powerpc: Make load_hander handle upto 64k offset

If we change load_hander() to use an ori instead of addi, we can load handlers
upto 64k away provided we are still 64k aligned.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

diff --git a/arch/powerpc/include/asm/exception-64s.h b/arch/powerpc/include/asm/exception-64s.h
index a43c1473915fd745cc50cb8b574065ce7ad12507..9258daac4964121ddcc55c52ee054db28a69c7af 100644 (file)
--- a/arch/powerpc/include/asm/exception-64s.h
+++ b/arch/powerpc/include/asm/exception-64s.h
@@ -55,7 +55,8 @@
  * word.
  */
 #define LOAD_HANDLER(reg, label)                                       \
-       addi    reg,reg,(label)-_stext; /* virt addr of handler ... */
+       /* Handlers must be within 64K of kbase, which must be 64k aligned */ \
+       ori     reg,reg,(label)-_stext; /* virt addr of handler ... */
 
 /* Exception register prefixes */
 #define EXC_HV H

diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S
index de029640ba26549b32fb8357335819725a7b7602..0969b7ff0f87c77550cdbc7a6acc6afad8ee758e 100644 (file)
--- a/arch/powerpc/kernel/exceptions-64s.S
+++ b/arch/powerpc/kernel/exceptions-64s.S
@@ -585,8 +585,8 @@ __end_interrupts:
  * Code from here down to __end_handlers is invoked from the
  * exception prologs above.  Because the prologs assemble the
  * addresses of these handlers using the LOAD_HANDLER macro,
- * which uses an addi instruction, these handlers must be in
- * the first 32k of the kernel image.
+ * which uses an ori instruction, these handlers must be in
+ * the first 64k of the kernel image.
  */
 
 /*** Common interrupt handlers ***/

diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c
index efb6a41b3131bc1f115ba0b15ec82dba8392b31a..6da881b35dacce0aede124897342a3f5ed1b9a6c 100644 (file)
--- a/arch/powerpc/kernel/setup_64.c
+++ b/arch/powerpc/kernel/setup_64.c
@@ -601,6 +601,11 @@ void __init setup_arch(char **cmdline_p)
 
        kvm_linear_init();
 
+       /* Interrupt code needs to be 64K-aligned */
+       if ((unsigned long)_stext & 0xffff)
+               panic("Kernelbase not 64K-aligned (0x%lx)!\n",
+                     (unsigned long)_stext);
+
        ppc64_boot_msg(0x15, "Setup Done");
 }