powerpc: Copy down exception vectors after feature fixups

kdump fails because we try to execute an HV only instruction. Feature
fixups are being applied after we copy the exception vectors down to 0
so they miss out on any updates.

We have always had this issue but it only became critical in v3.0
when we added CFAR support (breaks POWER5) and v3.1 when we added
POWERNV (breaks everyone).

Signed-off-by: Anton Blanchard <anton@samba.org>
Cc: <stable@kernel.org> [v3.0+]
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

6 files changed, 28 insertions, 2 deletions

diff --git a/arch/powerpc/include/asm/sections.h b/arch/powerpc/include/asm/sections.h
index 6fbce725c710..a0f358d4a00c 100644
--- a/arch/powerpc/include/asm/sections.h
+++ b/arch/powerpc/include/asm/sections.h
@@ -8,7 +8,7 @@
 
 #ifdef __powerpc64__
 
-extern char _end[];
+extern char __end_interrupts[];
 
 static inline int in_kernel_text(unsigned long addr)
 {
diff --git a/arch/powerpc/include/asm/synch.h b/arch/powerpc/include/asm/synch.h
index d7cab44643c5..87878c68d1c2 100644
--- a/arch/powerpc/include/asm/synch.h
+++ b/arch/powerpc/include/asm/synch.h
@@ -13,6 +13,7 @@
 extern unsigned int __start___lwsync_fixup, __stop___lwsync_fixup;
 extern void do_lwsync_fixups(unsigned long value, void *fixup_start,
                              void *fixup_end);
+extern void do_final_fixups(void);
 
 static inline void eieio(void)
 {
diff --git a/arch/powerpc/kernel/kvm.c b/arch/powerpc/kernel/kvm.c
index 35f27646c4ff..2985338d0e10 100644
--- a/arch/powerpc/kernel/kvm.c
+++ b/arch/powerpc/kernel/kvm.c
@@ -132,7 +132,6 @@ static void kvm_patch_ins_b(u32 *inst, int addr)
         /* On relocatable kernels interrupts handlers and our code
            can be in different regions, so we don't patch them */
 
-        extern u32 __end_interrupts;
         if ((ulong)inst < (ulong)&__end_interrupts)
                 return;
 #endif
diff --git a/arch/powerpc/kernel/setup_32.c b/arch/powerpc/kernel/setup_32.c
index c1ce86357ecb..ac7610815113 100644
--- a/arch/powerpc/kernel/setup_32.c
+++ b/arch/powerpc/kernel/setup_32.c
@@ -107,6 +107,8 @@ notrace unsigned long __init early_init(unsigned long dt_ptr)
                          PTRRELOC(&__start___lwsync_fixup),
                          PTRRELOC(&__stop___lwsync_fixup));
 
+        do_final_fixups();
+
         return KERNELBASE + offset;
 }
 
diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c
index 1a9dea80a69b..fb9bb46e7e88 100644
--- a/arch/powerpc/kernel/setup_64.c
+++ b/arch/powerpc/kernel/setup_64.c
@@ -359,6 +359,7 @@ void __init setup_system(void)
                           &__start___fw_ftr_fixup, &__stop___fw_ftr_fixup);
         do_lwsync_fixups(cur_cpu_spec->cpu_features,
                          &__start___lwsync_fixup, &__stop___lwsync_fixup);
+        do_final_fixups();
 
         /*
          * Unflatten the device-tree passed by prom_init or kexec
diff --git a/arch/powerpc/lib/feature-fixups.c b/arch/powerpc/lib/feature-fixups.c
index 0d08d0171392..7a8a7487cee8 100644
--- a/arch/powerpc/lib/feature-fixups.c
+++ b/arch/powerpc/lib/feature-fixups.c
@@ -18,6 +18,8 @@
 #include <linux/init.h>
 #include <asm/cputable.h>
 #include <asm/code-patching.h>
+#include <asm/page.h>
+#include <asm/sections.h>
 
 
 struct fixup_entry {
@@ -128,6 +130,27 @@ void do_lwsync_fixups(unsigned long value, void *fixup_start, void *fixup_end)
         }
 }
 
+void do_final_fixups(void)
+{
+#if defined(CONFIG_PPC64) && defined(CONFIG_RELOCATABLE)
+        int *src, *dest;
+        unsigned long length;
+
+        if (PHYSICAL_START == 0)
+                return;
+
+        src = (int *)(KERNELBASE + PHYSICAL_START);
+        dest = (int *)KERNELBASE;
+        length = (__end_interrupts - _stext) / sizeof(int);
+
+        while (length--) {
+                patch_instruction(dest, *src);
+                src++;
+                dest++;
+        }
+#endif
+}
+
 #ifdef CONFIG_FTR_FIXUP_SELFTEST
 
 #define check(x)        \