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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	stable@vger.kernel.org, Marc Zyngier <marc.zyngier@arm.com>,
	Ard Biesheuvel <ard.biesheuvel@linaro.org>,
	Russell King <rmk+kernel@armlinux.org.uk>
Subject: [PATCH 4.9 14/41] ARM: 8857/1: efi: enable CP15 DMB instructions before cleaning the cache
Date: Tue, 30 Apr 2019 13:38:25 +0200	[thread overview]
Message-ID: <20190430113528.465419917@linuxfoundation.org> (raw)
In-Reply-To: <20190430113524.451237916@linuxfoundation.org>

From: Ard Biesheuvel <ard.biesheuvel@linaro.org>

commit e17b1af96b2afc38e684aa2f1033387e2ed10029 upstream.

The EFI stub is entered with the caches and MMU enabled by the
firmware, and once the stub is ready to hand over to the decompressor,
we clean and disable the caches.

The cache clean routines use CP15 barrier instructions, which can be
disabled via SCTLR. Normally, when using the provided cache handling
routines to enable the caches and MMU, this bit is enabled as well.
However, but since we entered the stub with the caches already enabled,
this routine is not executed before we call the cache clean routines,
resulting in undefined instruction exceptions if the firmware never
enabled this bit.

So set the bit explicitly in the EFI entry code, but do so in a way that
guarantees that the resulting code can still run on v6 cores as well
(which are guaranteed to have CP15 barriers enabled)

Cc: <stable@vger.kernel.org> # v4.9+
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 arch/arm/boot/compressed/head.S |   16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

--- a/arch/arm/boot/compressed/head.S
+++ b/arch/arm/boot/compressed/head.S
@@ -1383,7 +1383,21 @@ ENTRY(efi_stub_entry)
 
 		@ Preserve return value of efi_entry() in r4
 		mov	r4, r0
-		bl	cache_clean_flush
+
+		@ our cache maintenance code relies on CP15 barrier instructions
+		@ but since we arrived here with the MMU and caches configured
+		@ by UEFI, we must check that the CP15BEN bit is set in SCTLR.
+		@ Note that this bit is RAO/WI on v6 and earlier, so the ISB in
+		@ the enable path will be executed on v7+ only.
+		mrc	p15, 0, r1, c1, c0, 0	@ read SCTLR
+		tst	r1, #(1 << 5)		@ CP15BEN bit set?
+		bne	0f
+		orr	r1, r1, #(1 << 5)	@ CP15 barrier instructions
+		mcr	p15, 0, r1, c1, c0, 0	@ write SCTLR
+ ARM(		.inst	0xf57ff06f		@ v7+ isb	)
+ THUMB(		isb						)
+
+0:		bl	cache_clean_flush
 		bl	cache_off
 
 		@ Set parameters for booting zImage according to boot protocol



  parent reply	other threads:[~2019-04-30 12:08 UTC|newest]

Thread overview: 48+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-04-30 11:38 [PATCH 4.9 00/41] 4.9.172-stable review Greg Kroah-Hartman
2019-04-30 11:38 ` [PATCH 4.9 01/41] kbuild: simplify ld-option implementation Greg Kroah-Hartman
2019-04-30 11:38 ` [PATCH 4.9 02/41] cifs: do not attempt cifs operation on smb2+ rename error Greg Kroah-Hartman
2019-04-30 11:38 ` [PATCH 4.9 03/41] tracing: Fix a memory leak by early error exit in trace_pid_write() Greg Kroah-Hartman
2019-04-30 11:38 ` [PATCH 4.9 04/41] MIPS: scall64-o32: Fix indirect syscall number load Greg Kroah-Hartman
2019-04-30 11:38 ` [PATCH 4.9 05/41] trace: Fix preempt_enable_no_resched() abuse Greg Kroah-Hartman
2019-04-30 11:38 ` [PATCH 4.9 06/41] IB/rdmavt: Fix frwr memory registration Greg Kroah-Hartman
2019-04-30 11:38 ` [PATCH 4.9 07/41] sched/numa: Fix a possible divide-by-zero Greg Kroah-Hartman
2019-04-30 11:38 ` [PATCH 4.9 08/41] ceph: ensure d_name stability in ceph_dentry_hash() Greg Kroah-Hartman
2019-04-30 11:38 ` [PATCH 4.9 09/41] ceph: fix ci->i_head_snapc leak Greg Kroah-Hartman
2019-04-30 11:38 ` [PATCH 4.9 10/41] nfsd: Dont release the callback slot unless it was actually held Greg Kroah-Hartman
2019-04-30 11:38 ` [PATCH 4.9 11/41] sunrpc: dont mark uninitialised items as VALID Greg Kroah-Hartman
2019-04-30 11:38 ` [PATCH 4.9 12/41] Input: synaptics-rmi4 - write config register values to the right offset Greg Kroah-Hartman
2019-04-30 11:38 ` [PATCH 4.9 13/41] dmaengine: sh: rcar-dmac: With cyclic DMA residue 0 is valid Greg Kroah-Hartman
2019-04-30 11:38 ` Greg Kroah-Hartman [this message]
2019-04-30 11:38 ` [PATCH 4.9 15/41] drm/vc4: Fix memory leak during gpu reset Greg Kroah-Hartman
2019-04-30 11:38 ` [PATCH 4.9 16/41] drm/vc4: Fix compilation error reported by kbuild test bot Greg Kroah-Hartman
2019-04-30 11:38 ` [PATCH 4.9 17/41] USB: Add new USB LPM helpers Greg Kroah-Hartman
2019-04-30 11:38 ` [PATCH 4.9 18/41] USB: Consolidate LPM checks to avoid enabling LPM twice Greg Kroah-Hartman
2019-04-30 11:38 ` [PATCH 4.9 19/41] vsock/virtio: fix kernel panic from virtio_transport_reset_no_sock Greg Kroah-Hartman
2019-04-30 11:38 ` [PATCH 4.9 20/41] tipc: handle the err returned from cmd header function Greg Kroah-Hartman
2019-04-30 11:38 ` [PATCH 4.9 21/41] slip: make slhc_free() silently accept an error pointer Greg Kroah-Hartman
2019-04-30 11:38 ` [PATCH 4.9 22/41] intel_th: gth: Fix an off-by-one in output unassigning Greg Kroah-Hartman
2019-04-30 11:38 ` [PATCH 4.9 23/41] fs/proc/proc_sysctl.c: Fix a NULL pointer dereference Greg Kroah-Hartman
2019-04-30 11:38 ` [PATCH 4.9 24/41] NFS: Forbid setting AF_INET6 to "struct sockaddr_in"->sin_family Greg Kroah-Hartman
2019-04-30 11:38 ` [PATCH 4.9 25/41] netfilter: ebtables: CONFIG_COMPAT: drop a bogus WARN_ON Greg Kroah-Hartman
2019-04-30 11:38 ` [PATCH 4.9 26/41] fm10k: Fix a potential NULL pointer dereference Greg Kroah-Hartman
2019-04-30 11:38 ` [PATCH 4.9 27/41] tipc: check bearer name with right length in tipc_nl_compat_bearer_enable Greg Kroah-Hartman
2019-04-30 11:38 ` [PATCH 4.9 28/41] tipc: check link name with right length in tipc_nl_compat_link_set Greg Kroah-Hartman
2019-04-30 11:38 ` [PATCH 4.9 29/41] Revert "block/loop: Use global lock for ioctl() operation." Greg Kroah-Hartman
2019-04-30 11:38 ` [PATCH 4.9 30/41] ipv4: add sanity checks in ipv4_link_failure() Greg Kroah-Hartman
2019-04-30 11:38 ` [PATCH 4.9 31/41] mlxsw: spectrum: Fix autoneg status in ethtool Greg Kroah-Hartman
2019-04-30 11:38 ` [PATCH 4.9 32/41] net/mlx5e: ethtool, Remove unsupported SFP EEPROM high pages query Greg Kroah-Hartman
2019-04-30 11:38 ` [PATCH 4.9 33/41] net: rds: exchange of 8K and 1M pool Greg Kroah-Hartman
2019-04-30 11:38 ` [PATCH 4.9 34/41] team: fix possible recursive locking when add slaves Greg Kroah-Hartman
2019-04-30 11:38 ` [PATCH 4.9 35/41] net: stmmac: move stmmac_check_ether_addr() to driver probe Greg Kroah-Hartman
2019-04-30 11:38 ` [PATCH 4.9 36/41] ipv4: set the tcp_min_rtt_wlen range from 0 to one day Greg Kroah-Hartman
2019-04-30 11:38 ` [PATCH 4.9 37/41] ipv6: frags: fix a lockdep false positive Greg Kroah-Hartman
2019-04-30 11:38 ` [PATCH 4.9 38/41] net: IP defrag: encapsulate rbtree defrag code into callable functions Greg Kroah-Hartman
2019-04-30 11:38 ` [PATCH 4.9 39/41] ipv6: remove dependency of nf_defrag_ipv6 on ipv6 module Greg Kroah-Hartman
2019-04-30 11:38 ` [PATCH 4.9 40/41] net: IP6 defrag: use rbtrees for IPv6 defrag Greg Kroah-Hartman
2019-04-30 11:38 ` [PATCH 4.9 41/41] net: IP6 defrag: use rbtrees in nf_conntrack_reasm.c Greg Kroah-Hartman
2019-04-30 22:26 ` [PATCH 4.9 00/41] 4.9.172-stable review kernelci.org bot
2019-04-30 22:30 ` shuah
2019-05-01  6:01 ` Naresh Kamboju
2019-05-01  8:24 ` Jon Hunter
2019-05-01  8:24   ` Jon Hunter
2019-05-01 16:43 ` Guenter Roeck

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