arm64/boot: Disable trapping of PMZR_EL0 writes to EL2grafted

__init_el2_fgt2() writes one mask to both HDFGRTR2_EL2 and HDFGWTR2_EL2.
PMZR_EL0 is write-only, so its trap bit, nPMZR_EL0, exists only in
HDFGWTR2_EL2 and is therefore never set: a PMZR_EL0 write from the host
traps to EL2, where the nVHE hypervisor has no handler and BUG()s. The
kernel never writes PMZR_EL0, but kernel.perf_user_access=1 has the PMU
driver set PMUSERENR_EL0.UEN for a task with a user-read event, so a
write from EL0 reaches the trap and takes the host down without a panic
message.

Accumulate the HDFGWTR2_EL2 bits separately, as __init_el2_fgt() already
does for HDFGWTR_EL2, and set nPMZR_EL0 with the other FEAT_PMUv3p9
bits.

Fixes: 858c7bfcb35e1 ("arm64/boot: Enable EL2 requirements for FEAT_PMUv3p9")
Cc: stable@vger.kernel.org
Signed-off-by: Fuad Tabba <fuad.tabba@linux.dev>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: Oliver Upton <oupton@kernel.org>
Signed-off-by: Will Deacon <will@kernel.org>

1 files changed, 25 insertions, 0 deletions

diff --git a/drivers/misc/lkdtm/Makefile b/drivers/misc/lkdtm/Makefile
new file mode 100644
index 000000000..4e58d16fc
--- /dev/null
+++ b/drivers/misc/lkdtm/Makefile
@@ -0,0 +1,25 @@
+# SPDX-License-Identifier: GPL-2.0
+obj-$(CONFIG_LKDTM)		+= lkdtm.o
+
+lkdtm-$(CONFIG_LKDTM)		+= core.o
+lkdtm-$(CONFIG_LKDTM)		+= bugs.o
+lkdtm-$(CONFIG_LKDTM)		+= heap.o
+lkdtm-$(CONFIG_LKDTM)		+= perms.o
+lkdtm-$(CONFIG_LKDTM)		+= refcount.o
+lkdtm-$(CONFIG_LKDTM)		+= rodata_objcopy.o
+lkdtm-$(CONFIG_LKDTM)		+= usercopy.o
+lkdtm-$(CONFIG_LKDTM)		+= kstack_erase.o
+lkdtm-$(CONFIG_LKDTM)		+= cfi.o
+lkdtm-$(CONFIG_LKDTM)		+= fortify.o
+lkdtm-$(CONFIG_PPC_BOOK3S_64)	+= powerpc.o
+
+KASAN_SANITIZE_stackleak.o	:= n
+
+CFLAGS_REMOVE_rodata.o			+= $(CC_FLAGS_LTO) $(RETHUNK_CFLAGS) $(CC_FLAGS_CFI)
+
+OBJCOPYFLAGS :=
+OBJCOPYFLAGS_rodata_objcopy.o	:= \
+			--rename-section .noinstr.text=.rodata,alloc,readonly,load,contents
+targets += rodata.o rodata_objcopy.o
+$(obj)/rodata_objcopy.o: $(obj)/rodata.o FORCE
+	$(call if_changed,objcopy)