Patch "[PATCH stable v4.14 03/32] powerpc/64s: Enable barrier_nospec based on firmware settings" has been added to the 4.14-stable tree
gregkh at linuxfoundation.org
gregkh at linuxfoundation.org
Sat Mar 30 01:54:46 AEDT 2019
This is a note to let you know that I've just added the patch titled
[PATCH stable v4.14 03/32] powerpc/64s: Enable barrier_nospec based on firmware settings
to the 4.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
powerpc-64s-enable-barrier_nospec-based-on-firmware-settings.patch
and it can be found in the queue-4.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable at vger.kernel.org> know about it.
>From foo at baz Fri Mar 29 15:53:50 CET 2019
From: Michael Ellerman <mpe at ellerman.id.au>
Date: Fri, 29 Mar 2019 22:25:51 +1100
Subject: [PATCH stable v4.14 03/32] powerpc/64s: Enable barrier_nospec based on firmware settings
To: stable at vger.kernel.org, gregkh at linuxfoundation.org
Cc: linuxppc-dev at ozlabs.org, diana.craciun at nxp.com, msuchanek at suse.de, christophe.leroy at c-s.fr
Message-ID: <20190329112620.14489-4-mpe at ellerman.id.au>
From: Michael Ellerman <mpe at ellerman.id.au>
From: Michal Suchanek <msuchanek at suse.de>
commit cb3d6759a93c6d0aea1c10deb6d00e111c29c19c upstream.
Check what firmware told us and enable/disable the barrier_nospec as
appropriate.
We err on the side of enabling the barrier, as it's no-op on older
systems, see the comment for more detail.
Signed-off-by: Michael Ellerman <mpe at ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
---
arch/powerpc/include/asm/setup.h | 1
arch/powerpc/kernel/security.c | 59 +++++++++++++++++++++++++++++++++
arch/powerpc/platforms/powernv/setup.c | 1
arch/powerpc/platforms/pseries/setup.c | 1
4 files changed, 62 insertions(+)
--- a/arch/powerpc/include/asm/setup.h
+++ b/arch/powerpc/include/asm/setup.h
@@ -52,6 +52,7 @@ enum l1d_flush_type {
void setup_rfi_flush(enum l1d_flush_type, bool enable);
void do_rfi_flush_fixups(enum l1d_flush_type types);
+void setup_barrier_nospec(void);
void do_barrier_nospec_fixups(bool enable);
extern bool barrier_nospec_enabled;
--- a/arch/powerpc/kernel/security.c
+++ b/arch/powerpc/kernel/security.c
@@ -23,6 +23,65 @@ static void enable_barrier_nospec(bool e
do_barrier_nospec_fixups(enable);
}
+void setup_barrier_nospec(void)
+{
+ bool enable;
+
+ /*
+ * It would make sense to check SEC_FTR_SPEC_BAR_ORI31 below as well.
+ * But there's a good reason not to. The two flags we check below are
+ * both are enabled by default in the kernel, so if the hcall is not
+ * functional they will be enabled.
+ * On a system where the host firmware has been updated (so the ori
+ * functions as a barrier), but on which the hypervisor (KVM/Qemu) has
+ * not been updated, we would like to enable the barrier. Dropping the
+ * check for SEC_FTR_SPEC_BAR_ORI31 achieves that. The only downside is
+ * we potentially enable the barrier on systems where the host firmware
+ * is not updated, but that's harmless as it's a no-op.
+ */
+ enable = security_ftr_enabled(SEC_FTR_FAVOUR_SECURITY) &&
+ security_ftr_enabled(SEC_FTR_BNDS_CHK_SPEC_BAR);
+
+ enable_barrier_nospec(enable);
+}
+
+#ifdef CONFIG_DEBUG_FS
+static int barrier_nospec_set(void *data, u64 val)
+{
+ switch (val) {
+ case 0:
+ case 1:
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ if (!!val == !!barrier_nospec_enabled)
+ return 0;
+
+ enable_barrier_nospec(!!val);
+
+ return 0;
+}
+
+static int barrier_nospec_get(void *data, u64 *val)
+{
+ *val = barrier_nospec_enabled ? 1 : 0;
+ return 0;
+}
+
+DEFINE_SIMPLE_ATTRIBUTE(fops_barrier_nospec,
+ barrier_nospec_get, barrier_nospec_set, "%llu\n");
+
+static __init int barrier_nospec_debugfs_init(void)
+{
+ debugfs_create_file("barrier_nospec", 0600, powerpc_debugfs_root, NULL,
+ &fops_barrier_nospec);
+ return 0;
+}
+device_initcall(barrier_nospec_debugfs_init);
+#endif /* CONFIG_DEBUG_FS */
+
ssize_t cpu_show_meltdown(struct device *dev, struct device_attribute *attr, char *buf)
{
bool thread_priv;
--- a/arch/powerpc/platforms/powernv/setup.c
+++ b/arch/powerpc/platforms/powernv/setup.c
@@ -123,6 +123,7 @@ static void pnv_setup_rfi_flush(void)
security_ftr_enabled(SEC_FTR_L1D_FLUSH_HV));
setup_rfi_flush(type, enable);
+ setup_barrier_nospec();
}
static void __init pnv_setup_arch(void)
--- a/arch/powerpc/platforms/pseries/setup.c
+++ b/arch/powerpc/platforms/pseries/setup.c
@@ -534,6 +534,7 @@ void pseries_setup_rfi_flush(void)
security_ftr_enabled(SEC_FTR_L1D_FLUSH_PR);
setup_rfi_flush(types, enable);
+ setup_barrier_nospec();
}
static void __init pSeries_setup_arch(void)
Patches currently in stable-queue which might be from mpe at ellerman.id.au are
queue-4.14/powerpc-fsl-emulate-sprn_bucsr-register.patch
queue-4.14/powerpc-64-make-stf-barrier-ppc_book3s_64-specific.patch
queue-4.14/powerpc-fsl-fix-spectre_v2-mitigations-reporting.patch
queue-4.14/powerpc-64s-patch-barrier_nospec-in-modules.patch
queue-4.14/powerpc-pseries-query-hypervisor-for-count-cache-flush-settings.patch
queue-4.14/powerpc-64s-add-support-for-software-count-cache-flush.patch
queue-4.14/powerpc64s-show-ori31-availability-in-spectre_v1-sysfs-file-not-v2.patch
queue-4.14/powerpc-fsl-flush-the-branch-predictor-at-each-kernel-entry-64bit.patch
queue-4.14/powerpc-fsl-update-spectre-v2-reporting.patch
queue-4.14/powerpc-64-make-meltdown-reporting-book3s-64-specific.patch
queue-4.14/powerpc-64s-add-support-for-ori-barrier_nospec-patching.patch
queue-4.14/powerpc-use-barrier_nospec-in-copy_from_user.patch
queue-4.14/powerpc-fsl-sanitize-the-syscall-table-for-nxp-powerpc-32-bit-platforms.patch
queue-4.14/powerpc-fsl-add-macro-to-flush-the-branch-predictor.patch
queue-4.14/powerpc-fsl-add-barrier_nospec-implementation-for-nxp-powerpc-book3e.patch
queue-4.14/powerpc-security-fix-spectre_v2-reporting.patch
queue-4.14/powerpc-64-disable-the-speculation-barrier-from-the-command-line.patch
queue-4.14/powerpc-fsl-fix-the-flush-of-branch-predictor.patch
queue-4.14/powerpc-64-add-config_ppc_barrier_nospec.patch
queue-4.14/powerpc-fsl-enable-runtime-patching-if-nospectre_v2-boot-arg-is-used.patch
queue-4.14/powerpc-64-use-barrier_nospec-in-syscall-entry.patch
queue-4.14/powerpc-fsl-fixed-warning-orphan-section-__btb_flush_fixup.patch
queue-4.14/powerpc-fsl-add-nospectre_v2-command-line-argument.patch
queue-4.14/powerpc-64s-add-new-security-feature-flags-for-count-cache-flush.patch
queue-4.14/powerpc-fsl-add-infrastructure-to-fixup-branch-predictor-flush.patch
queue-4.14/powerpc-64s-enhance-the-information-in-cpu_show_spectre_v1.patch
queue-4.14/powerpc-64-call-setup_barrier_nospec-from-setup_arch.patch
queue-4.14/powerpc-asm-add-a-patch_site-macro-helpers-for-patching-instructions.patch
queue-4.14/powerpc-fsl-flush-the-branch-predictor-at-each-kernel-entry-32-bit.patch
queue-4.14/powerpc-64s-enable-barrier_nospec-based-on-firmware-settings.patch
queue-4.14/powerpc-fsl-flush-branch-predictor-when-entering-kvm.patch
queue-4.14/powerpc-powernv-query-firmware-for-count-cache-flush-settings.patch
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