Commit 072e3d96 authored by Pavel Tatashin's avatar Pavel Tatashin Committed by Will Deacon
Browse files

arm64: hibernate: move page handling function to new trans_pgd.c 



Now, that we abstracted the required functions move them to a new home.
Later, we will generalize these function in order to be useful outside
of hibernation.

Signed-off-by: default avatarPavel Tatashin <pasha.tatashin@soleen.com>
Reviewed-by: default avatarJames Morse <james.morse@arm.com>
Link: https://lore.kernel.org/r/20210125191923.1060122-4-pasha.tatashin@soleen.com


Signed-off-by: default avatarWill Deacon <will@kernel.org>
parent 41f67d40

arch/arm64/Kconfig

+4 −0
Original line number Diff line number Diff line
@@ -1132,6 +1132,10 @@ config CRASH_DUMP 


	  For more details see Documentation/admin-guide/kdump/kdump.rst



config TRANS_TABLE

	def_bool y

	depends on HIBERNATION



config XEN_DOM0

	def_bool y

	depends on XEN

arch/arm64/include/asm/trans_pgd.h

0 → 100644
+21 −0
Original line number Diff line number Diff line 
/* SPDX-License-Identifier: GPL-2.0 */



/*

 * Copyright (c) 2020, Microsoft Corporation.

 * Pavel Tatashin <pasha.tatashin@soleen.com>

 */



#ifndef _ASM_TRANS_TABLE_H

#define _ASM_TRANS_TABLE_H



#include <linux/bits.h>

#include <linux/types.h>

#include <asm/pgtable-types.h>



int trans_pgd_create_copy(pgd_t **dst_pgdp, unsigned long start,

			  unsigned long end);



int trans_pgd_map_page(pgd_t *trans_pgd, void *page, unsigned long dst_addr,

		       pgprot_t pgprot);



#endif /* _ASM_TRANS_TABLE_H */

arch/arm64/kernel/hibernate.c

+1 −227
Original line number Diff line number Diff line
@@ -16,7 +16,6 @@ 
#define pr_fmt(x) "hibernate: " x

#include <linux/cpu.h>

#include <linux/kvm_host.h>

#include <linux/mm.h>

#include <linux/pm.h>

#include <linux/sched.h>

#include <linux/suspend.h>
@@ -31,13 +30,12 @@ 
#include <asm/memory.h>

#include <asm/mmu_context.h>

#include <asm/mte.h>

#include <asm/pgalloc.h>

#include <asm/pgtable-hwdef.h>

#include <asm/sections.h>

#include <asm/smp.h>

#include <asm/smp_plat.h>

#include <asm/suspend.h>

#include <asm/sysreg.h>

#include <asm/trans_pgd.h>

#include <asm/virt.h>



/*
@@ -178,54 +176,6 @@ int arch_hibernation_header_restore(void *addr) 
}

EXPORT_SYMBOL(arch_hibernation_header_restore);



static int trans_pgd_map_page(pgd_t *trans_pgd, void *page,

		       unsigned long dst_addr,

		       pgprot_t pgprot)

{

	pgd_t *pgdp;

	p4d_t *p4dp;

	pud_t *pudp;

	pmd_t *pmdp;

	pte_t *ptep;



	pgdp = pgd_offset_pgd(trans_pgd, dst_addr);

	if (pgd_none(READ_ONCE(*pgdp))) {

		p4dp = (void *)get_safe_page(GFP_ATOMIC);

		if (!pgdp)

			return -ENOMEM;

		pgd_populate(&init_mm, pgdp, p4dp);

	}



	p4dp = p4d_offset(pgdp, dst_addr);

	if (p4d_none(READ_ONCE(*p4dp))) {

		pudp = (void *)get_safe_page(GFP_ATOMIC);

		if (!pudp)

			return -ENOMEM;

		p4d_populate(&init_mm, p4dp, pudp);

	}



	pudp = pud_offset(p4dp, dst_addr);

	if (pud_none(READ_ONCE(*pudp))) {

		pmdp = (void *)get_safe_page(GFP_ATOMIC);

		if (!pmdp)

			return -ENOMEM;

		pud_populate(&init_mm, pudp, pmdp);

	}



	pmdp = pmd_offset(pudp, dst_addr);

	if (pmd_none(READ_ONCE(*pmdp))) {

		ptep = (void *)get_safe_page(GFP_ATOMIC);

		if (!ptep)

			return -ENOMEM;

		pmd_populate_kernel(&init_mm, pmdp, ptep);

	}



	ptep = pte_offset_kernel(pmdp, dst_addr);

	set_pte(ptep, pfn_pte(virt_to_pfn(page), PAGE_KERNEL_EXEC));



	return 0;

}



/*

 * Copies length bytes, starting at src_start into an new page,

 * perform cache maintenance, then maps it at the specified address low
@@ -462,182 +412,6 @@ int swsusp_arch_suspend(void) 
	return ret;

}



static void _copy_pte(pte_t *dst_ptep, pte_t *src_ptep, unsigned long addr)

{

	pte_t pte = READ_ONCE(*src_ptep);



	if (pte_valid(pte)) {

		/*

		 * Resume will overwrite areas that may be marked

		 * read only (code, rodata). Clear the RDONLY bit from

		 * the temporary mappings we use during restore.

		 */

		set_pte(dst_ptep, pte_mkwrite(pte));

	} else if (debug_pagealloc_enabled() && !pte_none(pte)) {

		/*

		 * debug_pagealloc will removed the PTE_VALID bit if

		 * the page isn't in use by the resume kernel. It may have

		 * been in use by the original kernel, in which case we need

		 * to put it back in our copy to do the restore.

		 *

		 * Before marking this entry valid, check the pfn should

		 * be mapped.

		 */

		BUG_ON(!pfn_valid(pte_pfn(pte)));



		set_pte(dst_ptep, pte_mkpresent(pte_mkwrite(pte)));

	}

}



static int copy_pte(pmd_t *dst_pmdp, pmd_t *src_pmdp, unsigned long start,

		    unsigned long end)

{

	pte_t *src_ptep;

	pte_t *dst_ptep;

	unsigned long addr = start;



	dst_ptep = (pte_t *)get_safe_page(GFP_ATOMIC);

	if (!dst_ptep)

		return -ENOMEM;

	pmd_populate_kernel(&init_mm, dst_pmdp, dst_ptep);

	dst_ptep = pte_offset_kernel(dst_pmdp, start);



	src_ptep = pte_offset_kernel(src_pmdp, start);

	do {

		_copy_pte(dst_ptep, src_ptep, addr);

	} while (dst_ptep++, src_ptep++, addr += PAGE_SIZE, addr != end);



	return 0;

}



static int copy_pmd(pud_t *dst_pudp, pud_t *src_pudp, unsigned long start,

		    unsigned long end)

{

	pmd_t *src_pmdp;

	pmd_t *dst_pmdp;

	unsigned long next;

	unsigned long addr = start;



	if (pud_none(READ_ONCE(*dst_pudp))) {

		dst_pmdp = (pmd_t *)get_safe_page(GFP_ATOMIC);

		if (!dst_pmdp)

			return -ENOMEM;

		pud_populate(&init_mm, dst_pudp, dst_pmdp);

	}

	dst_pmdp = pmd_offset(dst_pudp, start);



	src_pmdp = pmd_offset(src_pudp, start);

	do {

		pmd_t pmd = READ_ONCE(*src_pmdp);



		next = pmd_addr_end(addr, end);

		if (pmd_none(pmd))

			continue;

		if (pmd_table(pmd)) {

			if (copy_pte(dst_pmdp, src_pmdp, addr, next))

				return -ENOMEM;

		} else {

			set_pmd(dst_pmdp,

				__pmd(pmd_val(pmd) & ~PMD_SECT_RDONLY));

		}

	} while (dst_pmdp++, src_pmdp++, addr = next, addr != end);



	return 0;

}



static int copy_pud(p4d_t *dst_p4dp, p4d_t *src_p4dp, unsigned long start,

		    unsigned long end)

{

	pud_t *dst_pudp;

	pud_t *src_pudp;

	unsigned long next;

	unsigned long addr = start;



	if (p4d_none(READ_ONCE(*dst_p4dp))) {

		dst_pudp = (pud_t *)get_safe_page(GFP_ATOMIC);

		if (!dst_pudp)

			return -ENOMEM;

		p4d_populate(&init_mm, dst_p4dp, dst_pudp);

	}

	dst_pudp = pud_offset(dst_p4dp, start);



	src_pudp = pud_offset(src_p4dp, start);

	do {

		pud_t pud = READ_ONCE(*src_pudp);



		next = pud_addr_end(addr, end);

		if (pud_none(pud))

			continue;

		if (pud_table(pud)) {

			if (copy_pmd(dst_pudp, src_pudp, addr, next))

				return -ENOMEM;

		} else {

			set_pud(dst_pudp,

				__pud(pud_val(pud) & ~PUD_SECT_RDONLY));

		}

	} while (dst_pudp++, src_pudp++, addr = next, addr != end);



	return 0;

}



static int copy_p4d(pgd_t *dst_pgdp, pgd_t *src_pgdp, unsigned long start,

		    unsigned long end)

{

	p4d_t *dst_p4dp;

	p4d_t *src_p4dp;

	unsigned long next;

	unsigned long addr = start;



	dst_p4dp = p4d_offset(dst_pgdp, start);

	src_p4dp = p4d_offset(src_pgdp, start);

	do {

		next = p4d_addr_end(addr, end);

		if (p4d_none(READ_ONCE(*src_p4dp)))

			continue;

		if (copy_pud(dst_p4dp, src_p4dp, addr, next))

			return -ENOMEM;

	} while (dst_p4dp++, src_p4dp++, addr = next, addr != end);



	return 0;

}



static int copy_page_tables(pgd_t *dst_pgdp, unsigned long start,

			    unsigned long end)

{

	unsigned long next;

	unsigned long addr = start;

	pgd_t *src_pgdp = pgd_offset_k(start);



	dst_pgdp = pgd_offset_pgd(dst_pgdp, start);

	do {

		next = pgd_addr_end(addr, end);

		if (pgd_none(READ_ONCE(*src_pgdp)))

			continue;

		if (copy_p4d(dst_pgdp, src_pgdp, addr, next))

			return -ENOMEM;

	} while (dst_pgdp++, src_pgdp++, addr = next, addr != end);



	return 0;

}



static int trans_pgd_create_copy(pgd_t **dst_pgdp, unsigned long start,

			  unsigned long end)

{

	int rc;

	pgd_t *trans_pgd = (pgd_t *)get_safe_page(GFP_ATOMIC);



	if (!trans_pgd) {

		pr_err("Failed to allocate memory for temporary page tables.\n");

		return -ENOMEM;

	}



	rc = copy_page_tables(trans_pgd, start, end);

	if (!rc)

		*dst_pgdp = trans_pgd;



	return rc;

}



/*

 * Setup then Resume from the hibernate image using swsusp_arch_suspend_exit().

 *

arch/arm64/mm/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -6,6 +6,7 @@ obj-y := dma-mapping.o extable.o fault.o init.o \ 
obj-$(CONFIG_HUGETLB_PAGE)	+= hugetlbpage.o

obj-$(CONFIG_PTDUMP_CORE)	+= ptdump.o

obj-$(CONFIG_PTDUMP_DEBUGFS)	+= ptdump_debugfs.o

obj-$(CONFIG_TRANS_TABLE)	+= trans_pgd.o

obj-$(CONFIG_NUMA)		+= numa.o

obj-$(CONFIG_DEBUG_VIRTUAL)	+= physaddr.o

obj-$(CONFIG_ARM64_MTE)		+= mteswap.o

arch/arm64/mm/trans_pgd.c

0 → 100644
+250 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0



/*

 * Transitional page tables for kexec and hibernate

 *

 * This file derived from: arch/arm64/kernel/hibernate.c

 *

 * Copyright (c) 2020, Microsoft Corporation.

 * Pavel Tatashin <pasha.tatashin@soleen.com>

 *

 */



/*

 * Transitional tables are used during system transferring from one world to

 * another: such as during hibernate restore, and kexec reboots. During these

 * phases one cannot rely on page table not being overwritten. This is because

 * hibernate and kexec can overwrite the current page tables during transition.

 */



#include <asm/trans_pgd.h>

#include <asm/pgalloc.h>

#include <asm/pgtable.h>

#include <linux/suspend.h>

#include <linux/bug.h>

#include <linux/mm.h>

#include <linux/mmzone.h>



static void _copy_pte(pte_t *dst_ptep, pte_t *src_ptep, unsigned long addr)

{

	pte_t pte = READ_ONCE(*src_ptep);



	if (pte_valid(pte)) {

		/*

		 * Resume will overwrite areas that may be marked

		 * read only (code, rodata). Clear the RDONLY bit from

		 * the temporary mappings we use during restore.

		 */

		set_pte(dst_ptep, pte_mkwrite(pte));

	} else if (debug_pagealloc_enabled() && !pte_none(pte)) {

		/*

		 * debug_pagealloc will removed the PTE_VALID bit if

		 * the page isn't in use by the resume kernel. It may have

		 * been in use by the original kernel, in which case we need

		 * to put it back in our copy to do the restore.

		 *

		 * Before marking this entry valid, check the pfn should

		 * be mapped.

		 */

		BUG_ON(!pfn_valid(pte_pfn(pte)));



		set_pte(dst_ptep, pte_mkpresent(pte_mkwrite(pte)));

	}

}



static int copy_pte(pmd_t *dst_pmdp, pmd_t *src_pmdp, unsigned long start,

		    unsigned long end)

{

	pte_t *src_ptep;

	pte_t *dst_ptep;

	unsigned long addr = start;



	dst_ptep = (pte_t *)get_safe_page(GFP_ATOMIC);

	if (!dst_ptep)

		return -ENOMEM;

	pmd_populate_kernel(&init_mm, dst_pmdp, dst_ptep);

	dst_ptep = pte_offset_kernel(dst_pmdp, start);



	src_ptep = pte_offset_kernel(src_pmdp, start);

	do {

		_copy_pte(dst_ptep, src_ptep, addr);

	} while (dst_ptep++, src_ptep++, addr += PAGE_SIZE, addr != end);



	return 0;

}



static int copy_pmd(pud_t *dst_pudp, pud_t *src_pudp, unsigned long start,

		    unsigned long end)

{

	pmd_t *src_pmdp;

	pmd_t *dst_pmdp;

	unsigned long next;

	unsigned long addr = start;



	if (pud_none(READ_ONCE(*dst_pudp))) {

		dst_pmdp = (pmd_t *)get_safe_page(GFP_ATOMIC);

		if (!dst_pmdp)

			return -ENOMEM;

		pud_populate(&init_mm, dst_pudp, dst_pmdp);

	}

	dst_pmdp = pmd_offset(dst_pudp, start);



	src_pmdp = pmd_offset(src_pudp, start);

	do {

		pmd_t pmd = READ_ONCE(*src_pmdp);



		next = pmd_addr_end(addr, end);

		if (pmd_none(pmd))

			continue;

		if (pmd_table(pmd)) {

			if (copy_pte(dst_pmdp, src_pmdp, addr, next))

				return -ENOMEM;

		} else {

			set_pmd(dst_pmdp,

				__pmd(pmd_val(pmd) & ~PMD_SECT_RDONLY));

		}

	} while (dst_pmdp++, src_pmdp++, addr = next, addr != end);



	return 0;

}



static int copy_pud(p4d_t *dst_p4dp, p4d_t *src_p4dp, unsigned long start,

		    unsigned long end)

{

	pud_t *dst_pudp;

	pud_t *src_pudp;

	unsigned long next;

	unsigned long addr = start;



	if (p4d_none(READ_ONCE(*dst_p4dp))) {

		dst_pudp = (pud_t *)get_safe_page(GFP_ATOMIC);

		if (!dst_pudp)

			return -ENOMEM;

		p4d_populate(&init_mm, dst_p4dp, dst_pudp);

	}

	dst_pudp = pud_offset(dst_p4dp, start);



	src_pudp = pud_offset(src_p4dp, start);

	do {

		pud_t pud = READ_ONCE(*src_pudp);



		next = pud_addr_end(addr, end);

		if (pud_none(pud))

			continue;

		if (pud_table(pud)) {

			if (copy_pmd(dst_pudp, src_pudp, addr, next))

				return -ENOMEM;

		} else {

			set_pud(dst_pudp,

				__pud(pud_val(pud) & ~PUD_SECT_RDONLY));

		}

	} while (dst_pudp++, src_pudp++, addr = next, addr != end);



	return 0;

}



static int copy_p4d(pgd_t *dst_pgdp, pgd_t *src_pgdp, unsigned long start,

		    unsigned long end)

{

	p4d_t *dst_p4dp;

	p4d_t *src_p4dp;

	unsigned long next;

	unsigned long addr = start;



	dst_p4dp = p4d_offset(dst_pgdp, start);

	src_p4dp = p4d_offset(src_pgdp, start);

	do {

		next = p4d_addr_end(addr, end);

		if (p4d_none(READ_ONCE(*src_p4dp)))

			continue;

		if (copy_pud(dst_p4dp, src_p4dp, addr, next))

			return -ENOMEM;

	} while (dst_p4dp++, src_p4dp++, addr = next, addr != end);



	return 0;

}



static int copy_page_tables(pgd_t *dst_pgdp, unsigned long start,

			    unsigned long end)

{

	unsigned long next;

	unsigned long addr = start;

	pgd_t *src_pgdp = pgd_offset_k(start);



	dst_pgdp = pgd_offset_pgd(dst_pgdp, start);

	do {

		next = pgd_addr_end(addr, end);

		if (pgd_none(READ_ONCE(*src_pgdp)))

			continue;

		if (copy_p4d(dst_pgdp, src_pgdp, addr, next))

			return -ENOMEM;

	} while (dst_pgdp++, src_pgdp++, addr = next, addr != end);



	return 0;

}



int trans_pgd_create_copy(pgd_t **dst_pgdp, unsigned long start,

			  unsigned long end)

{

	int rc;

	pgd_t *trans_pgd = (pgd_t *)get_safe_page(GFP_ATOMIC);



	if (!trans_pgd) {

		pr_err("Failed to allocate memory for temporary page tables.\n");

		return -ENOMEM;

	}



	rc = copy_page_tables(trans_pgd, start, end);

	if (!rc)

		*dst_pgdp = trans_pgd;



	return rc;

}



int trans_pgd_map_page(pgd_t *trans_pgd, void *page,

		       unsigned long dst_addr,

		       pgprot_t pgprot)

{

	pgd_t *pgdp;

	p4d_t *p4dp;

	pud_t *pudp;

	pmd_t *pmdp;

	pte_t *ptep;



	pgdp = pgd_offset_pgd(trans_pgd, dst_addr);

	if (pgd_none(READ_ONCE(*pgdp))) {

		p4dp = (void *)get_safe_page(GFP_ATOMIC);

		if (!pgdp)

			return -ENOMEM;

		pgd_populate(&init_mm, pgdp, p4dp);

	}



	p4dp = p4d_offset(pgdp, dst_addr);

	if (p4d_none(READ_ONCE(*p4dp))) {

		pudp = (void *)get_safe_page(GFP_ATOMIC);

		if (!pudp)

			return -ENOMEM;

		p4d_populate(&init_mm, p4dp, pudp);

	}



	pudp = pud_offset(p4dp, dst_addr);

	if (pud_none(READ_ONCE(*pudp))) {

		pmdp = (void *)get_safe_page(GFP_ATOMIC);

		if (!pmdp)

			return -ENOMEM;

		pud_populate(&init_mm, pudp, pmdp);

	}



	pmdp = pmd_offset(pudp, dst_addr);

	if (pmd_none(READ_ONCE(*pmdp))) {

		ptep = (void *)get_safe_page(GFP_ATOMIC);

		if (!ptep)

			return -ENOMEM;

		pmd_populate_kernel(&init_mm, pmdp, ptep);

	}



	ptep = pte_offset_kernel(pmdp, dst_addr);

	set_pte(ptep, pfn_pte(virt_to_pfn(page), PAGE_KERNEL_EXEC));



	return 0;

}