powerpc/8xx: Make pinning of ITLBs optional

As stated in a comment in head_8xx.S, today we "Always pin the first
8 MB ITLB to prevent ITLB misses while mucking around with SRR0/SRR1
in asm".

This issue has just been cleared by the preceding patch, therefore
we can make this pinning optional (on by default) and independent
of DATA pinning.

This patch also makes pinning of IMMR independent of pinning of DATA.

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

arch/powerpc/mm/8xx_mmu.c

@@ -65,7 +65,7 @@ unsigned long p_block_mapped(phys_addr_t pa)
 void __init MMU_init_hw(void)
 {
 	/* PIN up to the 3 first 8Mb after IMMR in DTLB table */
-#ifdef CONFIG_PIN_TLB
+#ifdef CONFIG_PIN_TLB_DATA
 	unsigned long ctr = mfspr(SPRN_MD_CTR) & 0xfe000000;
 	unsigned long flags = 0xf0 | MD_SPS16K | _PAGE_SHARED | _PAGE_DIRTY;
 #ifdef CONFIG_PIN_TLB_IMMR
@@ -103,6 +103,9 @@ static void mmu_mapin_immr(void)
 extern unsigned int DTLBMiss_jmp;
 #endif
 extern unsigned int DTLBMiss_cmp, FixupDAR_cmp;
+#ifndef CONFIG_PIN_TLB_TEXT
+extern unsigned int ITLBMiss_cmp;
+#endif
 
 void mmu_patch_cmp_limit(unsigned int *addr, unsigned long mapped)
 {
@@ -122,6 +125,9 @@ unsigned long __init mmu_mapin_ram(unsigned long top)
 		mmu_mapin_immr();
 #ifndef CONFIG_PIN_TLB_IMMR
 		patch_instruction(&DTLBMiss_jmp, PPC_INST_NOP);
+#endif
+#ifndef CONFIG_PIN_TLB_TEXT
+		mmu_patch_cmp_limit(&ITLBMiss_cmp, 0);
 #endif
 	} else {
 		mapped = top & ~(LARGE_PAGE_SIZE_8M - 1);