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Date: Thu, 19 Sep 2013 16:54:47 +0200 From: Borislav Petkov <bp@...en8.de> To: X86 ML <x86@...nel.org> Cc: LKML <linux-kernel@...r.kernel.org>, Borislav Petkov <bp@...e.de>, Matt Fleming <matt@...sole-pimps.org>, Matthew Garrett <mjg59@...f.ucam.org>, "H. Peter Anvin" <hpa@...or.com>, James Bottomley <James.Bottomley@...senPartnership.com>, Vivek Goyal <vgoyal@...hat.com>, Dave Young <dyoung@...hat.com>, linux-efi@...r.kernel.org Subject: [PATCH 04/11] x86, pageattr: Add a PGD pagetable populating function From: Borislav Petkov <bp@...e.de> This allocates, if necessary, and populates the corresponding PGD entry with a PUD page. The next population level is a dummy macro which will be removed by the next patch and it is added here to keep the patch small and easily reviewable but not break bisection, at the same time. Signed-off-by: Borislav Petkov <bp@...e.de> --- arch/x86/mm/pageattr.c | 39 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 39 insertions(+) diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c index c53de62a1170..21a31e85283c 100644 --- a/arch/x86/mm/pageattr.c +++ b/arch/x86/mm/pageattr.c @@ -666,6 +666,45 @@ static int split_large_page(pte_t *kpte, unsigned long address) return 0; } +#define populate_pud(cpa, addr, pgd, pgprot) (-1) + +/* + * Restrictions for kernel page table do not necessarily apply when mapping in + * an alternate PGD. + */ +static int populate_pgd(struct cpa_data *cpa, unsigned long addr) +{ + pgprot_t pgprot = __pgprot(_KERNPG_TABLE); + bool allocd_pgd = false; + pgd_t *pgd_entry; + pud_t *pud; + int ret; + + pgd_entry = cpa->pgd + pgd_index(addr); + + /* + * Allocate a PUD page and hand it down for mapping. + */ + if (pgd_none(*pgd_entry)) { + pud = (pud_t *)get_zeroed_page(GFP_KERNEL | __GFP_NOTRACK); + if (!pud) + return -1; + + set_pgd(pgd_entry, __pgd(__pa(pud) | _KERNPG_TABLE)); + allocd_pgd = true; + } + + pgprot_val(pgprot) &= ~pgprot_val(cpa->mask_clr); + pgprot_val(pgprot) |= pgprot_val(cpa->mask_set); + + ret = populate_pud(cpa, addr, pgd_entry, pgprot); + if (ret < 0) + return ret; + + cpa->numpages = ret; + return 0; +} + static int __cpa_process_fault(struct cpa_data *cpa, unsigned long vaddr, int primary) { -- 1.8.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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