From: James Morse <james.morse@arm.com>
To: linux-arm-kernel@lists.infradead.org
Cc: Marc Zyngier <marc.zyngier@arm.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will.deacon@arm.com>,
Christoffer Dall <christoffer.dall@arm.com>,
james.morse@arm.com, Masami Hiramatsu <mhiramat@kernel.org>,
kvmarm@lists.cs.columbia.edu
Subject: [PATCH v2 3/4] arm64: hyp-stub: Forbid kprobing of the hyp-stub
Date: Thu, 24 Jan 2019 16:32:56 +0000 [thread overview]
Message-ID: <20190124163257.233929-4-james.morse@arm.com> (raw)
In-Reply-To: <20190124163257.233929-1-james.morse@arm.com>
The hyp-stub is loaded by the kernel's early startup code at EL2
during boot, before KVM takes ownership later. The hyp-stub's
text is part of the regular kernel text, meaning it can be kprobed.
A breakpoint in the hyp-stub causes the CPU to spin in el2_sync_invalid.
Add it to the __hyp_text.
Signed-off-by: James Morse <james.morse@arm.com>
Cc: stable@vger.kernel.org
---
This has been a problem since kprobes was merged, it should
probably have been covered in 888b3c8720e0.
I'm not sure __hyp_text is the right place. Its not idmaped,
and as it contains a set of vectors, adding it to the host/hyp
idmap sections could grow them beyond a page... but it does
run with the MMU off, so does need to be cleaned to PoC when
anything wacky, like hibernate happens. With this patch,
hibernate should clean the __hyp_text to PoC too.
---
arch/arm64/kernel/hyp-stub.S | 2 ++
1 file changed, 2 insertions(+)
diff --git a/arch/arm64/kernel/hyp-stub.S b/arch/arm64/kernel/hyp-stub.S
index e1261fbaa374..17f325ba831e 100644
--- a/arch/arm64/kernel/hyp-stub.S
+++ b/arch/arm64/kernel/hyp-stub.S
@@ -28,6 +28,8 @@
#include <asm/virt.h>
.text
+ .pushsection .hyp.text, "ax"
+
.align 11
ENTRY(__hyp_stub_vectors)
--
2.20.1
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next prev parent reply other threads:[~2019-01-24 16:34 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-24 16:32 [PATCH v2 0/4] Fix some KVM/HYP interactions with kprobes James Morse
2019-01-24 16:32 ` [PATCH v2 1/4] KVM: arm64: Forbid kprobing of the VHE world-switch code James Morse
2019-01-25 1:28 ` Masami Hiramatsu
2019-01-31 8:08 ` Christoffer Dall
2019-01-31 18:53 ` James Morse
2019-02-01 8:04 ` Christoffer Dall
2019-02-01 13:34 ` Marc Zyngier
2019-01-24 16:32 ` [PATCH v2 2/4] arm64: kprobe: Always blacklist the KVM " James Morse
2019-01-31 8:08 ` Christoffer Dall
2019-01-24 16:32 ` James Morse [this message]
2019-01-31 8:04 ` [PATCH v2 3/4] arm64: hyp-stub: Forbid kprobing of the hyp-stub Christoffer Dall
2019-02-01 12:02 ` James Morse
2019-01-24 16:32 ` [PATCH v2 4/4] arm64: hibernate: Clean the __hyp_text to PoC after resume James Morse
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