arch/hexagon/mm/init.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * Memory subsystem initialization for Hexagon
  *
  * Copyright (c) 2010-2013, The Linux Foundation. All rights reserved.
  */

 #include <linux/init.h>
 #include <linux/mm.h>
 #include <linux/memblock.h>
 #include <asm/atomic.h>
 #include <linux/highmem.h>
 #include <asm/tlb.h>
 #include <asm/sections.h>
 #include <asm/setup.h>
 #include <asm/vm_mmu.h>

 /*
  * Define a startpg just past the end of the kernel image and a lastpg
  * that corresponds to the end of real or simulated platform memory.
  */
 #define bootmem_startpg (PFN_UP(((unsigned long) _end) - PAGE_OFFSET + PHYS_OFFSET))

 unsigned long bootmem_lastpg;	/*  Should be set by platform code  */
 unsigned long __phys_offset;	/*  physical kernel offset >> 12  */

 /*  Set as variable to limit PMD copies  */
 int max_kernel_seg = 0x303;

 /*  indicate pfn's of high memory  */
 unsigned long highstart_pfn, highend_pfn;

 /* Default cache attribute for newly created page tables */
 unsigned long _dflt_cache_att = CACHEDEF;

 /*
  * The current "generation" of kernel map, which should not roll
  * over until Hell freezes over.  Actual bound in years needs to be
  * calculated to confirm.
  */
 DEFINE_SPINLOCK(kmap_gen_lock);

 /*  checkpatch says don't init this to 0.  */
 unsigned long long kmap_generation;

 /*
  * mem_init - initializes memory
  *
  * Frees up bootmem
  * Fixes up more stuff for HIGHMEM
  * Calculates and displays memory available/used
  */
 void __init mem_init(void)
 {
 	/*  No idea where this is actually declared.  Seems to evade LXR.  */
 	memblock_free_all();

 	/*
 	 *  To-Do:  someone somewhere should wipe out the bootmem map
 	 *  after we're done?
 	 */

 	/*
 	 * This can be moved to some more virtual-memory-specific
 	 * initialization hook at some point.  Set the init_mm
 	 * descriptors "context" value to point to the initial
 	 * kernel segment table's physical address.
 	 */
 	init_mm.context.ptbase = __pa(init_mm.pgd);
 }

 void sync_icache_dcache(pte_t pte)
 {
 	unsigned long addr;
 	struct page *page;

 	page = pte_page(pte);
 	addr = (unsigned long) page_address(page);

 	__vmcache_idsync(addr, PAGE_SIZE);
 }

 /*
  * In order to set up page allocator "nodes",
  * somebody has to call free_area_init() for UMA.
  *
  * In this mode, we only have one pg_data_t
  * structure: contig_mem_data.
  */
 static void __init paging_init(void)
 {
 	unsigned long max_zone_pfn[MAX_NR_ZONES] = {0, };

 	/*
 	 *  This is not particularly well documented anywhere, but
 	 *  give ZONE_NORMAL all the memory, including the big holes
 	 *  left by the kernel+bootmem_map which are already left as reserved
 	 *  in the bootmem_map; free_area_init should see those bits and
 	 *  adjust accordingly.
 	 */

 	max_zone_pfn[ZONE_NORMAL] = max_low_pfn;

 	free_area_init(max_zone_pfn);  /*  sets up the zonelists and mem_map  */

 	/*
 	 * Start of high memory area.  Will probably need something more
 	 * fancy if we...  get more fancy.
 	 */
 	high_memory = (void *)((bootmem_lastpg + 1) << PAGE_SHIFT);
 }

 #ifndef DMA_RESERVE
 #define DMA_RESERVE		(4)
 #endif

 #define DMA_CHUNKSIZE		(1<<22)
 #define DMA_RESERVED_BYTES	(DMA_RESERVE * DMA_CHUNKSIZE)

 /*
  * Pick out the memory size.  We look for mem=size,
  * where size is "size[KkMm]"
  */
 static int __init early_mem(char *p)
 {
 	unsigned long size;
 	char *endp;

 	size = memparse(p, &endp);

 	bootmem_lastpg = PFN_DOWN(size);

 	return 0;
 }
 early_param("mem", early_mem);

 size_t hexagon_coherent_pool_size = (size_t) (DMA_RESERVE << 22);

 void __init setup_arch_memory(void)
 {
 	/*  XXX Todo: this probably should be cleaned up  */
 	u32 *segtable = (u32 *) &swapper_pg_dir[0];
 	u32 *segtable_end;

 	/*
 	 * Set up boot memory allocator
 	 *
 	 * The Gorman book also talks about these functions.
 	 * This needs to change for highmem setups.
 	 */

 	/*  Prior to this, bootmem_lastpg is actually mem size  */
 	bootmem_lastpg += ARCH_PFN_OFFSET;

 	/* Memory size needs to be a multiple of 16M */
 	bootmem_lastpg = PFN_DOWN((bootmem_lastpg << PAGE_SHIFT) &
 		~((BIG_KERNEL_PAGE_SIZE) - 1));

 	memblock_add(PHYS_OFFSET,
 		     (bootmem_lastpg - ARCH_PFN_OFFSET) << PAGE_SHIFT);

 	/* Reserve kernel text/data/bss */
 	memblock_reserve(PHYS_OFFSET,
 			 (bootmem_startpg - ARCH_PFN_OFFSET) << PAGE_SHIFT);
 	/*
 	 * Reserve the top DMA_RESERVE bytes of RAM for DMA (uncached)
 	 * memory allocation
 	 */
 	max_low_pfn = bootmem_lastpg - PFN_DOWN(DMA_RESERVED_BYTES);
 	min_low_pfn = ARCH_PFN_OFFSET;
 	memblock_reserve(PFN_PHYS(max_low_pfn), DMA_RESERVED_BYTES);

 	printk(KERN_INFO "bootmem_startpg:  0x%08lx\n", bootmem_startpg);
 	printk(KERN_INFO "bootmem_lastpg:  0x%08lx\n", bootmem_lastpg);
 	printk(KERN_INFO "min_low_pfn:  0x%08lx\n", min_low_pfn);
 	printk(KERN_INFO "max_low_pfn:  0x%08lx\n", max_low_pfn);

 	/*
 	 * The default VM page tables (will be) populated with
 	 * VA=PA+PAGE_OFFSET mapping.  We go in and invalidate entries
 	 * higher than what we have memory for.
 	 */

 	/*  this is pointer arithmetic; each entry covers 4MB  */
 	segtable = segtable + (PAGE_OFFSET >> 22);

 	/*  this actually only goes to the end of the first gig  */
 	segtable_end = segtable + (1<<(30-22));

 	/*
 	 * Move forward to the start of empty pages; take into account
 	 * phys_offset shift.
 	 */

 	segtable += (bootmem_lastpg-ARCH_PFN_OFFSET)>>(22-PAGE_SHIFT);
 	{
 		int i;

 		for (i = 1 ; i <= DMA_RESERVE ; i++)
 			segtable[-i] = ((segtable[-i] & __HVM_PTE_PGMASK_4MB)
 				| __HVM_PTE_R | __HVM_PTE_W | __HVM_PTE_X
 				| __HEXAGON_C_UNC << 6
 				| __HVM_PDE_S_4MB);
 	}

 	printk(KERN_INFO "clearing segtable from %p to %p\n", segtable,
 		segtable_end);
 	while (segtable < (segtable_end-8))
 		*(segtable++) = __HVM_PDE_S_INVALID;
 	/* stop the pointer at the device I/O 4MB page  */

 	printk(KERN_INFO "segtable = %p (should be equal to _K_io_map)\n",
 		segtable);

 #if 0
 	/*  Other half of the early device table from vm_init_segtable. */
 	printk(KERN_INFO "&_K_init_devicetable = 0x%08x\n",
 		(unsigned long) _K_init_devicetable-PAGE_OFFSET);
 	*segtable = ((u32) (unsigned long) _K_init_devicetable-PAGE_OFFSET) |
 		__HVM_PDE_S_4KB;
 	printk(KERN_INFO "*segtable = 0x%08x\n", *segtable);
 #endif

 	/*
 	 *  The bootmem allocator seemingly just lives to feed memory
 	 *  to the paging system
 	 */
 	printk(KERN_INFO "PAGE_SIZE=%lu\n", PAGE_SIZE);
 	paging_init();  /*  See Gorman Book, 2.3  */

 	/*
 	 *  At this point, the page allocator is kind of initialized, but
 	 *  apparently no pages are available (just like with the bootmem
 	 *  allocator), and need to be freed themselves via mem_init(),
 	 *  which is called by start_kernel() later on in the process
 	 */
 }

 static const pgprot_t protection_map[16] = {
 	[VM_NONE]					= __pgprot(_PAGE_PRESENT | _PAGE_USER |
 								   CACHEDEF),
 	[VM_READ]					= __pgprot(_PAGE_PRESENT | _PAGE_USER |
 								   _PAGE_READ | CACHEDEF),
 	[VM_WRITE]					= __pgprot(_PAGE_PRESENT | _PAGE_USER |
 								   CACHEDEF),
 	[VM_WRITE | VM_READ]				= __pgprot(_PAGE_PRESENT | _PAGE_USER |
 								   _PAGE_READ | CACHEDEF),
 	[VM_EXEC]					= __pgprot(_PAGE_PRESENT | _PAGE_USER |
 								   _PAGE_EXECUTE | CACHEDEF),
 	[VM_EXEC | VM_READ]				= __pgprot(_PAGE_PRESENT | _PAGE_USER |
 								   _PAGE_EXECUTE | _PAGE_READ |
 								   CACHEDEF),
 	[VM_EXEC | VM_WRITE]				= __pgprot(_PAGE_PRESENT | _PAGE_USER |
 								   _PAGE_EXECUTE | CACHEDEF),
 	[VM_EXEC | VM_WRITE | VM_READ]			= __pgprot(_PAGE_PRESENT | _PAGE_USER |
 								   _PAGE_EXECUTE | _PAGE_READ |
 								   CACHEDEF),
 	[VM_SHARED]                                     = __pgprot(_PAGE_PRESENT | _PAGE_USER |
 								   CACHEDEF),
 	[VM_SHARED | VM_READ]				= __pgprot(_PAGE_PRESENT | _PAGE_USER |
 								   _PAGE_READ | CACHEDEF),
 	[VM_SHARED | VM_WRITE]				= __pgprot(_PAGE_PRESENT | _PAGE_USER |
 								   _PAGE_WRITE | CACHEDEF),
 	[VM_SHARED | VM_WRITE | VM_READ]		= __pgprot(_PAGE_PRESENT | _PAGE_USER |
 								   _PAGE_READ | _PAGE_WRITE |
 								   CACHEDEF),
 	[VM_SHARED | VM_EXEC]				= __pgprot(_PAGE_PRESENT | _PAGE_USER |
 								   _PAGE_EXECUTE | CACHEDEF),
 	[VM_SHARED | VM_EXEC | VM_READ]			= __pgprot(_PAGE_PRESENT | _PAGE_USER |
 								   _PAGE_EXECUTE | _PAGE_READ |
 								   CACHEDEF),
 	[VM_SHARED | VM_EXEC | VM_WRITE]		= __pgprot(_PAGE_PRESENT | _PAGE_USER |
 								   _PAGE_EXECUTE | _PAGE_WRITE |
 								   CACHEDEF),
 	[VM_SHARED | VM_EXEC | VM_WRITE | VM_READ]	= __pgprot(_PAGE_PRESENT | _PAGE_USER |
 								   _PAGE_READ | _PAGE_EXECUTE |
 								   _PAGE_WRITE | CACHEDEF)
 };
 DECLARE_VM_GET_PAGE_PROT
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* Memory subsystem initialization for Hexagon
	*
	* Copyright (c) 2010-2013, The Linux Foundation. All rights reserved.
	*/

	#include <linux/init.h>
	#include <linux/mm.h>
	#include <linux/memblock.h>
	#include <asm/atomic.h>
	#include <linux/highmem.h>
	#include <asm/tlb.h>
	#include <asm/sections.h>
	#include <asm/setup.h>
	#include <asm/vm_mmu.h>

	/*
	* Define a startpg just past the end of the kernel image and a lastpg
	* that corresponds to the end of real or simulated platform memory.
	*/
	#define bootmem_startpg (PFN_UP(((unsigned long) _end) - PAGE_OFFSET + PHYS_OFFSET))

	unsigned long bootmem_lastpg; /* Should be set by platform code */
	unsigned long __phys_offset; /* physical kernel offset >> 12 */

	/* Set as variable to limit PMD copies */
	int max_kernel_seg = 0x303;

	/* indicate pfn's of high memory */
	unsigned long highstart_pfn, highend_pfn;

	/* Default cache attribute for newly created page tables */
	unsigned long _dflt_cache_att = CACHEDEF;

	/*
	* The current "generation" of kernel map, which should not roll
	* over until Hell freezes over. Actual bound in years needs to be
	* calculated to confirm.
	*/
	DEFINE_SPINLOCK(kmap_gen_lock);

	/* checkpatch says don't init this to 0. */
	unsigned long long kmap_generation;

	/*
	* mem_init - initializes memory
	*
	* Frees up bootmem
	* Fixes up more stuff for HIGHMEM
	* Calculates and displays memory available/used
	*/
	void __init mem_init(void)
	{
	/* No idea where this is actually declared. Seems to evade LXR. */
	memblock_free_all();

	/*
	* To-Do: someone somewhere should wipe out the bootmem map
	* after we're done?
	*/

	/*
	* This can be moved to some more virtual-memory-specific
	* initialization hook at some point. Set the init_mm
	* descriptors "context" value to point to the initial
	* kernel segment table's physical address.
	*/
	init_mm.context.ptbase = __pa(init_mm.pgd);
	}

	void sync_icache_dcache(pte_t pte)
	{
	unsigned long addr;
	struct page *page;

	page = pte_page(pte);
	addr = (unsigned long) page_address(page);

	__vmcache_idsync(addr, PAGE_SIZE);
	}

	/*
	* In order to set up page allocator "nodes",
	* somebody has to call free_area_init() for UMA.
	*
	* In this mode, we only have one pg_data_t
	* structure: contig_mem_data.
	*/
	static void __init paging_init(void)
	{
	unsigned long max_zone_pfn[MAX_NR_ZONES] = {0, };

	/*
	* This is not particularly well documented anywhere, but
	* give ZONE_NORMAL all the memory, including the big holes
	* left by the kernel+bootmem_map which are already left as reserved
	* in the bootmem_map; free_area_init should see those bits and
	* adjust accordingly.
	*/

	max_zone_pfn[ZONE_NORMAL] = max_low_pfn;

	free_area_init(max_zone_pfn); /* sets up the zonelists and mem_map */

	/*
	* Start of high memory area. Will probably need something more
	* fancy if we... get more fancy.
	*/
	high_memory = (void *)((bootmem_lastpg + 1) << PAGE_SHIFT);
	}

	#ifndef DMA_RESERVE
	#define DMA_RESERVE (4)
	#endif

	#define DMA_CHUNKSIZE (1<<22)
	#define DMA_RESERVED_BYTES (DMA_RESERVE * DMA_CHUNKSIZE)

	/*
	* Pick out the memory size. We look for mem=size,
	* where size is "size[KkMm]"
	*/
	static int __init early_mem(char *p)
	{
	unsigned long size;
	char *endp;

	size = memparse(p, &endp);

	bootmem_lastpg = PFN_DOWN(size);

	return 0;
	}
	early_param("mem", early_mem);

	size_t hexagon_coherent_pool_size = (size_t) (DMA_RESERVE << 22);

	void __init setup_arch_memory(void)
	{
	/* XXX Todo: this probably should be cleaned up */
	u32 segtable = (u32 ) &swapper_pg_dir[0];
	u32 *segtable_end;

	/*
	* Set up boot memory allocator
	*
	* The Gorman book also talks about these functions.
	* This needs to change for highmem setups.
	*/

	/* Prior to this, bootmem_lastpg is actually mem size */
	bootmem_lastpg += ARCH_PFN_OFFSET;

	/* Memory size needs to be a multiple of 16M */
	bootmem_lastpg = PFN_DOWN((bootmem_lastpg << PAGE_SHIFT) &
	~((BIG_KERNEL_PAGE_SIZE) - 1));

	memblock_add(PHYS_OFFSET,
	(bootmem_lastpg - ARCH_PFN_OFFSET) << PAGE_SHIFT);

	/* Reserve kernel text/data/bss */
	memblock_reserve(PHYS_OFFSET,
	(bootmem_startpg - ARCH_PFN_OFFSET) << PAGE_SHIFT);
	/*
	* Reserve the top DMA_RESERVE bytes of RAM for DMA (uncached)
	* memory allocation
	*/
	max_low_pfn = bootmem_lastpg - PFN_DOWN(DMA_RESERVED_BYTES);
	min_low_pfn = ARCH_PFN_OFFSET;
	memblock_reserve(PFN_PHYS(max_low_pfn), DMA_RESERVED_BYTES);

	printk(KERN_INFO "bootmem_startpg: 0x%08lx\n", bootmem_startpg);
	printk(KERN_INFO "bootmem_lastpg: 0x%08lx\n", bootmem_lastpg);
	printk(KERN_INFO "min_low_pfn: 0x%08lx\n", min_low_pfn);
	printk(KERN_INFO "max_low_pfn: 0x%08lx\n", max_low_pfn);

	/*
	* The default VM page tables (will be) populated with
	* VA=PA+PAGE_OFFSET mapping. We go in and invalidate entries
	* higher than what we have memory for.
	*/

	/* this is pointer arithmetic; each entry covers 4MB */
	segtable = segtable + (PAGE_OFFSET >> 22);

	/* this actually only goes to the end of the first gig */
	segtable_end = segtable + (1<<(30-22));

	/*
	* Move forward to the start of empty pages; take into account
	* phys_offset shift.
	*/

	segtable += (bootmem_lastpg-ARCH_PFN_OFFSET)>>(22-PAGE_SHIFT);
	{
	int i;

	for (i = 1 ; i <= DMA_RESERVE ; i++)
	segtable[-i] = ((segtable[-i] & __HVM_PTE_PGMASK_4MB)
	\| __HVM_PTE_R \| __HVM_PTE_W \| __HVM_PTE_X
	\| __HEXAGON_C_UNC << 6
	\| __HVM_PDE_S_4MB);
	}

	printk(KERN_INFO "clearing segtable from %p to %p\n", segtable,
	segtable_end);
	while (segtable < (segtable_end-8))
	*(segtable++) = __HVM_PDE_S_INVALID;
	/* stop the pointer at the device I/O 4MB page */

	printk(KERN_INFO "segtable = %p (should be equal to _K_io_map)\n",
	segtable);

	#if 0
	/* Other half of the early device table from vm_init_segtable. */
	printk(KERN_INFO "&_K_init_devicetable = 0x%08x\n",
	(unsigned long) _K_init_devicetable-PAGE_OFFSET);
	*segtable = ((u32) (unsigned long) _K_init_devicetable-PAGE_OFFSET) \|
	__HVM_PDE_S_4KB;
	printk(KERN_INFO "segtable = 0x%08x\n", segtable);
	#endif

	/*
	* The bootmem allocator seemingly just lives to feed memory
	* to the paging system
	*/
	printk(KERN_INFO "PAGE_SIZE=%lu\n", PAGE_SIZE);
	paging_init(); /* See Gorman Book, 2.3 */

	/*
	* At this point, the page allocator is kind of initialized, but
	* apparently no pages are available (just like with the bootmem
	* allocator), and need to be freed themselves via mem_init(),
	* which is called by start_kernel() later on in the process
	*/
	}

	static const pgprot_t protection_map[16] = {
	[VM_NONE] = __pgprot(_PAGE_PRESENT \| _PAGE_USER \|
	CACHEDEF),
	[VM_READ] = __pgprot(_PAGE_PRESENT \| _PAGE_USER \|
	_PAGE_READ \| CACHEDEF),
	[VM_WRITE] = __pgprot(_PAGE_PRESENT \| _PAGE_USER \|
	CACHEDEF),
	[VM_WRITE \| VM_READ] = __pgprot(_PAGE_PRESENT \| _PAGE_USER \|
	_PAGE_READ \| CACHEDEF),
	[VM_EXEC] = __pgprot(_PAGE_PRESENT \| _PAGE_USER \|
	_PAGE_EXECUTE \| CACHEDEF),
	[VM_EXEC \| VM_READ] = __pgprot(_PAGE_PRESENT \| _PAGE_USER \|
	_PAGE_EXECUTE \| _PAGE_READ \|
	CACHEDEF),
	[VM_EXEC \| VM_WRITE] = __pgprot(_PAGE_PRESENT \| _PAGE_USER \|
	_PAGE_EXECUTE \| CACHEDEF),
	[VM_EXEC \| VM_WRITE \| VM_READ] = __pgprot(_PAGE_PRESENT \| _PAGE_USER \|
	_PAGE_EXECUTE \| _PAGE_READ \|
	CACHEDEF),
	[VM_SHARED] = __pgprot(_PAGE_PRESENT \| _PAGE_USER \|
	CACHEDEF),
	[VM_SHARED \| VM_READ] = __pgprot(_PAGE_PRESENT \| _PAGE_USER \|
	_PAGE_READ \| CACHEDEF),
	[VM_SHARED \| VM_WRITE] = __pgprot(_PAGE_PRESENT \| _PAGE_USER \|
	_PAGE_WRITE \| CACHEDEF),
	[VM_SHARED \| VM_WRITE \| VM_READ] = __pgprot(_PAGE_PRESENT \| _PAGE_USER \|
	_PAGE_READ \| _PAGE_WRITE \|
	CACHEDEF),
	[VM_SHARED \| VM_EXEC] = __pgprot(_PAGE_PRESENT \| _PAGE_USER \|
	_PAGE_EXECUTE \| CACHEDEF),
	[VM_SHARED \| VM_EXEC \| VM_READ] = __pgprot(_PAGE_PRESENT \| _PAGE_USER \|
	_PAGE_EXECUTE \| _PAGE_READ \|
	CACHEDEF),
	[VM_SHARED \| VM_EXEC \| VM_WRITE] = __pgprot(_PAGE_PRESENT \| _PAGE_USER \|
	_PAGE_EXECUTE \| _PAGE_WRITE \|
	CACHEDEF),
	[VM_SHARED \| VM_EXEC \| VM_WRITE \| VM_READ] = __pgprot(_PAGE_PRESENT \| _PAGE_USER \|
	_PAGE_READ \| _PAGE_EXECUTE \|
	_PAGE_WRITE \| CACHEDEF)
	};
	DECLARE_VM_GET_PAGE_PROT