powerpc/code-patching: Move patch_exception() outside code-patching.c

patch_exception() is dedicated to book3e/64 is nothing more than
a normal use of patch_branch(), so move it into a place dedicated
to book3e/64.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/0968622b98b1fb51838c35b844c42ad6609de62e.1638446239.git.christophe.leroy@csgroup.eu

1 files changed, 15 insertions, 0 deletions

diff --git a/arch/powerpc/mm/nohash/book3e_pgtable.c b/arch/powerpc/mm/nohash/book3e_pgtable.c
index 77884e24281d..7d4368d055a6 100644
--- a/arch/powerpc/mm/nohash/book3e_pgtable.c
+++ b/arch/powerpc/mm/nohash/book3e_pgtable.c
@@ -10,6 +10,7 @@
 #include <asm/pgalloc.h>
 #include <asm/tlb.h>
 #include <asm/dma.h>
+#include <asm/code-patching.h>
 
 #include <mm/mmu_decl.h>
 
@@ -115,3 +116,17 @@ int __ref map_kernel_page(unsigned long ea, unsigned long pa, pgprot_t prot)
 	smp_wmb();
 	return 0;
 }
+
+void __patch_exception(int exc, unsigned long addr)
+{
+	unsigned int *ibase = &interrupt_base_book3e;
+
+	/*
+	 * Our exceptions vectors start with a NOP and -then- a branch
+	 * to deal with single stepping from userspace which stops on
+	 * the second instruction. Thus we need to patch the second
+	 * instruction of the exception, not the first one.
+	 */
+
+	patch_branch(ibase + (exc / 4) + 1, addr, 0);
+}