1 files changed, 444 insertions, 0 deletions
diff --git a/arch/powerpc/mm/book3s32/mmu.c b/arch/powerpc/mm/book3s32/mmu.c
new file mode 100644
index 000000000..850783cfa
--- /dev/null
+++ b/arch/powerpc/mm/book3s32/mmu.c
@@ -0,0 +1,444 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * This file contains the routines for handling the MMU on those
+ * PowerPC implementations where the MMU substantially follows the
+ * architecture specification.  This includes the 6xx, 7xx, 7xxx,
+ * and 8260 implementations but excludes the 8xx and 4xx.
+ *  -- paulus
+ *
+ *  Derived from arch/ppc/mm/init.c:
+ *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
+ *
+ *  Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au)
+ *  and Cort Dougan (PReP) (cort@cs.nmt.edu)
+ *    Copyright (C) 1996 Paul Mackerras
+ *
+ *  Derived from "arch/i386/mm/init.c"
+ *    Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
+ */
+
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/init.h>
+#include <linux/highmem.h>
+#include <linux/memblock.h>
+
+#include <asm/mmu.h>
+#include <asm/machdep.h>
+#include <asm/code-patching.h>
+#include <asm/sections.h>
+
+#include <mm/mmu_decl.h>
+
+u8 __initdata early_hash[SZ_256K] __aligned(SZ_256K) = {0};
+
+static struct hash_pte __initdata *Hash = (struct hash_pte *)early_hash;
+static unsigned long __initdata Hash_size, Hash_mask;
+static unsigned int __initdata hash_mb, hash_mb2;
+unsigned long __initdata _SDR1;
+
+struct ppc_bat BATS[8][2];	/* 8 pairs of IBAT, DBAT */
+
+static struct batrange {	/* stores address ranges mapped by BATs */
+	unsigned long start;
+	unsigned long limit;
+	phys_addr_t phys;
+} bat_addrs[8];
+
+#ifdef CONFIG_SMP
+unsigned long mmu_hash_lock;
+#endif
+
+/*
+ * Return PA for this VA if it is mapped by a BAT, or 0
+ */
+phys_addr_t v_block_mapped(unsigned long va)
+{
+	int b;
+	for (b = 0; b < ARRAY_SIZE(bat_addrs); ++b)
+		if (va >= bat_addrs[b].start && va < bat_addrs[b].limit)
+			return bat_addrs[b].phys + (va - bat_addrs[b].start);
+	return 0;
+}
+
+/*
+ * Return VA for a given PA or 0 if not mapped
+ */
+unsigned long p_block_mapped(phys_addr_t pa)
+{
+	int b;
+	for (b = 0; b < ARRAY_SIZE(bat_addrs); ++b)
+		if (pa >= bat_addrs[b].phys
+	    	    && pa < (bat_addrs[b].limit-bat_addrs[b].start)
+		              +bat_addrs[b].phys)
+			return bat_addrs[b].start+(pa-bat_addrs[b].phys);
+	return 0;
+}
+
+int __init find_free_bat(void)
+{
+	int b;
+	int n = mmu_has_feature(MMU_FTR_USE_HIGH_BATS) ? 8 : 4;
+
+	for (b = 0; b < n; b++) {
+		struct ppc_bat *bat = BATS[b];
+
+		if (!(bat[1].batu & 3))
+			return b;
+	}
+	return -1;
+}
+
+/*
+ * This function calculates the size of the larger block usable to map the
+ * beginning of an area based on the start address and size of that area:
+ * - max block size is 256 on 6xx.
+ * - base address must be aligned to the block size. So the maximum block size
+ *   is identified by the lowest bit set to 1 in the base address (for instance
+ *   if base is 0x16000000, max size is 0x02000000).
+ * - block size has to be a power of two. This is calculated by finding the
+ *   highest bit set to 1.
+ */
+unsigned int bat_block_size(unsigned long base, unsigned long top)
+{
+	unsigned int max_size = SZ_256M;
+	unsigned int base_shift = (ffs(base) - 1) & 31;
+	unsigned int block_shift = (fls(top - base) - 1) & 31;
+
+	return min3(max_size, 1U << base_shift, 1U << block_shift);
+}
+
+/*
+ * Set up one of the IBAT (block address translation) register pairs.
+ * The parameters are not checked; in particular size must be a power
+ * of 2 between 128k and 256M.
+ */
+static void setibat(int index, unsigned long virt, phys_addr_t phys,
+		    unsigned int size, pgprot_t prot)
+{
+	unsigned int bl = (size >> 17) - 1;
+	int wimgxpp;
+	struct ppc_bat *bat = BATS[index];
+	unsigned long flags = pgprot_val(prot);
+
+	if (!cpu_has_feature(CPU_FTR_NEED_COHERENT))
+		flags &= ~_PAGE_COHERENT;
+
+	wimgxpp = (flags & _PAGE_COHERENT) | (_PAGE_EXEC ? BPP_RX : BPP_XX);
+	bat[0].batu = virt | (bl << 2) | 2; /* Vs=1, Vp=0 */
+	bat[0].batl = BAT_PHYS_ADDR(phys) | wimgxpp;
+	if (flags & _PAGE_USER)
+		bat[0].batu |= 1;	/* Vp = 1 */
+}
+
+static void clearibat(int index)
+{
+	struct ppc_bat *bat = BATS[index];
+
+	bat[0].batu = 0;
+	bat[0].batl = 0;
+}
+
+static unsigned long __init __mmu_mapin_ram(unsigned long base, unsigned long top)
+{
+	int idx;
+
+	while ((idx = find_free_bat()) != -1 && base != top) {
+		unsigned int size = bat_block_size(base, top);
+
+		if (size < 128 << 10)
+			break;
+		setbat(idx, PAGE_OFFSET + base, base, size, PAGE_KERNEL_X);
+		base += size;
+	}
+
+	return base;
+}
+
+unsigned long __init mmu_mapin_ram(unsigned long base, unsigned long top)
+{
+	unsigned long done;
+	unsigned long border = (unsigned long)__srwx_boundary - PAGE_OFFSET;
+	unsigned long size;
+
+	size = roundup_pow_of_two((unsigned long)_einittext - PAGE_OFFSET);
+	setibat(0, PAGE_OFFSET, 0, size, PAGE_KERNEL_X);
+
+	if (debug_pagealloc_enabled_or_kfence()) {
+		pr_debug_once("Read-Write memory mapped without BATs\n");
+		if (base >= border)
+			return base;
+		if (top >= border)
+			top = border;
+	}
+
+	if (!strict_kernel_rwx_enabled() || base >= border || top <= border)
+		return __mmu_mapin_ram(base, top);
+
+	done = __mmu_mapin_ram(base, border);
+	if (done != border)
+		return done;
+
+	return __mmu_mapin_ram(border, top);
+}
+
+static bool is_module_segment(unsigned long addr)
+{
+	if (!IS_ENABLED(CONFIG_MODULES))
+		return false;
+	if (addr < ALIGN_DOWN(MODULES_VADDR, SZ_256M))
+		return false;
+	if (addr > ALIGN(MODULES_END, SZ_256M) - 1)
+		return false;
+	return true;
+}
+
+void mmu_mark_initmem_nx(void)
+{
+	int nb = mmu_has_feature(MMU_FTR_USE_HIGH_BATS) ? 8 : 4;
+	int i;
+	unsigned long base = (unsigned long)_stext - PAGE_OFFSET;
+	unsigned long top = ALIGN((unsigned long)_etext - PAGE_OFFSET, SZ_128K);
+	unsigned long border = (unsigned long)__init_begin - PAGE_OFFSET;
+	unsigned long size;
+
+	for (i = 0; i < nb - 1 && base < top;) {
+		size = bat_block_size(base, top);
+		setibat(i++, PAGE_OFFSET + base, base, size, PAGE_KERNEL_TEXT);
+		base += size;
+	}
+	if (base < top) {
+		size = bat_block_size(base, top);
+		if ((top - base) > size) {
+			size <<= 1;
+			if (strict_kernel_rwx_enabled() && base + size > border)
+				pr_warn("Some RW data is getting mapped X. "
+					"Adjust CONFIG_DATA_SHIFT to avoid that.\n");
+		}
+		setibat(i++, PAGE_OFFSET + base, base, size, PAGE_KERNEL_TEXT);
+		base += size;
+	}
+	for (; i < nb; i++)
+		clearibat(i);
+
+	update_bats();
+
+	for (i = TASK_SIZE >> 28; i < 16; i++) {
+		/* Do not set NX on VM space for modules */
+		if (is_module_segment(i << 28))
+			continue;
+
+		mtsr(mfsr(i << 28) | 0x10000000, i << 28);
+	}
+}
+
+void mmu_mark_rodata_ro(void)
+{
+	int nb = mmu_has_feature(MMU_FTR_USE_HIGH_BATS) ? 8 : 4;
+	int i;
+
+	for (i = 0; i < nb; i++) {
+		struct ppc_bat *bat = BATS[i];
+
+		if (bat_addrs[i].start < (unsigned long)__end_rodata)
+			bat[1].batl = (bat[1].batl & ~BPP_RW) | BPP_RX;
+	}
+
+	update_bats();
+}
+
+/*
+ * Set up one of the D BAT (block address translation) register pairs.
+ * The parameters are not checked; in particular size must be a power
+ * of 2 between 128k and 256M.
+ */
+void __init setbat(int index, unsigned long virt, phys_addr_t phys,
+		   unsigned int size, pgprot_t prot)
+{
+	unsigned int bl;
+	int wimgxpp;
+	struct ppc_bat *bat;
+	unsigned long flags = pgprot_val(prot);
+
+	if (index == -1)
+		index = find_free_bat();
+	if (index == -1) {
+		pr_err("%s: no BAT available for mapping 0x%llx\n", __func__,
+		       (unsigned long long)phys);
+		return;
+	}
+	bat = BATS[index];
+
+	if ((flags & _PAGE_NO_CACHE) ||
+	    (cpu_has_feature(CPU_FTR_NEED_COHERENT) == 0))
+		flags &= ~_PAGE_COHERENT;
+
+	bl = (size >> 17) - 1;
+	/* Do DBAT first */
+	wimgxpp = flags & (_PAGE_WRITETHRU | _PAGE_NO_CACHE
+			   | _PAGE_COHERENT | _PAGE_GUARDED);
+	wimgxpp |= (flags & _PAGE_RW)? BPP_RW: BPP_RX;
+	bat[1].batu = virt | (bl << 2) | 2; /* Vs=1, Vp=0 */
+	bat[1].batl = BAT_PHYS_ADDR(phys) | wimgxpp;
+	if (flags & _PAGE_USER)
+		bat[1].batu |= 1; 	/* Vp = 1 */
+	if (flags & _PAGE_GUARDED) {
+		/* G bit must be zero in IBATs */
+		flags &= ~_PAGE_EXEC;
+	}
+
+	bat_addrs[index].start = virt;
+	bat_addrs[index].limit = virt + ((bl + 1) << 17) - 1;
+	bat_addrs[index].phys = phys;
+}
+
+/*
+ * Preload a translation in the hash table
+ */
+static void hash_preload(struct mm_struct *mm, unsigned long ea)
+{
+	pmd_t *pmd;
+
+	if (!mmu_has_feature(MMU_FTR_HPTE_TABLE))
+		return;
+	pmd = pmd_off(mm, ea);
+	if (!pmd_none(*pmd))
+		add_hash_page(mm->context.id, ea, pmd_val(*pmd));
+}
+
+/*
+ * This is called at the end of handling a user page fault, when the
+ * fault has been handled by updating a PTE in the linux page tables.
+ * We use it to preload an HPTE into the hash table corresponding to
+ * the updated linux PTE.
+ *
+ * This must always be called with the pte lock held.
+ */
+void __update_mmu_cache(struct vm_area_struct *vma, unsigned long address,
+		      pte_t *ptep)
+{
+	/*
+	 * We don't need to worry about _PAGE_PRESENT here because we are
+	 * called with either mm->page_table_lock held or ptl lock held
+	 */
+
+	/* We only want HPTEs for linux PTEs that have _PAGE_ACCESSED set */
+	if (!pte_young(*ptep) || address >= TASK_SIZE)
+		return;
+
+	/* We have to test for regs NULL since init will get here first thing at boot */
+	if (!current->thread.regs)
+		return;
+
+	/* We also avoid filling the hash if not coming from a fault */
+	if (TRAP(current->thread.regs) != 0x300 && TRAP(current->thread.regs) != 0x400)
+		return;
+
+	hash_preload(vma->vm_mm, address);
+}
+
+/*
+ * Initialize the hash table and patch the instructions in hashtable.S.
+ */
+void __init MMU_init_hw(void)
+{
+	unsigned int n_hpteg, lg_n_hpteg;
+
+	if (!mmu_has_feature(MMU_FTR_HPTE_TABLE))
+		return;
+
+	if ( ppc_md.progress ) ppc_md.progress("hash:enter", 0x105);
+
+#define LG_HPTEG_SIZE	6		/* 64 bytes per HPTEG */
+#define SDR1_LOW_BITS	((n_hpteg - 1) >> 10)
+#define MIN_N_HPTEG	1024		/* min 64kB hash table */
+
+	/*
+	 * Allow 1 HPTE (1/8 HPTEG) for each page of memory.
+	 * This is less than the recommended amount, but then
+	 * Linux ain't AIX.
+	 */
+	n_hpteg = total_memory / (PAGE_SIZE * 8);
+	if (n_hpteg < MIN_N_HPTEG)
+		n_hpteg = MIN_N_HPTEG;
+	lg_n_hpteg = __ilog2(n_hpteg);
+	if (n_hpteg & (n_hpteg - 1)) {
+		++lg_n_hpteg;		/* round up if not power of 2 */
+		n_hpteg = 1 << lg_n_hpteg;
+	}
+	Hash_size = n_hpteg << LG_HPTEG_SIZE;
+
+	/*
+	 * Find some memory for the hash table.
+	 */
+	if ( ppc_md.progress ) ppc_md.progress("hash:find piece", 0x322);
+	Hash = memblock_alloc(Hash_size, Hash_size);
+	if (!Hash)
+		panic("%s: Failed to allocate %lu bytes align=0x%lx\n",
+		      __func__, Hash_size, Hash_size);
+	_SDR1 = __pa(Hash) | SDR1_LOW_BITS;
+
+	pr_info("Total memory = %lldMB; using %ldkB for hash table\n",
+		(unsigned long long)(total_memory >> 20), Hash_size >> 10);
+
+
+	Hash_mask = n_hpteg - 1;
+	hash_mb2 = hash_mb = 32 - LG_HPTEG_SIZE - lg_n_hpteg;
+	if (lg_n_hpteg > 16)
+		hash_mb2 = 16 - LG_HPTEG_SIZE;
+}
+
+void __init MMU_init_hw_patch(void)
+{
+	unsigned int hmask = Hash_mask >> (16 - LG_HPTEG_SIZE);
+	unsigned int hash = (unsigned int)Hash - PAGE_OFFSET;
+
+	if (!mmu_has_feature(MMU_FTR_HPTE_TABLE))
+		return;
+
+	if (ppc_md.progress)
+		ppc_md.progress("hash:patch", 0x345);
+	if (ppc_md.progress)
+		ppc_md.progress("hash:done", 0x205);
+
+	/* WARNING: Make sure nothing can trigger a KASAN check past this point */
+
+	/*
+	 * Patch up the instructions in hashtable.S:create_hpte
+	 */
+	modify_instruction_site(&patch__hash_page_A0, 0xffff, hash >> 16);
+	modify_instruction_site(&patch__hash_page_A1, 0x7c0, hash_mb << 6);
+	modify_instruction_site(&patch__hash_page_A2, 0x7c0, hash_mb2 << 6);
+	modify_instruction_site(&patch__hash_page_B, 0xffff, hmask);
+	modify_instruction_site(&patch__hash_page_C, 0xffff, hmask);
+
+	/*
+	 * Patch up the instructions in hashtable.S:flush_hash_page
+	 */
+	modify_instruction_site(&patch__flush_hash_A0, 0xffff, hash >> 16);
+	modify_instruction_site(&patch__flush_hash_A1, 0x7c0, hash_mb << 6);
+	modify_instruction_site(&patch__flush_hash_A2, 0x7c0, hash_mb2 << 6);
+	modify_instruction_site(&patch__flush_hash_B, 0xffff, hmask);
+}
+
+void 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);
+
+	memblock_set_current_limit(min_t(u64, first_memblock_size, SZ_256M));
+}
+
+void __init print_system_hash_info(void)
+{
+	pr_info("Hash_size         = 0x%lx\n", Hash_size);
+	if (Hash_mask)
+		pr_info("Hash_mask         = 0x%lx\n", Hash_mask);
+}
+
+void __init early_init_mmu(void)
+{
+}