diff options
| author | Daniel Axtens <dja@axtens.net> | 2022-05-18 13:06:17 +0300 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2022-05-22 08:58:29 +0300 |
| commit | 5352090a999570c6e8a701bcb755fd91e8c5a2cd (patch) | |
| tree | 18f1d9a7167012d317526c8c61208f5e7f365efd /arch/powerpc/lib | |
| parent | f08aed52412c860f68e30da148da58ad8e40a43b (diff) | |
| download | linux-5352090a999570c6e8a701bcb755fd91e8c5a2cd.tar.xz | |
powerpc/kasan: Don't instrument non-maskable or raw interrupts
Disable address sanitization for raw and non-maskable interrupt
handlers, because they can run in real mode, where we cannot access
the shadow memory. (Note that kasan_arch_is_ready() doesn't test for
real mode, since it is a static branch for speed, and in any case not
all the entry points to the generic KASAN code are protected by
kasan_arch_is_ready guards.)
The changes to interrupt_nmi_enter/exit_prepare() look larger than
they actually are. The changes are equivalent to adding
!IS_ENABLED(CONFIG_KASAN) to the conditions for calling nmi_enter() or
nmi_exit() in real mode. That is, the code is equivalent to using the
following condition for calling nmi_enter/exit:
if (((!IS_ENABLED(CONFIG_PPC_BOOK3S_64) ||
!firmware_has_feature(FW_FEATURE_LPAR) ||
radix_enabled()) &&
!IS_ENABLED(CONFIG_KASAN) ||
(mfmsr() & MSR_DR))
That unwieldy condition has been split into several statements with
comments, for easier reading.
The nmi_ipi_lock functions that call atomic functions (i.e.,
nmi_ipi_lock_start(), nmi_ipi_lock() and nmi_ipi_unlock()), besides
being marked noinstr, now call arch_atomic_* functions instead of
atomic_* functions because with KASAN enabled, the atomic_* functions
are wrappers which explicitly do address sanitization on their
arguments. Since we are trying to avoid address sanitization, we have
to use the lower-level arch_atomic_* versions.
In hv_nmi_check_nonrecoverable(), the regs_set_unrecoverable() call
has been open-coded so as to avoid having to either trust the inlining
or mark regs_set_unrecoverable() as noinstr.
[paulus@ozlabs.org: combined a few work-in-progress commits of
Daniel's and wrote the commit message.]
Signed-off-by: Daniel Axtens <dja@axtens.net>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/YoTFGaKM8Pd46PIK@cleo
Diffstat (limited to 'arch/powerpc/lib')
| -rw-r--r-- | arch/powerpc/lib/Makefile | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/powerpc/lib/Makefile b/arch/powerpc/lib/Makefile index 5d1881d2e39a..8560c912186d 100644 --- a/arch/powerpc/lib/Makefile +++ b/arch/powerpc/lib/Makefile @@ -13,6 +13,9 @@ CFLAGS_REMOVE_feature-fixups.o = $(CC_FLAGS_FTRACE) KASAN_SANITIZE_code-patching.o := n KASAN_SANITIZE_feature-fixups.o := n +# restart_table.o contains functions called in the NMI interrupt path +# which can be in real mode. Disable KASAN. +KASAN_SANITIZE_restart_table.o := n ifdef CONFIG_KASAN CFLAGS_code-patching.o += -DDISABLE_BRANCH_PROFILING |