The HYP rodata section is currently lumped together with the BSS,
which isn't exactly what is expected (it gets registered with
kmemleak, for example).
Move it away so that it is actually marked RO. As an added
benefit, it isn't registered with kmemleak anymore.
Fixes: 380e18ade4a5 ("KVM: arm64: Introduce a BSS section for use at Hyp")
Suggested-by: Catalin Marinas <catalin.marinas(a)arm.com>
Signed-off-by: Marc Zyngier <maz(a)kernel.org>
Cc: stable(a)vger.kernel.org #5.13
---
arch/arm64/kernel/vmlinux.lds.S | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/arm64/kernel/vmlinux.lds.S b/arch/arm64/kernel/vmlinux.lds.S
index 709d2c433c5e..f6b1a88245db 100644
--- a/arch/arm64/kernel/vmlinux.lds.S
+++ b/arch/arm64/kernel/vmlinux.lds.S
@@ -181,6 +181,8 @@ SECTIONS
/* everything from this point to __init_begin will be marked RO NX */
RO_DATA(PAGE_SIZE)
+ HYPERVISOR_DATA_SECTIONS
+
idmap_pg_dir = .;
. += IDMAP_DIR_SIZE;
idmap_pg_end = .;
@@ -260,8 +262,6 @@ SECTIONS
_sdata = .;
RW_DATA(L1_CACHE_BYTES, PAGE_SIZE, THREAD_ALIGN)
- HYPERVISOR_DATA_SECTIONS
-
/*
* Data written with the MMU off but read with the MMU on requires
* cache lines to be invalidated, discarding up to a Cache Writeback
--
2.30.2
Booting a KVM host in protected mode with kmemleak quickly results
in a pretty bad crash, as kmemleak doesn't know that the HYP sections
have been taken away. This is specially true for the BSS section,
which is part of the kernel BSS section and registered at boot time
by kmemleak itself.
Unregister the HYP part of the BSS before making that section
HYP-private. The rest of the HYP-specific data is obtained via
the page allocator or lives in other sections, none of which is
subjected to kmemleak.
Fixes: 90134ac9cabb ("KVM: arm64: Protect the .hyp sections from the host")
Reviewed-by: Quentin Perret <qperret(a)google.com>
Signed-off-by: Marc Zyngier <maz(a)kernel.org>
Cc: Catalin Marinas <catalin.marinas(a)arm.com>
Cc: stable(a)vger.kernel.org # 5.13
---
arch/arm64/kvm/arm.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index e9a2b8f27792..52242f32c4be 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -15,6 +15,7 @@
#include <linux/fs.h>
#include <linux/mman.h>
#include <linux/sched.h>
+#include <linux/kmemleak.h>
#include <linux/kvm.h>
#include <linux/kvm_irqfd.h>
#include <linux/irqbypass.h>
@@ -1982,6 +1983,12 @@ static int finalize_hyp_mode(void)
if (ret)
return ret;
+ /*
+ * Exclude HYP BSS from kmemleak so that it doesn't get peeked
+ * at, which would end badly once the section is inaccessible.
+ * None of other sections should ever be introspected.
+ */
+ kmemleak_free_part(__hyp_bss_start, __hyp_bss_end - __hyp_bss_start);
ret = pkvm_mark_hyp_section(__hyp_bss);
if (ret)
return ret;
--
2.30.2
A recent change in LLVM causes module_{c,d}tor sections to appear when
CONFIG_K{A,C}SAN are enabled, which results in orphan section warnings
because these are not handled anywhere:
ld.lld: warning: arch/x86/pci/built-in.a(legacy.o):(.text.asan.module_ctor) is being placed in '.text.asan.module_ctor'
ld.lld: warning: arch/x86/pci/built-in.a(legacy.o):(.text.asan.module_dtor) is being placed in '.text.asan.module_dtor'
ld.lld: warning: arch/x86/pci/built-in.a(legacy.o):(.text.tsan.module_ctor) is being placed in '.text.tsan.module_ctor'
Place them in the TEXT_TEXT section so that these technologies continue
to work with the newer compiler versions. All of the KASAN and KCSAN
KUnit tests continue to pass after this change.
Cc: stable(a)vger.kernel.org
Link: https://github.com/ClangBuiltLinux/linux/issues/1432
Link: https://github.com/llvm/llvm-project/commit/7b789562244ee941b7bf2cefeb3fc08…
Signed-off-by: Nathan Chancellor <nathan(a)kernel.org>
---
include/asm-generic/vmlinux.lds.h | 1 +
1 file changed, 1 insertion(+)
diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
index 17325416e2de..3b79b1e76556 100644
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -586,6 +586,7 @@
NOINSTR_TEXT \
*(.text..refcount) \
*(.ref.text) \
+ *(.text.asan .text.asan.*) \
TEXT_CFI_JT \
MEM_KEEP(init.text*) \
MEM_KEEP(exit.text*) \
base-commit: 4669e13cd67f8532be12815ed3d37e775a9bdc16
--
2.32.0.264.g75ae10bc75