1 files changed, 268 insertions, 0 deletions
diff --git a/arch/arm/mm/nommu.c b/arch/arm/mm/nommu.c
new file mode 100644
index 000000000..c4d5b3bac
--- /dev/null
+++ b/arch/arm/mm/nommu.c
@@ -0,0 +1,268 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *  linux/arch/arm/mm/nommu.c
+ *
+ * ARM uCLinux supporting functions.
+ */
+#include <linux/module.h>
+#include <linux/mm.h>
+#include <linux/pagemap.h>
+#include <linux/io.h>
+#include <linux/memblock.h>
+#include <linux/kernel.h>
+
+#include <asm/cacheflush.h>
+#include <asm/cp15.h>
+#include <asm/sections.h>
+#include <asm/page.h>
+#include <asm/setup.h>
+#include <asm/traps.h>
+#include <asm/mach/arch.h>
+#include <asm/cputype.h>
+#include <asm/mpu.h>
+#include <asm/procinfo.h>
+
+#include "mm.h"
+
+unsigned long vectors_base;
+
+/*
+ * empty_zero_page is a special page that is used for
+ * zero-initialized data and COW.
+ */
+struct page *empty_zero_page;
+EXPORT_SYMBOL(empty_zero_page);
+
+#ifdef CONFIG_ARM_MPU
+struct mpu_rgn_info mpu_rgn_info;
+#endif
+
+#ifdef CONFIG_CPU_CP15
+#ifdef CONFIG_CPU_HIGH_VECTOR
+unsigned long setup_vectors_base(void)
+{
+	unsigned long reg = get_cr();
+
+	set_cr(reg | CR_V);
+	return 0xffff0000;
+}
+#else /* CONFIG_CPU_HIGH_VECTOR */
+/* Write exception base address to VBAR */
+static inline void set_vbar(unsigned long val)
+{
+	asm("mcr p15, 0, %0, c12, c0, 0" : : "r" (val) : "cc");
+}
+
+/*
+ * Security extensions, bits[7:4], permitted values,
+ * 0b0000 - not implemented, 0b0001/0b0010 - implemented
+ */
+static inline bool security_extensions_enabled(void)
+{
+	/* Check CPUID Identification Scheme before ID_PFR1 read */
+	if ((read_cpuid_id() & 0x000f0000) == 0x000f0000)
+		return cpuid_feature_extract(CPUID_EXT_PFR1, 4) ||
+			cpuid_feature_extract(CPUID_EXT_PFR1, 20);
+	return 0;
+}
+
+unsigned long setup_vectors_base(void)
+{
+	unsigned long base = 0, reg = get_cr();
+
+	set_cr(reg & ~CR_V);
+	if (security_extensions_enabled()) {
+		if (IS_ENABLED(CONFIG_REMAP_VECTORS_TO_RAM))
+			base = CONFIG_DRAM_BASE;
+		set_vbar(base);
+	} else if (IS_ENABLED(CONFIG_REMAP_VECTORS_TO_RAM)) {
+		if (CONFIG_DRAM_BASE != 0)
+			pr_err("Security extensions not enabled, vectors cannot be remapped to RAM, vectors base will be 0x00000000\n");
+	}
+
+	return base;
+}
+#endif /* CONFIG_CPU_HIGH_VECTOR */
+#endif /* CONFIG_CPU_CP15 */
+
+void __init arm_mm_memblock_reserve(void)
+{
+#ifndef CONFIG_CPU_V7M
+	vectors_base = IS_ENABLED(CONFIG_CPU_CP15) ? setup_vectors_base() : 0;
+	/*
+	 * Register the exception vector page.
+	 * some architectures which the DRAM is the exception vector to trap,
+	 * alloc_page breaks with error, although it is not NULL, but "0."
+	 */
+	memblock_reserve(vectors_base, 2 * PAGE_SIZE);
+#else /* ifndef CONFIG_CPU_V7M */
+	/*
+	 * There is no dedicated vector page on V7-M. So nothing needs to be
+	 * reserved here.
+	 */
+#endif
+	/*
+	 * In any case, always ensure address 0 is never used as many things
+	 * get very confused if 0 is returned as a legitimate address.
+	 */
+	memblock_reserve(0, 1);
+}
+
+static void __init adjust_lowmem_bounds_mpu(void)
+{
+	unsigned long pmsa = read_cpuid_ext(CPUID_EXT_MMFR0) & MMFR0_PMSA;
+
+	switch (pmsa) {
+	case MMFR0_PMSAv7:
+		pmsav7_adjust_lowmem_bounds();
+		break;
+	case MMFR0_PMSAv8:
+		pmsav8_adjust_lowmem_bounds();
+		break;
+	default:
+		break;
+	}
+}
+
+static void __init mpu_setup(void)
+{
+	unsigned long pmsa = read_cpuid_ext(CPUID_EXT_MMFR0) & MMFR0_PMSA;
+
+	switch (pmsa) {
+	case MMFR0_PMSAv7:
+		pmsav7_setup();
+		break;
+	case MMFR0_PMSAv8:
+		pmsav8_setup();
+		break;
+	default:
+		break;
+	}
+}
+
+void __init adjust_lowmem_bounds(void)
+{
+	phys_addr_t end;
+	adjust_lowmem_bounds_mpu();
+	end = memblock_end_of_DRAM();
+	high_memory = __va(end - 1) + 1;
+	memblock_set_current_limit(end);
+}
+
+/*
+ * paging_init() sets up the page tables, initialises the zone memory
+ * maps, and sets up the zero page, bad page and bad page tables.
+ */
+void __init paging_init(const struct machine_desc *mdesc)
+{
+	void *zero_page;
+
+	early_trap_init((void *)vectors_base);
+	mpu_setup();
+
+	/* allocate the zero page. */
+	zero_page = (void *)memblock_alloc(PAGE_SIZE, PAGE_SIZE);
+	if (!zero_page)
+		panic("%s: Failed to allocate %lu bytes align=0x%lx\n",
+		      __func__, PAGE_SIZE, PAGE_SIZE);
+
+	bootmem_init();
+
+	empty_zero_page = virt_to_page(zero_page);
+	flush_dcache_page(empty_zero_page);
+}
+
+/*
+ * We don't need to do anything here for nommu machines.
+ */
+void setup_mm_for_reboot(void)
+{
+}
+
+void flush_dcache_page(struct page *page)
+{
+	__cpuc_flush_dcache_area(page_address(page), PAGE_SIZE);
+}
+EXPORT_SYMBOL(flush_dcache_page);
+
+void flush_kernel_dcache_page(struct page *page)
+{
+	__cpuc_flush_dcache_area(page_address(page), PAGE_SIZE);
+}
+EXPORT_SYMBOL(flush_kernel_dcache_page);
+
+void copy_to_user_page(struct vm_area_struct *vma, struct page *page,
+		       unsigned long uaddr, void *dst, const void *src,
+		       unsigned long len)
+{
+	memcpy(dst, src, len);
+	if (vma->vm_flags & VM_EXEC)
+		__cpuc_coherent_user_range(uaddr, uaddr + len);
+}
+
+void __iomem *__arm_ioremap_pfn(unsigned long pfn, unsigned long offset,
+				size_t size, unsigned int mtype)
+{
+	if (pfn >= (0x100000000ULL >> PAGE_SHIFT))
+		return NULL;
+	return (void __iomem *) (offset + (pfn << PAGE_SHIFT));
+}
+EXPORT_SYMBOL(__arm_ioremap_pfn);
+
+void __iomem *__arm_ioremap_caller(phys_addr_t phys_addr, size_t size,
+				   unsigned int mtype, void *caller)
+{
+	return (void __iomem *)phys_addr;
+}
+
+void __iomem * (*arch_ioremap_caller)(phys_addr_t, size_t, unsigned int, void *);
+
+void __iomem *ioremap(resource_size_t res_cookie, size_t size)
+{
+	return __arm_ioremap_caller(res_cookie, size, MT_DEVICE,
+				    __builtin_return_address(0));
+}
+EXPORT_SYMBOL(ioremap);
+
+void __iomem *ioremap_cache(resource_size_t res_cookie, size_t size)
+{
+	return __arm_ioremap_caller(res_cookie, size, MT_DEVICE_CACHED,
+				    __builtin_return_address(0));
+}
+EXPORT_SYMBOL(ioremap_cache);
+
+void __iomem *ioremap_wc(resource_size_t res_cookie, size_t size)
+{
+	return __arm_ioremap_caller(res_cookie, size, MT_DEVICE_WC,
+				    __builtin_return_address(0));
+}
+EXPORT_SYMBOL(ioremap_wc);
+
+#ifdef CONFIG_PCI
+
+#include <asm/mach/map.h>
+
+void __iomem *pci_remap_cfgspace(resource_size_t res_cookie, size_t size)
+{
+	return arch_ioremap_caller(res_cookie, size, MT_UNCACHED,
+				   __builtin_return_address(0));
+}
+EXPORT_SYMBOL_GPL(pci_remap_cfgspace);
+#endif
+
+void *arch_memremap_wb(phys_addr_t phys_addr, size_t size)
+{
+	return (void *)phys_addr;
+}
+
+void __iounmap(volatile void __iomem *addr)
+{
+}
+EXPORT_SYMBOL(__iounmap);
+
+void (*arch_iounmap)(volatile void __iomem *);
+
+void iounmap(volatile void __iomem *addr)
+{
+}
+EXPORT_SYMBOL(iounmap);