From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Zijlstra Subject: Re: [PATCH V3 3/5] x86/efi: Permanently save the EFI_MEMORY_MAP passed by the firmware Date: Wed, 5 Sep 2018 13:48:33 +0200 Message-ID: <20180905114833.GW24082@hirez.programming.kicks-ass.net> References: <1536099149-12564-1-git-send-email-sai.praneeth.prakhya@intel.com> <1536099149-12564-4-git-send-email-sai.praneeth.prakhya@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <1536099149-12564-4-git-send-email-sai.praneeth.prakhya@intel.com> Sender: linux-kernel-owner@vger.kernel.org To: Sai Praneeth Prakhya Cc: linux-efi@vger.kernel.org, linux-kernel@vger.kernel.org, x86@kernel.org, ricardo.neri@intel.com, matt@codeblueprint.co.uk, Al Stone , Borislav Petkov , Ingo Molnar , Andy Lutomirski , Bhupesh Sharma , Thomas Gleixner , Ard Biesheuvel List-Id: linux-efi@vger.kernel.org On Tue, Sep 04, 2018 at 03:12:27PM -0700, Sai Praneeth Prakhya wrote: > +void __init efi_save_original_memmap(void) > +{ > + efi_memory_desc_t *md; > + void *remapped_phys, *new_md; > + phys_addr_t new_phys, new_size; > + > + new_size = efi.memmap.desc_size * efi.memmap.nr_map; > + new_phys = efi_memmap_alloc(efi.memmap.nr_map); > + if (!new_phys) { > + pr_err("Failed to allocate new EFI memmap\n"); > + return; > + } > + > + remapped_phys = memremap(new_phys, new_size, MEMREMAP_WB); > + if (!remapped_phys) { > + pr_err("Failed to remap new EFI memmap\n"); > + __free_pages(pfn_to_page(PHYS_PFN(new_phys)), get_order(new_size)); > + return; > + } > + > + new_md = remapped_phys; > + for_each_efi_memory_desc(md) { > + memcpy(new_md, md, efi.memmap.desc_size); > + new_md += efi.memmap.desc_size; > + } Should we ioremap_prot(remapped_phys, new_size, PROT_NONE), here? Such that nobody can accidentally use this thing? > + original_memory_map.late = 1; > + original_memory_map.phys_map = new_phys; > + original_memory_map.map = remapped_phys; > + original_memory_map.nr_map = efi.memmap.nr_map; > + original_memory_map.desc_size = efi.memmap.desc_size; > + original_memory_map.map_end = remapped_phys + new_size; > + original_memory_map.desc_version = efi.memmap.desc_version; > + > + original_memory_map_present = true; > +} > +#endif /* CONFIG_EFI_WARN_ON_ILLEGAL_ACCESS */ > -- > 2.7.4 >