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.
---
arch/powerpc/include/asm/exception-64s.h | 3 ++-
arch/powerpc/kernel/exceptions-64s.S | 4 ++--
arch/powerpc/kernel/setup_64.c | 5 +++++
3 files changed, 9 insertions(+), 3 deletions(-)
diff --git a/arch/powerpc/include/asm/exception-64s.h
b/arch/powerpc/include/asm/exception-64s.h
index a43c147..9258daa 100644
--- 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 de02964..0969b7f 100644
--- 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 efb6a41..6da881b 100644
--- 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");
}
--
1.7.9.5
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