From: James Morse <james.morse@arm.com>
To: stable@vger.kernel.org, linux-arm-kernel@lists.infradead.org
Cc: Catalin Marinas <catalin.marinas@arm.com>,
James Morse <james.morse@arm.com>,
Sumit Gupta <sumitg@nvidia.com>
Subject: [stable:PATCH v4.9.323] arm64: entry: Restore tramp_map_kernel ISB
Date: Thu, 14 Jul 2022 17:22:25 +0100 [thread overview]
Message-ID: <20220714162225.280073-1-james.morse@arm.com> (raw)
Summit reports that the BHB backports for v4.9 prevent vulnerable
platforms from booting when CONFIG_RANDOMIZE_BASE is enabled.
This is because the trampoline code takes a translation fault when
accessing the data page, because the TTBR write hasn't been completed
by an ISB before the access is made.
Upstream has a complex erratum workaround for QCOM_FALKOR_E1003 in
this area, which removes the ISB when the workaround has been applied.
v4.9 lacks this workaround, but should still have the ISB.
Restore the barrier.
Fixes: aee10c2dd013 ("arm64: entry: Add macro for reading symbol addresses from the trampoline")
Reported-by: Sumit Gupta <sumitg@nvidia.com>
Tested-by: Sumit Gupta <sumitg@nvidia.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: James Morse <james.morse@arm.com>
---
This only applies to the v4.9 backport, as v4.14 has the QCOM_FALKOR_E1003
workaround.
arch/arm64/kernel/entry.S | 1 +
1 file changed, 1 insertion(+)
diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
index 1f79abb1e5dd..4551c0f35fc4 100644
--- a/arch/arm64/kernel/entry.S
+++ b/arch/arm64/kernel/entry.S
@@ -964,6 +964,7 @@ __ni_sys_trace:
b .
2:
tramp_map_kernel x30
+ isb
tramp_data_read_var x30, vectors
prfm plil1strm, [x30, #(1b - \vector_start)]
msr vbar_el1, x30
--
2.30.2
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next reply other threads:[~2022-07-14 16:23 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-14 16:22 James Morse [this message]
2022-07-14 18:33 ` Patch "arm64: entry: Restore tramp_map_kernel ISB" has been added to the 4.9-stable tree gregkh
2022-07-14 18:33 ` [stable:PATCH v4.9.323] arm64: entry: Restore tramp_map_kernel ISB Greg KH
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