Commit 36ddc5a7 authored by Will Deacon's avatar Will Deacon Committed by Linus Torvalds
Browse files

lib/ioremap: ensure phys_addr actually corresponds to a physical address 

The current ioremap() code uses a phys_addr variable at each level of page
table, which is confusingly offset by subtracting the base virtual address
being mapped so that adding the current virtual address back on when
iterating through the page table entries gives back the corresponding
physical address.

This is fairly confusing and results in all users of phys_addr having to
add the current virtual address back on.  Instead, this patch just updates
phys_addr when iterating over the page table entries, ensuring that it's
always up-to-date and doesn't require explicit offsetting.

Link: http://lkml.kernel.org/r/1544120495-17438-5-git-send-email-will.deacon@arm.com


Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
Tested-by: default avatarSean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: default avatarSean Christopherson <sean.j.christopherson@intel.com>
Cc: Chintan Pandya <cpandya@codeaurora.org>
Cc: Toshi Kani <toshi.kani@hpe.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 48e178ab

lib/ioremap.c

+12 −16
Original line number Diff line number Diff line
@@ -101,19 +101,18 @@ static inline int ioremap_pmd_range(pud_t *pud, unsigned long addr, 
	pmd_t *pmd;

	unsigned long next;



	phys_addr -= addr;

	pmd = pmd_alloc(&init_mm, pud, addr);

	if (!pmd)

		return -ENOMEM;

	do {

		next = pmd_addr_end(addr, end);



		if (ioremap_try_huge_pmd(pmd, addr, next, phys_addr + addr, prot))

		if (ioremap_try_huge_pmd(pmd, addr, next, phys_addr, prot))

			continue;



		if (ioremap_pte_range(pmd, addr, next, phys_addr + addr, prot))

		if (ioremap_pte_range(pmd, addr, next, phys_addr, prot))

			return -ENOMEM;

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

	} while (pmd++, phys_addr += (next - addr), addr = next, addr != end);

	return 0;

}
@@ -142,19 +141,18 @@ static inline int ioremap_pud_range(p4d_t *p4d, unsigned long addr, 
	pud_t *pud;

	unsigned long next;



	phys_addr -= addr;

	pud = pud_alloc(&init_mm, p4d, addr);

	if (!pud)

		return -ENOMEM;

	do {

		next = pud_addr_end(addr, end);



		if (ioremap_try_huge_pud(pud, addr, next, phys_addr + addr, prot))

		if (ioremap_try_huge_pud(pud, addr, next, phys_addr, prot))

			continue;



		if (ioremap_pmd_range(pud, addr, next, phys_addr + addr, prot))

		if (ioremap_pmd_range(pud, addr, next, phys_addr, prot))

			return -ENOMEM;

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

	} while (pud++, phys_addr += (next - addr), addr = next, addr != end);

	return 0;

}
@@ -164,7 +162,6 @@ static inline int ioremap_p4d_range(pgd_t *pgd, unsigned long addr, 
	p4d_t *p4d;

	unsigned long next;



	phys_addr -= addr;

	p4d = p4d_alloc(&init_mm, pgd, addr);

	if (!p4d)

		return -ENOMEM;
@@ -173,14 +170,14 @@ static inline int ioremap_p4d_range(pgd_t *pgd, unsigned long addr, 


		if (ioremap_p4d_enabled() &&

		    ((next - addr) == P4D_SIZE) &&

		    IS_ALIGNED(phys_addr + addr, P4D_SIZE)) {

			if (p4d_set_huge(p4d, phys_addr + addr, prot))

		    IS_ALIGNED(phys_addr, P4D_SIZE)) {

			if (p4d_set_huge(p4d, phys_addr, prot))

				continue;

		}



		if (ioremap_pud_range(p4d, addr, next, phys_addr + addr, prot))

		if (ioremap_pud_range(p4d, addr, next, phys_addr, prot))

			return -ENOMEM;

	} while (p4d++, addr = next, addr != end);

	} while (p4d++, phys_addr += (next - addr), addr = next, addr != end);

	return 0;

}
@@ -196,14 +193,13 @@ int ioremap_page_range(unsigned long addr, 
	BUG_ON(addr >= end);



	start = addr;

	phys_addr -= addr;

	pgd = pgd_offset_k(addr);

	do {

		next = pgd_addr_end(addr, end);

		err = ioremap_p4d_range(pgd, addr, next, phys_addr+addr, prot);

		err = ioremap_p4d_range(pgd, addr, next, phys_addr, prot);

		if (err)

			break;

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

	} while (pgd++, phys_addr += (next - addr), addr = next, addr != end);



	flush_cache_vmap(start, end);

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