[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, 5 insertions, 1 deletions

diff --git a/arch/powerpc/kernel/prom.c b/arch/powerpc/kernel/prom.c
index 3bf968e74095..9aac77ca3167 100644
--- a/arch/powerpc/kernel/prom.c
+++ b/arch/powerpc/kernel/prom.c
@@ -37,6 +37,7 @@
 #include <asm/processor.h>
 #include <asm/irq.h>
 #include <asm/io.h>
+#include <asm/kdump.h>
 #include <asm/smp.h>
 #include <asm/system.h>
 #include <asm/mmu.h>
@@ -1335,11 +1336,14 @@ void __init early_init_devtree(void *params)
         of_scan_flat_dt(early_init_dt_scan_memory, NULL);
         lmb_enforce_memory_limit(memory_limit);
         lmb_analyze();
-        lmb_reserve(0, __pa(klimit));
 
         DBG("Phys. mem: %lx\n", lmb_phys_mem_size());
 
         /* Reserve LMB regions used by kernel, initrd, dt, etc... */
+        lmb_reserve(PHYSICAL_START, __pa(klimit) - PHYSICAL_START);
+#ifdef CONFIG_CRASH_DUMP
+        lmb_reserve(0, KDUMP_RESERVE_LIMIT);
+#endif
         early_reserve_mem();
 
         DBG("Scanning CPUs ...\n");