KEXEC Support for ppc440X
The patch adds kexec support for PPC440x based boards. This work is based
on the KEXEC patches for FSL BookE.
The FSL BookE patch and the code flow could be found at the link below:
http://patchwork.ozlabs.org/patch/49359/
We invalidate all the TLB entries except the one this code is run from,
and create a 1:1 mapping for 0-2GiB in blocks of 256M. Later we jump to
the 1:1 mapping.
I have tested this patches on Ebony and Sequoia boards. It would be great
if somebody could test this on the other boards.
Signed-off-by: Suzuki K. Poulose <suz...@in.ibm.com>
---
arch/powerpc/Kconfig | 2
arch/powerpc/include/asm/kexec.h | 2
arch/powerpc/kernel/44x_kexec_mapping.S | 66 ++++++++++++++++++++++++++++++++
arch/powerpc/kernel/misc_32.S | 22 ++++++++++
4 files changed, 90 insertions(+), 2 deletions(-)
Index: powerpc/arch/powerpc/Kconfig
===================================================================
--- powerpc.orig/arch/powerpc/Kconfig
+++ powerpc/arch/powerpc/Kconfig
@@ -349,7 +349,7 @@ config ARCH_ENABLE_MEMORY_HOTREMOVE
config KEXEC
bool "kexec system call (EXPERIMENTAL)"
- depends on (PPC_BOOK3S || FSL_BOOKE) && EXPERIMENTAL
+ depends on (PPC_BOOK3S || FSL_BOOKE || (44x && !SMP && !47x)) &&
EXPERIMENTAL
help
kexec is a system call that implements the ability to shutdown your
current kernel, and to start another kernel. It is like a reboot
Index: powerpc/arch/powerpc/include/asm/kexec.h
===================================================================
--- powerpc.orig/arch/powerpc/include/asm/kexec.h
+++ powerpc/arch/powerpc/include/asm/kexec.h
@@ -2,7 +2,7 @@
#define _ASM_POWERPC_KEXEC_H
#ifdef __KERNEL__
-#ifdef CONFIG_FSL_BOOKE
+#if defined(CONFIG_FSL_BOOKE) || defined(CONFIG_44x)
/*
* On FSL-BookE we setup a 1:1 mapping which covers the first 2GiB of memory
Index: powerpc/arch/powerpc/kernel/44x_kexec_mapping.S
===================================================================
--- /dev/null
+++ powerpc/arch/powerpc/kernel/44x_kexec_mapping.S
@@ -0,0 +1,66 @@
+/*
+ * Copyright (C) 2011 IBM
+ *
+ * Author : Suzuki K. Poulose <suz...@in.ibm.com>
+ *
+ * This source code is licensed under the GNU General Public License,
+ * Version 2. See the file COPYING for more details.
+ *
+ * Code for setting up 1:1 mapping for PPC440x for KEXEC
+ *
+ * We cannot switch off the MMU on PPC44x.
+ * So we:
+ * 1) Invalidate all the mappings except the one we are
+ * running from.
+ * 2) Create a 1:1 mapping for 0-2GiB
+ *
+ * - Based on the kexec support code for FSL BookE
+ * - Based on the boot up code for ppc44x from head_44x.S
+ * - Doesn't support 47x yet.
+ * - Doesn't support SMP.
+ *
+ */
+ bl nxtins /* Find our address */
+nxtins: mflr r5 /* Make it accessible */
+ tlbsx r23,0,r5 /* Find entry we are in */
+ li r4,0 /* Start at TLB entry 0 */
+ li r3,0 /* Set PAGEID inval value */
+1: cmpw r23,r4 /* Is this our entry? */
+ beq skip /* If so, skip the inval */
+ tlbwe r3,r4,PPC44x_TLB_PAGEID /* If not, inval the entry */
+skip: addi r4,r4,1 /* Increment */
+ cmpwi r4,64 /* Are we done? */
+ bne 1b /* If not, repeat */
+ isync
+
+/*
+ * Setup 1:1 mapping for 0-2GiB in blocks of 256M.
+ * r23 is the index to the mapping of this code.
+ * Skip it.
+ */
+ /* attribute fields. rwx for SUPERVISOR mode */
+ li r5, 0
+ ori r5, r5, (PPC44x_TLB_SW | PPC44x_TLB_SR | PPC44x_TLB_SX |
PPC44x_TLB_G)
+
+ li r11, 0 /* PageNumber */
+ li r6, 0 /* TLB Index */
+
+next_tlb:
+ rotlwi r3, r11, 28 /* Create EPN (bits 0-3) */
+ mr r4, r3 /* RPN = EPN */
+ ori r3, r3, PPC44x_TLB_VALID | PPC44x_TLB_256M /* SIZE = 256M,
Valid */
+ cmpw r6, r23 /* Is this our TLB entry ? */
+ bne write_tlb
+ addi r6, r6, 1 /* Skip our entry */
+
+write_tlb:
+ tlbwe r3, r6, PPC44x_TLB_PAGEID /* PageID field : EPN, V, SIZE
*/
+ tlbwe r4, r6, PPC44x_TLB_XLAT /* Address translation : RPN
*/
+ tlbwe r5, r6, PPC44x_TLB_ATTRIB /* Attributes */
+
+ addi r11, r11, 1 /* Increment PN */
+ addi r6, r6, 1 /* Increment TLB Index */
+ cmpwi r11, 8 /* Are we done ? */
+ bne next_tlb
+ isync
+
Index: powerpc/arch/powerpc/kernel/misc_32.S
===================================================================
--- powerpc.orig/arch/powerpc/kernel/misc_32.S
+++ powerpc/arch/powerpc/kernel/misc_32.S
@@ -736,6 +736,28 @@ relocate_new_kernel:
mr r5, r31
li r0, 0
+#elif defined(CONFIG_44x) && !defined(CONFIG_47x)
+
+ mr r29, r3
+ mr r30, r4
+ mr r31, r5
+
+#include "44x_kexec_mapping.S"
+
+ mr r3, r29
+ mr r4, r30
+ mr r5, r31
+
+ li r0, 0
+
+ /* Jump back to the 1:1 address */
+ mr r8, r0
+ mtspr SPRN_SRR1, r8
+ addi r8, r4, 1f - relocate_new_kernel
+ mtspr SPRN_SRR0, r8
+ sync
+ rfi
+1:
#else
li r0, 0
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