Commit 8e2d4340 authored by Will Deacon's avatar Will Deacon Committed by Linus Torvalds
Browse files

lib/ioremap: ensure break-before-make is used for huge p4d mappings 

Whilst no architectures actually enable support for huge p4d mappings in
the vmap area, the code that is implemented should be using
break-before-make, as we do for pud and pmd huge entries.

Link: http://lkml.kernel.org/r/1544120495-17438-6-git-send-email-will.deacon@arm.com


Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
Reviewed-by: default avatarToshi Kani <toshi.kani@hpe.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: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 36ddc5a7

arch/arm64/mm/mmu.c

+5 −0
Original line number Diff line number Diff line
@@ -1043,6 +1043,11 @@ int pud_free_pmd_page(pud_t *pudp, unsigned long addr) 
	return 1;

}



int p4d_free_pud_page(p4d_t *p4d, unsigned long addr)

{

	return 0;	/* Don't attempt a block mapping */

}



#ifdef CONFIG_MEMORY_HOTPLUG

int arch_add_memory(int nid, u64 start, u64 size, struct vmem_altmap *altmap,

		    bool want_memblock)

arch/x86/mm/pgtable.c

+8 −0
Original line number Diff line number Diff line
@@ -794,6 +794,14 @@ int pmd_clear_huge(pmd_t *pmd) 
	return 0;

}



/*

 * Until we support 512GB pages, skip them in the vmap area.

 */

int p4d_free_pud_page(p4d_t *p4d, unsigned long addr)

{

	return 0;

}



#ifdef CONFIG_X86_64

/**

 * pud_free_pmd_page - Clear pud entry and free pmd page.

include/asm-generic/pgtable.h

+5 −0
Original line number Diff line number Diff line
@@ -1057,6 +1057,7 @@ int pud_set_huge(pud_t *pud, phys_addr_t addr, pgprot_t prot); 
int pmd_set_huge(pmd_t *pmd, phys_addr_t addr, pgprot_t prot);

int pud_clear_huge(pud_t *pud);

int pmd_clear_huge(pmd_t *pmd);

int p4d_free_pud_page(p4d_t *p4d, unsigned long addr);

int pud_free_pmd_page(pud_t *pud, unsigned long addr);

int pmd_free_pte_page(pmd_t *pmd, unsigned long addr);

#else	/* !CONFIG_HAVE_ARCH_HUGE_VMAP */
@@ -1084,6 +1085,10 @@ static inline int pmd_clear_huge(pmd_t *pmd) 
{

	return 0;

}

static inline int p4d_free_pud_page(p4d_t *p4d, unsigned long addr)

{

	return 0;

}

static inline int pud_free_pmd_page(pud_t *pud, unsigned long addr)

{

	return 0;

lib/ioremap.c

+21 −6
Original line number Diff line number Diff line
@@ -156,6 +156,25 @@ static inline int ioremap_pud_range(p4d_t *p4d, unsigned long addr, 
	return 0;

}



static int ioremap_try_huge_p4d(p4d_t *p4d, unsigned long addr,

				unsigned long end, phys_addr_t phys_addr,

				pgprot_t prot)

{

	if (!ioremap_p4d_enabled())

		return 0;



	if ((end - addr) != P4D_SIZE)

		return 0;



	if (!IS_ALIGNED(phys_addr, P4D_SIZE))

		return 0;



	if (p4d_present(*p4d) && !p4d_free_pud_page(p4d, addr))

		return 0;



	return p4d_set_huge(p4d, phys_addr, prot);

}



static inline int ioremap_p4d_range(pgd_t *pgd, unsigned long addr,

		unsigned long end, phys_addr_t phys_addr, pgprot_t prot)

{
@@ -168,12 +187,8 @@ static inline int ioremap_p4d_range(pgd_t *pgd, unsigned long addr, 
	do {

		next = p4d_addr_end(addr, end);



		if (ioremap_p4d_enabled() &&

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

		    IS_ALIGNED(phys_addr, P4D_SIZE)) {

			if (p4d_set_huge(p4d, phys_addr, prot))

		if (ioremap_try_huge_p4d(p4d, addr, next, phys_addr, prot))

			continue;

		}



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

			return -ENOMEM;

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