- 11 Dec, 2017 1 commit
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Karol Herbst authored
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.comSigned-off-by:
Ingo Molnar <mingo@kernel.org>
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- 07 Dec, 2017 3 commits
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Kirill A. Shutemov authored
If the machine does not support the paging mode for which the kernel was compiled, the boot process cannot continue. It's not possible to let the kernel detect the mismatch as it does not even reach the point where cpu features can be evaluted due to a triple fault in the KASLR setup. Instead of instantaneous silent reboot, emit an error message which gives the user the information why the boot fails. Fixes: 77ef56e4 ("x86: Enable 5-level paging support via CONFIG_X86_5LEVEL=y") Reported-by:
Borislav Petkov <bp@suse.de> Signed-off-by:
Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by:
Thomas Gleixner <tglx@linutronix.de> Tested-by:
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Kirill A. Shutemov authored
Prerequisite for fixing the current problem of instantaneous reboots when a 5-level paging kernel is booted on 4-level paging hardware. At the same time this change prepares the decompression code to boot-time switching between 4- and 5-level paging. [ tglx: Folded the GCC < 5 fix. ] Fixes: 77ef56e4 ("x86: Enable 5-level paging support via CONFIG_X86_5LEVEL=y") Signed-off-by:
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Prarit Bhargava authored
Documentation/x86/topology.txt defines smp_num_siblings as "The number of threads in a core". Since commit bbb65d2d ("x86: use cpuid vector 0xb when available for detecting cpu topology") smp_num_siblings is the maximum number of threads in a core. If Simultaneous MultiThreading (SMT) is disabled on a system, smp_num_siblings is 2 and not 1 as expected. Use topology_max_smt_threads(), which contains the active numer of threads, in the __max_logical_packages calculation. On a single socket, single core, single thread system __max_smt_threads has not been updated when the __max_logical_packages calculation happens, so its zero which makes the package estimate fail. Initialize it to one, which is the minimum number of threads on a core. [ tglx: Folded the __max_smt_threads fix in ] Fixes: b4c0a732 ("x86/smpboot: Fix __max_logical_packages estimate") Reported-by:
Jakub Kicinski <kubakici@wp.pl> Signed-off-by: Prarit Bhargava <prarit@redhat.com Signed-off-by:
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- 06 Dec, 2017 6 commits
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Arnd Bergmann authored
gcc-8 warns that time() is an alias for __vdso_time() but the two have different prototypes: arch/x86/entry/vdso/vclock_gettime.c:327:5: error: 'time' alias between functions of incompatible types 'int(time_t *)' {aka 'int(long int *)'} and 'time_t(time_t *)' {aka 'long int(long int *)'} [-Werror=attribute-alias] int time(time_t *t) ^~~~ arch/x86/entry/vdso/vclock_gettime.c:318:16: note: aliased declaration here I could not figure out whether this is intentional, but I see that changing it to return time_t avoids the warning. Returning 'int' from time() is also a bit questionable, as it causes an overflow in y2038 even on 64-bit architectures that use a 64-bit time_t type. On 32-bit architecture with 64-bit time_t, time() should always be implement by the C library by calling a (to be added) clock_gettime() variant that takes a sufficiently wide argument. Signed-off-by:Arnd Bergmann <arnd@arndb.de> Acked-by:
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Colin Ian King authored
Functions x86_vector_debug_show(), uv_handle_nmi() and uv_nmi_setup_common() are local to the source and do not need to be in global scope, so make them static. Fixes up various sparse warnings. Signed-off-by:
Colin Ian King <colin.king@canonical.com> Acked-by:
Mike Travis <mike.travis@hpe.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Jiri Kosina <trivial@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Russ Anderson <russ.anderson@hpe.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: kernel-janitors@vger.kernel.org Cc: travis@sgi.com Link: http://lkml.kernel.org/r/20171206173358.24388-1-colin.king@canonical.comSigned-off-by:
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Andy Lutomirski authored
__restore_processor_context() had a couple of ordering bugs. It restored GSBASE after calling load_gs_index(), and the latter can call into tracing code. It also tried to restore segment registers before restoring the LDT, which is straight-up wrong. Reorder the code so that we restore GSBASE, then the descriptor tables, then the segments. This fixes two bugs. First, it fixes a regression that broke resume under certain configurations due to irqflag tracing in native_load_gs_index(). Second, it fixes resume when the userspace process that initiated suspect had funny segments. The latter can be reproduced by compiling this: // SPDX-License-Identifier: GPL-2.0 /* * ldt_echo.c - Echo argv[1] while using an LDT segment */ int main(int argc, char **argv) { int ret; size_t len; char *buf; const struct user_desc desc = { .entry_number = 0, .base_addr = 0, .limit = 0xfffff, .seg_32bit = 1, .contents = 0, /* Data, grow-up */ .read_exec_only = 0, .limit_in_pages = 1, .seg_not_present = 0, .useable = 0 }; if (argc != 2) errx(1, "Usage: %s STRING", argv[0]); len = asprintf(&buf, "%s\n", argv[1]); if (len < 0) errx(1, "Out of memory"); ret = syscall(SYS_modify_ldt, 1, &desc, sizeof(desc)); if (ret < -1) errno = -ret; if (ret) err(1, "modify_ldt"); asm volatile ("movw %0, %%es" :: "rm" ((unsigned short)7)); write(1, buf, len); return 0; } and running ldt_echo >/sys/power/mem Without the fix, the latter causes a triple fault on resume. Fixes: ca37e57b ("x86/entry/64: Add missing irqflags tracing to native_load_gs_index()") Reported-by:Jarkko Nikula <jarkko.nikula@linux.intel.com> Signed-off-by:
Andy Lutomirski <luto@kernel.org> Signed-off-by:
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Rafael J. Wysocki authored
acpi_os_get_root_pointer() may return a valid address even if acpi_disabled is set, but the host bridge information from the ACPI tables is not going to be used in that case and the Broadcom host bridge initialization should not be skipped then, So make broadcom_postcore_init() check acpi_disabled too to avoid this issue. Fixes: 6361d72b (x86/PCI: read Broadcom CNB20LE host bridge info before PCI scan) Reported-by:
Dave Hansen <dave.hansen@linux.intel.com> Signed-off-by:
Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by:
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Tom Lendacky authored
The size for the Microcode Patch Block (MPB) for an AMD family 17h processor is 3200 bytes. Add a #define for fam17h so that it does not default to 2048 bytes and fail a microcode load/update. Signed-off-by:
Tom Lendacky <thomas.lendacky@amd.com> Signed-off-by:
Borislav Petkov <bp@alien8.de> Link: https://lkml.kernel.org/r/20171130224640.15391.40247.stgit@tlendack-t1.amdoffice.netSigned-off-by:
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Rudolf Marek authored
The latest AMD AMD64 Architecture Programmer's Manual adds a CPUID feature XSaveErPtr (CPUID_Fn80000008_EBX[2]). If this feature is set, the FXSAVE, XSAVE, FXSAVEOPT, XSAVEC, XSAVES / FXRSTOR, XRSTOR, XRSTORS always save/restore error pointers, thus making the X86_BUG_FXSAVE_LEAK workaround obsolete on such CPUs. Signed-off-by:
Rudolf Marek <r.marek@assembler.cz> Signed-off-by:
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- 28 Nov, 2017 1 commit
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Chunyu Hu authored
On a secondary, idt is first loaded in cpu_init() with load_current_idt(), i.e. no exceptions can be handled before that point. The conversion of WARN() to use UD requires the IDT being loaded earlier as any warning between start_secondary() and load_curren_idt() in cpu_init() will result in an unhandled @UD exception and therefore fail the bringup of the CPU. Install the IDT handlers right in start_secondary() before calling cpu_init(). [ tglx: Massaged changelog ] Fixes: 9a93848f ("x86/debug: Implement __WARN() using UD0") Signed-off-by:
Chunyu Hu <chuhu@redhat.com> Signed-off-by:
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- 27 Nov, 2017 1 commit
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Juergen Gross authored
Add early interrupt handlers activated by idt_setup_early_handler() to the handlers supported by Xen pv guests. This will allow for early WARN() calls not crashing the guest. Suggested-by:
Juergen Gross <jgross@suse.com> Signed-off-by:
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- 25 Nov, 2017 2 commits
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Nadav Amit authored
CR4 modifications are implemented as RMW operations which update a shadow variable and write the result to CR4. The RMW operation is protected by preemption disable, but there is no enforcement or debugging mechanism. CR4 modifications happen also in interrupt context via __native_flush_tlb_global(). This implementation does not affect a interrupted thread context CR4 operation, because the CR4 toggle restores the original content and does not modify the shadow variable. So the current situation seems to be safe, but a recent patch tried to add an actual RMW operation in interrupt context, which will cause subtle corruptions. To prevent that and make the CR4 handling future proof: - Add a lockdep assertion to __cr4_set() which will catch interrupt enabled invocations - Disable interrupts in the cr4 manipulator inlines - Rename cr4_toggle_bits() to cr4_toggle_bits_irqsoff(). This is called from __switch_to_xtra() where interrupts are already disabled and performance matters. All other call sites are not performance critical, so the extra overhead of an additional local_irq_save/restore() pair is not a problem. If new call sites care about performance then the necessary _irqsoff() variants can be added. [ tglx: Condensed the patch by moving the irq protection inside the manipulator functions. Updated changelog ] Signed-off-by:
Nadav Amit <namit@vmware.com> Signed-off-by:
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Nadav Amit authored
Refactor the write to CR4 and its shadow value. This is done in preparation for the addition of an assertion to check that IRQs are disabled during CR4 update. No functional change. Signed-off-by:
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- 24 Nov, 2017 1 commit
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Masami Hiramatsu authored
The kbuild test robot reported this build warning: Warning: arch/x86/tools/test_get_len found difference at <jump_table>:ffffffff8103dd2c Warning: ffffffff8103dd82: f6 09 d8 testb $0xd8,(%rcx) Warning: objdump says 3 bytes, but insn_get_length() says 2 Warning: decoded and checked 1569014 instructions with 1 warnings This sequence seems to be a new instruction not in the opcode map in the Intel SDM. The instruction sequence is "F6 09 d8", means Group3(F6), MOD(00)REG(001)RM(001), and 0xd8. Intel SDM vol2 A.4 Table A-6 said the table index in the group is "Encoding of Bits 5,4,3 of the ModR/M Byte (bits 2,1,0 in parenthesis)" In that table, opcodes listed by the index REG bits as: 000 001 010 011 100 101 110 111 TEST Ib/Iz,(undefined),NOT,NEG,MUL AL/rAX,IMUL AL/rAX,DIV AL/rAX,IDIV AL/rAX So, it seems TEST Ib is assigned to 001. Add the new pattern. Reported-by:
kbuild test robot <fengguang.wu@intel.com> Signed-off-by:
Masami Hiramatsu <mhiramat@kernel.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: <stable@vger.kernel.org> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by:
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- 23 Nov, 2017 4 commits
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Bjorn Helgaas authored
There are no in-tree callers of ht_create_irq(), the driver interface for HyperTransport interrupts, left. Remove the unused entry point and all the supporting code. See 8b955b0d ("[PATCH] Initial generic hypertransport interrupt support"). Signed-off-by:
Bjorn Helgaas <bhelgaas@google.com> Signed-off-by:
"Eric W. Biederman" <ebiederm@xmission.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: linux-pci@vger.kernel.org Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Link: https://lkml.kernel.org/r/20171122221337.3877.23362.stgit@bhelgaas-glaptop.roam.corp.google.com
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Borislav Petkov authored
In order to save on redundant structs definitions insn_get_code_seg_params() was made to return two 4-bit values in a char but clang complains: arch/x86/lib/insn-eval.c:780:10: warning: implicit conversion from 'int' to 'char' changes value from 132 to -124 [-Wconstant-conversion] return INSN_CODE_SEG_PARAMS(4, 8); ~~~~~~ ^~~~~~~~~~~~~~~~~~~~~~~~~~ ./arch/x86/include/asm/insn-eval.h:16:57: note: expanded from macro 'INSN_CODE_SEG_PARAMS' #define INSN_CODE_SEG_PARAMS(oper_sz, addr_sz) (oper_sz | (addr_sz << 4)) Those two values do get picked apart afterwards the opposite way of how they were ORed so wrt to the LSByte, the return value is the same. But this function returns -EINVAL in the error case, which is an int. So make it return an int which is the native word size anyway and thus fix the clang warning. Reported-by:Kees Cook <keescook@google.com> Reported-by:
Nick Desaulniers <nick.desaulniers@gmail.com> Signed-off-by:
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Chao Fan authored
There are two variables "rc" in mem_avoid_memmap. One at the top of the function and another one inside the while() loop. Drop the outer one as it is unused. Cleanup some whitespace damage while at it. Signed-off-by:
Chao Fan <fanc.fnst@cn.fujitsu.com> Signed-off-by:
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Andy Lutomirski authored
Running this code with IRQs enabled (where dummy_lock is a spinlock): static void check_load_gs_index(void) { /* This will fail. */ load_gs_index(0xffff); spin_lock(&dummy_lock); spin_unlock(&dummy_lock); } Will generate a lockdep warning. The issue is that the actual write to %gs would cause an exception with IRQs disabled, and the exception handler would, as an inadvertent side effect, update irqflag tracing to reflect the IRQs-off status. native_load_gs_index() would then turn IRQs back on and return with irqflag tracing still thinking that IRQs were off. The dummy lock-and-unlock causes lockdep to notice the error and warn. Fix it by adding the missing tracing. Apparently nothing did this in a context where it mattered. I haven't tried to find a code path that would actually exhibit the warning if appropriately nasty user code were running. I suspect that the security impact of this bug is very, very low -- production systems don't run with lockdep enabled, and the warning is mostly harmless anyway. Found during a quick audit of the entry code to try to track down an unrelated bug that Ingo found in some still-in-development code. Signed-off-by:
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- 22 Nov, 2017 2 commits
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Andrey Ryabinin authored
[ Note, this commit is a cherry-picked version of: d17a1d97: ("x86/mm/kasan: don't use vmemmap_populate() to initialize shadow") ... for easier x86 entry code testing and back-porting. ] The KASAN shadow is currently mapped using vmemmap_populate() since that provides a semi-convenient way to map pages into init_top_pgt. However, since that no longer zeroes the mapped pages, it is not suitable for KASAN, which requires zeroed shadow memory. Add kasan_populate_shadow() interface and use it instead of vmemmap_populate(). Besides, this allows us to take advantage of gigantic pages and use them to populate the shadow, which should save us some memory wasted on page tables and reduce TLB pressure. Link: http://lkml.kernel.org/r/20171103185147.2688-2-pasha.tatashin@oracle.comSigned-off-by:Andrey Ryabinin <aryabinin@virtuozzo.com> Signed-off-by:
Pavel Tatashin <pasha.tatashin@oracle.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Steven Sistare <steven.sistare@oracle.com> Cc: Daniel Jordan <daniel.m.jordan@oracle.com> Cc: Bob Picco <bob.picco@oracle.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Alexander Potapenko <glider@google.com> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: David S. Miller <davem@davemloft.net> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Michal Hocko <mhocko@kernel.org> Cc: Sam Ravnborg <sam@ravnborg.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by:
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Andy Lutomirski authored
When I added entry_SYSCALL_64_after_hwframe(), I left TRACE_IRQS_OFF before it. This means that users of entry_SYSCALL_64_after_hwframe() were responsible for invoking TRACE_IRQS_OFF, and the one and only user (Xen, added in the same commit) got it wrong. I think this would manifest as a warning if a Xen PV guest with CONFIG_DEBUG_LOCKDEP=y were used with context tracking. (The context tracking bit is to cause lockdep to get invoked before we turn IRQs back on.) I haven't tested that for real yet because I can't get a kernel configured like that to boot at all on Xen PV. Move TRACE_IRQS_OFF below the label. Signed-off-by:
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- 21 Nov, 2017 5 commits
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Dave Hansen authored
write() is marked as having a must-check return value. Check it and abort if we fail to write an error message from a signal handler. Signed-off-by:
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Dave Hansen authored
'si_pkey' is now #defined to be the name of the new siginfo field that protection keys uses. Rename it not to conflict. Signed-off-by:
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Dave Hansen authored
The MPX hardware data structurse are defined in a weird way: they define their size in bytes and then union that with the type with which we want to access them. Yes, this is weird, but it does work. But, new GCC's complain that we are accessing the array out of bounds. Just make it a zero-sized array so gcc will stop complaining. There was not really a bug here. Signed-off-by:
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Dave Hansen authored
Now that CPUs that implement Memory Protection Keys are publicly available we can be a bit less oblique about where it is available. Signed-off-by:
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Ricardo Neri authored
Print a rate-limited warning when a user-space program attempts to execute any of the instructions that UMIP protects (i.e., SGDT, SIDT, SLDT, STR and SMSW). This is useful, because when CONFIG_X86_INTEL_UMIP=y is selected and supported by the hardware, user space programs that try to execute such instructions will receive a SIGSEGV signal that they might not expect. In the specific cases for which emulation is provided (instructions SGDT, SIDT and SMSW in protected and virtual-8086 modes), no signal is generated. However, a warning is helpful to encourage updates in such programs to avoid the use of such instructions. Warnings are printed via a customized printk() function that also provides information about the program that attempted to use the affected instructions. Utility macros are defined to wrap umip_printk() for the error and warning kernel log levels. While here, replace an existing call to the generic rate-limited pr_err() with the new umip_pr_err(). Suggested-by:
Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Reviewed-by:
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- 17 Nov, 2017 6 commits
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Prarit Bhargava authored
A system booted with a small number of cores enabled per package panics because the estimate of __max_logical_packages is too low. This occurs when the total number of active cores across all packages is less than the maximum core count for a single package. e.g.: On a 4 package system with 20 cores/package where only 4 cores are enabled on each package, the value of __max_logical_packages is calculated as DIV_ROUND_UP(16 / 20) = 1 and not 4. Calculate __max_logical_packages after the cpu enumeration has completed. Use the boot cpu's data to extrapolate the number of packages. Signed-off-by:
Prarit Bhargava <prarit@redhat.com> Signed-off-by:
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Andi Kleen authored
Analyzing large early boot allocations unveiled the logical package id storage as a prominent memory waste. Since commit 1f12e32f ("x86/topology: Create logical package id") every 64-bit system allocates a 128k array to convert logical package ids. This happens because the array is sized for MAX_LOCAL_APIC which is always 32k on 64bit systems, and it needs 4 bytes for each entry. This is fairly wasteful, especially for the common case of having only one socket, which uses exactly 4 byte out of 128K. There is no user of the package id map which is performance critical, so the lookup is not required to be O(1). Store the logical processor id in cpu_data and use a loop based lookup. To keep the mapping stable accross cpu hotplug operations, add a flag to cpu_data which is set when the CPU is brought up the first time. When the flag is set, then cpu_data is not reinitialized by copying boot_cpu_data on subsequent bringups. [ tglx: Rename the flag to 'initialized', use proper pointers instead of repeated cpu_data(x) evaluation and massage changelog. ] Signed-off-by:
Andi Kleen <ak@linux.intel.com> Signed-off-by:
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Andi Kleen authored
The SNB-EP uncore driver is the only user of topology_phys_to_logical_pkg in a performance critical path. Change it query the logical pkg ID only once at initialization time and then cache it in box structure. This allows to change the logical package management without affecting the performance critical path. Signed-off-by:
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Vikas C Sajjan authored
The new function mp_register_ioapic_irq() is a subset of the code in mp_override_legacy_irq(). Replace the code duplication by invoking mp_register_ioapic_irq() from mp_override_legacy_irq(). Signed-off-by:
Vikas C Sajjan <vikas.cha.sajjan@hpe.com> Signed-off-by:
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Vikas C Sajjan authored
Platforms which support only IOAPIC mode, pass the SCI information above the legacy space (0-15) via the FADT mechanism and not via MADT. In such cases mp_override_legacy_irq() which is invoked from acpi_sci_ioapic_setup() to register SCI interrupts fails for interrupts greater equal 16, since it is meant to handle only the legacy space and emits error "Invalid bus_irq %u for legacy override". Add a new function to handle SCI interrupts >= 16 and invoke it conditionally in acpi_sci_ioapic_setup(). The code duplication due to this new function will be cleaned up in a separate patch. Co-developed-by:
Sunil V L <sunil.vl@hpe.com> Signed-off-by:
Abdul Lateef Attar <abdul-lateef.attar@hpe.com> Acked-by:
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Tom Lendacky authored
When crosvm is used to boot a kernel as a VM, the SMP MP-table is found at physical address 0x0. This causes mpf_base to be set to 0 and a subsequent "if (!mpf_base)" check in default_get_smp_config() results in the MP-table not being parsed. Further into the boot this results in an oops when attempting a read_apic_id(). Add a boolean variable that is set to true when the MP-table is found. Use this variable for testing if the MP-table was found so that even a value of 0 for mpf_base will result in continued parsing of the MP-table. Fixes: 5997efb9 ("x86/boot: Use memremap() to map the MPF and MPC data") Reported-by:
Tomeu Vizoso <tomeu@tomeuvizoso.net> Signed-off-by:
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- 16 Nov, 2017 3 commits
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Craig Bergstrom authored
One thing /dev/mem access APIs should verify is that there's no way that excessively large pfn's can leak into the high bits of the page table entry. In particular, if people can use "very large physical page addresses" through /dev/mem to set the bits past bit 58 - SOFTW4 and permission key bits and NX bit, that could *really* confuse the kernel. We had an earlier attempt: ce56a86e ("x86/mm: Limit mmap() of /dev/mem to valid physical addresses") ... which turned out to be too restrictive (breaking mem=... bootups for example) and had to be reverted in: 90edaac6 ("Revert "x86/mm: Limit mmap() of /dev/mem to valid physical addresses"") This v2 attempt modifies the original patch and makes sure that mmap(/dev/mem) limits the pfns so that it at least fits in the actual pteval_t architecturally: - Make sure mmap_mem() actually validates that the offset fits in phys_addr_t ( This may be indirectly true due to some other check, but it's not entirely obvious. ) - Change valid_mmap_phys_addr_range() to just use phys_addr_valid() on the top byte ( Top byte is sufficient, because mmap_mem() has already checked that it cannot wrap. ) - Add a few comments about what the valid_phys_addr_range() vs. valid_mmap_phys_addr_range() difference is. Signed-off-by:
Craig Bergstrom <craigb@google.com> [ Fixed the checks and added comments. ] Signed-off-by:
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Kirill A. Shutemov authored
5-level paging provides a 56-bit virtual address space for user space application. But the kernel defaults to mappings below the 47-bit address space boundary, which is the upper bound for 4-level paging, unless an application explicitely request it by using a mmap(2) address hint above the 47-bit boundary. The kernel prevents mappings which spawn across the 47-bit boundary unless mmap(2) was invoked with MAP_FIXED. Add a self-test that covers the corner cases of the interface and validates the correctness of the implementation. [ tglx: Massaged changelog once more ] Signed-off-by:
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Kirill A. Shutemov authored
In case of 5-level paging, the kernel does not place any mapping above 47-bit, unless userspace explicitly asks for it. Userspace can request an allocation from the full address space by specifying the mmap address hint above 47-bit. Nicholas noticed that the current implementation violates this interface: If user space requests a mapping at the end of the 47-bit address space with a length which causes the mapping to cross the 47-bit border (DEFAULT_MAP_WINDOW), then the vma is partially in the address space below and above. Sanity check the mmap address hint so that start and end of the resulting vma are on the same side of the 47-bit border. If that's not the case fall back to the code path which ignores the address hint and allocate from the regular address space below 47-bit. To make the checks consistent, mask out the address hints lower bits (either PAGE_MASK or huge_page_mask()) instead of using ALIGN() which can push them up to the next boundary. [ tglx: Moved the address check to a function and massaged comment and changelog ] Reported-by:
Nicholas Piggin <npiggin@gmail.com> Signed-off-by:
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- 14 Nov, 2017 5 commits
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Ricardo Neri authored
The STR and SLDT instructions are not emulated by the UMIP code, thus there's no functionality in the decoder to identify them. However, a subsequent commit will introduce a warning about the use of all the instructions that UMIP protect/changes, not only those that are emulated. A first step for that is to add the ability to decode/identify them. Plus, now that STR and SLDT are identified, we need to explicitly avoid their emulation (i.e., not rely on successful identification). Group together all the cases that we do not want to emulate: STR, SLDT and user long mode processes. Signed-off-by:
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Ricardo Neri authored
Indicate that this feature has been enabled. Suggested-by:
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Ricardo Neri authored
UMIP does cause any performance penalty to the vast majority of x86 code that does not use the legacy instructions affected by UMIP. Also describe UMIP more accurately and explain the behavior that can be expected by the (few) applications that use the affected instructions. Suggested-by:
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Rafael J. Wysocki authored
Even though aperfmperf_snapshot_khz() caches the samples.khz value to return if called again in a sufficiently short time, its caller, arch_freq_get_on_cpu(), still uses smp_call_function_single() to run it which may allow user space to trigger an IPI storm by reading from the scaling_cur_freq cpufreq sysfs file in a tight loop. To avoid that, move the decision on whether or not to return the cached samples.khz value to arch_freq_get_on_cpu(). This change was part of commit 941f5f0f ("x86: CPU: Fix up "cpu MHz" in /proc/cpuinfo"), but it was not the reason for the revert and it remains applicable. Fixes: 4815d3c5 (cpufreq: x86: Make scaling_cur_freq behave more as expected) Signed-off-by:
WANG Chao <chao.wang@ucloud.cn> Signed-off-by:
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tipLinus Torvalds authored
Pull x86 timer updates from Thomas Gleixner: "These updates are related to TSC handling: - Support platforms which have synchronized TSCs but the boot CPU has a non zero TSC_ADJUST value, which is considered a firmware bug on normal systems. This applies to HPE/SGI UV platforms where the platform firmware uses TSC_ADJUST to ensure TSC synchronization across a huge number of sockets, but due to power on timings the boot CPU cannot be guaranteed to have a zero TSC_ADJUST register value. - Fix the ordering of udelay calibration and kvmclock_init() - Cleanup the udelay and calibration code" * 'x86-timers-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/tsc: Mark cyc2ns_init() and detect_art() __init x86/platform/UV: Mark tsc_check_sync as an init function x86/tsc: Make CONFIG_X86_TSC=n build work again x86/platform/UV: Add check of TSC state set by UV BIOS x86/tsc: Provide a means to disable TSC ART x86/tsc: Drastically reduce the number of firmware bug warnings x86/tsc: Skip TSC test and error messages if already unstable x86/tsc: Add option that TSC on Socket 0 being non-zero is valid x86/timers: Move simple_udelay_calibration() past kvmclock_init() x86/timers: Make recalibrate_cpu_khz() void x86/timers: Move the simple udelay calibration to tsc.h
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