patch-2.4.20 linux-2.4.20/arch/ppc/mm/ppc_mmu.c

• Lines: 181
• Date: Thu Nov 28 15:53:11 2002
• Orig file: linux-2.4.19/arch/ppc/mm/ppc_mmu.c
• Orig date: Fri Aug 2 17:39:43 2002

diff -urN linux-2.4.19/arch/ppc/mm/ppc_mmu.c linux-2.4.20/arch/ppc/mm/ppc_mmu.c
@@ -51,7 +51,7 @@
 	u64	word[2];
 #else
 	u32	word[2];
-#endif	
+#endif
 } BATS[4][2];			/* 4 pairs of IBAT, DBAT */
 
 struct batrange {		/* stores address ranges mapped by BATs */
@@ -158,31 +158,13 @@
  */
 void __init MMU_init_hw(void)
 {
-	int Hash_bits, mb, mb2;
-	unsigned int hmask;
+	unsigned int hmask, mb, mb2;
+	unsigned int n_hpteg, lg_n_hpteg;
 
 	extern unsigned int hash_page_patch_A[];
 	extern unsigned int hash_page_patch_B[], hash_page_patch_C[];
 	extern unsigned int flush_hash_patch_A[], flush_hash_patch_B[];
 
-#ifdef CONFIG_PPC64BRIDGE
-	/* The hash table has already been allocated and initialized
-	   in prom.c */
-	Hash_mask = (Hash_size >> 7) - 1;
-	hmask = Hash_mask >> 9;
-	Hash_bits = __ilog2(Hash_size) - 7;
-	mb = 25 - Hash_bits;
-	if (Hash_bits > 16)
-		Hash_bits = 16;
-	mb2 = 25 - Hash_bits;
-
-	/* Remove the hash table from the available memory */
-	if (Hash)
-		reserve_phys_mem(__pa(Hash), Hash_size);
-
-#else /* CONFIG_PPC64BRIDGE */
-	unsigned int h;
-
 	if ((cur_cpu_spec[0]->cpu_features & CPU_FTR_HPTE_TABLE) == 0) {
 		Hash_size = 0;
 		Hash_end = 0;
@@ -192,72 +174,78 @@
 
 	if ( ppc_md.progress ) ppc_md.progress("hash:enter", 0x105);
 
+#ifdef CONFIG_PPC64BRIDGE
+#define LG_HPTEG_SIZE	7		/* 128 bytes per HPTEG */
+#define SDR1_LOW_BITS	(lg_n_hpteg - 11)
+#define MIN_N_HPTEG	2048		/* min 256kB hash table */
+#else
+#define LG_HPTEG_SIZE	6		/* 64 bytes per HPTEG */
+#define SDR1_LOW_BITS	((n_hpteg - 1) >> 10)
+#define MIN_N_HPTEG	1024		/* min 64kB hash table */
+#endif
+
 	/*
-	 * Allow 64k of hash table for every 16MB of memory,
-	 * up to a maximum of 2MB.
+	 * Allow 1 HPTE (1/8 HPTEG) for each page of memory.
+	 * This is less than the recommended amount, but then
+	 * Linux ain't AIX.
 	 */
-	for (h = 64<<10; h < total_memory / 256 && h < (2<<20); h *= 2)
-		;
-	Hash_size = h;
-	Hash_mask = (h >> 6) - 1;
-	hmask = Hash_mask >> 10;
-	Hash_bits = __ilog2(h) - 6;
-	mb = 26 - Hash_bits;
-	if (Hash_bits > 16)
-		Hash_bits = 16;
-	mb2 = 26 - Hash_bits;
+	n_hpteg = total_memory / (PAGE_SIZE * 8);
+	if (n_hpteg < MIN_N_HPTEG)
+		n_hpteg = MIN_N_HPTEG;
+	lg_n_hpteg = __ilog2(n_hpteg);
+	if (n_hpteg & (n_hpteg - 1)) {
+		++lg_n_hpteg;		/* round up if not power of 2 */
+		n_hpteg = 1 << lg_n_hpteg;
+	}
+	Hash_size = n_hpteg << LG_HPTEG_SIZE;
 
+	/*
+	 * Find some memory for the hash table.
+	 */
 	if ( ppc_md.progress ) ppc_md.progress("hash:find piece", 0x322);
-	/* Find some memory for the hash table. */
-	if ( Hash_size ) {
-		Hash = mem_pieces_find(Hash_size, Hash_size);
-		cacheable_memzero(Hash, Hash_size);
-		_SDR1 = __pa(Hash) | (Hash_mask >> 10);
-	} else
-		Hash = 0;
-#endif /* CONFIG_PPC64BRIDGE */
+	Hash = mem_pieces_find(Hash_size, Hash_size);
+	cacheable_memzero(Hash, Hash_size);
+	_SDR1 = __pa(Hash) | SDR1_LOW_BITS;
+	Hash_end = (PTE *) ((unsigned long)Hash + Hash_size);
 
 	printk("Total memory = %ldMB; using %ldkB for hash table (at %p)\n",
 	       total_memory >> 20, Hash_size >> 10, Hash);
-	if (Hash_size) {
-		if ( ppc_md.progress ) ppc_md.progress("hash:patch", 0x345);
-		Hash_end = (PTE *) ((unsigned long)Hash + Hash_size);
-
-		/*
-		 * Patch up the instructions in hashtable.S:create_hpte
-		 */
-		hash_page_patch_A[0] = (hash_page_patch_A[0] & ~0xffff)
-			| ((unsigned int)(Hash) >> 16);
-		hash_page_patch_A[1] = (hash_page_patch_A[1] & ~0x7c0)
-			| (mb << 6);
-		hash_page_patch_A[2] = (hash_page_patch_A[2] & ~0x7c0)
-			| (mb2 << 6);
-		hash_page_patch_B[0] = (hash_page_patch_B[0] & ~0xffff)
-			| hmask;
-		hash_page_patch_C[0] = (hash_page_patch_C[0] & ~0xffff)
-			| hmask;
-		/*
-		 * Ensure that the locations we've patched have been written
-		 * out from the data cache and invalidated in the instruction
-		 * cache, on those machines with split caches.
-		 */
-		flush_icache_range((unsigned long) &hash_page_patch_A[0],
-				   (unsigned long) &hash_page_patch_C[1]);
-		/*
-		 * Patch up the instructions in hashtable.S:flush_hash_page
-		 */
-		flush_hash_patch_A[0] = (flush_hash_patch_A[0] & ~0xffff)
-			| ((unsigned int)(Hash) >> 16);
-		flush_hash_patch_A[1] = (flush_hash_patch_A[1] & ~0x7c0)
-			| (mb << 6);
-		flush_hash_patch_A[2] = (flush_hash_patch_A[2] & ~0x7c0)
-			| (mb2 << 6);
-		flush_hash_patch_B[0] = (flush_hash_patch_B[0] & ~0xffff)
-			| hmask;
-		flush_icache_range((unsigned long) &flush_hash_patch_A[0],
-				   (unsigned long) &flush_hash_patch_B[1]);
-	}
-	
+
+	/*
+	 * Patch up the instructions in hashtable.S:create_hpte
+	 */
+	if ( ppc_md.progress ) ppc_md.progress("hash:patch", 0x345);
+	Hash_mask = n_hpteg - 1;
+	hmask = Hash_mask >> (16 - LG_HPTEG_SIZE);
+	mb2 = mb = 32 - LG_HPTEG_SIZE - lg_n_hpteg;
+	if (lg_n_hpteg > 16)
+		mb2 = 16 - LG_HPTEG_SIZE;
+	hash_page_patch_A[0] = (hash_page_patch_A[0] & ~0xffff)
+		| ((unsigned int)(Hash) >> 16);
+	hash_page_patch_A[1] = (hash_page_patch_A[1] & ~0x7c0) | (mb << 6);
+	hash_page_patch_A[2] = (hash_page_patch_A[2] & ~0x7c0) | (mb2 << 6);
+	hash_page_patch_B[0] = (hash_page_patch_B[0] & ~0xffff) | hmask;
+	hash_page_patch_C[0] = (hash_page_patch_C[0] & ~0xffff) | hmask;
+
+	/*
+	 * Ensure that the locations we've patched have been written
+	 * out from the data cache and invalidated in the instruction
+	 * cache, on those machines with split caches.
+	 */
+	flush_icache_range((unsigned long) &hash_page_patch_A[0],
+			   (unsigned long) &hash_page_patch_C[1]);
+
+	/*
+	 * Patch up the instructions in hashtable.S:flush_hash_page
+	 */
+	flush_hash_patch_A[0] = (flush_hash_patch_A[0] & ~0xffff)
+		| ((unsigned int)(Hash) >> 16);
+	flush_hash_patch_A[1] = (flush_hash_patch_A[1] & ~0x7c0) | (mb << 6);
+	flush_hash_patch_A[2] = (flush_hash_patch_A[2] & ~0x7c0) | (mb2 << 6);
+	flush_hash_patch_B[0] = (flush_hash_patch_B[0] & ~0xffff) | hmask;
+	flush_icache_range((unsigned long) &flush_hash_patch_A[0],
+			   (unsigned long) &flush_hash_patch_B[1]);
+
 	if ( ppc_md.progress ) ppc_md.progress("hash:done", 0x205);
 }