powerpc/book3s/32: Use MMU_FTR_HPTE_TABLE in head_32.S

Instead of manually patching a blr at hash_page() entry in
MMU_init_hw(), this patch adds a features section in head_32.S

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/kernel/head_32.S

@@ -393,7 +393,9 @@ DataAccess:
 	bne	1f			/* if not, try to put a PTE */
 	mfspr	r4,SPRN_DAR		/* into the hash table */
 	rlwinm	r3,r10,32-15,21,21	/* DSISR_STORE -> _PAGE_RW */
+BEGIN_MMU_FTR_SECTION
 	bl	hash_page
+END_MMU_FTR_SECTION_IFSET(MMU_FTR_HPTE_TABLE)
 1:	lwz	r5,_DSISR(r11)		/* get DSISR value */
 	mfspr	r4,SPRN_DAR
 	EXC_XFER_LITE(0x300, handle_page_fault)
@@ -408,7 +410,9 @@ InstructionAccess:
 	beq	1f			/* if so, try to put a PTE */
 	li	r3,0			/* into the hash table */
 	mr	r4,r12			/* SRR0 is fault address */
+BEGIN_MMU_FTR_SECTION
 	bl	hash_page
+END_MMU_FTR_SECTION_IFSET(MMU_FTR_HPTE_TABLE)
 1:	mr	r4,r12
 	andis.	r5,r9,DSISR_SRR1_MATCH_32S@h /* Filter relevant SRR1 bits */
 	EXC_XFER_LITE(0x400, handle_page_fault)

arch/powerpc/mm/ppc_mmu_32.c

@@ -184,20 +184,10 @@ void __init MMU_init_hw(void)
 
 	extern unsigned int hash_page_patch_A[];
 	extern unsigned int hash_page_patch_B[], hash_page_patch_C[];
-	extern unsigned int hash_page[];
 	extern unsigned int flush_hash_patch_A[], flush_hash_patch_B[];
 
-	if (!mmu_has_feature(MMU_FTR_HPTE_TABLE)) {
-		/*
-		 * Put a blr (procedure return) instruction at the
-		 * start of hash_page, since we can still get DSI
-		 * exceptions on a 603.
-		 */
-		hash_page[0] = 0x4e800020;
-		flush_icache_range((unsigned long) &hash_page[0],
-				   (unsigned long) &hash_page[1]);
+	if (!mmu_has_feature(MMU_FTR_HPTE_TABLE))
 		return;
-	}
 
 	if ( ppc_md.progress ) ppc_md.progress("hash:enter", 0x105);