- 17 Apr, 2019 38 commits
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Diana Craciun authored
commit 7fef4362 upstream. In order to protect against speculation attacks on indirect branches, the branch predictor is flushed at kernel entry to protect for the following situations: - userspace process attacking another userspace process - userspace process attacking the kernel Basically when the privillege level change (i.e.the kernel is entered), the branch predictor state is flushed. Signed-off-by:
Diana Craciun <diana.craciun@nxp.com> Signed-off-by:
Michael Ellerman <mpe@ellerman.id.au> Signed-off-by:
Sasha Levin <sashal@kernel.org>
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Diana Craciun authored
commit 10c5e83a upstream. In order to protect against speculation attacks on indirect branches, the branch predictor is flushed at kernel entry to protect for the following situations: - userspace process attacking another userspace process - userspace process attacking the kernel Basically when the privillege level change (i.e. the kernel is entered), the branch predictor state is flushed. Signed-off-by:
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Diana Craciun authored
commit f633a8ad upstream. When the command line argument is present, the Spectre variant 2 mitigations are disabled. Signed-off-by:
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Diana Craciun authored
commit 98518c4d upstream. In order to flush the branch predictor the guest kernel performs writes to the BUCSR register which is hypervisor privilleged. However, the branch predictor is flushed at each KVM entry, so the branch predictor has been already flushed, so just return as soon as possible to guest. Signed-off-by:
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Diana Craciun authored
commit 7d8bad99 upstream. Currently for CONFIG_PPC_FSL_BOOK3E the spectre_v2 file is incorrect: $ cat /sys/devices/system/cpu/vulnerabilities/spectre_v2 "Mitigation: Software count cache flush" Which is wrong. Fix it to report vulnerable for now. Fixes: ee13cb24 ("powerpc/64s: Add support for software count cache flush") Cc: stable@vger.kernel.org # v4.19+ Signed-off-by:
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Diana Craciun authored
commit 1cbf8990 upstream. The BUCSR register can be used to invalidate the entries in the branch prediction mechanisms. Signed-off-by:
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Diana Craciun authored
commit 76a5eaa3 upstream. In order to protect against speculation attacks (Spectre variant 2) on NXP PowerPC platforms, the branch predictor should be flushed when the privillege level is changed. This patch is adding the infrastructure to fixup at runtime the code sections that are performing the branch predictor flush depending on a boot arg parameter which is added later in a separate patch. Signed-off-by:
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Michael Ellerman authored
commit 99d54754 upstream. Look for fw-features properties to determine the appropriate settings for the count cache flush, and then call the generic powerpc code to set it up based on the security feature flags. Signed-off-by:
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Michael Ellerman authored
commit ba72dc17 upstream. Use the existing hypercall to determine the appropriate settings for the count cache flush, and then call the generic powerpc code to set it up based on the security feature flags. Signed-off-by:
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Michael Ellerman authored
commit ee13cb24 upstream. Some CPU revisions support a mode where the count cache needs to be flushed by software on context switch. Additionally some revisions may have a hardware accelerated flush, in which case the software flush sequence can be shortened. If we detect the appropriate flag from firmware we patch a branch into _switch() which takes us to a count cache flush sequence. That sequence in turn may be patched to return early if we detect that the CPU supports accelerating the flush sequence in hardware. Add debugfs support for reporting the state of the flush, as well as runtime disabling it. And modify the spectre_v2 sysfs file to report the state of the software flush. Signed-off-by:
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Michael Ellerman authored
commit dc8c6cce upstream. Add security feature flags to indicate the need for software to flush the count cache on context switch, and for the presence of a hardware assisted count cache flush. Signed-off-by:
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Michael Ellerman authored
commit 06d0bbc6 upstream. Add a macro and some helper C functions for patching single asm instructions. The gas macro means we can do something like: 1: nop patch_site 1b, patch__foo Which is less visually distracting than defining a GLOBAL symbol at 1, and also doesn't pollute the symbol table which can confuse eg. perf. These are obviously similar to our existing feature sections, but are not automatically patched based on CPU/MMU features, rather they are designed to be manually patched by C code at some arbitrary point. Signed-off-by:
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Diana Craciun authored
commit c28218d4 upstream. Used barrier_nospec to sanitize the syscall table. Signed-off-by:
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Diana Craciun authored
commit ebcd1bfc upstream. Implement the barrier_nospec as a isync;sync instruction sequence. The implementation uses the infrastructure built for BOOK3S 64. Signed-off-by:
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Diana Craciun authored
commit 406d2b6a upstream. In a subsequent patch we will enable building security.c for Book3E. However the NXP platforms are not vulnerable to Meltdown, so make the Meltdown vulnerability reporting PPC_BOOK3S_64 specific. Signed-off-by:
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Michael Ellerman authored
commit af375eef upstream. Currently we require platform code to call setup_barrier_nospec(). But if we add an empty definition for the !CONFIG_PPC_BARRIER_NOSPEC case then we can call it in setup_arch(). Signed-off-by:
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Michael Ellerman authored
commit 179ab1cb upstream. Add a config symbol to encode which platforms support the barrier_nospec speculation barrier. Currently this is just Book3S 64 but we will add Book3E in a future patch. Signed-off-by:
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Diana Craciun authored
commit 6453b532 upstream. NXP Book3E platforms are not vulnerable to speculative store bypass, so make the mitigations PPC_BOOK3S_64 specific. Signed-off-by:
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Diana Craciun authored
commit cf175dc3 upstream. The speculation barrier can be disabled from the command line with the parameter: "nospectre_v1". Signed-off-by:
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Michael Ellerman authored
commit 6d44acae upstream. When I added the spectre_v2 information in sysfs, I included the availability of the ori31 speculation barrier. Although the ori31 barrier can be used to mitigate v2, it's primarily intended as a spectre v1 mitigation. Spectre v2 is mitigated by hardware changes. So rework the sysfs files to show the ori31 information in the spectre_v1 file, rather than v2. Currently we display eg: $ grep . spectre_v* spectre_v1:Mitigation: __user pointer sanitization spectre_v2:Mitigation: Indirect branch cache disabled, ori31 speculation barrier enabled After: $ grep . spectre_v* spectre_v1:Mitigation: __user pointer sanitization, ori31 speculation barrier enabled spectre_v2:Mitigation: Indirect branch cache disabled Fixes: d6fbe1c5 ("powerpc/64s: Wire up cpu_show_spectre_v2()") Cc: stable@vger.kernel.org # v4.17+ Signed-off-by:
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Michal Suchanek authored
commit a3775145 upstream. We now have barrier_nospec as mitigation so print it in cpu_show_spectre_v1() when enabled. Signed-off-by:
Michal Suchanek <msuchanek@suse.de> Signed-off-by:
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Michael Ellerman authored
commit 51973a81 upstream. Our syscall entry is done in assembly so patch in an explicit barrier_nospec. Based on a patch by Michal Suchanek. Signed-off-by:
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Michael Ellerman authored
commit ddf35cf3 upstream. Based on the x86 commit doing the same. See commit 304ec1b0 ("x86/uaccess: Use __uaccess_begin_nospec() and uaccess_try_nospec") and b3bbfb3f ("x86: Introduce __uaccess_begin_nospec() and uaccess_try_nospec") for more detail. In all cases we are ordering the load from the potentially user-controlled pointer vs a previous branch based on an access_ok() check or similar. Base on a patch from Michal Suchanek. Signed-off-by:
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Michal Suchanek authored
commit cb3d6759 upstream. Check what firmware told us and enable/disable the barrier_nospec as appropriate. We err on the side of enabling the barrier, as it's no-op on older systems, see the comment for more detail. Signed-off-by:
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Michal Suchanek authored
commit 815069ca upstream. Note that unlike RFI which is patched only in kernel the nospec state reflects settings at the time the module was loaded. Iterating all modules and re-patching every time the settings change is not implemented. Based on lwsync patching. Signed-off-by:
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Michael Neuling authored
commit 51c3c62b upstream. This stops us from doing code patching in init sections after they've been freed. In this chain: kvm_guest_init() -> kvm_use_magic_page() -> fault_in_pages_readable() -> __get_user() -> __get_user_nocheck() -> barrier_nospec(); We have a code patching location at barrier_nospec() and kvm_guest_init() is an init function. This whole chain gets inlined, so when we free the init section (hence kvm_guest_init()), this code goes away and hence should no longer be patched. We seen this as userspace memory corruption when using a memory checker while doing partition migration testing on powervm (this starts the code patching post migration via /sys/kernel/mobility/migration). In theory, it could also happen when using /sys/kernel/debug/powerpc/barrier_nospec. Cc: stable@vger.kernel.org # 4.13+ Signed-off-by:
Michael Neuling <mikey@neuling.org> Reviewed-by:
Nicholas Piggin <npiggin@gmail.com> Reviewed-by:
Christophe Leroy <christophe.leroy@c-s.fr> Signed-off-by:
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Michal Suchanek authored
commit 2eea7f06 upstream. Based on the RFI patching. This is required to be able to disable the speculation barrier. Only one barrier type is supported and it does nothing when the firmware does not enable it. Also re-patching modules is not supported So the only meaningful thing that can be done is patching out the speculation barrier at boot when the user says it is not wanted. Signed-off-by:
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Michal Suchanek authored
commit a6b3964a upstream. A no-op form of ori (or immediate of 0 into r31 and the result stored in r31) has been re-tasked as a speculation barrier. The instruction only acts as a barrier on newer machines with appropriate firmware support. On older CPUs it remains a harmless no-op. Implement barrier_nospec using this instruction. mpe: The semantics of the instruction are believed to be that it prevents execution of subsequent instructions until preceding branches have been fully resolved and are no longer executing speculatively. There is no further documentation available at this time. Signed-off-by:
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Andreas Schwab authored
commit 8a583c0a upstream. binutils >= 2.26 now warns about misuse of register expressions in assembler operands that are actually literals, for example: arch/powerpc/kernel/entry_64.S:535: Warning: invalid register expression In practice these are almost all uses of r0 that should just be a literal 0. Signed-off-by:
Andreas Schwab <schwab@linux-m68k.org> [mpe: Mention r0 is almost always the culprit, fold in purgatory change] Signed-off-by:
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Nick Desaulniers authored
[ Upstream commit 5f074f3e ] A recent optimization in Clang (r355672) lowers comparisons of the return value of memcmp against zero to comparisons of the return value of bcmp against zero. This helps some platforms that implement bcmp more efficiently than memcmp. glibc simply aliases bcmp to memcmp, but an optimized implementation is in the works. This results in linkage failures for all targets with Clang due to the undefined symbol. For now, just implement bcmp as a tailcail to memcmp to unbreak the build. This routine can be further optimized in the future. Other ideas discussed: * A weak alias was discussed, but breaks for architectures that define their own implementations of memcmp since aliases to declarations are not permitted (only definitions). Arch-specific memcmp implementations typically declare memcmp in C headers, but implement them in assembly. * -ffreestanding also is used sporadically throughout the kernel. * -fno-builtin-bcmp doesn't work when doing LTO. Link: https://bugs.llvm.org/show_bug.cgi?id=41035 Link: https://code.woboq.org/userspace/glibc/string/memcmp.c.html#bcmp Link: https://github.com/llvm/llvm-project/commit/8e16d73346f8091461319a7dfc4ddd18eedcff13 Link: https://github.com/ClangBuiltLinux/linux/issues/416 Link: http://lkml.kernel.org/r/20190313211335.165605-1-ndesaulniers@google.comSigned-off-by:
Nick Desaulniers <ndesaulniers@google.com> Reported-by:
Nathan Chancellor <natechancellor@gmail.com> Reported-by:
Adhemerval Zanella <adhemerval.zanella@linaro.org> Suggested-by:
Arnd Bergmann <arnd@arndb.de> Suggested-by:
James Y Knight <jyknight@google.com> Suggested-by:
Masahiro Yamada <yamada.masahiro@socionext.com> Suggested-by:
Rasmus Villemoes <linux@rasmusvillemoes.dk> Acked-by:
Steven Rostedt (VMware) <rostedt@goodmis.org> Reviewed-by:
Andy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: David Laight <David.Laight@ACULAB.COM> Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Dan Williams <dan.j.williams@intel.com> 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:
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Nick Desaulniers authored
GNU linker's -z common-page-size's default value is based on the target architecture. arch/x86/entry/vdso/Makefile sets it to the architecture default, which is implicit and redundant. Drop it. Fixes: 2aae950b ("x86_64: Add vDSO for x86-64 with gettimeofday/clock_gettime/getcpu") Reported-by:
Dmitry Golovin <dima@golovin.in> Reported-by:
Bill Wendling <morbo@google.com> Suggested-by:
Rui Ueyama <ruiu@google.com> Signed-off-by:
Borislav Petkov <bp@suse.de> Acked-by:
Andy Lutomirski <luto@kernel.org> Cc: Andi Kleen <andi@firstfloor.org> Cc: Fangrui Song <maskray@google.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: x86-ml <x86@kernel.org> Link: https://lkml.kernel.org/r/20181206191231.192355-1-ndesaulniers@google.com Link: https://bugs.llvm.org/show_bug.cgi?id=38774 Link: https://github.com/ClangBuiltLinux/linux/issues/31Signed-off-by:
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Alistair Strachan authored
The vdso{32,64}.so can fail to link with CC=clang when clang tries to find a suitable GCC toolchain to link these libraries with. /usr/bin/ld: arch/x86/entry/vdso/vclock_gettime.o: access beyond end of merged section (782) This happens because the host environment leaked into the cross compiler environment due to the way clang searches for suitable GCC toolchains. Clang is a retargetable compiler, and each invocation of it must provide --target=<something> --gcc-toolchain=<something> to allow it to find the correct binutils for cross compilation. These flags had been added to KBUILD_CFLAGS, but the vdso code uses CC and not KBUILD_CFLAGS (for various reasons) which breaks clang's ability to find the correct linker when cross compiling. Most of the time this goes unnoticed because the host linker is new enough to work anyway, or is incompatible and skipped, but this cannot be reliably assumed. This change alters the vdso makefile to just use LD directly, which bypasses clang and thus the searching problem. The makefile will just use ${CROSS_COMPILE}ld instead, which is always what we want. This matches the method used to link vmlinux. This drops references to DISABLE_LTO; this option doesn't seem to be set anywhere, and not knowing what its possible values are, it's not clear how to convert it from CC to LD flag. Signed-off-by:Alistair Strachan <astrachan@google.com> Signed-off-by:
Thomas Gleixner <tglx@linutronix.de> Acked-by:
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Nick Desaulniers authored
commit ad15006c upstream. This causes an issue when trying to build with `make LD=ld.lld` if ld.lld and the rest of your cross tools aren't in the same directory (ex. /usr/local/bin) (as is the case for Android's build system), as the GCC_TOOLCHAIN_DIR then gets set based on `which $(LD)` which will point where LLVM tools are, not GCC/binutils tools are located. Instead, select the GCC_TOOLCHAIN_DIR based on another tool provided by binutils for which LLVM does not provide a substitute for, such as elfedit. Fixes: 785f11aa ("kbuild: Add better clang cross build support") Link: https://github.com/ClangBuiltLinux/linux/issues/341Suggested-by:
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Breno Leitao authored
[ Upstream commit 897bc3df ] Commit e1c3743e ("powerpc/tm: Set MSR[TS] just prior to recheckpoint") moved a code block around and this block uses a 'msr' variable outside of the CONFIG_PPC_TRANSACTIONAL_MEM, however the 'msr' variable is declared inside a CONFIG_PPC_TRANSACTIONAL_MEM block, causing a possible error when CONFIG_PPC_TRANSACTION_MEM is not defined. error: 'msr' undeclared (first use in this function) This is not causing a compilation error in the mainline kernel, because 'msr' is being used as an argument of MSR_TM_ACTIVE(), which is defined as the following when CONFIG_PPC_TRANSACTIONAL_MEM is *not* set: #define MSR_TM_ACTIVE(x) 0 This patch just fixes this issue avoiding the 'msr' variable usage outside the CONFIG_PPC_TRANSACTIONAL_MEM block, avoiding trusting in the MSR_TM_ACTIVE() definition. Cc: stable@vger.kernel.org Reported-by:
Christoph Biedl <linux-kernel.bfrz@manchmal.in-ulm.de> Fixes: e1c3743e ("powerpc/tm: Set MSR[TS] just prior to recheckpoint") Signed-off-by:
Breno Leitao <leitao@debian.org> Signed-off-by:
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Andy Lutomirski authored
[ Upstream commit 7ee18d67 ] My previous attempt to fix a couple of bugs in __restore_processor_context(): 5b06bbcf ("x86/power: Fix some ordering bugs in __restore_processor_context()") ... introduced yet another bug, breaking suspend-resume. Rather than trying to come up with a minimal fix, let's try to clean it up for real. This patch fixes quite a few things: - The old code saved a nonsensical subset of segment registers. The only registers that need to be saved are those that contain userspace state or those that can't be trivially restored without percpu access working. (On x86_32, we can restore percpu access by writing __KERNEL_PERCPU to %fs. On x86_64, it's easier to save and restore the kernel's GSBASE.) With this patch, we restore hardcoded values to the kernel state where applicable and explicitly restore the user state after fixing all the descriptor tables. - We used to use an unholy mix of inline asm and C helpers for segment register access. Let's get rid of the inline asm. This fixes the reported s2ram hangs and make the code all around more logical. Analyzed-by:
Jarkko Nikula <jarkko.nikula@linux.intel.com> Reported-by:
Pavel Machek <pavel@ucw.cz> Tested-by:
Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by:
Ingo Molnar <mingo@kernel.org> Signed-off-by:
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Andy Lutomirski authored
[ Upstream commit 896c80be ] x86_64 restores system call MSRs in fix_processor_context(), and x86_32 restored them along with segment registers. The 64-bit variant makes more sense, so move the 32-bit code to match the 64-bit code. No side effects are expected to runtime behavior. Tested-by:
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Andy Lutomirski authored
[ Upstream commit 090edbe2 ] x86_64's saved_context nonsensically used separate idt_limit and idt_base fields and then cast &idt_limit to struct desc_ptr *. This was correct (with -fno-strict-aliasing), but it's confusing, served no purpose, and required #ifdeffery. Simplify this by using struct desc_ptr directly. No change in functionality. Tested-by:
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Andy Lutomirski authored
[ Upstream commit 5b06bbcf ] __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:
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- 05 Apr, 2019 2 commits
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Greg Kroah-Hartman authored
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Hans de Goede authored
[ Upstream commit d693c008 ] Commit 53fa1f6e ("ACPI / video: Only default only_lcd to true on Win8-ready _desktops_") introduced chassis type detection, limiting the lcd_only check for the backlight to devices where the chassis-type indicates their is no builtin LCD panel. The purpose of the lcd_only check is to avoid advertising a backlight interface on desktops, since skylake and newer machines seem to always have a backlight interface even if there is no LCD panel. The limiting of this check to desktops only was done to avoid breaking backlight support on some laptops which do not have the lcd flag set. The Fujitsu ESPRIMO Q910 which is a compact (NUC like) desktop machine has a chassis type of 0x10 aka "Lunch Box". Without the lcd_only check we end up falsely advertising backlight/brightness control on this device. This commit extend the dmi_is_desktop check to return true for type 0x10 to fix this. Fixes: 53fa1f6e ("ACPI / video: Only default only_lcd to true ...") Signed-off-by:
Hans de Goede <hdegoede@redhat.com> Signed-off-by:
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