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2018-11-10Revert "x86/mm: Expand static page table for fixmap space"Sasha Levin1-9/+0
This reverts commit 3a8304b7ad2e291777e8499e39390145d932a2fd, which was upstream commit 05ab1d8a4b36ee912b7087c6da127439ed0a903e. Ben Hutchings writes: This backport is incorrect. The part that updated __startup_64() in arch/x86/kernel/head64.c was dropped, presumably because that function doesn't exist in 4.9. However that seems to be an essential of the fix. In 4.9 the startup_64 routine in arch/x86/kernel/head_64.S would need to be changed instead. I also found that this introduces new boot-time warnings on some systems if CONFIG_DEBUG_WX is enabled. So, unless someone provides fixes for those issues, I think this should be reverted for the 4.9 branch. Signed-off-by: Sasha Levin <sashal@kernel.org>
2018-10-13x86/fpu: Finish excising 'eagerfpu'Andy Lutomirski1-2/+1
commit e63650840e8b053aa09ad934877e87e9941ed135 upstream. Now that eagerfpu= is gone, remove it from the docs and some comments. Also sync the changes to tools/. Signed-off-by: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com> Cc: Rik van Riel <riel@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/cf430dd4481d41280e93ac6cf0def1007a67fc8e.1476740397.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: Daniel Sangorrin <daniel.sangorrin@toshiba.co.jp> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-10-13x86/mm: Expand static page table for fixmap spaceFeng Tang1-0/+9
commit 05ab1d8a4b36ee912b7087c6da127439ed0a903e upstream. We met a kernel panic when enabling earlycon, which is due to the fixmap address of earlycon is not statically setup. Currently the static fixmap setup in head_64.S only covers 2M virtual address space, while it actually could be in 4M space with different kernel configurations, e.g. when VSYSCALL emulation is disabled. So increase the static space to 4M for now by defining FIXMAP_PMD_NUM to 2, and add a build time check to ensure that the fixmap is covered by the initial static page tables. Fixes: 1ad83c858c7d ("x86_64,vsyscall: Make vsyscall emulation configurable") Suggested-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Feng Tang <feng.tang@intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: kernel test robot <rong.a.chen@intel.com> Reviewed-by: Juergen Gross <jgross@suse.com> (Xen parts) Cc: H Peter Anvin <hpa@linux.intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Yinghai Lu <yinghai@kernel.org> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Andy Lutomirsky <luto@kernel.org> Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20180920025828.23699-1-feng.tang@intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-10-04x86/numa_emulation: Fix emulated-to-physical node mappingDan Williams1-1/+1
[ Upstream commit 3b6c62f363a19ce82bf378187ab97c9dc01e3927 ] Without this change the distance table calculation for emulated nodes may use the wrong numa node and report an incorrect distance. Signed-off-by: Dan Williams <dan.j.williams@intel.com> Cc: David Rientjes <rientjes@google.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Wei Yang <richard.weiyang@gmail.com> Cc: linux-mm@kvack.org Link: http://lkml.kernel.org/r/153089328103.27680.14778434392225818887.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-09-19x86/mm: Remove in_nmi() warning from vmalloc_fault()Joerg Roedel1-2/+0
[ Upstream commit 6863ea0cda8725072522cd78bda332d9a0b73150 ] It is perfectly okay to take page-faults, especially on the vmalloc area while executing an NMI handler. Remove the warning. Signed-off-by: Joerg Roedel <jroedel@suse.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: David H. Gutteridge <dhgutteridge@sympatico.ca> Cc: "H . Peter Anvin" <hpa@zytor.com> Cc: linux-mm@kvack.org Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Juergen Gross <jgross@suse.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: Brian Gerst <brgerst@gmail.com> Cc: David Laight <David.Laight@aculab.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Eduardo Valentin <eduval@amazon.com> Cc: Greg KH <gregkh@linuxfoundation.org> Cc: Will Deacon <will.deacon@arm.com> Cc: aliguori@amazon.com Cc: daniel.gruss@iaik.tugraz.at Cc: hughd@google.com Cc: keescook@google.com Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Waiman Long <llong@redhat.com> Cc: Pavel Machek <pavel@ucw.cz> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: joro@8bytes.org Link: https://lkml.kernel.org/r/1532533683-5988-2-git-send-email-joro@8bytes.org Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-09-05x86/speculation/l1tf: Fix off-by-one error when warning that system has too ↵Vlastimil Babka2-2/+2
much RAM commit b0a182f875689647b014bc01d36b340217792852 upstream. Two users have reported [1] that they have an "extremely unlikely" system with more than MAX_PA/2 memory and L1TF mitigation is not effective. In fact it's a CPU with 36bits phys limit (64GB) and 32GB memory, but due to holes in the e820 map, the main region is almost 500MB over the 32GB limit: [ 0.000000] BIOS-e820: [mem 0x0000000100000000-0x000000081effffff] usable Suggestions to use 'mem=32G' to enable the L1TF mitigation while losing the 500MB revealed, that there's an off-by-one error in the check in l1tf_select_mitigation(). l1tf_pfn_limit() returns the last usable pfn (inclusive) and the range check in the mitigation path does not take this into account. Instead of amending the range check, make l1tf_pfn_limit() return the first PFN which is over the limit which is less error prone. Adjust the other users accordingly. [1] https://bugzilla.suse.com/show_bug.cgi?id=1105536 Fixes: 17dbca119312 ("x86/speculation/l1tf: Add sysfs reporting for l1tf") Reported-by: George Anchev <studio@anchev.net> Reported-by: Christopher Snowhill <kode54@gmail.com> Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: "H . Peter Anvin" <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andi Kleen <ak@linux.intel.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20180823134418.17008-1-vbabka@suse.cz Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-09-05x86/speculation/l1tf: Fix overflow in l1tf_pfn_limit() on 32bitVlastimil Babka1-2/+2
commit 9df9516940a61d29aedf4d91b483ca6597e7d480 upstream. On 32bit PAE kernels on 64bit hardware with enough physical bits, l1tf_pfn_limit() will overflow unsigned long. This in turn affects max_swapfile_size() and can lead to swapon returning -EINVAL. This has been observed in a 32bit guest with 42 bits physical address size, where max_swapfile_size() overflows exactly to 1 << 32, thus zero, and produces the following warning to dmesg: [ 6.396845] Truncating oversized swap area, only using 0k out of 2047996k Fix this by using unsigned long long instead. Fixes: 17dbca119312 ("x86/speculation/l1tf: Add sysfs reporting for l1tf") Fixes: 377eeaa8e11f ("x86/speculation/l1tf: Limit swap file size to MAX_PA/2") Reported-by: Dominique Leuenberger <dimstar@suse.de> Reported-by: Adrian Schroeter <adrian@suse.de> Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Andi Kleen <ak@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: "H . Peter Anvin" <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20180820095835.5298-1-vbabka@suse.cz Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-08-17x86/mm: Add TLB purge to free pmd/pte page interfacesToshi Kani1-6/+30
commit 5e0fb5df2ee871b841f96f9cb6a7f2784e96aa4e upstream. ioremap() calls pud_free_pmd_page() / pmd_free_pte_page() when it creates a pud / pmd map. The following preconditions are met at their entry. - All pte entries for a target pud/pmd address range have been cleared. - System-wide TLB purges have been peformed for a target pud/pmd address range. The preconditions assure that there is no stale TLB entry for the range. Speculation may not cache TLB entries since it requires all levels of page entries, including ptes, to have P & A-bits set for an associated address. However, speculation may cache pud/pmd entries (paging-structure caches) when they have P-bit set. Add a system-wide TLB purge (INVLPG) to a single page after clearing pud/pmd entry's P-bit. SDM 4.10.4.1, Operation that Invalidate TLBs and Paging-Structure Caches, states that: INVLPG invalidates all paging-structure caches associated with the current PCID regardless of the liner addresses to which they correspond. Fixes: 28ee90fe6048 ("x86/mm: implement free pmd/pte page interfaces") Signed-off-by: Toshi Kani <toshi.kani@hpe.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: mhocko@suse.com Cc: akpm@linux-foundation.org Cc: hpa@zytor.com Cc: cpandya@codeaurora.org Cc: linux-mm@kvack.org Cc: linux-arm-kernel@lists.infradead.org Cc: Joerg Roedel <joro@8bytes.org> Cc: stable@vger.kernel.org Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Michal Hocko <mhocko@suse.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: <stable@vger.kernel.org> Link: https://lkml.kernel.org/r/20180627141348.21777-4-toshi.kani@hpe.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-08-17ioremap: Update pgtable free interfaces with addrChintan Pandya1-5/+7
commit 785a19f9d1dd8a4ab2d0633be4656653bd3de1fc upstream. The following kernel panic was observed on ARM64 platform due to a stale TLB entry. 1. ioremap with 4K size, a valid pte page table is set. 2. iounmap it, its pte entry is set to 0. 3. ioremap the same address with 2M size, update its pmd entry with a new value. 4. CPU may hit an exception because the old pmd entry is still in TLB, which leads to a kernel panic. Commit b6bdb7517c3d ("mm/vmalloc: add interfaces to free unmapped page table") has addressed this panic by falling to pte mappings in the above case on ARM64. To support pmd mappings in all cases, TLB purge needs to be performed in this case on ARM64. Add a new arg, 'addr', to pud_free_pmd_page() and pmd_free_pte_page() so that TLB purge can be added later in seprate patches. [toshi.kani@hpe.com: merge changes, rewrite patch description] Fixes: 28ee90fe6048 ("x86/mm: implement free pmd/pte page interfaces") Signed-off-by: Chintan Pandya <cpandya@codeaurora.org> Signed-off-by: Toshi Kani <toshi.kani@hpe.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: mhocko@suse.com Cc: akpm@linux-foundation.org Cc: hpa@zytor.com Cc: linux-mm@kvack.org Cc: linux-arm-kernel@lists.infradead.org Cc: Will Deacon <will.deacon@arm.com> Cc: Joerg Roedel <joro@8bytes.org> Cc: stable@vger.kernel.org Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Michal Hocko <mhocko@suse.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: <stable@vger.kernel.org> Link: https://lkml.kernel.org/r/20180627141348.21777-3-toshi.kani@hpe.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-08-17x86/mm: Disable ioremap free page handling on x86-PAEToshi Kani1-0/+19
commit f967db0b9ed44ec3057a28f3b28efc51df51b835 upstream. ioremap() supports pmd mappings on x86-PAE. However, kernel's pmd tables are not shared among processes on x86-PAE. Therefore, any update to sync'd pmd entries need re-syncing. Freeing a pte page also leads to a vmalloc fault and hits the BUG_ON in vmalloc_sync_one(). Disable free page handling on x86-PAE. pud_free_pmd_page() and pmd_free_pte_page() simply return 0 if a given pud/pmd entry is present. This assures that ioremap() does not update sync'd pmd entries at the cost of falling back to pte mappings. Fixes: 28ee90fe6048 ("x86/mm: implement free pmd/pte page interfaces") Reported-by: Joerg Roedel <joro@8bytes.org> Signed-off-by: Toshi Kani <toshi.kani@hpe.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: mhocko@suse.com Cc: akpm@linux-foundation.org Cc: hpa@zytor.com Cc: cpandya@codeaurora.org Cc: linux-mm@kvack.org Cc: linux-arm-kernel@lists.infradead.org Cc: stable@vger.kernel.org Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Michal Hocko <mhocko@suse.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: <stable@vger.kernel.org> Link: https://lkml.kernel.org/r/20180627141348.21777-2-toshi.kani@hpe.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-08-15x86/init: fix build with CONFIG_SWAP=nVlastimil Babka1-0/+2
commit 792adb90fa724ce07c0171cbc96b9215af4b1045 upstream. The introduction of generic_max_swapfile_size and arch-specific versions has broken linking on x86 with CONFIG_SWAP=n due to undefined reference to 'generic_max_swapfile_size'. Fix it by compiling the x86-specific max_swapfile_size() only with CONFIG_SWAP=y. Reported-by: Tomas Pruzina <pruzinat@gmail.com> Fixes: 377eeaa8e11f ("x86/speculation/l1tf: Limit swap file size to MAX_PA/2") Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Cc: stable@vger.kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-08-15x86/mm/kmmio: Make the tracer robust against L1TFAndi Kleen1-10/+15
commit 1063711b57393c1999248cccb57bebfaf16739e7 upstream The mmio tracer sets io mapping PTEs and PMDs to non present when enabled without inverting the address bits, which makes the PTE entry vulnerable for L1TF. Make it use the right low level macros to actually invert the address bits to protect against L1TF. In principle this could be avoided because MMIO tracing is not likely to be enabled on production machines, but the fix is straigt forward and for consistency sake it's better to get rid of the open coded PTE manipulation. Signed-off-by: Andi Kleen <ak@linux.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-08-15x86/mm/pat: Make set_memory_np() L1TF safeAndi Kleen1-4/+4
commit 958f79b9ee55dfaf00c8106ed1c22a2919e0028b upstream set_memory_np() is used to mark kernel mappings not present, but it has it's own open coded mechanism which does not have the L1TF protection of inverting the address bits. Replace the open coded PTE manipulation with the L1TF protecting low level PTE routines. Passes the CPA self test. Signed-off-by: Andi Kleen <ak@linux.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> [ dwmw2: Pull in pud_mkhuge() from commit a00cc7d9dd, and pfn_pud() ] Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-08-15x86: Don't include linux/irq.h from asm/hardirq.hNicolai Stange2-0/+2
commit 447ae316670230d7d29430e2cbf1f5db4f49d14c upstream The next patch in this series will have to make the definition of irq_cpustat_t available to entering_irq(). Inclusion of asm/hardirq.h into asm/apic.h would cause circular header dependencies like asm/smp.h asm/apic.h asm/hardirq.h linux/irq.h linux/topology.h linux/smp.h asm/smp.h or linux/gfp.h linux/mmzone.h asm/mmzone.h asm/mmzone_64.h asm/smp.h asm/apic.h asm/hardirq.h linux/irq.h linux/irqdesc.h linux/kobject.h linux/sysfs.h linux/kernfs.h linux/idr.h linux/gfp.h and others. This causes compilation errors because of the header guards becoming effective in the second inclusion: symbols/macros that had been defined before wouldn't be available to intermediate headers in the #include chain anymore. A possible workaround would be to move the definition of irq_cpustat_t into its own header and include that from both, asm/hardirq.h and asm/apic.h. However, this wouldn't solve the real problem, namely asm/harirq.h unnecessarily pulling in all the linux/irq.h cruft: nothing in asm/hardirq.h itself requires it. Also, note that there are some other archs, like e.g. arm64, which don't have that #include in their asm/hardirq.h. Remove the linux/irq.h #include from x86' asm/hardirq.h. Fix resulting compilation errors by adding appropriate #includes to *.c files as needed. Note that some of these *.c files could be cleaned up a bit wrt. to their set of #includes, but that should better be done from separate patches, if at all. Signed-off-by: Nicolai Stange <nstange@suse.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> [dwmw2: More fixes for EFI and Xen in 4.9] Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-08-15x86/speculation/l1tf: Protect PAE swap entries against L1TFVlastimil Babka1-1/+1
commit 0d0f6249058834ffe1ceaad0bb31464af66f6e7a upstream The PAE 3-level paging code currently doesn't mitigate L1TF by flipping the offset bits, and uses the high PTE word, thus bits 32-36 for type, 37-63 for offset. The lower word is zeroed, thus systems with less than 4GB memory are safe. With 4GB to 128GB the swap type selects the memory locations vulnerable to L1TF; with even more memory, also the swap offfset influences the address. This might be a problem with 32bit PAE guests running on large 64bit hosts. By continuing to keep the whole swap entry in either high or low 32bit word of PTE we would limit the swap size too much. Thus this patch uses the whole PAE PTE with the same layout as the 64bit version does. The macros just become a bit tricky since they assume the arch-dependent swp_entry_t to be 32bit. Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-08-15x86/speculation/l1tf: Extend 64bit swap file size limitVlastimil Babka1-1/+9
commit 1a7ed1ba4bba6c075d5ad61bb75e3fbc870840d6 upstream The previous patch has limited swap file size so that large offsets cannot clear bits above MAX_PA/2 in the pte and interfere with L1TF mitigation. It assumed that offsets are encoded starting with bit 12, same as pfn. But on x86_64, offsets are encoded starting with bit 9. Thus the limit can be raised by 3 bits. That means 16TB with 42bit MAX_PA and 256TB with 46bit MAX_PA. Fixes: 377eeaa8e11f ("x86/speculation/l1tf: Limit swap file size to MAX_PA/2") Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-08-15x86/speculation/l1tf: Limit swap file size to MAX_PA/2Andi Kleen1-0/+15
commit 377eeaa8e11fe815b1d07c81c4a0e2843a8c15eb upstream For the L1TF workaround its necessary to limit the swap file size to below MAX_PA/2, so that the higher bits of the swap offset inverted never point to valid memory. Add a mechanism for the architecture to override the swap file size check in swapfile.c and add a x86 specific max swapfile check function that enforces that limit. The check is only enabled if the CPU is vulnerable to L1TF. In VMs with 42bit MAX_PA the typical limit is 2TB now, on a native system with 46bit PA it is 32TB. The limit is only per individual swap file, so it's always possible to exceed these limits with multiple swap files or partitions. Signed-off-by: Andi Kleen <ak@linux.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Dave Hansen <dave.hansen@intel.com> Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-08-15x86/speculation/l1tf: Disallow non privileged high MMIO PROT_NONE mappingsAndi Kleen1-0/+21
commit 42e4089c7890725fcd329999252dc489b72f2921 upstream For L1TF PROT_NONE mappings are protected by inverting the PFN in the page table entry. This sets the high bits in the CPU's address space, thus making sure to point to not point an unmapped entry to valid cached memory. Some server system BIOSes put the MMIO mappings high up in the physical address space. If such an high mapping was mapped to unprivileged users they could attack low memory by setting such a mapping to PROT_NONE. This could happen through a special device driver which is not access protected. Normal /dev/mem is of course access protected. To avoid this forbid PROT_NONE mappings or mprotect for high MMIO mappings. Valid page mappings are allowed because the system is then unsafe anyways. It's not expected that users commonly use PROT_NONE on MMIO. But to minimize any impact this is only enforced if the mapping actually refers to a high MMIO address (defined as the MAX_PA-1 bit being set), and also skip the check for root. For mmaps this is straight forward and can be handled in vm_insert_pfn and in remap_pfn_range(). For mprotect it's a bit trickier. At the point where the actual PTEs are accessed a lot of state has been changed and it would be difficult to undo on an error. Since this is a uncommon case use a separate early page talk walk pass for MMIO PROT_NONE mappings that checks for this condition early. For non MMIO and non PROT_NONE there are no changes. [dwmw2: Backport to 4.9] Signed-off-by: Andi Kleen <ak@linux.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com> Acked-by: Dave Hansen <dave.hansen@intel.com> Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-07-03mm: fix devmem_is_allowed() for sub-page System RAM intersectionsDan Williams1-1/+3
commit 2bdce74412c249ac01dfe36b6b0043ffd7a5361e upstream. Hussam reports: I was poking around and for no real reason, I did cat /dev/mem and strings /dev/mem. Then I saw the following warning in dmesg. I saved it and rebooted immediately. memremap attempted on mixed range 0x000000000009c000 size: 0x1000 ------------[ cut here ]------------ WARNING: CPU: 0 PID: 11810 at kernel/memremap.c:98 memremap+0x104/0x170 [..] Call Trace: xlate_dev_mem_ptr+0x25/0x40 read_mem+0x89/0x1a0 __vfs_read+0x36/0x170 The memremap() implementation checks for attempts to remap System RAM with MEMREMAP_WB and instead redirects those mapping attempts to the linear map. However, that only works if the physical address range being remapped is page aligned. In low memory we have situations like the following: 00000000-00000fff : Reserved 00001000-0009fbff : System RAM 0009fc00-0009ffff : Reserved ...where System RAM intersects Reserved ranges on a sub-page page granularity. Given that devmem_is_allowed() special cases any attempt to map System RAM in the first 1MB of memory, replace page_is_ram() with the more precise region_intersects() to trap attempts to map disallowed ranges. Link: https://bugzilla.kernel.org/show_bug.cgi?id=199999 Link: http://lkml.kernel.org/r/152856436164.18127.2847888121707136898.stgit@dwillia2-desk3.amr.corp.intel.com Fixes: 92281dee825f ("arch: introduce memremap()") Signed-off-by: Dan Williams <dan.j.williams@intel.com> Reported-by: Hussam Al-Tayeb <me@hussam.eu.org> Tested-by: Hussam Al-Tayeb <me@hussam.eu.org> Cc: Christoph Hellwig <hch@lst.de> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-05-30x86/mm: Do not forbid _PAGE_RW before init for __ro_after_initDave Hansen1-2/+4
[ Upstream commit 639d6aafe437a7464399d2a77d006049053df06f ] __ro_after_init data gets stuck in the .rodata section. That's normally fine because the kernel itself manages the R/W properties. But, if we run __change_page_attr() on an area which is __ro_after_init, the .rodata checks will trigger and force the area to be immediately read-only, even if it is early-ish in boot. This caused problems when trying to clear the _PAGE_GLOBAL bit for these area in the PTI code: it cleared _PAGE_GLOBAL like I asked, but also took it up on itself to clear _PAGE_RW. The kernel then oopses the next time it wrote to a __ro_after_init data structure. To fix this, add the kernel_set_to_readonly check, just like we have for kernel text, just a few lines below in this function. Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Acked-by: Kees Cook <keescook@chromium.org> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Dan Williams <dan.j.williams@intel.com> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Hugh Dickins <hughd@google.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Juergen Gross <jgross@suse.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Nadav Amit <namit@vmware.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-mm@kvack.org Link: http://lkml.kernel.org/r/20180406205514.8D898241@viggo.jf.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-05-30x86/pgtable: Don't set huge PUD/PMD on non-leaf entriesJoerg Roedel1-0/+9
[ Upstream commit e3e288121408c3abeed5af60b87b95c847143845 ] The pmd_set_huge() and pud_set_huge() functions are used from the generic ioremap() code to establish large mappings where this is possible. But the generic ioremap() code does not check whether the PMD/PUD entries are already populated with a non-leaf entry, so that any page-table pages these entries point to will be lost. Further, on x86-32 with SHARED_KERNEL_PMD=0, this causes a BUG_ON() in vmalloc_sync_one() when PMD entries are synced from swapper_pg_dir to the current page-table. This happens because the PMD entry from swapper_pg_dir was promoted to a huge-page entry while the current PGD still contains the non-leaf entry. Because both entries are present and point to a different page, the BUG_ON() triggers. This was actually triggered with pti-x32 enabled in a KVM virtual machine by the graphics driver. A real and better fix for that would be to improve the page-table handling in the generic ioremap() code. But that is out-of-scope for this patch-set and left for later work. Reported-by: David H. Gutteridge <dhgutteridge@sympatico.ca> Signed-off-by: Joerg Roedel <jroedel@suse.de> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: David Laight <David.Laight@aculab.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Eduardo Valentin <eduval@amazon.com> Cc: Greg KH <gregkh@linuxfoundation.org> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Juergen Gross <jgross@suse.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Pavel Machek <pavel@ucw.cz> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Waiman Long <llong@redhat.com> Cc: Will Deacon <will.deacon@arm.com> Cc: aliguori@amazon.com Cc: daniel.gruss@iaik.tugraz.at Cc: hughd@google.com Cc: keescook@google.com Cc: linux-mm@kvack.org Link: http://lkml.kernel.org/r/20180411152437.GC15462@8bytes.org Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-05-30vfs/proc/kcore, x86/mm/kcore: Fix SMAP fault when dumping vsyscall user pageJia Zhang1-2/+1
[ Upstream commit 595dd46ebfc10be041a365d0a3fa99df50b6ba73 ] Commit: df04abfd181a ("fs/proc/kcore.c: Add bounce buffer for ktext data") ... introduced a bounce buffer to work around CONFIG_HARDENED_USERCOPY=y. However, accessing the vsyscall user page will cause an SMAP fault. Replace memcpy() with copy_from_user() to fix this bug works, but adding a common way to handle this sort of user page may be useful for future. Currently, only vsyscall page requires KCORE_USER. Signed-off-by: Jia Zhang <zhang.jia@linux.alibaba.com> Reviewed-by: Jiri Olsa <jolsa@kernel.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: jolsa@redhat.com Link: http://lkml.kernel.org/r/1518446694-21124-2-git-send-email-zhang.jia@linux.alibaba.com Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-05-22x86/pkeys: Override pkey when moving away from PROT_EXECDave Hansen1-10/+11
commit 0a0b152083cfc44ec1bb599b57b7aab41327f998 upstream. I got a bug report that the following code (roughly) was causing a SIGSEGV: mprotect(ptr, size, PROT_EXEC); mprotect(ptr, size, PROT_NONE); mprotect(ptr, size, PROT_READ); *ptr = 100; The problem is hit when the mprotect(PROT_EXEC) is implicitly assigned a protection key to the VMA, and made that key ACCESS_DENY|WRITE_DENY. The PROT_NONE mprotect() failed to remove the protection key, and the PROT_NONE-> PROT_READ left the PTE usable, but the pkey still in place and left the memory inaccessible. To fix this, we ensure that we always "override" the pkee at mprotect() if the VMA does not have execute-only permissions, but the VMA has the execute-only pkey. We had a check for PROT_READ/WRITE, but it did not work for PROT_NONE. This entirely removes the PROT_* checks, which ensures that PROT_NONE now works. Reported-by: Shakeel Butt <shakeelb@google.com> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Michael Ellermen <mpe@ellerman.id.au> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ram Pai <linuxram@us.ibm.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-mm@kvack.org Cc: stable@vger.kernel.org Fixes: 62b5f7d013f ("mm/core, x86/mm/pkeys: Add execute-only protection keys support") Link: http://lkml.kernel.org/r/20180509171351.084C5A71@viggo.jf.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-03-28x86/mm: implement free pmd/pte page interfacesToshi Kani1-2/+26
commit 28ee90fe6048fa7b7ceaeb8831c0e4e454a4cf89 upstream. Implement pud_free_pmd_page() and pmd_free_pte_page() on x86, which clear a given pud/pmd entry and free up lower level page table(s). The address range associated with the pud/pmd entry must have been purged by INVLPG. Link: http://lkml.kernel.org/r/20180314180155.19492-3-toshi.kani@hpe.com Fixes: e61ce6ade404e ("mm: change ioremap to set up huge I/O mappings") Signed-off-by: Toshi Kani <toshi.kani@hpe.com> Reported-by: Lei Li <lious.lilei@hisilicon.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Borislav Petkov <bp@suse.de> Cc: Matthew Wilcox <willy@infradead.org> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-03-28mm/vmalloc: add interfaces to free unmapped page tableToshi Kani1-0/+24
commit b6bdb7517c3d3f41f20e5c2948d6bc3f8897394e upstream. On architectures with CONFIG_HAVE_ARCH_HUGE_VMAP set, ioremap() may create pud/pmd mappings. A kernel panic was observed on arm64 systems with Cortex-A75 in the following steps as described by Hanjun Guo. 1. ioremap a 4K size, valid page table will build, 2. iounmap it, pte0 will set to 0; 3. ioremap the same address with 2M size, pgd/pmd is unchanged, then set the a new value for pmd; 4. pte0 is leaked; 5. CPU may meet exception because the old pmd is still in TLB, which will lead to kernel panic. This panic is not reproducible on x86. INVLPG, called from iounmap, purges all levels of entries associated with purged address on x86. x86 still has memory leak. The patch changes the ioremap path to free unmapped page table(s) since doing so in the unmap path has the following issues: - The iounmap() path is shared with vunmap(). Since vmap() only supports pte mappings, making vunmap() to free a pte page is an overhead for regular vmap users as they do not need a pte page freed up. - Checking if all entries in a pte page are cleared in the unmap path is racy, and serializing this check is expensive. - The unmap path calls free_vmap_area_noflush() to do lazy TLB purges. Clearing a pud/pmd entry before the lazy TLB purges needs extra TLB purge. Add two interfaces, pud_free_pmd_page() and pmd_free_pte_page(), which clear a given pud/pmd entry and free up a page for the lower level entries. This patch implements their stub functions on x86 and arm64, which work as workaround. [akpm@linux-foundation.org: fix typo in pmd_free_pte_page() stub] Link: http://lkml.kernel.org/r/20180314180155.19492-2-toshi.kani@hpe.com Fixes: e61ce6ade404e ("mm: change ioremap to set up huge I/O mappings") Reported-by: Lei Li <lious.lilei@hisilicon.com> Signed-off-by: Toshi Kani <toshi.kani@hpe.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Wang Xuefeng <wxf.wang@hisilicon.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Hanjun Guo <guohanjun@huawei.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Borislav Petkov <bp@suse.de> Cc: Matthew Wilcox <willy@infradead.org> Cc: Chintan Pandya <cpandya@codeaurora.org> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-03-22x86/mm: Fix vmalloc_fault to use pXd_largeToshi Kani1-3/+3
commit 18a955219bf7d9008ce480d4451b6b8bf4483a22 upstream. Gratian Crisan reported that vmalloc_fault() crashes when CONFIG_HUGETLBFS is not set since the function inadvertently uses pXn_huge(), which always return 0 in this case. ioremap() does not depend on CONFIG_HUGETLBFS. Fix vmalloc_fault() to call pXd_large() instead. Fixes: f4eafd8bcd52 ("x86/mm: Fix vmalloc_fault() to handle large pages properly") Reported-by: Gratian Crisan <gratian.crisan@ni.com> Signed-off-by: Toshi Kani <toshi.kani@hpe.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: stable@vger.kernel.org Cc: linux-mm@kvack.org Cc: Borislav Petkov <bp@alien8.de> Cc: Andy Lutomirski <luto@kernel.org> Link: https://lkml.kernel.org/r/20180313170347.3829-2-toshi.kani@hpe.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-03-11x86/speculation: Use Indirect Branch Prediction Barrier in context switchTim Chen1-0/+31
commit 18bf3c3ea8ece8f03b6fc58508f2dfd23c7711c7 upstream. Flush indirect branches when switching into a process that marked itself non dumpable. This protects high value processes like gpg better, without having too high performance overhead. If done naïvely, we could switch to a kernel idle thread and then back to the original process, such as: process A -> idle -> process A In such scenario, we do not have to do IBPB here even though the process is non-dumpable, as we are switching back to the same process after a hiatus. To avoid the redundant IBPB, which is expensive, we track the last mm user context ID. The cost is to have an extra u64 mm context id to track the last mm we were using before switching to the init_mm used by idle. Avoiding the extra IBPB is probably worth the extra memory for this common scenario. For those cases where tlb_defer_switch_to_init_mm() returns true (non PCID), lazy tlb will defer switch to init_mm, so we will not be changing the mm for the process A -> idle -> process A switch. So IBPB will be skipped for this case. Thanks to the reviewers and Andy Lutomirski for the suggestion of using ctx_id which got rid of the problem of mm pointer recycling. Signed-off-by: Tim Chen <tim.c.chen@linux.intel.com> Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: ak@linux.intel.com Cc: karahmed@amazon.de Cc: arjan@linux.intel.com Cc: torvalds@linux-foundation.org Cc: linux@dominikbrodowski.net Cc: peterz@infradead.org Cc: bp@alien8.de Cc: luto@kernel.org Cc: pbonzini@redhat.com Link: https://lkml.kernel.org/r/1517263487-3708-1-git-send-email-dwmw@amazon.co.uk Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-03-11x86/mm: Give each mm TLB flush generation a unique IDAndy Lutomirski1-0/+2
commit f39681ed0f48498b80455095376f11535feea332 upstream. This adds two new variables to mmu_context_t: ctx_id and tlb_gen. ctx_id uniquely identifies the mm_struct and will never be reused. For a given mm_struct (and hence ctx_id), tlb_gen is a monotonic count of the number of times that a TLB flush has been requested. The pair (ctx_id, tlb_gen) can be used as an identifier for TLB flush actions and will be used in subsequent patches to reliably determine whether all needed TLB flushes have occurred on a given CPU. This patch is split out for ease of review. By itself, it has no real effect other than creating and updating the new variables. Signed-off-by: Andy Lutomirski <luto@kernel.org> Reviewed-by: Nadav Amit <nadav.amit@gmail.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: linux-mm@kvack.org Link: http://lkml.kernel.org/r/413a91c24dab3ed0caa5f4e4d017d87b0857f920.1498751203.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Tim Chen <tim.c.chen@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-02-25x86/mm/kmmio: Fix mmiotrace for page unaligned addressesKarol Herbst2-7/+9
[ Upstream commit 6d60ce384d1d5ca32b595244db4077a419acc687 ] If something calls ioremap() with an address not aligned to PAGE_SIZE, the returned address might be not aligned as well. This led to a probe registered on exactly the returned address, but the entire page was armed for mmiotracing. On calling iounmap() the address passed to unregister_kmmio_probe() was PAGE_SIZE aligned by the caller leading to a complete freeze of the machine. We should always page align addresses while (un)registerung mappings, because the mmiotracer works on top of pages, not mappings. We still keep track of the probes based on their real addresses and lengths though, because the mmiotrace still needs to know what are mapped memory regions. Also move the call to mmiotrace_iounmap() prior page aligning the address, so that all probes are unregistered properly, otherwise the kernel ends up failing memory allocations randomly after disabling the mmiotracer. Tested-by: Lyude <lyude@redhat.com> Signed-off-by: Karol Herbst <kherbst@redhat.com> Acked-by: Pekka Paalanen <ppaalanen@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: nouveau@lists.freedesktop.org Link: http://lkml.kernel.org/r/20171127075139.4928-1-kherbst@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-01-31vsyscall: Fix permissions for emulate mode with KAISER/PTIBen Hutchings1-1/+1
The backport of KAISER to 4.4 turned vsyscall emulate mode into native mode. Add a vsyscall_pgprot variable to hold the correct page protections, like Borislav and Hugh did for 3.2 and 3.18. Cc: Borislav Petkov <bp@suse.de> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Ben Hutchings <ben.hutchings@codethink.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-01-23x86/mm/pkeys: Fix fill_sig_info_pkeyEric W. Biederman1-3/+4
commit beacd6f7ed5e2915959442245b3b2480c2e37490 upstream. SEGV_PKUERR is a signal specific si_code which happens to have the same numeric value as several others: BUS_MCEERR_AR, ILL_ILLTRP, FPE_FLTOVF, TRAP_HWBKPT, CLD_TRAPPED, POLL_ERR, SEGV_THREAD_ID, as such it is not safe to just test the si_code the signal number must also be tested to prevent a false positive in fill_sig_info_pkey. This error was by inspection, and BUS_MCEERR_AR appears to be a real candidate for confusion. So pass in si_signo and check for SIG_SEGV to verify that it is actually a SEGV_PKUERR Fixes: 019132ff3daf ("x86/mm/pkeys: Fill in pkey field in siginfo") Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: linux-arch@vger.kernel.org Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Link: https://lkml.kernel.org/r/20180112203135.4669-2-ebiederm@xmission.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-01-17x86/pti/efi: broken conversion from efi to kernel page tablePavel Tatashin1-7/+0
The page table order must be increased for EFI table in order to avoid a bug where NMI tries to change the page table to kernel page table, while efi page table is active. For more disccussion about this bug, see this thread: http://lkml.iu.edu/hypermail/linux/kernel/1801.1/00951.html Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com> Reviewed-by: Steven Sistare <steven.sistare@oracle.com> Acked-by: Jiri Kosina <jkosina@suse.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-01-17x86/asm: Use register variable to get stack pointer valueAndrey Ryabinin1-1/+1
commit 196bd485ee4f03ce4c690bfcf38138abfcd0a4bc upstream. Currently we use current_stack_pointer() function to get the value of the stack pointer register. Since commit: f5caf621ee35 ("x86/asm: Fix inline asm call constraints for Clang") ... we have a stack register variable declared. It can be used instead of current_stack_pointer() function which allows to optimize away some excessive "mov %rsp, %<dst>" instructions: -mov %rsp,%rdx -sub %rdx,%rax -cmp $0x3fff,%rax -ja ffffffff810722fd <ist_begin_non_atomic+0x2d> +sub %rsp,%rax +cmp $0x3fff,%rax +ja ffffffff810722fa <ist_begin_non_atomic+0x2a> Remove current_stack_pointer(), rename __asm_call_sp to current_stack_pointer and use it instead of the removed function. Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20170929141537.29167-1-aryabinin@virtuozzo.com Signed-off-by: Ingo Molnar <mingo@kernel.org> [dwmw2: We want ASM_CALL_CONSTRAINT for retpoline] Signed-off-by: David Woodhouse <dwmw@amazon.co.ku> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-01-17kaiser: Set _PAGE_NX only if supportedLepton Wu1-0/+2
This finally resolve crash if loaded under qemu + haxm. Haitao Shan pointed out that the reason of that crash is that NX bit get set for page tables. It seems we missed checking if _PAGE_NX is supported in kaiser_add_user_map Link: https://www.spinics.net/lists/kernel/msg2689835.html Reviewed-by: Guenter Roeck <groeck@chromium.org> Signed-off-by: Lepton Wu <ytht.net@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-01-10Map the vsyscall page with _PAGE_USERBorislav Petkov1-4/+30
This needs to happen early in kaiser_pagetable_walk(), before the hierarchy is established so that _PAGE_USER permission can be really set. A proper fix would be to teach kaiser_pagetable_walk() to update those permissions but the vsyscall page is the only exception here so ... Signed-off-by: Borislav Petkov <bp@suse.de> Acked-by: Hugh Dickins <hughd@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-01-10x86/tlb: Drop the _GPL from the cpu_tlbstate exportThomas Gleixner1-1/+1
commit 1e5476815fd7f98b888e01a0f9522b63085f96c9 upstream. The recent changes for PTI touch cpu_tlbstate from various tlb_flush inlines. cpu_tlbstate is exported as GPL symbol, so this causes a regression when building out of tree drivers for certain graphics cards. Aside of that the export was wrong since it was introduced as it should have been EXPORT_PER_CPU_SYMBOL_GPL(). Use the correct PER_CPU export and drop the _GPL to restore the previous state which allows users to utilize the cards they payed for. As always I'm really thrilled to make this kind of change to support the #friends (or however the hot hashtag of today is spelled) from that closet sauce graphics corp. Fixes: 1e02ce4cccdc ("x86: Store a per-cpu shadow copy of CR4") Fixes: 6fd166aae78c ("x86/mm: Use/Fix PCID to optimize user/kernel switches") Reported-by: Kees Cook <keescook@google.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Thomas Backlund <tmb@mageia.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-01-05kaiser: Set _PAGE_NX only if supportedGuenter Roeck1-1/+2
This resolves a crash if loaded under qemu + haxm under windows. See https://www.spinics.net/lists/kernel/msg2689835.html for details. Here is a boot log (the log is from chromeos-4.4, but Tao Wu says that the same log is also seen with vanilla v4.4.110-rc1). [ 0.712750] Freeing unused kernel memory: 552K [ 0.721821] init: Corrupted page table at address 57b029b332e0 [ 0.722761] PGD 80000000bb238067 PUD bc36a067 PMD bc369067 PTE 45d2067 [ 0.722761] Bad pagetable: 000b [#1] PREEMPT SMP [ 0.722761] Modules linked in: [ 0.722761] CPU: 1 PID: 1 Comm: init Not tainted 4.4.96 #31 [ 0.722761] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.7.5.1-0-g8936dbb-20141113_115728-nilsson.home.kraxel.org 04/01/2014 [ 0.722761] task: ffff8800bc290000 ti: ffff8800bc28c000 task.ti: ffff8800bc28c000 [ 0.722761] RIP: 0010:[<ffffffff83f4129e>] [<ffffffff83f4129e>] __clear_user+0x42/0x67 [ 0.722761] RSP: 0000:ffff8800bc28fcf8 EFLAGS: 00010202 [ 0.722761] RAX: 0000000000000000 RBX: 00000000000001a4 RCX: 00000000000001a4 [ 0.722761] RDX: 0000000000000000 RSI: 0000000000000008 RDI: 000057b029b332e0 [ 0.722761] RBP: ffff8800bc28fd08 R08: ffff8800bc290000 R09: ffff8800bb2f4000 [ 0.722761] R10: ffff8800bc290000 R11: ffff8800bb2f4000 R12: 000057b029b332e0 [ 0.722761] R13: 0000000000000000 R14: 000057b029b33340 R15: ffff8800bb1e2a00 [ 0.722761] FS: 0000000000000000(0000) GS:ffff8800bfb00000(0000) knlGS:0000000000000000 [ 0.722761] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b [ 0.722761] CR2: 000057b029b332e0 CR3: 00000000bb2f8000 CR4: 00000000000006e0 [ 0.722761] Stack: [ 0.722761] 000057b029b332e0 ffff8800bb95fa80 ffff8800bc28fd18 ffffffff83f4120c [ 0.722761] ffff8800bc28fe18 ffffffff83e9e7a1 ffff8800bc28fd68 0000000000000000 [ 0.722761] ffff8800bc290000 ffff8800bc290000 ffff8800bc290000 ffff8800bc290000 [ 0.722761] Call Trace: [ 0.722761] [<ffffffff83f4120c>] clear_user+0x2e/0x30 [ 0.722761] [<ffffffff83e9e7a1>] load_elf_binary+0xa7f/0x18f7 [ 0.722761] [<ffffffff83de2088>] search_binary_handler+0x86/0x19c [ 0.722761] [<ffffffff83de389e>] do_execveat_common.isra.26+0x909/0xf98 [ 0.722761] [<ffffffff844febe0>] ? rest_init+0x87/0x87 [ 0.722761] [<ffffffff83de40be>] do_execve+0x23/0x25 [ 0.722761] [<ffffffff83c002e3>] run_init_process+0x2b/0x2d [ 0.722761] [<ffffffff844fec4d>] kernel_init+0x6d/0xda [ 0.722761] [<ffffffff84505b2f>] ret_from_fork+0x3f/0x70 [ 0.722761] [<ffffffff844febe0>] ? rest_init+0x87/0x87 [ 0.722761] Code: 86 84 be 12 00 00 00 e8 87 0d e8 ff 66 66 90 48 89 d8 48 c1 eb 03 4c 89 e7 83 e0 07 48 89 d9 be 08 00 00 00 31 d2 48 85 c9 74 0a <48> 89 17 48 01 f7 ff c9 75 f6 48 89 c1 85 c9 74 09 88 17 48 ff [ 0.722761] RIP [<ffffffff83f4129e>] __clear_user+0x42/0x67 [ 0.722761] RSP <ffff8800bc28fcf8> [ 0.722761] ---[ end trace def703879b4ff090 ]--- [ 0.722761] BUG: sleeping function called from invalid context at /mnt/host/source/src/third_party/kernel/v4.4/kernel/locking/rwsem.c:21 [ 0.722761] in_atomic(): 0, irqs_disabled(): 1, pid: 1, name: init [ 0.722761] CPU: 1 PID: 1 Comm: init Tainted: G D 4.4.96 #31 [ 0.722761] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.7.5.1-0-g8936dbb-20141113_115728-nilsson.home.kraxel.org 04/01/2014 [ 0.722761] 0000000000000086 dcb5d76098c89836 ffff8800bc28fa30 ffffffff83f34004 [ 0.722761] ffffffff84839dc2 0000000000000015 ffff8800bc28fa40 ffffffff83d57dc9 [ 0.722761] ffff8800bc28fa68 ffffffff83d57e6a ffffffff84a53640 0000000000000000 [ 0.722761] Call Trace: [ 0.722761] [<ffffffff83f34004>] dump_stack+0x4d/0x63 [ 0.722761] [<ffffffff83d57dc9>] ___might_sleep+0x13a/0x13c [ 0.722761] [<ffffffff83d57e6a>] __might_sleep+0x9f/0xa6 [ 0.722761] [<ffffffff84502788>] down_read+0x20/0x31 [ 0.722761] [<ffffffff83cc5d9b>] __blocking_notifier_call_chain+0x35/0x63 [ 0.722761] [<ffffffff83cc5ddd>] blocking_notifier_call_chain+0x14/0x16 [ 0.800374] usb 1-1: new full-speed USB device number 2 using uhci_hcd [ 0.722761] [<ffffffff83cefe97>] profile_task_exit+0x1a/0x1c [ 0.802309] [<ffffffff83cac84e>] do_exit+0x39/0xe7f [ 0.802309] [<ffffffff83ce5938>] ? vprintk_default+0x1d/0x1f [ 0.802309] [<ffffffff83d7bb95>] ? printk+0x57/0x73 [ 0.802309] [<ffffffff83c46e25>] oops_end+0x80/0x85 [ 0.802309] [<ffffffff83c7b747>] pgtable_bad+0x8a/0x95 [ 0.802309] [<ffffffff83ca7f4a>] __do_page_fault+0x8c/0x352 [ 0.802309] [<ffffffff83eefba5>] ? file_has_perm+0xc4/0xe5 [ 0.802309] [<ffffffff83ca821c>] do_page_fault+0xc/0xe [ 0.802309] [<ffffffff84507682>] page_fault+0x22/0x30 [ 0.802309] [<ffffffff83f4129e>] ? __clear_user+0x42/0x67 [ 0.802309] [<ffffffff83f4127f>] ? __clear_user+0x23/0x67 [ 0.802309] [<ffffffff83f4120c>] clear_user+0x2e/0x30 [ 0.802309] [<ffffffff83e9e7a1>] load_elf_binary+0xa7f/0x18f7 [ 0.802309] [<ffffffff83de2088>] search_binary_handler+0x86/0x19c [ 0.802309] [<ffffffff83de389e>] do_execveat_common.isra.26+0x909/0xf98 [ 0.802309] [<ffffffff844febe0>] ? rest_init+0x87/0x87 [ 0.802309] [<ffffffff83de40be>] do_execve+0x23/0x25 [ 0.802309] [<ffffffff83c002e3>] run_init_process+0x2b/0x2d [ 0.802309] [<ffffffff844fec4d>] kernel_init+0x6d/0xda [ 0.802309] [<ffffffff84505b2f>] ret_from_fork+0x3f/0x70 [ 0.802309] [<ffffffff844febe0>] ? rest_init+0x87/0x87 [ 0.830559] Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000009 [ 0.830559] [ 0.831305] Kernel Offset: 0x2c00000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff) [ 0.831305] ---[ end Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000009 The crash part of this problem may be solved with the following patch (thanks to Hugh for the hint). There is still another problem, though - with this patch applied, the qemu session aborts with "VCPU Shutdown request", whatever that means. Cc: lepton <ytht.net@gmail.com> Signed-off-by: Guenter Roeck <groeck@chromium.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-01-05KPTI: Report when enabledKees Cook1-1/+6
Make sure dmesg reports when KPTI is enabled. Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-01-05KPTI: Rename to PAGE_TABLE_ISOLATIONKees Cook2-2/+2
This renames CONFIG_KAISER to CONFIG_PAGE_TABLE_ISOLATION. Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-01-05x86/kaiser: Move feature detection upBorislav Petkov1-2/+0
... before the first use of kaiser_enabled as otherwise funky things happen: about to get started... (XEN) d0v0 Unhandled page fault fault/trap [#14, ec=0000] (XEN) Pagetable walk from ffff88022a449090: (XEN) L4[0x110] = 0000000229e0e067 0000000000001e0e (XEN) L3[0x008] = 0000000000000000 ffffffffffffffff (XEN) domain_crash_sync called from entry.S: fault at ffff82d08033fd08 entry.o#create_bounce_frame+0x135/0x14d (XEN) Domain 0 (vcpu#0) crashed on cpu#0: (XEN) ----[ Xen-4.9.1_02-3.21 x86_64 debug=n Not tainted ]---- (XEN) CPU: 0 (XEN) RIP: e033:[<ffffffff81007460>] (XEN) RFLAGS: 0000000000000286 EM: 1 CONTEXT: pv guest (d0v0) Signed-off-by: Borislav Petkov <bp@suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-01-05kaiser: disabled on Xen PVJiri Kosina1-0/+5
Kaiser cannot be used on paravirtualized MMUs (namely reading and writing CR3). This does not work with KAISER as the CR3 switch from and to user space PGD would require to map the whole XEN_PV machinery into both. More importantly, enabling KAISER on Xen PV doesn't make too much sense, as PV guests use distinct %cr3 values for kernel and user already. Signed-off-by: Jiri Kosina <jkosina@suse.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-01-05kaiser: kaiser_flush_tlb_on_return_to_user() check PCIDHugh Dickins2-7/+7
Let kaiser_flush_tlb_on_return_to_user() do the X86_FEATURE_PCID check, instead of each caller doing it inline first: nobody needs to optimize for the noPCID case, it's clearer this way, and better suits later changes. Replace those no-op X86_CR3_PCID_KERN_FLUSH lines by a BUILD_BUG_ON() in load_new_mm_cr3(), in case something changes. Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Jiri Kosina <jkosina@suse.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-01-05kaiser: drop is_atomic arg to kaiser_pagetable_walk()Hugh Dickins1-8/+2
I have not observed a might_sleep() warning from setup_fixmap_gdt()'s use of kaiser_add_mapping() in our tree (why not?), but like upstream we have not provided a way for that to pass is_atomic true down to kaiser_pagetable_walk(), and at startup it's far from a likely source of trouble: so just delete the walk's is_atomic arg and might_sleep(). Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Jiri Kosina <jkosina@suse.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-01-05kaiser: use ALTERNATIVE instead of x86_cr3_pcid_noflushHugh Dickins1-10/+1
Now that we're playing the ALTERNATIVE game, use that more efficient method: instead of user-mapping an extra page, and reading an extra cacheline each time for x86_cr3_pcid_noflush. Neel has found that __stringify(bts $X86_CR3_PCID_NOFLUSH_BIT, %rax) is a working substitute for the "bts $63, %rax" in these ALTERNATIVEs; but the one line with $63 in looks clearer, so let's stick with that. Worried about what happens with an ALTERNATIVE between the jump and jump label in another ALTERNATIVE? I was, but have checked the combinations in SWITCH_KERNEL_CR3_NO_STACK at entry_SYSCALL_64, and it does a good job. Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Jiri Kosina <jkosina@suse.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-01-05x86/kaiser: Check boottime cmdline paramsBorislav Petkov1-18/+41
AMD (and possibly other vendors) are not affected by the leak KAISER is protecting against. Keep the "nopti" for traditional reasons and add pti=<on|off|auto> like upstream. Signed-off-by: Borislav Petkov <bp@suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-01-05x86/kaiser: Rename and simplify X86_FEATURE_KAISER handlingBorislav Petkov1-1/+19
Concentrate it in arch/x86/mm/kaiser.c and use the upstream string "nopti". Signed-off-by: Borislav Petkov <bp@suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-01-05kaiser: add "nokaiser" boot option, using ALTERNATIVEHugh Dickins5-14/+36
Added "nokaiser" boot option: an early param like "noinvpcid". Most places now check int kaiser_enabled (#defined 0 when not CONFIG_KAISER) instead of #ifdef CONFIG_KAISER; but entry_64.S and entry_64_compat.S are using the ALTERNATIVE technique, which patches in the preferred instructions at runtime. That technique is tied to x86 cpu features, so X86_FEATURE_KAISER is fabricated. Prior to "nokaiser", Kaiser #defined _PAGE_GLOBAL 0: revert that, but be careful with both _PAGE_GLOBAL and CR4.PGE: setting them when nokaiser like when !CONFIG_KAISER, but not setting either when kaiser - neither matters on its own, but it's hard to be sure that _PAGE_GLOBAL won't get set in some obscure corner, or something add PGE into CR4. By omitting _PAGE_GLOBAL from __supported_pte_mask when kaiser_enabled, all page table setup which uses pte_pfn() masks it out of the ptes. It's slightly shameful that the same declaration versus definition of kaiser_enabled appears in not one, not two, but in three header files (asm/kaiser.h, asm/pgtable.h, asm/tlbflush.h). I felt safer that way, than with #including any of those in any of the others; and did not feel it worth an asm/kaiser_enabled.h - kernel/cpu/common.c includes them all, so we shall hear about it if they get out of synch. Cleanups while in the area: removed the silly #ifdef CONFIG_KAISER from kaiser.c; removed the unused native_get_normal_pgd(); removed the spurious reg clutter from SWITCH_*_CR3 macro stubs; corrected some comments. But more interestingly, set CR4.PSE in secondary_startup_64: the manual is clear that it does not matter whether it's 0 or 1 when 4-level-pts are enabled, but I was distracted to find cr4 different on BSP and auxiliaries - BSP alone was adding PSE, in probe_page_size_mask(). Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Jiri Kosina <jkosina@suse.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-01-05kaiser: kaiser_remove_mapping() move along the pgdHugh Dickins1-4/+6
When removing the bogus comment from kaiser_remove_mapping(), I really ought to have checked the extent of its bogosity: as Neel points out, there is nothing to stop unmap_pud_range_nofree() from continuing beyond the end of a pud (and starting in the wrong position on the next). Fix kaiser_remove_mapping() to constrain the extent and advance pgd pointer correctly: use pgd_addr_end() macro as used throughout base mm (but don't assume page-rounded start and size in this case). But this bug was very unlikely to trigger in this backport: since any buddy allocation is contained within a single pud extent, and we are not using vmapped stacks (and are only mapping one page of stack anyway): the only way to hit this bug here would be when freeing a large modified ldt. Signed-off-by: Hugh Dickins <hughd@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-01-05kaiser: x86_cr3_pcid_noflush and x86_cr3_pcid_userHugh Dickins1-6/+7
Mostly this commit is just unshouting X86_CR3_PCID_KERN_VAR and X86_CR3_PCID_USER_VAR: we usually name variables in lower-case. But why does x86_cr3_pcid_noflush need to be __aligned(PAGE_SIZE)? Ah, it's a leftover from when kaiser_add_user_map() once complained about mapping the same page twice. Make it __read_mostly instead. (I'm a little uneasy about all the unrelated data which shares its page getting user-mapped too, but that was so before, and not a big deal: though we call it user-mapped, it's not mapped with _PAGE_USER.) And there is a little change around the two calls to do_nmi(). Previously they set the NOFLUSH bit (if PCID supported) when forcing to kernel context before do_nmi(); now they also have the NOFLUSH bit set (if PCID supported) when restoring context after: nothing done in do_nmi() should require a TLB to be flushed here. Signed-off-by: Hugh Dickins <hughd@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-01-05kaiser: PCID 0 for kernel and 128 for userHugh Dickins1-0/+3
Why was 4 chosen for kernel PCID and 6 for user PCID? No good reason in a backport where PCIDs are only used for Kaiser. If we continue with those, then we shall need to add Andy Lutomirski's 4.13 commit 6c690ee1039b ("x86/mm: Split read_cr3() into read_cr3_pa() and __read_cr3()"), which deals with the problem of read_cr3() callers finding stray bits in the cr3 that they expected to be page-aligned; and for hibernation, his 4.14 commit f34902c5c6c0 ("x86/hibernate/64: Mask off CR3's PCID bits in the saved CR3"). But if 0 is used for kernel PCID, then there's no need to add in those commits - whenever the kernel looks, it sees 0 in the lower bits; and 0 for kernel seems an obvious choice. And I naughtily propose 128 for user PCID. Because there's a place in _SWITCH_TO_USER_CR3 where it takes note of the need for TLB FLUSH, but needs to reset that to NOFLUSH for the next occasion. Currently it does so with a "movb $(0x80)" into the high byte of the per-cpu quadword, but that will cause a machine without PCID support to crash. Now, if %al just happened to have 0x80 in it at that point, on a machine with PCID support, but 0 on a machine without PCID support... (That will go badly wrong once the pgd can be at a physical address above 2^56, but even with 5-level paging, physical goes up to 2^52.) Signed-off-by: Hugh Dickins <hughd@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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