linux-kernel - [tip:x86/efi] x86/efi: Map RAM into the identity page table for mixed mode

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <tip-b61a76f8850d2979550abc42d7e09154ebb8d785@git.kernel.org>
Date:	Sun, 29 Nov 2015 01:04:24 -0800
From:	tip-bot for Matt Fleming <tipbot@...or.com>
To:	linux-tip-commits@...r.kernel.org
Cc:	hpa@...or.com, torvalds@...ux-foundation.org,
	sai.praneeth.prakhya@...el.com, peterz@...radead.org,
	luto@...capital.net, linux-kernel@...r.kernel.org,
	dvlasenk@...hat.com, mingo@...nel.org, ard.biesheuvel@...aro.org,
	tglx@...utronix.de, bp@...e.de, bp@...en8.de,
	matt@...eblueprint.co.uk, brgerst@...il.com, toshi.kani@...com
Subject: [tip:x86/efi] x86/efi:
  Map RAM into the identity page table for mixed mode

Commit-ID:  b61a76f8850d2979550abc42d7e09154ebb8d785
Gitweb:     http://git.kernel.org/tip/b61a76f8850d2979550abc42d7e09154ebb8d785
Author:     Matt Fleming <matt@...eblueprint.co.uk>
AuthorDate: Fri, 27 Nov 2015 21:09:32 +0000
Committer:  Ingo Molnar <mingo@...nel.org>
CommitDate: Sun, 29 Nov 2015 09:15:42 +0100

x86/efi: Map RAM into the identity page table for mixed mode

We are relying on the pre-existing mappings in 'trampoline_pgd'
when accessing function arguments in the EFI mixed mode thunking
code.

Instead let's map memory explicitly so that things will continue
to work when we move to a separate page table in the future.

Signed-off-by: Matt Fleming <matt@...eblueprint.co.uk>
Reviewed-by: Borislav Petkov <bp@...e.de>
Acked-by: Borislav Petkov <bp@...e.de>
Cc: Andy Lutomirski <luto@...capital.net>
Cc: Ard Biesheuvel <ard.biesheuvel@...aro.org>
Cc: Borislav Petkov <bp@...en8.de>
Cc: Brian Gerst <brgerst@...il.com>
Cc: Denys Vlasenko <dvlasenk@...hat.com>
Cc: H. Peter Anvin <hpa@...or.com>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Sai Praneeth Prakhya <sai.praneeth.prakhya@...el.com>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Toshi Kani <toshi.kani@...com>
Cc: linux-efi@...r.kernel.org
Link: http://lkml.kernel.org/r/1448658575-17029-4-git-send-email-matt@codeblueprint.co.uk
Signed-off-by: Ingo Molnar <mingo@...nel.org>
---
 arch/x86/platform/efi/efi_64.c | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/arch/x86/platform/efi/efi_64.c b/arch/x86/platform/efi/efi_64.c
index 5aa186d..102976d 100644
--- a/arch/x86/platform/efi/efi_64.c
+++ b/arch/x86/platform/efi/efi_64.c
@@ -144,6 +144,7 @@ void efi_sync_low_kernel_mappings(void)
 int __init efi_setup_page_tables(unsigned long pa_memmap, unsigned num_pages)
 {
 	unsigned long pfn, text;
+	efi_memory_desc_t *md;
 	struct page *page;
 	unsigned npages;
 	pgd_t *pgd;
@@ -177,6 +178,25 @@ int __init efi_setup_page_tables(unsigned long pa_memmap, unsigned num_pages)
 	if (!IS_ENABLED(CONFIG_EFI_MIXED))
 		return 0;
 
+	/*
+	 * Map all of RAM so that we can access arguments in the 1:1
+	 * mapping when making EFI runtime calls.
+	 */
+	for_each_efi_memory_desc(&memmap, md) {
+		if (md->type != EFI_CONVENTIONAL_MEMORY &&
+		    md->type != EFI_LOADER_DATA &&
+		    md->type != EFI_LOADER_CODE)
+			continue;
+
+		pfn = md->phys_addr >> PAGE_SHIFT;
+		npages = md->num_pages;
+
+		if (kernel_map_pages_in_pgd(pgd, pfn, md->phys_addr, npages, 0)) {
+			pr_err("Failed to map 1:1 memory\n");
+			return 1;
+		}
+	}
+
 	page = alloc_page(GFP_KERNEL|__GFP_DMA32);
 	if (!page)
 		panic("Unable to allocate EFI runtime stack < 4GB\n");
--
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/