Revert "powerpc/kasan: Fix shadow pages allocation failure"

This reverts commit d2a91cef.

This commit moved too much work in kasan_init(). The allocation
of shadow pages has to be moved for the reason explained in that
patch, but the allocation of page tables still need to be done
before switching to the final hash table.

First revert the incorrect commit, following patch redoes it
properly.

Fixes: d2a91cef ("powerpc/kasan: Fix shadow pages allocation failure")
Cc: stable@vger.kernel.org
Reported-by: Erhard F. <erhard_f@mailbox.org>
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://bugzilla.kernel.org/show_bug.cgi?id=208181
Link: https://lore.kernel.org/r/3667deb0911affbf999b99f87c31c77d5e870cd2.1593690707.git.christophe.leroy@csgroup.eu

arch/powerpc/include/asm/kasan.h

@@ -27,10 +27,12 @@
 
 #ifdef CONFIG_KASAN
 void kasan_early_init(void);
+void kasan_mmu_init(void);
 void kasan_init(void);
 void kasan_late_init(void);
 #else
 static inline void kasan_init(void) { }
+static inline void kasan_mmu_init(void) { }
 static inline void kasan_late_init(void) { }
 #endif
 

arch/powerpc/mm/init_32.c

@@ -171,6 +171,8 @@ void __init MMU_init(void)
 	btext_unmap();
 #endif
 
+	kasan_mmu_init();
+
 	setup_kup();
 
 	/* Shortly after that, the entire linear mapping will be available */

arch/powerpc/mm/kasan/kasan_init_32.c

@@ -117,7 +117,7 @@ static void __init kasan_unmap_early_shadow_vmalloc(void)
 	kasan_update_early_region(k_start, k_end, __pte(0));
 }
 
-static void __init kasan_mmu_init(void)
+void __init kasan_mmu_init(void)
 {
 	int ret;
 	struct memblock_region *reg;
@@ -146,8 +146,6 @@ static void __init kasan_mmu_init(void)
 
 void __init kasan_init(void)
 {
-	kasan_mmu_init();
-
 	kasan_remap_early_shadow_ro();
 
 	clear_page(kasan_early_shadow_page);