powerpc/32: Wire up the trampoline code for kdump

Wire up the trampoline code for ppc32 to relay exceptions from the
vectors at address 0 to vectors at address 32MB, and modify Kconfig
to enable Kdump support for all classic powerpcs.

Signed-off-by: Dale Farnsworth <dale@farnsworth.org>
Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>

3 files changed, 16 insertions, 1 deletions

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index be4f99b7cbbb..f7f5448f863d 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -326,7 +326,7 @@ config KEXEC
 
 config CRASH_DUMP
         bool "Build a kdump crash kernel"
-        depends on PPC_MULTIPLATFORM && PPC64 && RELOCATABLE
+        depends on (PPC64 && RELOCATABLE) || 6xx
         help
           Build a kernel suitable for use as a kdump capture kernel.
           The same kernel binary can be used as production kernel and dump
diff --git a/arch/powerpc/include/asm/kdump.h b/arch/powerpc/include/asm/kdump.h
index b07ebb9784d3..5ebfe5d3c61f 100644
--- a/arch/powerpc/include/asm/kdump.h
+++ b/arch/powerpc/include/asm/kdump.h
@@ -1,6 +1,8 @@
 #ifndef _PPC64_KDUMP_H
 #define _PPC64_KDUMP_H
 
+#include <asm/page.h>
+
 /* Kdump kernel runs at 32 MB, change at your peril. */
 #define KDUMP_KERNELBASE        0x2000000
 
@@ -11,8 +13,19 @@
 
 #ifdef CONFIG_CRASH_DUMP
 
+/*
+ * On PPC64 translation is disabled during trampoline setup, so we use
+ * physical addresses. Though on PPC32 translation is already enabled,
+ * so we can't do the same. Luckily create_trampoline() creates relative
+ * branches, so we can just add the PAGE_OFFSET and don't worry about it.
+ */
+#ifdef __powerpc64__
 #define KDUMP_TRAMPOLINE_START  0x0100
 #define KDUMP_TRAMPOLINE_END    0x3000
+#else
+#define KDUMP_TRAMPOLINE_START  (0x0100 + PAGE_OFFSET)
+#define KDUMP_TRAMPOLINE_END    (0x3000 + PAGE_OFFSET)
+#endif /* __powerpc64__ */
 
 #define KDUMP_MIN_TCE_ENTRIES   2048
 
diff --git a/arch/powerpc/kernel/setup_32.c b/arch/powerpc/kernel/setup_32.c
index d72ef39f2b37..9e1ca745d8f0 100644
--- a/arch/powerpc/kernel/setup_32.c
+++ b/arch/powerpc/kernel/setup_32.c
@@ -126,6 +126,8 @@ notrace void __init machine_init(unsigned long dt_ptr)
 
         probe_machine();
 
+        setup_kdump_trampoline();
+
 #ifdef CONFIG_6xx
         if (cpu_has_feature(CPU_FTR_CAN_DOZE) ||
             cpu_has_feature(CPU_FTR_CAN_NAP))