Add functions to allocate p4d/pud/pmd/pte pages for an decorated page-table and keep track of them.
Signed-off-by: Alexandre Chartre <[email protected]> --- arch/x86/mm/dpt.c | 110 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 110 insertions(+) diff --git a/arch/x86/mm/dpt.c b/arch/x86/mm/dpt.c index 44aad99bc3dc..a2f54ba00255 100644 --- a/arch/x86/mm/dpt.c +++ b/arch/x86/mm/dpt.c @@ -4,6 +4,7 @@ * */ +#include <linux/mm.h> #include <linux/slab.h> #include <asm/dpt.h> @@ -148,6 +149,115 @@ static p4d_t *dpt_p4d_offset(struct dpt *dpt, return p4d; } +/* + * dpt_pXX_alloc() functions are equivalent to kernel pXX_alloc() functions + * but, in addition, they keep track of new pages allocated for the specified + * decorated page-table. + */ + +static pte_t *dpt_pte_alloc(struct dpt *dpt, pmd_t *pmd, unsigned long addr) +{ + struct page *page; + pte_t *pte; + int err; + + if (pmd_none(*pmd)) { + page = alloc_page(GFP_KERNEL | __GFP_ZERO); + if (!page) + return ERR_PTR(-ENOMEM); + pte = (pte_t *)page_address(page); + err = dpt_add_backend_page(dpt, pte, PGT_LEVEL_PTE); + if (err) { + free_page((unsigned long)pte); + return ERR_PTR(err); + } + set_pmd_safe(pmd, __pmd(__pa(pte) | _KERNPG_TABLE)); + pte = pte_offset_map(pmd, addr); + } else { + pte = dpt_pte_offset(dpt, pmd, addr); + } + + return pte; +} + +static pmd_t *dpt_pmd_alloc(struct dpt *dpt, pud_t *pud, unsigned long addr) +{ + struct page *page; + pmd_t *pmd; + int err; + + if (pud_none(*pud)) { + page = alloc_page(GFP_KERNEL | __GFP_ZERO); + if (!page) + return ERR_PTR(-ENOMEM); + pmd = (pmd_t *)page_address(page); + err = dpt_add_backend_page(dpt, pmd, PGT_LEVEL_PMD); + if (err) { + free_page((unsigned long)pmd); + return ERR_PTR(err); + } + set_pud_safe(pud, __pud(__pa(pmd) | _KERNPG_TABLE)); + pmd = pmd_offset(pud, addr); + } else { + pmd = dpt_pmd_offset(dpt, pud, addr); + } + + return pmd; +} + +static pud_t *dpt_pud_alloc(struct dpt *dpt, p4d_t *p4d, unsigned long addr) +{ + struct page *page; + pud_t *pud; + int err; + + if (p4d_none(*p4d)) { + page = alloc_page(GFP_KERNEL | __GFP_ZERO); + if (!page) + return ERR_PTR(-ENOMEM); + pud = (pud_t *)page_address(page); + err = dpt_add_backend_page(dpt, pud, PGT_LEVEL_PUD); + if (err) { + free_page((unsigned long)pud); + return ERR_PTR(err); + } + set_p4d_safe(p4d, __p4d(__pa(pud) | _KERNPG_TABLE)); + pud = pud_offset(p4d, addr); + } else { + pud = dpt_pud_offset(dpt, p4d, addr); + } + + return pud; +} + +static p4d_t *dpt_p4d_alloc(struct dpt *dpt, pgd_t *pgd, unsigned long addr) +{ + struct page *page; + p4d_t *p4d; + int err; + + if (!pgtable_l5_enabled()) + return (p4d_t *)pgd; + + if (pgd_none(*pgd)) { + page = alloc_page(GFP_KERNEL | __GFP_ZERO); + if (!page) + return ERR_PTR(-ENOMEM); + p4d = (p4d_t *)page_address(page); + err = dpt_add_backend_page(dpt, p4d, PGT_LEVEL_P4D); + if (err) { + free_page((unsigned long)p4d); + return ERR_PTR(err); + } + set_pgd_safe(pgd, __pgd(__pa(p4d) | _KERNPG_TABLE)); + p4d = p4d_offset(pgd, addr); + } else { + p4d = dpt_p4d_offset(dpt, pgd, addr); + } + + return p4d; +} + /* * dpt_create - allocate a page-table and create a corresponding * decorated page-table. The page-table is allocated and aligned -- 2.18.2
