linux-kernel - [tip:x86/mm] x86/boot/compressed/64: Use stack from trampoline memory

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-f7ff53e4702be9ac49deacd518dd243de45c9980@git.kernel.org>
Date:   Mon, 12 Mar 2018 05:19:14 -0700
From:   "tip-bot for Kirill A. Shutemov" <tipbot@...or.com>
To:     linux-tip-commits@...r.kernel.org
Cc:     mingo@...nel.org, linux-kernel@...r.kernel.org, luto@...nel.org,
        tglx@...utronix.de, peterz@...radead.org, bp@...e.de,
        gorcunov@...nvz.org, jpoimboe@...hat.com, dvlasenk@...hat.com,
        bp@...en8.de, brgerst@...il.com, hpa@...or.com,
        luto@...capital.net, willy@...radead.org,
        torvalds@...ux-foundation.org, kirill.shutemov@...ux.intel.com
Subject: [tip:x86/mm] x86/boot/compressed/64: Use stack from trampoline
 memory

Commit-ID:  f7ff53e4702be9ac49deacd518dd243de45c9980
Gitweb:     https://git.kernel.org/tip/f7ff53e4702be9ac49deacd518dd243de45c9980
Author:     Kirill A. Shutemov <kirill.shutemov@...ux.intel.com>
AuthorDate: Mon, 12 Mar 2018 13:02:44 +0300
Committer:  Ingo Molnar <mingo@...nel.org>
CommitDate: Mon, 12 Mar 2018 11:49:24 +0100

x86/boot/compressed/64: Use stack from trampoline memory

As the first step on using trampoline memory, let's make 32-bit code use
stack there.

Separate stack is required to return back from trampoline and we cannot
user stack from 64-bit mode as it may be above 4G.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@...ux.intel.com>
Cc: Andy Lutomirski <luto@...capital.net>
Cc: Andy Lutomirski <luto@...nel.org>
Cc: Borislav Petkov <bp@...en8.de>
Cc: Borislav Petkov <bp@...e.de>
Cc: Brian Gerst <brgerst@...il.com>
Cc: Cyrill Gorcunov <gorcunov@...nvz.org>
Cc: Denys Vlasenko <dvlasenk@...hat.com>
Cc: H. Peter Anvin <hpa@...or.com>
Cc: Josh Poimboeuf <jpoimboe@...hat.com>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Matthew Wilcox <willy@...radead.org>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: linux-mm@...ck.org
Link: http://lkml.kernel.org/r/20180312100246.89175-3-kirill.shutemov@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@...nel.org>
---
 arch/x86/boot/compressed/head_64.S | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S
index f0c3a2f7e528..12915511be61 100644
--- a/arch/x86/boot/compressed/head_64.S
+++ b/arch/x86/boot/compressed/head_64.S
@@ -33,6 +33,7 @@
 #include <asm/processor-flags.h>
 #include <asm/asm-offsets.h>
 #include <asm/bootparam.h>
+#include "pgtable.h"
 
 /*
  * Locally defined symbols should be marked hidden:
@@ -359,6 +360,8 @@ ENTRY(startup_64)
 	pushq	%rax
 	lretq
 lvl5:
+	/* Restore the stack, the 32-bit trampoline uses its own stack */
+	leaq	boot_stack_end(%rbx), %rsp
 
 	/*
 	 * cleanup_trampoline() would restore trampoline memory.
@@ -513,6 +516,9 @@ compatible_mode:
 	movl	%eax, %ds
 	movl	%eax, %ss
 
+	/* Set up new stack */
+	leal	TRAMPOLINE_32BIT_STACK_END(%ecx), %esp
+
 	/* Disable paging */
 	movl	%cr0, %eax
 	btrl	$X86_CR0_PG_BIT, %eax