[PATCH] powerpc: Reroute interrupts from 0 + offset to PHYSICAL_START + offset

Regardless of where the kernel's linked we always get interrupts at low
addresses. This patch creates a trampoline in the first 3 pages of memory,
where interrupts land, and patches those addresses to jump into the real
kernel code at PHYSICAL_START.

We also need to reserve the trampoline code and a bit more in prom.c

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

1 files changed, 13 insertions, 0 deletions

diff --git a/include/asm-powerpc/kdump.h b/include/asm-powerpc/kdump.h
new file mode 100644
index 000000000000..a87aed00d61f
--- /dev/null
+++ b/include/asm-powerpc/kdump.h
@@ -0,0 +1,13 @@
+#ifndef _PPC64_KDUMP_H
+#define _PPC64_KDUMP_H
+
+/* How many bytes to reserve at zero for kdump. The reserve limit should
+ * be greater or equal to the trampoline's end address. */
+#define KDUMP_RESERVE_LIMIT     0x8000
+
+#define KDUMP_TRAMPOLINE_START  0x0100
+#define KDUMP_TRAMPOLINE_END    0x3000
+
+extern void kdump_setup(void);
+
+#endif /* __PPC64_KDUMP_H */