PPC32: Use non-pinned large-page TLB entries for kernel RAM mapping.

arch/ppc/kernel/head_4xx.S

@@ -555,33 +555,40 @@ label:
 4:
 	tophys(r11, r11)
 	rlwimi	r11, r10, 12, 20, 29	/* Create L1 (pgdir/pmd) address */
-	lwz	r11, 0(r11)		/* Get L1 entry */
-	rlwinm.	r12, r11, 0, 0, 19	/* Extract L2 (pte) base address */
+	lwz	r12, 0(r11)		/* Get L1 entry */
+	andi.	r9, r12, _PMD_PRESENT	/* Check if it points to a PTE page */
 	beq	2f			/* Bail if no table */
 
 	rlwimi	r12, r10, 22, 20, 29	/* Compute PTE address */
 	lwz	r11, 0(r12)		/* Get Linux PTE */
 	andi.	r9, r11, _PAGE_PRESENT
-	beq	2f
+	beq	5f
 
 	ori	r11, r11, _PAGE_ACCESSED
 	stw	r11, 0(r12)
 
-	/* Most of the Linux PTE is ready to load into the TLB LO.
-	 * We set ZSEL, where only the LS-bit determines user access.
-	 * We set execute, because we don't have the granularity to
-	 * properly set this at the page level (Linux problem).
-	 * If shared is set, we cause a zero PID->TID load.
-	 * Many of these bits are software only.  Bits we don't set
-	 * here we (properly should) assume have the appropriate value.
+	/* Create TLB tag.  This is the faulting address plus a static
+	 * set of bits.  These are size, valid, E, U0.
 	*/
-	li	r12, 0x0ce2
-	andc	r11, r11, r12		/* Make sure 20, 21 are zero */
+	li	r12, 0x00c0
+	rlwimi	r10, r12, 0, 20, 31
 
 	b	finish_tlb_load
 
+2:	/* Check for possible large-page pmd entry */
+	rlwinm.	r9, r12, 2, 22, 24
+	beq	5f
 
-2:
+	/* Create TLB tag.  This is the faulting address, plus a static
+	 * set of bits (valid, E, U0) plus the size from the PMD.
+	 */
+	ori	r9, r9, 0x40
+	rlwimi	r10, r9, 0, 20, 31
+	mr	r11, r12
+
+	b	finish_tlb_load
+
+5:
 	/* The bailout.  Restore registers to pre-exception conditions
 	 * and call the heavyweights to help us out.
 	 */
@@ -647,55 +654,40 @@ label:
 4:
 	tophys(r11, r11)
 	rlwimi	r11, r10, 12, 20, 29	/* Create L1 (pgdir/pmd) address */
-	lwz	r11, 0(r11)		/* Get L1 entry */
-	rlwinm.	r12, r11, 0, 0, 19	/* Extract L2 (pte) base address */
+	lwz	r12, 0(r11)		/* Get L1 entry */
+	andi.	r9, r12, _PMD_PRESENT	/* Check if it points to a PTE page */
 	beq	2f			/* Bail if no table */
 
 	rlwimi	r12, r10, 22, 20, 29	/* Compute PTE address */
 	lwz	r11, 0(r12)		/* Get Linux PTE */
 	andi.	r9, r11, _PAGE_PRESENT
-	beq	2f
+	beq	5f
 
 	ori	r11, r11, _PAGE_ACCESSED
 	stw	r11, 0(r12)
 
-	/* Most of the Linux PTE is ready to load into the TLB LO.
-	 * We set ZSEL, where only the LS-bit determines user access.
-	 * We set execute, because we don't have the granularity to
-	 * properly set this at the page level (Linux problem).
-	 * If shared is set, we cause a zero PID->TID load.
-	 * Many of these bits are software only.  Bits we don't set
-	 * here we (properly should) assume have the appropriate value.
+	/* Create TLB tag.  This is the faulting address plus a static
+	 * set of bits.  These are size, valid, E, U0.
 	*/
-	li	r12, 0x0ce2
-	andc	r11, r11, r12		/* Make sure 20, 21 are zero */
+	li	r12, 0x00c0
+	rlwimi	r10, r12, 0, 20, 31
 
 	b	finish_tlb_load
 
-	/* Done...restore registers and get out of here.
+2:	/* Check for possible large-page pmd entry */
+	rlwinm.	r9, r12, 2, 22, 24
+	beq	5f
+
+	/* Create TLB tag.  This is the faulting address, plus a static
+	 * set of bits (valid, E, U0) plus the size from the PMD.
 	 */
-#ifdef CONFIG_403GCX
-	lwz     r12, 12(r0)
-	lwz     r11, 8(r0)
-	mtspr   SPRN_PID, r12
-	mtcr    r11
-	lwz     r9, 4(r0)
-	lwz     r12, 0(r0)
-#else
-	mfspr	r12, SPRG6
-	mfspr	r11, SPRG7
-	mtspr	SPRN_PID, r12
-	mtcr	r11
-	mfspr	r9, SPRG5
-	mfspr	r12, SPRG4
-#endif
-	mfspr	r11, SPRG1
-	mfspr	r10, SPRG0
-	PPC405_ERR77_SYNC
-	rfi			/* Should sync shadow TLBs */
-	b	.		/* prevent prefetch past rfi */
+	ori	r9, r9, 0x40
+	rlwimi	r10, r9, 0, 20, 31
+	mr	r11, r12
 
-2:
+	b	finish_tlb_load
+	
+5:
 	/* The bailout.  Restore registers to pre-exception conditions
 	 * and call the heavyweights to help us out.
 	 */
@@ -818,8 +810,8 @@ check_single_step_in_exception:
 	/* Damn, I came up one instruction too many to fit into the
 	 * exception space :-).  Both the instruction and data TLB
 	 * miss get to this point to load the TLB.
-	 * 	r10 - EA of fault
-	 * 	r11 - TLB LO (info from Linux PTE)
+	 * 	r10 - TLB_TAG value
+	 * 	r11 - Linux PTE
 	 *	r12, r9 - avilable to use
 	 *	PID - loaded with proper value when we get here
 	 *	Upon exit, we reload everything and RFI.
@@ -833,21 +825,19 @@ finish_tlb_load:
 	*/
 	lwz	r9, tlb_4xx_index@l(0)
 	addi	r9, r9, 1
-	cmpwi	0, r9, 61		/* reserve entries 62, 63 for kernel */
-	ble	7f
-	li	r9, 0
-7:
+	andi.	r9, r9, (PPC4XX_TLB_SIZE-1)
 	stw	r9, tlb_4xx_index@l(0)
 
 6:
-	tlbwe	r11, r9, TLB_DATA		/* Load TLB LO */
-
-	/* Create EPN.  This is the faulting address plus a static
-	 * set of bits.  These are size, valid, E, U0, and ensure
-	 * bits 20 and 21 are zero.
+	/*
+	 * Clear out the software-only bits in the PTE to generate the
+	 * TLB_DATA value.  These are the bottom 2 bits of the RPM, the
+	 * top 3 bits of the zone field, and M.
 	 */
-	li	r12, 0x00c0
-	rlwimi	r10, r12, 0, 20, 31
+	li	r12, 0x0ce2
+	andc	r11, r11, r12
+
+	tlbwe	r11, r9, TLB_DATA		/* Load TLB LO */
 	tlbwe	r10, r9, TLB_TAG		/* Load TLB HI */
 
 	/* Done...restore registers and get out of here.
@@ -929,7 +919,9 @@ start_here:
 
 /* Load up the kernel context */
 2:
-	SYNC			/* Force all PTE updates to finish */
+	sync			/* Flush to memory before changing TLB */
+	tlbia
+	isync			/* Flush shadow TLBs */
 
 	/* set up the PTE pointers for the Abatron bdiGDB.
 	*/
@@ -956,7 +948,7 @@ start_here:
  */
 initial_mmu:
 	tlbia			/* Invalidate all TLB entries */
-	sync 
+	isync 
 
 	/* We should still be executing code at physical address 0x0000xxxx
 	 * at this point. However, start_here is at virtual address
@@ -985,18 +977,30 @@ initial_mmu:
 	clrrwi	r3,r3,10		/* Mask off the effective page number */
 	ori	r3,r3,(TLB_VALID | TLB_PAGESZ(PAGESZ_16M))
 
-        li      r0,62                    /* TLB slot 62 */
+        li      r0,63                    /* TLB slot 63 */
 
 	tlbwe	r4,r0,TLB_DATA		/* Load the data portion of the entry */
 	tlbwe	r3,r0,TLB_TAG		/* Load the tag portion of the entry */
 
-	addis	r4, r4, 0x0100		/* Map next 16 M entries */
-	addis	r3, r3, 0x0100
+#if defined(CONFIG_SERIAL_TEXT_DEBUG) && defined(SERIAL_DEBUG_IO_BASE)
 	
-        li      r0,63                    /* TLB slot 63 */
+	/* Load a TLB entry for the UART, so that ppc4xx_progress() can use
+	 * the UARTs nice and early.  We use a 4k real==virtual mapping. */
+
+	lis	r3,SERIAL_DEBUG_IO_BASE@h
+	ori	r3,r3,SERIAL_DEBUG_IO_BASE@l
+	mr	r4,r3
+	clrrwi	r4,r4,12
+	ori	r4,r4,(TLB_WR|TLB_I|TLB_M|TLB_G)
 
+	clrrwi	r3,r3,12
+	ori	r3,r3,(TLB_VALID | TLB_PAGESZ(PAGESZ_4K))
+
+	li	r0,0			/* TLB slot 0 */
 	tlbwe	r4,r0,TLB_DATA
 	tlbwe	r3,r0,TLB_TAG
+#endif /* CONFIG_SERIAL_DEBUG_TEXT && SERIAL_DEBUG_IO_BASE */
+
 	isync
 
 	/* Establish the exception vector base

arch/ppc/kernel/misc.S

@@ -348,18 +348,9 @@ _GLOBAL(_nmask_and_or_msr)
  */
 _GLOBAL(_tlbia)
 #if defined(CONFIG_40x)
-	/* This needs to be coordinated with other pinning functions since
-	 * we don't keep a memory location of number of entries to reduce
-	 * cache pollution during these operations.
-	 */
-	lis	r3, 0
-	sync
-1:
-	tlbwe	r3, r3, TLB_TAG		/* just ensure V is clear */
-	addi	r3, r3, 1		/*   so r3 works fine for that */
-	cmpwi	0, r3, 61		/* reserve last two entries */
-	ble	1b
-	isync
+	sync			/* Flush to memory before changing mapping */
+	tlbia
+	isync			/* Flush shadow TLB */
 #else /* ! defined(CONFIG_40x) */
 #if defined(CONFIG_SMP)
 	rlwinm	r8,r1,0,0,18

arch/ppc/mm/4xx_mmu.c

@@ -50,6 +50,7 @@
 #include <asm/bootx.h>
 #include <asm/machdep.h>
 #include <asm/setup.h>
+#include "mmu_decl.h"
 
 /*
  * MMU_init_hw does the chip-specific initialization of the MMU hardware.
@@ -88,3 +89,49 @@ void __init MMU_init_hw(void)
         mtspr(SPRN_DCCR, 0xF0000000);	/* 512 MB of data space at 0x0. */
         mtspr(SPRN_ICCR, 0xF0000000);	/* 512 MB of instr. space at 0x0. */
 }
+
+#define LARGE_PAGE_SIZE_16M	(1<<24)
+#define LARGE_PAGE_SIZE_4M	(1<<22)
+
+unsigned long __init mmu_mapin_ram(void)
+{
+	unsigned long v, s;
+	phys_addr_t p;
+
+	v = KERNELBASE;
+	p = PPC_MEMSTART;
+	s = 0;
+
+	while (s <= (total_lowmem - LARGE_PAGE_SIZE_16M)) {
+		pmd_t *pmdp;
+		unsigned long val = p | _PMD_SIZE_16M | _PAGE_HWEXEC | _PAGE_HWWRITE;
+
+		spin_lock(&init_mm.page_table_lock);
+		pmdp = pmd_offset(pgd_offset_k(v), v);
+		pmd_val(*pmdp++) = val;
+		pmd_val(*pmdp++) = val;
+		pmd_val(*pmdp++) = val;
+		pmd_val(*pmdp++) = val;
+		spin_unlock(&init_mm.page_table_lock);
+
+		v += LARGE_PAGE_SIZE_16M;
+		p += LARGE_PAGE_SIZE_16M;
+		s += LARGE_PAGE_SIZE_16M;
+	}
+	
+	while (s <= (total_lowmem - LARGE_PAGE_SIZE_4M)) {
+		pmd_t *pmdp;
+		unsigned long val = p | _PMD_SIZE_4M | _PAGE_HWEXEC | _PAGE_HWWRITE;
+
+		spin_lock(&init_mm.page_table_lock);
+		pmdp = pmd_offset(pgd_offset_k(v), v);
+		pmd_val(*pmdp) = val;
+		spin_unlock(&init_mm.page_table_lock);
+
+		v += LARGE_PAGE_SIZE_4M;
+		p += LARGE_PAGE_SIZE_4M;
+		s += LARGE_PAGE_SIZE_4M;
+	}
+
+	return s;
+}

arch/ppc/mm/mmu_decl.h

@@ -50,7 +50,7 @@ extern unsigned long Hash_size, Hash_mask;
 #elif defined(CONFIG_4xx)
 #define flush_HPTE(X, va, pg)	_tlbie(va)
 extern void MMU_init_hw(void);
-#define mmu_mapin_ram()		(0UL)
+extern unsigned long mmu_mapin_ram(void);
 
 #else
 /* anything except 4xx or 8xx */