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* KVM: PPC: Book3S: Use new mutex to synchronize access to rtas token listPaul Mackerras2019-06-223-8/+8
| | | | | | | | | | | | | | | | | | | | | | | [ Upstream commit 1659e27d2bc1ef47b6d031abe01b467f18cb72d9 ] Currently the Book 3S KVM code uses kvm->lock to synchronize access to the kvm->arch.rtas_tokens list. Because this list is scanned inside kvmppc_rtas_hcall(), which is called with the vcpu mutex held, taking kvm->lock cause a lock inversion problem, which could lead to a deadlock. To fix this, we add a new mutex, kvm->arch.rtas_token_lock, which nests inside the vcpu mutexes, and use that instead of kvm->lock when accessing the rtas token list. This removes the lockdep_assert_held() in kvmppc_rtas_tokens_free(). At this point we don't hold the new mutex, but that is OK because kvmppc_rtas_tokens_free() is only called when the whole VM is being destroyed, and at that point nothing can be looking up a token in the list. Signed-off-by: Paul Mackerras <paulus@ozlabs.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
* powerpc/numa: improve control of topology updatesNathan Lynch2019-06-111-6/+12
| | | | | | | | | | | | | | | | | | | | [ Upstream commit 2d4d9b308f8f8dec68f6dbbff18c68ec7c6bd26f ] When booted with "topology_updates=no", or when "off" is written to /proc/powerpc/topology_updates, NUMA reassignments are inhibited for PRRN and VPHN events. However, migration and suspend unconditionally re-enable reassignments via start_topology_update(). This is incoherent. Check the topology_updates_enabled flag in start/stop_topology_update() so that callers of those APIs need not be aware of whether reassignments are enabled. This allows the administrative decision on reassignments to remain in force across migrations and suspensions. Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Sasha Levin <sashal@kernel.org>
* powerpc/boot: Fix missing check of lseek() return valueBo YU2019-06-111-1/+5
| | | | | | | | | | [ Upstream commit 5d085ec04a000fefb5182d3b03ee46ca96d8389b ] This is detected by Coverity scan: CID: 1440481 Signed-off-by: Bo YU <tsu.yubo@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Sasha Levin <sashal@kernel.org>
* powerpc/lib: fix book3s/32 boot failure due to code patchingChristophe Leroy2019-05-161-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | commit b45ba4a51cde29b2939365ef0c07ad34c8321789 upstream. Commit 51c3c62b58b3 ("powerpc: Avoid code patching freed init sections") accesses 'init_mem_is_free' flag too early, before the kernel is relocated. This provokes early boot failure (before the console is active). As it is not necessary to do this verification that early, this patch moves the test into patch_instruction() instead of __patch_instruction(). This modification also has the advantage of avoiding unnecessary remappings. Fixes: 51c3c62b58b3 ("powerpc: Avoid code patching freed init sections") Cc: stable@vger.kernel.org # 4.13+ Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc/booke64: set RI in default MSRLaurentiu Tudor2019-05-161-1/+1
| | | | | | | | | | | | | | | commit 5266e58d6cd90ac85c187d673093ad9cb649e16d upstream. Set RI in the default kernel's MSR so that the architected way of detecting unrecoverable machine check interrupts has a chance to work. This is inline with the MSR setup of the rest of booke powerpc architectures configured here. Signed-off-by: Laurentiu Tudor <laurentiu.tudor@nxp.com> Cc: stable@vger.kernel.org Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc/64s: Include cpu headerBreno Leitao2019-05-161-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 42e2acde1237878462b028f5a27d9cc5bea7502c upstream. Current powerpc security.c file is defining functions, as cpu_show_meltdown(), cpu_show_spectre_v{1,2} and others, that are being declared at linux/cpu.h header without including the header file that contains these declarations. This is being reported by sparse, which thinks that these functions are static, due to the lack of declaration: arch/powerpc/kernel/security.c:105:9: warning: symbol 'cpu_show_meltdown' was not declared. Should it be static? arch/powerpc/kernel/security.c:139:9: warning: symbol 'cpu_show_spectre_v1' was not declared. Should it be static? arch/powerpc/kernel/security.c:161:9: warning: symbol 'cpu_show_spectre_v2' was not declared. Should it be static? arch/powerpc/kernel/security.c:209:6: warning: symbol 'stf_barrier' was not declared. Should it be static? arch/powerpc/kernel/security.c:289:9: warning: symbol 'cpu_show_spec_store_bypass' was not declared. Should it be static? This patch simply includes the proper header (linux/cpu.h) to match function definition and declaration. Signed-off-by: Breno Leitao <leitao@debian.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Cc: Joel Stanley <joel@jms.id.au> Cc: Nathan Chancellor <natechancellor@gmail.com> Cc: Major Hayden <major@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc/fsl: Fixed warning: orphan section `__btb_flush_fixup'Diana Craciun2019-05-161-6/+12
| | | | | | | | | | | | | commit 039daac5526932ec731e4499613018d263af8b3e upstream. Fixed the following build warning: powerpc-linux-gnu-ld: warning: orphan section `__btb_flush_fixup' from `arch/powerpc/kernel/head_44x.o' being placed in section `__btb_flush_fixup'. Signed-off-by: Diana Craciun <diana.craciun@nxp.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc/fsl: Sanitize the syscall table for NXP PowerPC 32 bit platformsDiana Craciun2019-05-161-0/+10
| | | | | | | | | | commit c28218d4abbf4f2035495334d8bfcba64bda4787 upstream. Used barrier_nospec to sanitize the syscall table. Signed-off-by: Diana Craciun <diana.craciun@nxp.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc/fsl: Flush the branch predictor at each kernel entry (32 bit)Diana Craciun2019-05-162-0/+21
| | | | | | | | | | | | | | | | commit 7fef436295bf6c05effe682c8797dfcb0deb112a upstream. In order to protect against speculation attacks on indirect branches, the branch predictor is flushed at kernel entry to protect for the following situations: - userspace process attacking another userspace process - userspace process attacking the kernel Basically when the privillege level change (i.e.the kernel is entered), the branch predictor state is flushed. Signed-off-by: Diana Craciun <diana.craciun@nxp.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc/fsl: Emulate SPRN_BUCSR registerDiana Craciun2019-05-161-0/+7
| | | | | | | | | | | | | | | commit 98518c4d8728656db349f875fcbbc7c126d4c973 upstream. In order to flush the branch predictor the guest kernel performs writes to the BUCSR register which is hypervisor privilleged. However, the branch predictor is flushed at each KVM entry, so the branch predictor has been already flushed, so just return as soon as possible to guest. Signed-off-by: Diana Craciun <diana.craciun@nxp.com> [mpe: Tweak comment formatting] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc/fsl: Flush branch predictor when entering KVMDiana Craciun2019-05-161-0/+4
| | | | | | | | | | | | commit e7aa61f47b23afbec41031bc47ca8d6cb6516abc upstream. Switching from the guest to host is another place where the speculative accesses can be exploited. Flush the branch predictor when entering KVM. Signed-off-by: Diana Craciun <diana.craciun@nxp.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc/fsl: Enable runtime patching if nospectre_v2 boot arg is usedDiana Craciun2019-05-162-0/+2
| | | | | | | | | | | commit 3bc8ea8603ae4c1e09aca8de229ad38b8091fcb3 upstream. If the user choses not to use the mitigations, replace the code sequence with nops. Signed-off-by: Diana Craciun <diana.craciun@nxp.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc/fsl: Fix the flush of branch predictor.Christophe Leroy2019-05-161-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | commit 27da80719ef132cf8c80eb406d5aeb37dddf78cc upstream. The commit identified below adds MC_BTB_FLUSH macro only when CONFIG_PPC_FSL_BOOK3E is defined. This results in the following error on some configs (seen several times with kisskb randconfig_defconfig) arch/powerpc/kernel/exceptions-64e.S:576: Error: Unrecognized opcode: `mc_btb_flush' make[3]: *** [scripts/Makefile.build:367: arch/powerpc/kernel/exceptions-64e.o] Error 1 make[2]: *** [scripts/Makefile.build:492: arch/powerpc/kernel] Error 2 make[1]: *** [Makefile:1043: arch/powerpc] Error 2 make: *** [Makefile:152: sub-make] Error 2 This patch adds a blank definition of MC_BTB_FLUSH for other cases. Fixes: 10c5e83afd4a ("powerpc/fsl: Flush the branch predictor at each kernel entry (64bit)") Cc: Diana Craciun <diana.craciun@nxp.com> Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Reviewed-by: Daniel Axtens <dja@axtens.net> Reviewed-by: Diana Craciun <diana.craciun@nxp.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc/security: Fix spectre_v2 reportingMichael Ellerman2019-05-161-15/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 92edf8df0ff2ae86cc632eeca0e651fd8431d40d upstream. When I updated the spectre_v2 reporting to handle software count cache flush I got the logic wrong when there's no software count cache enabled at all. The result is that on systems with the software count cache flush disabled we print: Mitigation: Indirect branch cache disabled, Software count cache flush Which correctly indicates that the count cache is disabled, but incorrectly says the software count cache flush is enabled. The root of the problem is that we are trying to handle all combinations of options. But we know now that we only expect to see the software count cache flush enabled if the other options are false. So split the two cases, which simplifies the logic and fixes the bug. We were also missing a space before "(hardware accelerated)". The result is we see one of: Mitigation: Indirect branch serialisation (kernel only) Mitigation: Indirect branch cache disabled Mitigation: Software count cache flush Mitigation: Software count cache flush (hardware accelerated) Fixes: ee13cb249fab ("powerpc/64s: Add support for software count cache flush") Cc: stable@vger.kernel.org # v4.19+ Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Reviewed-by: Michael Neuling <mikey@neuling.org> Reviewed-by: Diana Craciun <diana.craciun@nxp.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc/fsl: Update Spectre v2 reportingDiana Craciun2019-05-161-1/+4
| | | | | | | | | | | commit dfa88658fb0583abb92e062c7a9cd5a5b94f2a46 upstream. Report branch predictor state flush as a mitigation for Spectre variant 2. Signed-off-by: Diana Craciun <diana.craciun@nxp.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc/fsl: Flush the branch predictor at each kernel entry (64bit)Diana Craciun2019-05-163-1/+37
| | | | | | | | | | | | | | | | commit 10c5e83afd4a3f01712d97d3bb1ae34d5b74a185 upstream. In order to protect against speculation attacks on indirect branches, the branch predictor is flushed at kernel entry to protect for the following situations: - userspace process attacking another userspace process - userspace process attacking the kernel Basically when the privillege level change (i.e. the kernel is entered), the branch predictor state is flushed. Signed-off-by: Diana Craciun <diana.craciun@nxp.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc/fsl: Add nospectre_v2 command line argumentDiana Craciun2019-05-162-0/+26
| | | | | | | | | | | commit f633a8ad636efb5d4bba1a047d4a0f1ef719aa06 upstream. When the command line argument is present, the Spectre variant 2 mitigations are disabled. Signed-off-by: Diana Craciun <diana.craciun@nxp.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc/fsl: Fix spectre_v2 mitigations reportingDiana Craciun2019-05-161-1/+1
| | | | | | | | | | | | | | | | | commit 7d8bad99ba5a22892f0cad6881289fdc3875a930 upstream. Currently for CONFIG_PPC_FSL_BOOK3E the spectre_v2 file is incorrect: $ cat /sys/devices/system/cpu/vulnerabilities/spectre_v2 "Mitigation: Software count cache flush" Which is wrong. Fix it to report vulnerable for now. Fixes: ee13cb249fab ("powerpc/64s: Add support for software count cache flush") Cc: stable@vger.kernel.org # v4.19+ Signed-off-by: Diana Craciun <diana.craciun@nxp.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc/fsl: Add macro to flush the branch predictorDiana Craciun2019-05-161-0/+11
| | | | | | | | | | | commit 1cbf8990d79ff69da8ad09e8a3df014e1494462b upstream. The BUCSR register can be used to invalidate the entries in the branch prediction mechanisms. Signed-off-by: Diana Craciun <diana.craciun@nxp.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc/fsl: Add infrastructure to fixup branch predictor flushDiana Craciun2019-05-164-0/+45
| | | | | | | | | | | | | | | | commit 76a5eaa38b15dda92cd6964248c39b5a6f3a4e9d upstream. In order to protect against speculation attacks (Spectre variant 2) on NXP PowerPC platforms, the branch predictor should be flushed when the privillege level is changed. This patch is adding the infrastructure to fixup at runtime the code sections that are performing the branch predictor flush depending on a boot arg parameter which is added later in a separate patch. Signed-off-by: Diana Craciun <diana.craciun@nxp.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc: Avoid code patching freed init sectionsMichael Neuling2019-05-163-0/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 51c3c62b58b357e8d35e4cc32f7b4ec907426fe3 upstream. This stops us from doing code patching in init sections after they've been freed. In this chain: kvm_guest_init() -> kvm_use_magic_page() -> fault_in_pages_readable() -> __get_user() -> __get_user_nocheck() -> barrier_nospec(); We have a code patching location at barrier_nospec() and kvm_guest_init() is an init function. This whole chain gets inlined, so when we free the init section (hence kvm_guest_init()), this code goes away and hence should no longer be patched. We seen this as userspace memory corruption when using a memory checker while doing partition migration testing on powervm (this starts the code patching post migration via /sys/kernel/mobility/migration). In theory, it could also happen when using /sys/kernel/debug/powerpc/barrier_nospec. Signed-off-by: Michael Neuling <mikey@neuling.org> Reviewed-by: Nicholas Piggin <npiggin@gmail.com> Reviewed-by: Christophe Leroy <christophe.leroy@c-s.fr> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc/powernv: Query firmware for count cache flush settingsMichael Ellerman2019-05-161-0/+7
| | | | | | | | | | | commit 99d54754d3d5f896a8f616b0b6520662bc99d66b upstream. Look for fw-features properties to determine the appropriate settings for the count cache flush, and then call the generic powerpc code to set it up based on the security feature flags. Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc/pseries: Query hypervisor for count cache flush settingsMichael Ellerman2019-05-162-0/+9
| | | | | | | | | | | commit ba72dc171954b782a79d25e0f4b3ed91090c3b1e upstream. Use the existing hypercall to determine the appropriate settings for the count cache flush, and then call the generic powerpc code to set it up based on the security feature flags. Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc/64s: Add support for software count cache flushMichael Ellerman2019-05-164-5/+169
| | | | | | | | | | | | | | | | | | | | | | | | commit ee13cb249fabdff8b90aaff61add347749280087 upstream. Some CPU revisions support a mode where the count cache needs to be flushed by software on context switch. Additionally some revisions may have a hardware accelerated flush, in which case the software flush sequence can be shortened. If we detect the appropriate flag from firmware we patch a branch into _switch() which takes us to a count cache flush sequence. That sequence in turn may be patched to return early if we detect that the CPU supports accelerating the flush sequence in hardware. Add debugfs support for reporting the state of the flush, as well as runtime disabling it. And modify the spectre_v2 sysfs file to report the state of the software flush. Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc/64s: Add new security feature flags for count cache flushMichael Ellerman2019-05-161-0/+6
| | | | | | | | | | | commit dc8c6cce9a26a51fc19961accb978217a3ba8c75 upstream. Add security feature flags to indicate the need for software to flush the count cache on context switch, and for the presence of a hardware assisted count cache flush. Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc/asm: Add a patch_site macro & helpers for patching instructionsMichael Ellerman2019-05-163-0/+36
| | | | | | | | | | | | | | | | | | | | | | commit 06d0bbc6d0f56dacac3a79900e9a9a0d5972d818 upstream. Add a macro and some helper C functions for patching single asm instructions. The gas macro means we can do something like: 1: nop patch_site 1b, patch__foo Which is less visually distracting than defining a GLOBAL symbol at 1, and also doesn't pollute the symbol table which can confuse eg. perf. These are obviously similar to our existing feature sections, but are not automatically patched based on CPU/MMU features, rather they are designed to be manually patched by C code at some arbitrary point. Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc/fsl: Add barrier_nospec implementation for NXP PowerPC Book3EDiana Craciun2019-05-164-2/+40
| | | | | | | | | | | | commit ebcd1bfc33c7a90df941df68a6e5d4018c022fba upstream. Implement the barrier_nospec as a isync;sync instruction sequence. The implementation uses the infrastructure built for BOOK3S 64. Signed-off-by: Diana Craciun <diana.craciun@nxp.com> [mpe: Add PPC_INST_ISYNC for backport] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc/64: Make meltdown reporting Book3S 64 specificDiana Craciun2019-05-161-0/+2
| | | | | | | | | | | | | commit 406d2b6ae3420f5bb2b3db6986dc6f0b6dbb637b upstream. In a subsequent patch we will enable building security.c for Book3E. However the NXP platforms are not vulnerable to Meltdown, so make the Meltdown vulnerability reporting PPC_BOOK3S_64 specific. Signed-off-by: Diana Craciun <diana.craciun@nxp.com> [mpe: Split out of larger patch] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc/64: Call setup_barrier_nospec() from setup_arch()Michael Ellerman2019-05-165-2/+8
| | | | | | | | | | | | commit af375eefbfb27cbb5b831984e66d724a40d26b5c upstream. Currently we require platform code to call setup_barrier_nospec(). But if we add an empty definition for the !CONFIG_PPC_BARRIER_NOSPEC case then we can call it in setup_arch(). Signed-off-by: Diana Craciun <diana.craciun@nxp.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc/64: Add CONFIG_PPC_BARRIER_NOSPECMichael Ellerman2019-05-167-10/+22
| | | | | | | | | | | | commit 179ab1cbf883575c3a585bcfc0f2160f1d22a149 upstream. Add a config symbol to encode which platforms support the barrier_nospec speculation barrier. Currently this is just Book3S 64 but we will add Book3E in a future patch. Signed-off-by: Diana Craciun <diana.craciun@nxp.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc/64: Make stf barrier PPC_BOOK3S_64 specific.Diana Craciun2019-05-161-0/+2
| | | | | | | | | | | commit 6453b532f2c8856a80381e6b9a1f5ea2f12294df upstream. NXP Book3E platforms are not vulnerable to speculative store bypass, so make the mitigations PPC_BOOK3S_64 specific. Signed-off-by: Diana Craciun <diana.craciun@nxp.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc/64: Disable the speculation barrier from the command lineDiana Craciun2019-05-161-1/+11
| | | | | | | | | | | commit cf175dc315f90185128fb061dc05b6fbb211aa2f upstream. The speculation barrier can be disabled from the command line with the parameter: "nospectre_v1". Signed-off-by: Diana Craciun <diana.craciun@nxp.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc64s: Show ori31 availability in spectre_v1 sysfs file not v2Michael Ellerman2019-05-161-10/+17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 6d44acae1937b81cf8115ada8958e04f601f3f2e upstream. When I added the spectre_v2 information in sysfs, I included the availability of the ori31 speculation barrier. Although the ori31 barrier can be used to mitigate v2, it's primarily intended as a spectre v1 mitigation. Spectre v2 is mitigated by hardware changes. So rework the sysfs files to show the ori31 information in the spectre_v1 file, rather than v2. Currently we display eg: $ grep . spectre_v* spectre_v1:Mitigation: __user pointer sanitization spectre_v2:Mitigation: Indirect branch cache disabled, ori31 speculation barrier enabled After: $ grep . spectre_v* spectre_v1:Mitigation: __user pointer sanitization, ori31 speculation barrier enabled spectre_v2:Mitigation: Indirect branch cache disabled Fixes: d6fbe1c55c55 ("powerpc/64s: Wire up cpu_show_spectre_v2()") Cc: stable@vger.kernel.org # v4.17+ Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc/64s: Enhance the information in cpu_show_spectre_v1()Michal Suchanek2019-05-161-0/+3
| | | | | | | | | | | commit a377514519b9a20fa1ea9adddbb4129573129cef upstream. We now have barrier_nospec as mitigation so print it in cpu_show_spectre_v1() when enabled. Signed-off-by: Michal Suchanek <msuchanek@suse.de> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc: Use barrier_nospec in copy_from_user()Michael Ellerman2019-05-161-2/+16
| | | | | | | | | | | | | | | | | | | | commit ddf35cf3764b5a182b178105f57515b42e2634f8 upstream. Based on the x86 commit doing the same. See commit 304ec1b05031 ("x86/uaccess: Use __uaccess_begin_nospec() and uaccess_try_nospec") and b3bbfb3fb5d2 ("x86: Introduce __uaccess_begin_nospec() and uaccess_try_nospec") for more detail. In all cases we are ordering the load from the potentially user-controlled pointer vs a previous branch based on an access_ok() check or similar. Base on a patch from Michal Suchanek. Signed-off-by: Michal Suchanek <msuchanek@suse.de> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc/64: Use barrier_nospec in syscall entryMichael Ellerman2019-05-161-0/+10
| | | | | | | | | | | | | commit 51973a815c6b46d7b23b68d6af371ad1c9d503ca upstream. Our syscall entry is done in assembly so patch in an explicit barrier_nospec. Based on a patch by Michal Suchanek. Signed-off-by: Michal Suchanek <msuchanek@suse.de> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc/64s: Enable barrier_nospec based on firmware settingsMichal Suchanek2019-05-164-0/+62
| | | | | | | | | | | | | 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@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc/64s: Patch barrier_nospec in modulesMichal Suchanek2019-05-164-4/+27
| | | | | | | | | | | | | | | | commit 815069ca57c142eb71d27439bc27f41a433a67b3 upstream. Note that unlike RFI which is patched only in kernel the nospec state reflects settings at the time the module was loaded. Iterating all modules and re-patching every time the settings change is not implemented. Based on lwsync patching. Signed-off-by: Michal Suchanek <msuchanek@suse.de> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc/64s: Add support for ori barrier_nospec patchingMichal Suchanek2019-05-166-1/+54
| | | | | | | | | | | | | | | | commit 2eea7f067f495e33b8b116b35b5988ab2b8aec55 upstream. Based on the RFI patching. This is required to be able to disable the speculation barrier. Only one barrier type is supported and it does nothing when the firmware does not enable it. Also re-patching modules is not supported So the only meaningful thing that can be done is patching out the speculation barrier at boot when the user says it is not wanted. Signed-off-by: Michal Suchanek <msuchanek@suse.de> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc/64s: Add barrier_nospecMichal Suchanek2019-05-161-0/+15
| | | | | | | | | | | | | | | | | | | | commit a6b3964ad71a61bb7c61d80a60bea7d42187b2eb upstream. A no-op form of ori (or immediate of 0 into r31 and the result stored in r31) has been re-tasked as a speculation barrier. The instruction only acts as a barrier on newer machines with appropriate firmware support. On older CPUs it remains a harmless no-op. Implement barrier_nospec using this instruction. mpe: The semantics of the instruction are believed to be that it prevents execution of subsequent instructions until preceding branches have been fully resolved and are no longer executing speculatively. There is no further documentation available at this time. Signed-off-by: Michal Suchanek <msuchanek@suse.de> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc/64s: Add support for a store forwarding barrier at kernel entry/exitNicholas Piggin2019-05-169-2/+365
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit a048a07d7f4535baa4cbad6bc024f175317ab938 upstream. On some CPUs we can prevent a vulnerability related to store-to-load forwarding by preventing store forwarding between privilege domains, by inserting a barrier in kernel entry and exit paths. This is known to be the case on at least Power7, Power8 and Power9 powerpc CPUs. Barriers must be inserted generally before the first load after moving to a higher privilege, and after the last store before moving to a lower privilege, HV and PR privilege transitions must be protected. Barriers are added as patch sections, with all kernel/hypervisor entry points patched, and the exit points to lower privilge levels patched similarly to the RFI flush patching. Firmware advertisement is not implemented yet, so CPU flush types are hard coded. Thanks to Michal Suchánek for bug fixes and review. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Mauricio Faria de Oliveira <mauricfo@linux.vnet.ibm.com> Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Michal Suchánek <msuchanek@suse.de> [mpe: 4.4 doesn't have EXC_REAL_OOL_MASKABLE, so do it manually] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc/64s: Fix section mismatch warnings from setup_rfi_flush()Michael Ellerman2019-05-161-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 501a78cbc17c329fabf8e9750a1e9ab810c88a0e upstream. The recent LPM changes to setup_rfi_flush() are causing some section mismatch warnings because we removed the __init annotation on setup_rfi_flush(): The function setup_rfi_flush() references the function __init ppc64_bolted_size(). the function __init memblock_alloc_base(). The references are actually in init_fallback_flush(), but that is inlined into setup_rfi_flush(). These references are safe because: - only pseries calls setup_rfi_flush() at runtime - pseries always passes L1D_FLUSH_FALLBACK at boot - so the fallback flush area will always be allocated - so the check in init_fallback_flush() will always return early: /* Only allocate the fallback flush area once (at boot time). */ if (l1d_flush_fallback_area) return; - and therefore we won't actually call the freed init routines. We should rework the code to make it safer by default rather than relying on the above, but for now as a quick-fix just add a __ref annotation to squash the warning. Fixes: abf110f3e1ce ("powerpc/rfi-flush: Make it possible to call setup_rfi_flush() again") Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc/pseries: Restore default security feature flags on setupMauricio Faria de Oliveira2019-05-161-0/+11
| | | | | | | | | | | | | | | | | | | | | | | commit 6232774f1599028a15418179d17f7df47ede770a upstream. After migration the security feature flags might have changed (e.g., destination system with unpatched firmware), but some flags are not set/clear again in init_cpu_char_feature_flags() because it assumes the security flags to be the defaults. Additionally, if the H_GET_CPU_CHARACTERISTICS hypercall fails then init_cpu_char_feature_flags() does not run again, which potentially might leave the system in an insecure or sub-optimal configuration. So, just restore the security feature flags to the defaults assumed by init_cpu_char_feature_flags() so it can set/clear them correctly, and to ensure safe settings are in place in case the hypercall fail. Fixes: f636c14790ea ("powerpc/pseries: Set or clear security feature flags") Depends-on: 19887d6a28e2 ("powerpc: Move default security feature flags") Signed-off-by: Mauricio Faria de Oliveira <mauricfo@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc: Move default security feature flagsMauricio Faria de Oliveira2019-05-162-6/+9
| | | | | | | | | | | | | commit e7347a86830f38dc3e40c8f7e28c04412b12a2e7 upstream. This moves the definition of the default security feature flags (i.e., enabled by default) closer to the security feature flags. This can be used to restore current flags to the default flags. Signed-off-by: Mauricio Faria de Oliveira <mauricfo@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc/pseries: Fix clearing of security feature flagsMauricio Faria de Oliveira2019-05-161-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 0f9bdfe3c77091e8704d2e510eb7c2c2c6cde524 upstream. The H_CPU_BEHAV_* flags should be checked for in the 'behaviour' field of 'struct h_cpu_char_result' -- 'character' is for H_CPU_CHAR_* flags. Found by playing around with QEMU's implementation of the hypercall: H_CPU_CHAR=0xf000000000000000 H_CPU_BEHAV=0x0000000000000000 This clears H_CPU_BEHAV_FAVOUR_SECURITY and H_CPU_BEHAV_L1D_FLUSH_PR so pseries_setup_rfi_flush() disables 'rfi_flush'; and it also clears H_CPU_CHAR_L1D_THREAD_PRIV flag. So there is no RFI flush mitigation at all for cpu_show_meltdown() to report; but currently it does: Original kernel: # cat /sys/devices/system/cpu/vulnerabilities/meltdown Mitigation: RFI Flush Patched kernel: # cat /sys/devices/system/cpu/vulnerabilities/meltdown Not affected H_CPU_CHAR=0x0000000000000000 H_CPU_BEHAV=0xf000000000000000 This sets H_CPU_BEHAV_BNDS_CHK_SPEC_BAR so cpu_show_spectre_v1() should report vulnerable; but currently it doesn't: Original kernel: # cat /sys/devices/system/cpu/vulnerabilities/spectre_v1 Not affected Patched kernel: # cat /sys/devices/system/cpu/vulnerabilities/spectre_v1 Vulnerable Brown-paper-bag-by: Michael Ellerman <mpe@ellerman.id.au> Fixes: f636c14790ea ("powerpc/pseries: Set or clear security feature flags") Signed-off-by: Mauricio Faria de Oliveira <mauricfo@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc/64s: Wire up cpu_show_spectre_v2()Michael Ellerman2019-05-161-0/+33
| | | | | | | | | | | | | | | | | | | | | | | commit d6fbe1c55c55c6937cbea3531af7da84ab7473c3 upstream. Add a definition for cpu_show_spectre_v2() to override the generic version. This has several permuations, though in practice some may not occur we cater for any combination. The most verbose is: Mitigation: Indirect branch serialisation (kernel only), Indirect branch cache disabled, ori31 speculation barrier enabled We don't treat the ori31 speculation barrier as a mitigation on its own, because it has to be *used* by code in order to be a mitigation and we don't know if userspace is doing that. So if that's all we see we say: Vulnerable, ori31 speculation barrier enabled Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc/64s: Wire up cpu_show_spectre_v1()Michael Ellerman2019-05-161-0/+8
| | | | | | | | | | | | | | | commit 56986016cb8cd9050e601831fe89f332b4e3c46e upstream. Add a definition for cpu_show_spectre_v1() to override the generic version. Currently this just prints "Not affected" or "Vulnerable" based on the firmware flag. Although the kernel does have array_index_nospec() in a few places, we haven't yet audited all the powerpc code to see where it's necessary, so for now we don't list that as a mitigation. Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc/pseries: Use the security flags in pseries_setup_rfi_flush()Michael Ellerman2019-05-161-15/+12
| | | | | | | | | | | commit 2e4a16161fcd324b1f9bf6cb6856529f7eaf0689 upstream. Now that we have the security flags we can simplify the code in pseries_setup_rfi_flush() because the security flags have pessimistic defaults. Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc/powernv: Use the security flags in pnv_setup_rfi_flush()Michael Ellerman2019-05-161-31/+10
| | | | | | | | | | | | commit 37c0bdd00d3ae83369ab60a6712c28e11e6458d5 upstream. Now that we have the security flags we can significantly simplify the code in pnv_setup_rfi_flush(), because we can use the flags instead of checking device tree properties and because the security flags have pessimistic defaults. Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc/64s: Enhance the information in cpu_show_meltdown()Michael Ellerman2019-05-162-2/+29
| | | | | | | | | | commit ff348355e9c72493947be337bb4fae4fc1a41eba upstream. Now that we have the security feature flags we can make the information displayed in the "meltdown" file more informative. Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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