1 files changed, 193 insertions, 0 deletions
diff --git a/arch/powerpc/include/asm/nohash/32/pte-8xx.h b/arch/powerpc/include/asm/nohash/32/pte-8xx.h
new file mode 100644
index 000000000..e6fe1d573
--- /dev/null
+++ b/arch/powerpc/include/asm/nohash/32/pte-8xx.h
@@ -0,0 +1,193 @@
+/* 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 */
+
+/* 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_PSIZE	_PAGE_SPS
+#else
+#define _PAGE_PSIZE		0
+#endif
+
+#define _PAGE_BASE_NC	(_PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_PSIZE)
+#define _PAGE_BASE	(_PAGE_BASE_NC)
+
+/* Permission masks used to generate the __P and __S table */
+#define PAGE_NONE	__pgprot(_PAGE_BASE | _PAGE_NA)
+#define PAGE_SHARED	__pgprot(_PAGE_BASE)
+#define PAGE_SHARED_X	__pgprot(_PAGE_BASE | _PAGE_EXEC)
+#define PAGE_COPY	__pgprot(_PAGE_BASE | _PAGE_RO)
+#define PAGE_COPY_X	__pgprot(_PAGE_BASE | _PAGE_RO | _PAGE_EXEC)
+#define PAGE_READONLY	__pgprot(_PAGE_BASE | _PAGE_RO)
+#define PAGE_READONLY_X	__pgprot(_PAGE_BASE | _PAGE_RO | _PAGE_EXEC)
+
+#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 bool pte_user(pte_t pte)
+{
+	return !(pte_val(pte) & _PAGE_SH);
+}
+
+#define pte_user pte_user
+
+static inline pte_t pte_mkprivileged(pte_t pte)
+{
+	return __pte(pte_val(pte) | _PAGE_SH);
+}
+
+#define pte_mkprivileged pte_mkprivileged
+
+static inline pte_t pte_mkuser(pte_t pte)
+{
+	return __pte(pte_val(pte) & ~_PAGE_SH);
+}
+
+#define pte_mkuser pte_mkuser
+
+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 *p,
+				     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 pgd_leaf_size(pgd_t pgd)
+{
+	if (pgd_val(pgd) & _PMD_PAGE_8M)
+		return SZ_8M;
+	return SZ_4M;
+}
+
+#define pgd_leaf_size pgd_leaf_size
+
+static inline unsigned long pte_leaf_size(pte_t pte)
+{
+	pte_basic_t val = pte_val(pte);
+
+	if (val & _PAGE_HUGE)
+		return SZ_512K;
+	if (val & _PAGE_SPS)
+		return SZ_16K;
+	return SZ_4K;
+}
+
+#define pte_leaf_size pte_leaf_size
+
+#endif
+
+#endif /* __KERNEL__ */
+#endif /*  _ASM_POWERPC_NOHASH_32_PTE_8xx_H */