linux/arch/powerpc/include/asm/nohash/32/pgtable.h

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _ASM_POWERPC_NOHASH_32_PGTABLE_H
#define _ASM_POWERPC_NOHASH_32_PGTABLE_H

#include <asm-generic/pgtable-nopmd.h>

#ifndef __ASSEMBLY__
#include <linux/sched.h>
#include <linux/threads.h>
#include <asm/mmu.h>			/* For sub-arch specific PPC_PIN_SIZE */

#endif /* __ASSEMBLY__ */

#define PTE_INDEX_SIZE	PTE_SHIFT
#define PMD_INDEX_SIZE	0
#define PUD_INDEX_SIZE	0
#define PGD_INDEX_SIZE	(32 - PGDIR_SHIFT)

#define PMD_CACHE_INDEX	PMD_INDEX_SIZE
#define PUD_CACHE_INDEX	PUD_INDEX_SIZE

#ifndef __ASSEMBLY__
#define PTE_TABLE_SIZE	(sizeof(pte_t) << PTE_INDEX_SIZE)
#define PMD_TABLE_SIZE	0
#define PUD_TABLE_SIZE	0
#define PGD_TABLE_SIZE	(sizeof(pgd_t) << PGD_INDEX_SIZE)

#define PMD_MASKED_BITS (PTE_TABLE_SIZE - 1)
#endif	/* __ASSEMBLY__ */

#define PTRS_PER_PTE	(1 << PTE_INDEX_SIZE)
#define PTRS_PER_PGD	(1 << PGD_INDEX_SIZE)

/*
 * The normal case is that PTEs are 32-bits and we have a 1-page
 * 1024-entry pgdir pointing to 1-page 1024-entry PTE pages.  -- paulus
 *
 * For any >32-bit physical address platform, we can use the following
 * two level page table layout where the pgdir is 8KB and the MS 13 bits
 * are an index to the second level table.  The combined pgdir/pmd first
 * level has 2048 entries and the second level has 512 64-bit PTE entries.
 * -Matt
 */
/* PGDIR_SHIFT determines what a top-level page table entry can map */
#define PGDIR_SHIFT	(PAGE_SHIFT + PTE_INDEX_SIZE)
#define PGDIR_SIZE	(1UL << PGDIR_SHIFT)
#define PGDIR_MASK	(~(PGDIR_SIZE-1))

/* Bits to mask out from a PGD to get to the PUD page */
#define PGD_MASKED_BITS		0

#define USER_PTRS_PER_PGD	(TASK_SIZE / PGDIR_SIZE)

#define pgd_ERROR(e) \
	pr_err("%s:%d: bad pgd %08llx.\n", __FILE__, __LINE__, (unsigned long long)pgd_val(e))

/*
 * This is the bottom of the PKMAP area with HIGHMEM or an arbitrary
 * value (for now) on others, from where we can start layout kernel
 * virtual space that goes below PKMAP and FIXMAP
 */

#define FIXADDR_SIZE	0
#ifdef CONFIG_KASAN
#include <asm/kasan.h>
#define FIXADDR_TOP	(KASAN_SHADOW_START - PAGE_SIZE)
#else
#define FIXADDR_TOP	((unsigned long)(-PAGE_SIZE))
#endif

/*
 * ioremap_bot starts at that address. Early ioremaps move down from there,
 * until mem_init() at which point this becomes the top of the vmalloc
 * and ioremap space
 */
#ifdef CONFIG_HIGHMEM
#define IOREMAP_TOP	PKMAP_BASE
#else
#define IOREMAP_TOP	FIXADDR_START
#endif

/* PPC32 shares vmalloc area with ioremap */
#define IOREMAP_START	VMALLOC_START
#define IOREMAP_END	VMALLOC_END

/*
 * Just any arbitrary offset to the start of the vmalloc VM area: the
 * current 16MB value just means that there will be a 64MB "hole" after the
 * physical memory until the kernel virtual memory starts.  That means that
 * any out-of-bounds memory accesses will hopefully be caught.
 * The vmalloc() routines leaves a hole of 4kB between each vmalloced
 * area for the same reason. ;)
 *
 * We no longer map larger than phys RAM with the BATs so we don't have
 * to worry about the VMALLOC_OFFSET causing problems.  We do have to worry
 * about clashes between our early calls to ioremap() that start growing down
 * from IOREMAP_TOP being run into the VM area allocations (growing upwards
 * from VMALLOC_START).  For this reason we have ioremap_bot to check when
 * we actually run into our mappings setup in the early boot with the VM
 * system.  This really does become a problem for machines with good amounts
 * of RAM.  -- Cort
 */
#define VMALLOC_OFFSET (0x1000000) /* 16M */
#ifdef PPC_PIN_SIZE
#define VMALLOC_START (((ALIGN((long)high_memory, PPC_PIN_SIZE) + VMALLOC_OFFSET) & ~(VMALLOC_OFFSET-1)))
#else
#define VMALLOC_START ((((long)high_memory + VMALLOC_OFFSET) & ~(VMALLOC_OFFSET-1)))
#endif

#ifdef CONFIG_KASAN_VMALLOC
#define VMALLOC_END	ALIGN_DOWN(ioremap_bot, PAGE_SIZE << KASAN_SHADOW_SCALE_SHIFT)
#else
#define VMALLOC_END	ioremap_bot
#endif

/*
 * Bits in a linux-style PTE.  These match the bits in the
 * (hardware-defined) PowerPC PTE as closely as possible.
 */

#if defined(CONFIG_44x)
#include <asm/nohash/32/pte-44x.h>
#elif defined(CONFIG_PPC_85xx) && defined(CONFIG_PTE_64BIT)
#include <asm/nohash/pte-e500.h>
#elif defined(CONFIG_PPC_85xx)
#include <asm/nohash/32/pte-85xx.h>
#elif defined(CONFIG_PPC_8xx)
#include <asm/nohash/32/pte-8xx.h>
#endif

/*
 * Location of the PFN in the PTE. Most 32-bit platforms use the same
 * as _PAGE_SHIFT here (ie, naturally aligned).
 * Platform who don't just pre-define the value so we don't override it here.
 */
#ifndef PTE_RPN_SHIFT
#define PTE_RPN_SHIFT	(PAGE_SHIFT)
#endif

/*
 * The mask covered by the RPN must be a ULL on 32-bit platforms with
 * 64-bit PTEs.
 */
#ifdef CONFIG_PTE_64BIT
#define PTE_RPN_MASK	(~((1ULL << PTE_RPN_SHIFT) - 1))
#define MAX_POSSIBLE_PHYSMEM_BITS 36
#else
#define PTE_RPN_MASK	(~((1UL << PTE_RPN_SHIFT) - 1))
#define MAX_POSSIBLE_PHYSMEM_BITS 32
#endif

#ifndef __ASSEMBLY__

#define pmd_none(pmd)		(!pmd_val(pmd))
#define	pmd_bad(pmd)		(pmd_val(pmd) & _PMD_BAD)
#define	pmd_present(pmd)	(pmd_val(pmd) & _PMD_PRESENT_MASK)
static inline void pmd_clear(pmd_t *pmdp)
{
	*pmdp = __pmd(0);
}

/*
 * Note that on Book E processors, the pmd contains the kernel virtual
 * (lowmem) address of the pte page.  The physical address is less useful
 * because everything runs with translation enabled (even the TLB miss
 * handler).  On everything else the pmd contains the physical address
 * of the pte page.  -- paulus
 */
#ifndef CONFIG_BOOKE
#define pmd_pfn(pmd)		(pmd_val(pmd) >> PAGE_SHIFT)
#else
#define pmd_page_vaddr(pmd)	\
	((const void *)((unsigned long)pmd_val(pmd) & ~(PTE_TABLE_SIZE - 1)))
#define pmd_pfn(pmd)		(__pa(pmd_val(pmd)) >> PAGE_SHIFT)
#endif

#define pmd_page(pmd)		pfn_to_page(pmd_pfn(pmd))

/*
 * Encode/decode swap entries and swap PTEs. Swap PTEs are all PTEs that
 * are !pte_none() && !pte_present().
 *
 * Format of swap PTEs (32bit PTEs):
 *
 *                         1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3
 *   0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 *   <------------------ offset -------------------> < type -> E 0 0
 *
 * E is the exclusive marker that is not stored in swap entries.
 *
 * For 64bit PTEs, the offset is extended by 32bit.
 */
#define __swp_type(entry)		((entry).val & 0x1f)
#define __swp_offset(entry)		((entry).val >> 5)
#define __swp_entry(type, offset)	((swp_entry_t) { ((type) & 0x1f) | ((offset) << 5) })
#define __pte_to_swp_entry(pte)		((swp_entry_t) { pte_val(pte) >> 3 })
#define __swp_entry_to_pte(x)		((pte_t) { (x).val << 3 })

/* We borrow LSB 2 to store the exclusive marker in swap PTEs. */
#define _PAGE_SWP_EXCLUSIVE	0x000004

#endif /* !__ASSEMBLY__ */

#endif /* __ASM_POWERPC_NOHASH_32_PGTABLE_H */