- 23 Jun, 2017 1 commit
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Dave Martin authored
This patch defines an extra_context signal frame record that can be used to describe an expanded signal frame, and modifies the context block allocator and signal frame setup and parsing code to create, populate, parse and decode this block as necessary. To avoid abuse by userspace, parse_user_sigframe() attempts to ensure that: * no more than one extra_context is accepted; * the extra context data is a sensible size, and properly placed and aligned. The extra_context data is required to start at the first 16-byte aligned address immediately after the dummy terminator record following extra_context in rt_sigframe.__reserved[] (as ensured during signal delivery). This serves as a sanity-check that the signal frame has not been moved or copied without taking the extra data into account. Signed-off-by:
Dave Martin <Dave.Martin@arm.com> Reviewed-by:
Catalin Marinas <catalin.marinas@arm.com> [will: add __force annotation when casting extra_datap to __user pointer] Signed-off-by:
Will Deacon <will.deacon@arm.com>
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- 22 Jun, 2017 4 commits
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Mark Rutland authored
When debugging a kernel panic(), it can be useful to know which CPU features have been detected by the kernel, as some code paths can depend on these (and may have been patched at runtime). This patch adds a notifier to dump the detected CPU caps (as a hex string) at panic(), when we log other information useful for debugging. On a Juno R1 system running v4.12-rc5, this looks like: [ 615.431249] Kernel panic - not syncing: Fatal exception in interrupt [ 615.437609] SMP: stopping secondary CPUs [ 615.441872] Kernel Offset: disabled [ 615.445372] CPU features: 0x02086 [ 615.448522] Memory Limit: none A developer can decode this by looking at the corresponding <asm/cpucaps.h> bits. For example, the above decodes as: * bit 1: ARM64_WORKAROUND_DEVICE_LOAD_ACQUIRE * bit 2: ARM64_WORKAROUND_845719 * bit 7: ARM64_WORKAROUND_834220 * bit 13: ARM64_HAS_32BIT_EL0 Signed-off-by:
Mark Rutland <mark.rutland@arm.com> Acked-by:
Steve Capper <steve.capper@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Suzuki K Poulose <suzuki.poulose@arm.com> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by:
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Dave Martin authored
When reading current's user-writable TLS register (which occurs when dumping core for native tasks), it is possible that userspace has modified it since the time the task was last scheduled out. The new TLS register value is not guaranteed to have been written immediately back to thread_struct in this case. As a result, a coredump can capture stale data for this register. Reading the register for a stopped task via ptrace is unaffected. For native tasks, this patch explicitly flushes the TPIDR_EL0 register back to thread_struct before dumping when operating on current, thus ensuring that coredump contents are up to date. For compat tasks, the TLS register is not user-writable and so cannot be out of sync, so no flush is required in compat_tls_get(). Signed-off-by:
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Dave Martin authored
When reading the FPSIMD state of current (which occurs when dumping core), it is possible that userspace has modified the FPSIMD registers since the time the task was last scheduled out. Such changes are not guaranteed to be reflected immedately in thread_struct. As a result, a coredump can contain stale values for these registers. Reading the registers of a stopped task via ptrace is unaffected. This patch explicitly flushes the CPU state back to thread_struct before dumping when operating on current, thus ensuring that coredump contents are up to date. Signed-off-by:
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Dave Martin authored
Currently, VFP registers are omitted from coredumps for compat processes, due to a bug in the REGSET_COMPAT_VFP regset implementation. compat_vfp_get() needs to transfer non-contiguous data from thread_struct.fpsimd_state, and uses put_user() to handle the offending trailing word (FPSCR). This fails when copying to a kernel address (i.e., kbuf && !ubuf), which is what happens when dumping core. As a result, the ELF coredump core code silently omits the NT_ARM_VFP note from the dump. It would be possible to work around this with additional special case code for the put_user(), but since user_regset_copyout() is explicitly designed to handle this scenario it is cleaner to port the put_user() to a user_regset_copyout() call, which this patch does. Signed-off-by:
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- 20 Jun, 2017 8 commits
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Luc Van Oostenryck authored
When using sparse on the arm64 tree we get many thousands of warnings like 'constant ... is so big it is unsigned long long' or 'shift too big (32) for type unsigned long'. This happens because by default sparse considers the machine as 32bit and defines the size of the types accordingly. Fix this by passing the '-m64' flag to sparse so that sparse can correctly define longs as being 64bit. CC: Catalin Marinas <catalin.marinas@arm.com> CC: Will Deacon <will.deacon@arm.com> CC: linux-arm-kernel@lists.infradead.org Signed-off-by:
Luc Van Oostenryck <luc.vanoostenryck@gmail.com> Signed-off-by:
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Dave Martin authored
This patch factors out the allocator for signal frame optional records into a separate function, to ensure consistency and facilitate later expansion. No overrun checking is currently done, because the allocation is in user memory and anyway the kernel never tries to allocate enough space in the signal frame yet for an overrun to occur. This behaviour will be refined in future patches. The approach taken in this patch to allocation of the terminator record is not very clean: this will also be replaced in subsequent patches. For future extension, a comment is added in sigcontext.h documenting the current static allocations in __reserved[]. This will be important for determining under what circumstances userspace may or may not see an expanded signal frame. Reviewed-by:
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Dave Martin authored
In preparation for expanding the signal frame, this patch refactors the signal frame setup code in setup_sigframe() into two separate passes. The first pass, setup_sigframe_layout(), determines the size of the signal frame and its internal layout, including the presence and location of optional records. The resulting knowledge is used to allocate and locate the user stack space required for the signal frame and to determine which optional records to include. The second pass, setup_sigframe(), is called once the stack frame is allocated in order to populate it with the necessary context information. As a result of these changes, it becomes more natural to represent locations in the signal frame by a base pointer and an offset, since the absolute address of each location is not known during the layout pass. To be more consistent with this logic, parse_user_sigframe() is refactored to describe signal frame locations in a similar way. This change has no effect on the signal ABI, but will make it easier to expand the signal frame in future patches. Reviewed-by:
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Dave Martin authored
Currently, rt_sigreturn does very limited checking on the sigcontext coming from userspace. Future additions to the sigcontext data will increase the potential for surprises. Also, it is not clear whether the sigcontext extension records are supposed to occur in a particular order. To allow the parsing code to be extended more easily, this patch factors out the sigcontext parsing into a separate function, and adds extra checks to validate the well-formedness of the sigcontext structure. Reviewed-by:
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Dave Martin authored
In order to be able to increase the amount of the data currently written to the __reserved[] array in the signal frame, it is necessary to overwrite the locations currently occupied by the {fp,lr} frame link record pushed at the top of the signal stack. In order for this to work, this patch detaches the frame link record from struct rt_sigframe and places it separately at the top of the signal stack. This will allow subsequent patches to insert data between it and __reserved[]. This change relies on the non-ABI status of the placement of the frame record with respect to struct sigframe: this status is undocumented, but the placement is not declared or described in the user headers, and known unwinder implementations (libgcc, libunwind, gdb) appear not to rely on it. Reviewed-by: -
Ard Biesheuvel authored
To avoid issues with the /proc/kcore code getting confused about the kernels block mappings in the VMALLOC region, enable the existing facility that describes the [_text, _end) interval as a separate KCORE_TEXT region, which supersedes the KCORE_VMALLOC region that it intersects with on arm64. Reported-by:
Tan Xiaojun <tanxiaojun@huawei.com> Tested-by:
Laura Abbott <labbott@redhat.com> Reviewed-by:
Jiri Olsa <jolsa@kernel.org> Signed-off-by:
Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by:
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Ard Biesheuvel authored
Instead of passing each start address into is_vmalloc_or_module_addr() to decide whether it falls into either the VMALLOC or the MODULES region, we can simply check the type field of the current kcore_list entry, since it will be set to KCORE_VMALLOC based on exactly the same conditions. As a bonus, when reading the KCORE_TEXT region on architectures that have one, this will avoid using vread() on the region if it happens to intersect with a KCORE_VMALLOC region. This is due the fact that the KCORE_TEXT region is the first one to be added to the kcore region list. Reported-by:
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Ard Biesheuvel authored
As it turns out, arm64 deviates from other architectures in the way it maps the VMALLOC region: on most (all?) other architectures, it resides strictly above the kernel's direct mapping of DRAM, but on arm64, this is the other way around. For instance, for a 48-bit VA configuration, we have modules : 0xffff000000000000 - 0xffff000008000000 ( 128 MB) vmalloc : 0xffff000008000000 - 0xffff7dffbfff0000 (129022 GB) ... vmemmap : 0xffff7e0000000000 - 0xffff800000000000 ( 2048 GB maximum) 0xffff7e0000000000 - 0xffff7e0003ff0000 ( 63 MB actual) memory : 0xffff800000000000 - 0xffff8000ffc00000 ( 4092 MB) This has mostly gone unnoticed until now, but it does appear that it breaks an assumption in the kmem read/write code, which does something like if (p < (unsigned long) high_memory) { ... use straight copy_[to|from]_user() using p as virtual address ... } ... if (count > 0) { ... use vread/vwrite for accesses past high_memory ... } The first condition will inadvertently hold for the VMALLOC region if VMALLOC_START < PAGE_OFFSET [which is the case on arm64], but the read or write will subsequently fail the virt_addr_valid() check, resulting in a -ENXIO return value. Given how kmem seems to be living in borrowed time anyway, and given the fact that nobody noticed that the read/write interface is broken on arm64 in the first place, let's not bother trying to fix it, but simply disable the /dev/kmem interface entirely for arm64. Acked-by:
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- 15 Jun, 2017 4 commits
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Dustin Brown authored
The kernel watchdog is a great debugging tool for finding tasks that consume a disproportionate amount of CPU time in contiguous chunks. One can imagine building a similar watchdog for arbitrary driver threads using save_stack_trace_tsk() and print_stack_trace(). However, this is not viable for dynamically loaded driver modules on ARM platforms because save_stack_trace_tsk() is not exported for those architectures. Export save_stack_trace_tsk() for the ARM64 architecture to align with x86 and support various debugging use cases such as arbitrary driver thread watchdog timers. Signed-off-by:
Dustin Brown <dustinb@codeaurora.org> Signed-off-by:
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Lorenzo Pieralisi authored
Commit 316ca880 ("ACPI/IORT: Remove linker section for IORT entries probing") removed the linker section for IORT entries probing. Since those IORT entries were the only iort_node_match() interface users, the iort_node_match() became obsolete and can then be removed. Remove the ACPI IORT iort_node_match() interface from the kernel. Acked-by:
Marc Zyngier <marc.zyngier@arm.com> Acked-by:
Hanjun Guo <hanjun.guo@linaro.org> Signed-off-by:
Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Cc: Hanjun Guo <hanjun.guo@linaro.org> Signed-off-by:
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Lorenzo Pieralisi authored
ACPI IORT is an ACPI addendum to describe the connection topology of devices with IOMMUs and interrupt controllers on ARM64 ACPI systems. Currently the ACPI IORT Kbuild symbol is selected whenever the Kbuild symbol ARM_GIC_V3_ITS is enabled, which in turn is selected by ARM64 Kbuild defaults. This makes the logic behind ACPI_IORT selection a bit twisted and not easy to follow. On ARM64 systems enabling ACPI the kbuild symbol ACPI_IORT should always be selected in that it is a kernel layer provided to the ARM64 arch code to parse and enable ACPI firmware bindings. Make the ACPI_IORT selection explicit in ARM64 Kbuild and remove the selection from ARM_GIC_V3_ITS entry, making the ACPI_IORT selection logic clearer to follow. Acked-by:
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Olav Haugan authored
The current null-pointer check in __dma_alloc_coherent and __dma_free_coherent is not needed anymore since the __dma_alloc/__dma_free functions won't be called if !dev (dummy ops will be called instead). Reviewed-by:
Olav Haugan <ohaugan@codeaurora.org> Signed-off-by:
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- 12 Jun, 2017 9 commits
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Jonathan (Zhixiong) Zhang authored
Declare ARCH_SUPPORTS_MEMORY_FAILURE, as arm64 does support memory failure recovery attempt. Signed-off-by:
Jonathan (Zhixiong) Zhang <zjzhang@codeaurora.org> Signed-off-by:
Tyler Baicar <tbaicar@codeaurora.org> (Dropped changes to ACPI APEI Kconfig and updated commit log) Signed-off-by:
Punit Agrawal <punit.agrawal@arm.com> Acked-by:
Manoj Iyer <manoj.iyer@canonical.com> Signed-off-by:
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Punit Agrawal authored
Re-organise the perf accounting for fault handling in preparation for enabling handling of hardware poison faults in subsequent commits. The change updates perf accounting to be inline with the behaviour on x86. With this update, the perf fault accounting - * Always report PERF_COUNT_SW_PAGE_FAULTS * Doesn't report anything else for VM_FAULT_ERROR (which includes hwpoison faults) * Reports PERF_COUNT_SW_PAGE_FAULTS_MAJ if it's a major fault (indicated by VM_FAULT_MAJOR) * Otherwise, reports PERF_COUNT_SW_PAGE_FAULTS_MIN Signed-off-by: -
Jonathan (Zhixiong) Zhang authored
Add VM_FAULT_HWPOISON[_LARGE] handling to the arm64 page fault handler. Handling of VM_FAULT_HWPOISON[_LARGE] is very similar to VM_FAULT_OOM, the only difference is that a different si_code (BUS_MCEERR_AR) is passed to user space and si_addr_lsb field is initialized. Signed-off-by:
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Punit Agrawal authored
When memory failure is enabled, a poisoned hugepage pte is marked as a swap entry. huge_pte_offset() does not return the poisoned page table entries when it encounters PUD/PMD hugepages. This behaviour of huge_pte_offset() leads to error such as below when munmap is called on poisoned hugepages. [ 344.165544] mm/pgtable-generic.c:33: bad pmd 000000083af00074. Fix huge_pte_offset() to return the poisoned pte which is then appropriately handled by the generic layer code. Signed-off-by:
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Will Deacon authored
When CONFIG_MODULES is disabled, we cannot dereference a module pointer: arch/arm64/kernel/ftrace.c: In function 'ftrace_make_call': arch/arm64/kernel/ftrace.c:107:36: error: dereferencing pointer to incomplete type 'struct module' trampoline = (unsigned long *)mod->arch.ftrace_trampoline; Also, the within_module() function is not defined: arch/arm64/kernel/ftrace.c: In function 'ftrace_make_nop': arch/arm64/kernel/ftrace.c:171:8: error: implicit declaration of function 'within_module'; did you mean 'init_module'? [-Werror=implicit-function-declaration] This addresses both by adding replacing the IS_ENABLED(CONFIG_ARM64_MODULE_PLTS) checks with #ifdef versions. Fixes: e71a4e1b ("arm64: ftrace: add support for far branches to dynamic ftrace") Reported-by:
Arnd Bergmann <arnd@arndb.de> Acked-by:
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Will Deacon authored
Whilst debugging a remote crash, I noticed that show_pte is unhelpful when it comes to describing the structure of the page table being walked. This is easily fixed by printing out the page table (swapper vs user), page size and virtual address size when displaying the PGD address. Acked-by:
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Kristina Martsenko authored
Print out the name of the file associated with the vma that faulted. This is usually the executable or shared library name. We already print out the task name, but also printing the library name is useful for pinpointing bugs to libraries. Also print the base address and size of the vma, which together with the PC (printed by __show_regs) gives the offset into the library. Fault prints now look like: test[2361]: unhandled level 2 translation fault (11) at 0x00000012, esr 0x92000006, in libfoo.so[ffffa0145000+1000] This is already done on x86, for more details see commit 03252919 ("x86: print which shared library/executable faulted in segfault etc. messages v3"). Acked-by:
Kristina Martsenko <kristina.martsenko@arm.com> Signed-off-by:
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Kristina Martsenko authored
When we take a fault from EL0 that can't be handled, we print out the page table entries associated with the faulting address. This allows userspace to print out any current page table entries, including kernel (TTBR1) entries. Exposing kernel mappings like this could pose a security risk, so don't print out page table information on EL0 faults. (But still print it out for EL1 faults.) This also follows the same behaviour as x86, printing out page table entries on kernel mode faults but not user mode faults. Acked-by:
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Kristina Martsenko authored
When we take a fault that can't be handled, we print out the page table entries associated with the faulting address. In some cases we currently print out the wrong entries. For a faulting TTBR1 address, we sometimes print out TTBR0 table entries instead, and for a faulting TTBR0 address we sometimes print out TTBR1 table entries. Fix this by choosing the tables based on the faulting address. Acked-by:
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- 07 Jun, 2017 2 commits
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Ard Biesheuvel authored
Currently, dynamic ftrace support in the arm64 kernel assumes that all core kernel code is within range of ordinary branch instructions that occur in module code, which is usually the case, but is no longer guaranteed now that we have support for module PLTs and address space randomization. Since on arm64, all patching of branch instructions involves function calls to the same entry point [ftrace_caller()], we can emit the modules with a trampoline that has unlimited range, and patch both the trampoline itself and the branch instruction to redirect the call via the trampoline. Signed-off-by:
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Ard Biesheuvel authored
When turning branch instructions into NOPs, we attempt to validate the action by comparing the old value at the call site with the opcode of a direct relative branch instruction pointing at the old target. However, these call sites are statically initialized to call _mcount(), and may be redirected via a PLT entry if the module is loaded far away from the kernel text, leading to false negatives and spurious errors. So skip the validation if CONFIG_ARM64_MODULE_PLTS is configured. Signed-off-by:
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- 06 Jun, 2017 1 commit
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Kees Cook authored
Adjust vdso_{start|end} to be char arrays to avoid compile-time analysis that flags "too large" memcmp() calls with CONFIG_FORTIFY_SOURCE. Cc: Jisheng Zhang <jszhang@marvell.com> Acked-by:Kees Cook <keescook@chromium.org> Signed-off-by:
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- 05 Jun, 2017 1 commit
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Will Deacon authored
Commit 3fde2999 ("arm64: cpufeature: Don't dump useless backtrace on CPU_OUT_OF_SPEC") changed the cpufeature detection code to use add_taint instead of WARN_TAINT_ONCE when detecting a heterogeneous system with mismatched feature support. Unfortunately, this resulted in all systems getting the taint, regardless of any feature mismatch. This patch fixes the problem by conditionalising the taint on detecting a feature mismatch. Acked-by:
Heiner Kallweit <hkallweit1@gmail.com> Signed-off-by:
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- 01 Jun, 2017 1 commit
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Ard Biesheuvel authored
When running lscpu on an AArch64 system that has SMBIOS version 2.0 tables, it will segfault in the following way: Unable to handle kernel paging request at virtual address ffff8000bfff0000 pgd = ffff8000f9615000 [ffff8000bfff0000] *pgd=0000000000000000 Internal error: Oops: 96000007 [#1] PREEMPT SMP Modules linked in: CPU: 0 PID: 1284 Comm: lscpu Not tainted 4.11.0-rc3+ #103 Hardware name: QEMU QEMU Virtual Machine, BIOS 0.0.0 02/06/2015 task: ffff8000fa78e800 task.stack: ffff8000f9780000 PC is at __arch_copy_to_user+0x90/0x220 LR is at read_mem+0xcc/0x140 This is caused by the fact that lspci issues a read() on /dev/mem at the offset where it expects to find the SMBIOS structure array. However, this region is classified as EFI_RUNTIME_SERVICE_DATA (as per the UEFI spec), and so it is omitted from the linear mapping. So let's restrict /dev/mem read/write access to those areas that are covered by the linear region. Reported-by:
Alexander Graf <agraf@suse.de> Fixes: 4dffbfc4 ("arm64/efi: mark UEFI reserved regions as MEMBLOCK_NOMAP") Signed-off-by:
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- 30 May, 2017 8 commits
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Lorenzo Pieralisi authored
PCI core requires the NUMA node for the struct pci_host_bridge.dev to be set by using the pcibus_to_node(struct pci_bus*) API, that on ARM64 systems relies on the struct pci_host_bridge->bus.dev NUMA node. The struct pci_host_bridge.dev NUMA node is then propagated through the PCI device hierarchy as PCI devices (and bridges) are enumerated under it. Therefore, in order to set-up the PCI NUMA hierarchy appropriately, the struct pci_host_bridge->bus.dev NUMA node must be set before core code calls pcibus_to_node(struct pci_bus*) on it so that PCI core can retrieve the NUMA node for the struct pci_host_bridge.dev device and can propagate it through the PCI bus tree. On ARM64 ACPI based systems the struct pci_host_bridge->bus.dev NUMA node can be set-up in pcibios_root_bridge_prepare() by parsing the root bridge ACPI device firmware binding. Add code to the pcibios_root_bridge_prepare() that, when booting with ACPI, parse the root bridge ACPI device companion NUMA binding and set the corresponding struct pci_host_bridge->bus.dev NUMA node appropriately. Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Reviewed-by:
Robert Richter <rrichter@cavium.com> Tested-by:
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Will Deacon authored
FUTEX_OP_OPARG_SHIFT instructs the futex code to treat the 12-bit oparg field as a shift value, potentially leading to a left shift value that is negative or with an absolute value that is significantly larger then the size of the type. UBSAN chokes with: ================================================================================ UBSAN: Undefined behaviour in ./arch/arm64/include/asm/futex.h:60:13 shift exponent -1 is negative CPU: 1 PID: 1449 Comm: syz-executor0 Not tainted 4.11.0-rc4-00005-g977eb52-dirty #11 Hardware name: linux,dummy-virt (DT) Call trace: [<ffff200008094778>] dump_backtrace+0x0/0x538 arch/arm64/kernel/traps.c:73 [<ffff200008094cd0>] show_stack+0x20/0x30 arch/arm64/kernel/traps.c:228 [<ffff200008c194a8>] __dump_stack lib/dump_stack.c:16 [inline] [<ffff200008c194a8>] dump_stack+0x120/0x188 lib/dump_stack.c:52 [<ffff200008cc24b8>] ubsan_epilogue+0x18/0x98 lib/ubsan.c:164 [<ffff200008cc3098>] __ubsan_handle_shift_out_of_bounds+0x250/0x294 lib/ubsan.c:421 [<ffff20000832002c>] futex_atomic_op_inuser arch/arm64/include/asm/futex.h:60 [inline] [<ffff20000832002c>] futex_wake_op kernel/futex.c:1489 [inline] [<ffff20000832002c>] do_futex+0x137c/0x1740 kernel/futex.c:3231 [<ffff200008320504>] SYSC_futex kernel/futex.c:3281 [inline] [<ffff200008320504>] SyS_futex+0x114/0x268 kernel/futex.c:3249 [<ffff200008084770>] el0_svc_naked+0x24/0x28 ================================================================================ syz-executor1 uses obsolete (PF_INET,SOCK_PACKET) sock: process `syz-executor0' is using obsolete setsockopt SO_BSDCOMPAT This patch attempts to fix some of this by: * Making encoded_op an unsigned type, so we can shift it left even if the top bit is set. * Casting to signed prior to shifting right when extracting oparg and cmparg * Consider only the bottom 5 bits of oparg when using it as a left-shift value. Whilst I think this catches all of the issues, I'd much prefer to remove this stuff, as I think it's unused and the bugs are copy-pasted between a bunch of architectures. Reviewed-by:Robin Murphy <robin.murphy@arm.com> Signed-off-by:
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Kefeng Wang authored
It's useless to print machine name and setup arch-specific system identifiers if of_flat_dt_get_machine_name() return NULL, especially when ACPI-based boot. Reviewed-by:
Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by:
Kefeng Wang <wangkefeng.wang@huawei.com> Signed-off-by:
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Will Deacon authored
Unfortunately, it turns out that mismatched CPU features in big.LITTLE systems are starting to appear in the wild. Whilst we should continue to taint the kernel with CPU_OUT_OF_SPEC for features that differ in ways that we can't fix up, dumping a useless backtrace out of the cpufeature code is pointless and irritating. This patch removes the backtrace from the taint. Signed-off-by:
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Tobias Klauser authored
arm64's mm/mmu.c uses vm_area_add_early, struct vm_area and other definitions but relies on implict inclusion of linux/vmalloc.h which means that changes in other headers could break the build. Thus, add an explicit include. Acked-by:
Tobias Klauser <tklauser@distanz.ch> Signed-off-by:
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Kefeng Wang authored
Generic code expects show_regs() to dump the stack, but arm64's show_regs() does not. This makes it hard to debug softlockups and other issues that result in show_regs() being called. This patch updates arm64's show_regs() to dump the stack, as common code expects. Acked-by:
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Kefeng Wang authored
Generic code expects show_regs() to also dump the stack, but arm64's show_reg() does not do this. Some arm64 callers of show_regs() *only* want the registers dumped, without the stack. To enable generic code to work as expected, we need to make show_regs() dump the stack. Where we only want the registers dumped, we must use __show_regs(). This patch updates code to use __show_regs() where only registers are desired. A subsequent patch will modify show_regs(). Acked-by:
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Dong Bo authored
Like arch/arm/, we inherit the READ_IMPLIES_EXEC personality flag across fork(). This is undesirable for a number of reasons: * ELF files that don't require executable stack can end up with it anyway * We end up performing un-necessary I-cache maintenance when mapping what should be non-executable pages * Restricting what is executable is generally desirable when defending against overflow attacks This patch clears the personality flag when setting up the personality for newly spwaned native tasks. Given that semi-recent AArch64 toolchains emit a non-executable PT_GNU_STACK header, userspace applications can already not rely on READ_IMPLIES_EXEC so shouldn't be adversely affected by this change. Cc: <stable@vger.kernel.org> Reported-by:Peter Maydell <peter.maydell@linaro.org> Signed-off-by:
Dong Bo <dongbo4@huawei.com> [will: added comment to compat code, rewrote commit message] Signed-off-by:
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- 29 May, 2017 1 commit
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Linus Torvalds authored
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