| From f0b2351f6ab425b8672ba6f74a842f1ab83e5d3c Mon Sep 17 00:00:00 2001 |
| From: James Morse <james.morse@arm.com> |
| Date: Thu, 24 Jan 2019 16:32:55 +0000 |
| Subject: 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 | 6 +++--- |
| 1 file changed, 3 insertions(+), 3 deletions(-) |
| |
| diff --git a/arch/arm64/kernel/probes/kprobes.c b/arch/arm64/kernel/probes/kprobes.c |
| index b5a367d4bba6..30bb13797034 100644 |
| --- a/arch/arm64/kernel/probes/kprobes.c |
| +++ b/arch/arm64/kernel/probes/kprobes.c |
| @@ -478,13 +478,13 @@ bool arch_within_kprobe_blacklist(unsigned long addr) |
| addr < (unsigned long)__entry_text_end) || |
| (addr >= (unsigned long)__idmap_text_start && |
| addr < (unsigned long)__idmap_text_end) || |
| + (addr >= (unsigned long)__hyp_text_start && |
| + addr < (unsigned long)__hyp_text_end) || |
| !!search_exception_tables(addr)) |
| return true; |
| |
| if (!is_kernel_in_hyp_mode()) { |
| - if ((addr >= (unsigned long)__hyp_text_start && |
| - addr < (unsigned long)__hyp_text_end) || |
| - (addr >= (unsigned long)__hyp_idmap_text_start && |
| + if ((addr >= (unsigned long)__hyp_idmap_text_start && |
| addr < (unsigned long)__hyp_idmap_text_end)) |
| return true; |
| } |
| -- |
| 2.19.1 |
| |
