arch/powerpc/mm/nohash/8xx.c - linux - Git at Google

 // 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);

 	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
	// 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);

	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