/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _ASM_POWERPC_NOHASH_32_PTE_8xx_H
#define _ASM_POWERPC_NOHASH_32_PTE_8xx_H
#ifdef __KERNEL__
/*
* The PowerPC MPC8xx uses a TLB with hardware assisted, software tablewalk.
* We also use the two level tables, but we can put the real bits in them
* needed for the TLB and tablewalk. These definitions require Mx_CTR.PPM = 0,
* Mx_CTR.PPCS = 0, and MD_CTR.TWAM = 1. The level 2 descriptor has
* additional page protection (when Mx_CTR.PPCS = 1) that allows TLB hit
* based upon user/super access. The TLB does not have accessed nor write
* protect. We assume that if the TLB get loaded with an entry it is
* accessed, and overload the changed bit for write protect. We use
* two bits in the software pte that are supposed to be set to zero in
* the TLB entry (24 and 25) for these indicators. Although the level 1
* descriptor contains the guarded and writethrough/copyback bits, we can
* set these at the page level since they get copied from the Mx_TWC
* register when the TLB entry is loaded. We will use bit 27 for guard, since
* that is where it exists in the MD_TWC, and bit 26 for writethrough.
* These will get masked from the level 2 descriptor at TLB load time, and
* copied to the MD_TWC before it gets loaded.
* Large page sizes added. We currently support two sizes, 4K and 8M.
* This also allows a TLB hander optimization because we can directly
* load the PMD into MD_TWC. The 8M pages are only used for kernel
* mapping of well known areas. The PMD (PGD) entries contain control
* flags in addition to the address, so care must be taken that the
* software no longer assumes these are only pointers.
*/
/* Definitions for 8xx embedded chips. */
#define _PAGE_PRESENT 0x0001 /* V: Page is valid */
#define _PAGE_NO_CACHE 0x0002 /* CI: cache inhibit */
#define _PAGE_SH 0x0004 /* SH: No ASID (context) compare */
#define _PAGE_SPS 0x0008 /* SPS: Small Page Size (1 if 16k, 512k or 8M)*/
#define _PAGE_DIRTY 0x0100 /* C: page changed */
/* These 4 software bits must be masked out when the L2 entry is loaded
* into the TLB.
*/
#define _PAGE_GUARDED 0x0010 /* Copied to L1 G entry in DTLB */
#define _PAGE_ACCESSED 0x0020 /* Copied to L1 APG 1 entry in I/DTLB */
#define _PAGE_EXEC 0x0040 /* Copied to PP (bit 21) in ITLB */
#define _PAGE_SPECIAL 0x0080 /* SW entry */
#define _PAGE_NA 0x0200 /* Supervisor NA, User no access */
#define _PAGE_RO 0x0600 /* Supervisor RO, User no access */
#define _PAGE_HUGE 0x0800 /* Copied to L1 PS bit 29 */
#define _PAGE_NAX (_PAGE_NA | _PAGE_EXEC)
#define _PAGE_ROX (_PAGE_RO | _PAGE_EXEC)
#define _PAGE_RW 0
#define _PAGE_RWX _PAGE_EXEC
/* cache related flags non existing on 8xx */
#define _PAGE_COHERENT 0
#define _PAGE_WRITETHRU 0
#define _PAGE_KERNEL_RO (_PAGE_SH | _PAGE_RO)
#define _PAGE_KERNEL_ROX (_PAGE_SH | _PAGE_RO | _PAGE_EXEC)
#define _PAGE_KERNEL_RW (_PAGE_SH | _PAGE_DIRTY)
#define _PAGE_KERNEL_RWX (_PAGE_SH | _PAGE_DIRTY | _PAGE_EXEC)
#define _PMD_PRESENT 0x0001
#define _PMD_PRESENT_MASK _PMD_PRESENT
#define _PMD_BAD 0x0f90
#define _PMD_PAGE_MASK 0x000c
#define _PMD_PAGE_8M 0x000c
#define _PMD_PAGE_512K 0x0004
#define _PMD_ACCESSED 0x0020 /* APG 1 */
#define _PMD_USER 0x0040 /* APG 2 */
#define _PTE_NONE_MASK 0
#ifdef CONFIG_PPC_16K_PAGES
#define _PAGE_BASE_NC (_PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_SPS)
#else
#define _PAGE_BASE_NC (_PAGE_PRESENT | _PAGE_ACCESSED)
#endif
#define _PAGE_BASE (_PAGE_BASE_NC)
#include <asm/pgtable-masks.h>
#ifndef __ASSEMBLY__
static inline pte_t pte_wrprotect(pte_t pte)
{
return __pte(pte_val(pte) | _PAGE_RO);
}
#define pte_wrprotect pte_wrprotect
static inline int pte_read(pte_t pte)
{
return (pte_val(pte) & _PAGE_RO) != _PAGE_NA;
}
#define pte_read pte_read
static inline int pte_write(pte_t pte)
{
return !(pte_val(pte) & _PAGE_RO);
}
#define pte_write pte_write
static inline pte_t pte_mkwrite_novma(pte_t pte)
{
return __pte(pte_val(pte) & ~_PAGE_RO);
}
#define pte_mkwrite_novma pte_mkwrite_novma
static inline pte_t pte_mkhuge(pte_t pte)
{
return __pte(pte_val(pte) | _PAGE_SPS | _PAGE_HUGE);
}
#define pte_mkhuge pte_mkhuge
static inline pte_basic_t pte_update(struct mm_struct *mm, unsigned long addr, pte_t *ptep,
unsigned long clr, unsigned long set, int huge);
static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
{
pte_update(mm, addr, ptep, 0, _PAGE_RO, 0);
}
#define ptep_set_wrprotect ptep_set_wrprotect
static inline void __ptep_set_access_flags(struct vm_area_struct *vma, pte_t *ptep,
pte_t entry, unsigned long address, int psize)
{
unsigned long set = pte_val(entry) & (_PAGE_DIRTY | _PAGE_ACCESSED | _PAGE_EXEC);
unsigned long clr = ~pte_val(entry) & _PAGE_RO;
int huge = psize > mmu_virtual_psize ? 1 : 0;
pte_update(vma->vm_mm, address, ptep, clr, set, huge);
flush_tlb_page(vma, address);
}
#define __ptep_set_access_flags __ptep_set_access_flags
static inline unsigned long __pte_leaf_size(pmd_t pmd, pte_t pte)
{
pte_basic_t val = pte_val(pte);
if (pmd_val(pmd) & _PMD_PAGE_8M)
return SZ_8M;
if (val & _PAGE_HUGE)
return SZ_512K;
if (val & _PAGE_SPS)
return SZ_16K;
return SZ_4K;
}
#define __pte_leaf_size __pte_leaf_size
/*
* On the 8xx, the page tables are a bit special. For 16k pages, we have
* 4 identical entries. For 512k pages, we have 128 entries as if it was
* 4k pages, but they are flagged as 512k pages for the hardware.
* For 8M pages, we have 1024 entries as if it was 4M pages (PMD_SIZE)
* but they are flagged as 8M pages for the hardware.
* For 4k pages, we have a single entry in the table.
*/
static pmd_t *pmd_off(struct mm_struct *mm, unsigned long addr);
static inline pte_t *pte_offset_kernel(pmd_t *pmd, unsigned long address);
static inline bool ptep_is_8m_pmdp(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
{
return (pmd_t *)ptep == pmd_off(mm, ALIGN_DOWN(addr, SZ_8M));
}
static inline int number_of_cells_per_pte(pmd_t *pmd, pte_basic_t val, int huge)
{
if (!huge)
return PAGE_SIZE / SZ_4K;
else if ((pmd_val(*pmd) & _PMD_PAGE_MASK) == _PMD_PAGE_8M)
return SZ_4M / SZ_4K;
else if (IS_ENABLED(CONFIG_PPC_4K_PAGES) && !(val & _PAGE_HUGE))
return SZ_16K / SZ_4K;
else
return SZ_512K / SZ_4K;
}
static inline pte_basic_t __pte_update(struct mm_struct *mm, unsigned long addr, pte_t *p,
unsigned long clr, unsigned long set, int huge)
{
pte_basic_t *entry = (pte_basic_t *)p;
pte_basic_t old = pte_val(*p);
pte_basic_t new = (old & ~(pte_basic_t)clr) | set;
int num, i;
pmd_t *pmd = pmd_off(mm, addr);
num = number_of_cells_per_pte(pmd, new, huge);
for (i = 0; i < num; i += PAGE_SIZE / SZ_4K, new += PAGE_SIZE) {
*entry++ = new;
if (IS_ENABLED(CONFIG_PPC_16K_PAGES)) {
*entry++ = new;
*entry++ = new;
*entry++ = new;
}
}
return old;
}
static inline pte_basic_t pte_update(struct mm_struct *mm, unsigned long addr, pte_t *ptep,
unsigned long clr, unsigned long set, int huge)
{
pte_basic_t old;
if (huge && ptep_is_8m_pmdp(mm, addr, ptep)) {
pmd_t *pmdp = (pmd_t *)ptep;
old = __pte_update(mm, addr, pte_offset_kernel(pmdp, 0), clr, set, huge);
__pte_update(mm, addr, pte_offset_kernel(pmdp + 1, 0), clr, set, huge);
} else {
old = __pte_update(mm, addr, ptep, clr, set, huge);
}
return old;
}
#define pte_update pte_update
#ifdef CONFIG_PPC_16K_PAGES
#define ptep_get ptep_get
static inline pte_t ptep_get(pte_t *ptep)
{
pte_basic_t val = READ_ONCE(ptep->pte);
pte_t pte = {val, val, val, val};
return pte;
}
#endif /* CONFIG_PPC_16K_PAGES */
#endif
#endif /* __KERNEL__ */
#endif /* _ASM_POWERPC_NOHASH_32_PTE_8xx_H */
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