In kernel/cputable.c, explicitly use memcpy() in order
to allow GCC to replace it with __memcpy() when KASAN is
selected.

Since commit 400c47d81ca38 ("powerpc32: memset: only use dcbz once cache is
enabled"), memset() can be used before activation of the cache,
so no need to use memset_io() for zeroing the BSS.

Acked-by: Dmitry Vyukov <dvyu...@google.com>
Signed-off-by: Christophe Leroy <christophe.le...@c-s.fr>
---
 arch/powerpc/kernel/cputable.c | 13 ++++++++++---
 arch/powerpc/kernel/setup_32.c |  6 ++----
 2 files changed, 12 insertions(+), 7 deletions(-)

diff --git a/arch/powerpc/kernel/cputable.c b/arch/powerpc/kernel/cputable.c
index 1eab54bc6ee9..cd12f362b61f 100644
--- a/arch/powerpc/kernel/cputable.c
+++ b/arch/powerpc/kernel/cputable.c
@@ -2147,7 +2147,11 @@ void __init set_cur_cpu_spec(struct cpu_spec *s)
        struct cpu_spec *t = &the_cpu_spec;
 
        t = PTRRELOC(t);
-       *t = *s;
+       /*
+        * use memcpy() instead of *t = *s so that GCC replaces it
+        * by __memcpy() when KASAN is active
+        */
+       memcpy(t, s, sizeof(*t));
 
        *PTRRELOC(&cur_cpu_spec) = &the_cpu_spec;
 }
@@ -2161,8 +2165,11 @@ static struct cpu_spec * __init setup_cpu_spec(unsigned 
long offset,
        t = PTRRELOC(t);
        old = *t;
 
-       /* Copy everything, then do fixups */
-       *t = *s;
+       /*
+        * Copy everything, then do fixups. Use memcpy() instead of *t = *s
+        * so that GCC replaces it by __memcpy() when KASAN is active
+        */
+       memcpy(t, s, sizeof(*t));
 
        /*
         * If we are overriding a previous value derived from the real
diff --git a/arch/powerpc/kernel/setup_32.c b/arch/powerpc/kernel/setup_32.c
index 947f904688b0..5e761eb16a6d 100644
--- a/arch/powerpc/kernel/setup_32.c
+++ b/arch/powerpc/kernel/setup_32.c
@@ -73,10 +73,8 @@ notrace unsigned long __init early_init(unsigned long dt_ptr)
 {
        unsigned long offset = reloc_offset();
 
-       /* First zero the BSS -- use memset_io, some platforms don't have
-        * caches on yet */
-       memset_io((void __iomem *)PTRRELOC(&__bss_start), 0,
-                       __bss_stop - __bss_start);
+       /* First zero the BSS */
+       memset(PTRRELOC(&__bss_start), 0, __bss_stop - __bss_start);
 
        /*
         * Identify the CPU type and fix up code sections
-- 
2.13.3

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