1 files changed, 269 insertions, 0 deletions
diff --git a/arch/powerpc/mm/nohash/8xx.c b/arch/powerpc/mm/nohash/8xx.c
new file mode 100644
index 000000000..231ca95f9
--- /dev/null
+++ b/arch/powerpc/mm/nohash/8xx.c
@@ -0,0 +1,269 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * This file contains the routines for initializing the MMU
+ * on the 8xx series of chips.
+ *  -- christophe
+ *
+ *  Derived from arch/powerpc/mm/40x_mmu.c:
+ */
+
+#include <linux/memblock.h>
+#include <linux/mmu_context.h>
+#include <linux/hugetlb.h>
+#include <asm/fixmap.h>
+#include <asm/code-patching.h>
+#include <asm/inst.h>
+
+#include <mm/mmu_decl.h>
+
+#define IMMR_SIZE (FIX_IMMR_SIZE << PAGE_SHIFT)
+
+extern int __map_without_ltlbs;
+
+static unsigned long block_mapped_ram;
+
+/*
+ * Return PA for this VA if it is in an area mapped with LTLBs or fixmap.
+ * Otherwise, returns 0
+ */
+phys_addr_t v_block_mapped(unsigned long va)
+{
+	unsigned long p = PHYS_IMMR_BASE;
+
+	if (va >= VIRT_IMMR_BASE && va < VIRT_IMMR_BASE + IMMR_SIZE)
+		return p + va - VIRT_IMMR_BASE;
+	if (__map_without_ltlbs)
+		return 0;
+	if (va >= PAGE_OFFSET && va < PAGE_OFFSET + block_mapped_ram)
+		return __pa(va);
+	return 0;
+}
+
+/*
+ * Return VA for a given PA mapped with LTLBs or fixmap
+ * Return 0 if not mapped
+ */
+unsigned long p_block_mapped(phys_addr_t pa)
+{
+	unsigned long p = PHYS_IMMR_BASE;
+
+	if (pa >= p && pa < p + IMMR_SIZE)
+		return VIRT_IMMR_BASE + pa - p;
+	if (__map_without_ltlbs)
+		return 0;
+	if (pa < block_mapped_ram)
+		return (unsigned long)__va(pa);
+	return 0;
+}
+
+static pte_t __init *early_hugepd_alloc_kernel(hugepd_t *pmdp, unsigned long va)
+{
+	if (hpd_val(*pmdp) == 0) {
+		pte_t *ptep = memblock_alloc(sizeof(pte_basic_t), SZ_4K);
+
+		if (!ptep)
+			return NULL;
+
+		hugepd_populate_kernel((hugepd_t *)pmdp, ptep, PAGE_SHIFT_8M);
+		hugepd_populate_kernel((hugepd_t *)pmdp + 1, ptep, PAGE_SHIFT_8M);
+	}
+	return hugepte_offset(*(hugepd_t *)pmdp, va, PGDIR_SHIFT);
+}
+
+static int __ref __early_map_kernel_hugepage(unsigned long va, phys_addr_t pa,
+					     pgprot_t prot, int psize, bool new)
+{
+	pmd_t *pmdp = pmd_off_k(va);
+	pte_t *ptep;
+
+	if (WARN_ON(psize != MMU_PAGE_512K && psize != MMU_PAGE_8M))
+		return -EINVAL;
+
+	if (new) {
+		if (WARN_ON(slab_is_available()))
+			return -EINVAL;
+
+		if (psize == MMU_PAGE_512K)
+			ptep = early_pte_alloc_kernel(pmdp, va);
+		else
+			ptep = early_hugepd_alloc_kernel((hugepd_t *)pmdp, va);
+	} else {
+		if (psize == MMU_PAGE_512K)
+			ptep = pte_offset_kernel(pmdp, va);
+		else
+			ptep = hugepte_offset(*(hugepd_t *)pmdp, va, PGDIR_SHIFT);
+	}
+
+	if (WARN_ON(!ptep))
+		return -ENOMEM;
+
+	/* The PTE should never be already present */
+	if (new && WARN_ON(pte_present(*ptep) && pgprot_val(prot)))
+		return -EINVAL;
+
+	set_huge_pte_at(&init_mm, va, ptep, pte_mkhuge(pfn_pte(pa >> PAGE_SHIFT, prot)));
+
+	return 0;
+}
+
+/*
+ * MMU_init_hw does the chip-specific initialization of the MMU hardware.
+ */
+void __init MMU_init_hw(void)
+{
+}
+
+static bool immr_is_mapped __initdata;
+
+void __init mmu_mapin_immr(void)
+{
+	if (immr_is_mapped)
+		return;
+
+	immr_is_mapped = true;
+
+	__early_map_kernel_hugepage(VIRT_IMMR_BASE, PHYS_IMMR_BASE,
+				    PAGE_KERNEL_NCG, MMU_PAGE_512K, true);
+}
+
+static void mmu_mapin_ram_chunk(unsigned long offset, unsigned long top,
+				pgprot_t prot, bool new)
+{
+	unsigned long v = PAGE_OFFSET + offset;
+	unsigned long p = offset;
+
+	WARN_ON(!IS_ALIGNED(offset, SZ_512K) || !IS_ALIGNED(top, SZ_512K));
+
+	for (; p < ALIGN(p, SZ_8M) && p < top; p += SZ_512K, v += SZ_512K)
+		__early_map_kernel_hugepage(v, p, prot, MMU_PAGE_512K, new);
+	for (; p < ALIGN_DOWN(top, SZ_8M) && p < top; p += SZ_8M, v += SZ_8M)
+		__early_map_kernel_hugepage(v, p, prot, MMU_PAGE_8M, new);
+	for (; p < ALIGN_DOWN(top, SZ_512K) && p < top; p += SZ_512K, v += SZ_512K)
+		__early_map_kernel_hugepage(v, p, prot, MMU_PAGE_512K, new);
+
+	if (!new)
+		flush_tlb_kernel_range(PAGE_OFFSET + v, PAGE_OFFSET + top);
+}
+
+unsigned long __init mmu_mapin_ram(unsigned long base, unsigned long top)
+{
+	unsigned long etext8 = ALIGN(__pa(_etext), SZ_8M);
+	unsigned long sinittext = __pa(_sinittext);
+	bool strict_boundary = strict_kernel_rwx_enabled() || debug_pagealloc_enabled();
+	unsigned long boundary = strict_boundary ? sinittext : etext8;
+	unsigned long einittext8 = ALIGN(__pa(_einittext), SZ_8M);
+
+	WARN_ON(top < einittext8);
+
+	mmu_mapin_immr();
+
+	if (__map_without_ltlbs)
+		return 0;
+
+	mmu_mapin_ram_chunk(0, boundary, PAGE_KERNEL_TEXT, true);
+	if (debug_pagealloc_enabled()) {
+		top = boundary;
+	} else {
+		mmu_mapin_ram_chunk(boundary, einittext8, PAGE_KERNEL_TEXT, true);
+		mmu_mapin_ram_chunk(einittext8, top, PAGE_KERNEL, true);
+	}
+
+	if (top > SZ_32M)
+		memblock_set_current_limit(top);
+
+	block_mapped_ram = top;
+
+	return top;
+}
+
+void mmu_mark_initmem_nx(void)
+{
+	unsigned long etext8 = ALIGN(__pa(_etext), SZ_8M);
+	unsigned long sinittext = __pa(_sinittext);
+	unsigned long boundary = strict_kernel_rwx_enabled() ? sinittext : etext8;
+	unsigned long einittext8 = ALIGN(__pa(_einittext), SZ_8M);
+
+	mmu_mapin_ram_chunk(0, boundary, PAGE_KERNEL_TEXT, false);
+	mmu_mapin_ram_chunk(boundary, einittext8, PAGE_KERNEL, false);
+
+	if (IS_ENABLED(CONFIG_PIN_TLB_TEXT))
+		mmu_pin_tlb(block_mapped_ram, false);
+}
+
+#ifdef CONFIG_STRICT_KERNEL_RWX
+void mmu_mark_rodata_ro(void)
+{
+	unsigned long sinittext = __pa(_sinittext);
+
+	mmu_mapin_ram_chunk(0, sinittext, PAGE_KERNEL_ROX, false);
+	if (IS_ENABLED(CONFIG_PIN_TLB_DATA))
+		mmu_pin_tlb(block_mapped_ram, true);
+}
+#endif
+
+void __init setup_initial_memory_limit(phys_addr_t first_memblock_base,
+				       phys_addr_t first_memblock_size)
+{
+	/* We don't currently support the first MEMBLOCK not mapping 0
+	 * physical on those processors
+	 */
+	BUG_ON(first_memblock_base != 0);
+
+	/* 8xx can only access 32MB at the moment */
+	memblock_set_current_limit(min_t(u64, first_memblock_size, SZ_32M));
+}
+
+/*
+ * Set up to use a given MMU context.
+ * id is context number, pgd is PGD pointer.
+ *
+ * We place the physical address of the new task page directory loaded
+ * into the MMU base register, and set the ASID compare register with
+ * the new "context."
+ */
+void set_context(unsigned long id, pgd_t *pgd)
+{
+	s16 offset = (s16)(__pa(swapper_pg_dir));
+
+	/* Context switch the PTE pointer for the Abatron BDI2000.
+	 * The PGDIR is passed as second argument.
+	 */
+	if (IS_ENABLED(CONFIG_BDI_SWITCH))
+		abatron_pteptrs[1] = pgd;
+
+	/* Register M_TWB will contain base address of level 1 table minus the
+	 * lower part of the kernel PGDIR base address, so that all accesses to
+	 * level 1 table are done relative to lower part of kernel PGDIR base
+	 * address.
+	 */
+	mtspr(SPRN_M_TWB, __pa(pgd) - offset);
+
+	/* Update context */
+	mtspr(SPRN_M_CASID, id - 1);
+	/* sync */
+	mb();
+}
+
+#ifdef CONFIG_PPC_KUEP
+void __init setup_kuep(bool disabled)
+{
+	if (disabled)
+		return;
+
+	pr_info("Activating Kernel Userspace Execution Prevention\n");
+
+	mtspr(SPRN_MI_AP, MI_APG_KUEP);
+}
+#endif
+
+#ifdef CONFIG_PPC_KUAP
+void __init setup_kuap(bool disabled)
+{
+	pr_info("Activating Kernel Userspace Access Protection\n");
+
+	if (disabled)
+		pr_warn("KUAP cannot be disabled yet on 8xx when compiled in\n");
+
+	mtspr(SPRN_MD_AP, MD_APG_KUAP);
+}
+#endif