]> git.ipfire.org Git - people/arne_f/kernel.git/commit
arm64: kprobe: Always blacklist the KVM world-switch code
authorJames Morse <james.morse@arm.com>
Thu, 24 Jan 2019 16:32:55 +0000 (16:32 +0000)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Wed, 13 Mar 2019 21:04:57 +0000 (14:04 -0700)
commit32d14df09a909fb333734e63c2f2e4facaead26b
tree0ebfd8e4f0dc473931b9ecfeb2af2d8f5760a32a
parent2b0ac76f1c943463d156d54c63f8555ca429fd34
arm64: kprobe: Always blacklist the KVM world-switch code

[ Upstream commit f2b3d8566d81deaca31f4e3163def0bea7746e11 ]

On systems with VHE the kernel and KVM's world-switch code run at the
same exception level. Code that is only used on a VHE system does not
need to be annotated as __hyp_text as it can reside anywhere in the
 kernel text.

__hyp_text was also used to prevent kprobes from patching breakpoint
instructions into this region, as this code runs at a different
exception level. While this is no longer true with VHE, KVM still
switches VBAR_EL1, meaning a kprobe's breakpoint executed in the
world-switch code will cause a hyp-panic.

Move the __hyp_text check in the kprobes blacklist so it applies on
VHE systems too, to cover the common code and guest enter/exit
assembly.

Fixes: 888b3c8720e0 ("arm64: Treat all entry code as non-kprobe-able")
Reviewed-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: James Morse <james.morse@arm.com>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
arch/arm64/kernel/probes/kprobes.c