From: Will Deacon will.deacon@arm.com
mainline inclusion from mainline-v5.0-rc1 commit 8e2d43405b22e98cf5f3730c1829ec1fdbe17ae7 category: feature bugzilla: NA CVE: NA
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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.c... Signed-off-by: Will Deacon will.deacon@arm.com Reviewed-by: Toshi 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: Andrew Morton akpm@linux-foundation.org Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Rui Xiang rui.xiang@huawei.com Reviewed-by: Ding Tianhong dingtianhong@huawei.com Reviewed-by: Zefan Li lizefan@huawei.com Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- arch/arm64/mm/mmu.c | 5 +++++ arch/x86/mm/pgtable.c | 8 ++++++++ include/asm-generic/pgtable.h | 5 +++++ lib/ioremap.c | 27 +++++++++++++++++++++------ 4 files changed, 39 insertions(+), 6 deletions(-)
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c index 5673db3b4cc4..99a86326a301 100644 --- a/arch/arm64/mm/mmu.c +++ b/arch/arm64/mm/mmu.c @@ -1036,6 +1036,11 @@ 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) diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c index bf52106ab9c4..5b97717b389b 100644 --- a/arch/x86/mm/pgtable.c +++ b/arch/x86/mm/pgtable.c @@ -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. diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h index b96231975552..a7912c229033 100644 --- a/include/asm-generic/pgtable.h +++ b/include/asm-generic/pgtable.h @@ -1059,6 +1059,7 @@ 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 */ @@ -1086,6 +1087,10 @@ 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; diff --git a/lib/ioremap.c b/lib/ioremap.c index 10d7c5485c39..063213685563 100644 --- a/lib/ioremap.c +++ b/lib/ioremap.c @@ -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)) - continue; - } + if (ioremap_try_huge_p4d(p4d, addr, next, phys_addr, prot)) + continue;
if (ioremap_pud_range(p4d, addr, next, phys_addr, prot)) return -ENOMEM;