
+	LOADADDR(6,stack)
+	ld      1,0(6)          #setup stack
 
+	subi    1,1,112
+	bl      .purgatory
+	nop
 
+	b       81f
+	.org purgatory_start + 0x60     # ABI: slaves start at 60 with r3=phys
+slave:
+	# load slave spin code address and branch into that
+	LOADADDR(6,slave_spin)
+	ld      4,0(6)
+	mtctr 4
+	bctr
 
-	.long	0		# just an eye-catcher, delete if space needed
-	.long	0		# just an eye-catcher, delete if space needed
+spin: .long 1
+slave_spin_code:
+	lis     5,spin@ha
+	lwz     5,spin@l(5)
+	cmpwi   0,5,0
+	bne     slave_spin_code
+	ba 0x60
 
 81:				# master continues here
 	or	3,3,3		# ok back to high, lets boot
@@ -85,7 +89,17 @@ slave:	ld	4,secondary_hold@l(0);
 	mtctr	6		# delay a bit for slaves to catch up
 83:	bdnz	83b		# before we overwrite 0-100 again
 
-	ld	4,-8(3)		# kernel pointer is at -8(bb) by loader
+	LOADADDR(16, dt_offset)
+	ld      3,0(16)         # load device-tree address
+	mr      16,3            # save dt address in reg16
+	lwz     6,20(3)         # fetch version number
+	cmpwi   0,6,2           # v2 ?
+	blt     80f
+	stw     17,28(3)        # save my cpu number as boot_cpu_phys
+80:
+	LOADADDR(6,kernel)
+	ld      4,0(6)          # load the kernel address
+
 	addi	5,4,-8		# prepare copy with update form instructions
 	li	6,0x100/8
 	mtctr	6
@@ -103,12 +117,12 @@ slave:	ld	4,secondary_hold@l(0);
 	icbi	0,6
 	sync
 	isync
-	std	6,-16(3)	# send slaves back down
+	lis     6,spin@ha
+	li      0,0
+	stw     0,spin@l(6)
+	mr      3,16            # restore dt address
+
 	bctr			# start kernel
 
-	.org 0xf0
-copied:	.llong 0
-kernel:	.llong 0
-	.org 0x100
-__end_stub:
-	.equ	boot_block,	. - start
+slave_spin: .llong  slave_spin_code
+