linux-kernel - [ 045/262] ARM: 7501/1: decompressor: reset ttbcr for VMSA ARMv7 cores

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]

Date:	Fri, 28 Sep 2012 11:49:34 -0700
From:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:	linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:	Greg KH <gregkh@...uxfoundation.org>, alan@...rguk.ukuu.org.uk,
	Nicolas Pitre <nico@...aro.org>,
	Matthew Leach <matthew.leach@....com>,
	Will Deacon <will.deacon@....com>,
	Russell King <rmk+kernel@....linux.org.uk>
Subject: [ 045/262] ARM: 7501/1: decompressor: reset ttbcr for VMSA ARMv7 cores

From: Greg KH <gregkh@...uxfoundation.org>

3.5-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Will Deacon <will.deacon@....com>

commit dbece45894d3ab1baac15a96dc4e1e8e23f64a93 upstream.

When enabling the MMU for ARMv7 CPUs, the decompressor does not touch
the ttbcr register, assuming that it will be zeroed (N == 0, EAE == 0).
Given that only EAE is defined as 0 for non-secure copies of the
register (and a bootloader such as kexec may leave it set to 1 anyway),
we should ensure that we reset the register ourselves before turning on
the MMU.

This patch zeroes TTBCR.EAE and TTBCR.N prior to enabling the MMU for
ARMv7 cores in the decompressor, configuring us exclusively for 32-bit
translation tables via TTBR0.

Acked-by: Nicolas Pitre <nico@...aro.org>
Signed-off-by: Matthew Leach <matthew.leach@....com>
Signed-off-by: Will Deacon <will.deacon@....com>
Signed-off-by: Russell King <rmk+kernel@....linux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 arch/arm/boot/compressed/head.S |    4 ++++
 1 file changed, 4 insertions(+)

--- a/arch/arm/boot/compressed/head.S
+++ b/arch/arm/boot/compressed/head.S
@@ -659,10 +659,14 @@ __armv7_mmu_cache_on:
 #ifdef CONFIG_CPU_ENDIAN_BE8
 		orr	r0, r0, #1 << 25	@ big-endian page tables
 #endif
+		mrcne   p15, 0, r6, c2, c0, 2   @ read ttb control reg
 		orrne	r0, r0, #1		@ MMU enabled
 		movne	r1, #0xfffffffd		@ domain 0 = client
+		bic     r6, r6, #1 << 31        @ 32-bit translation system
+		bic     r6, r6, #3 << 0         @ use only ttbr0
 		mcrne	p15, 0, r3, c2, c0, 0	@ load page table pointer
 		mcrne	p15, 0, r1, c3, c0, 0	@ load domain access control
+		mcrne   p15, 0, r6, c2, c0, 2   @ load ttb control
 #endif
 		mcr	p15, 0, r0, c7, c5, 4	@ ISB
 		mcr	p15, 0, r0, c1, c0, 0	@ load control register


--
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/