- 09 9月, 2016 12 次提交
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由 Suzuki K Poulose 提交于
Right now we trap some of the user space data cache operations based on a few Errata (ARM 819472, 826319, 827319 and 824069). We need to trap userspace access to CTR_EL0, if we detect mismatched cache line size. Since both these traps share the EC, refactor the handler a little bit to make it a bit more reader friendly. Cc: Mark Rutland <mark.rutland@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Acked-by: NAndre Przywara <andre.przywara@arm.com> Signed-off-by: NSuzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: NWill Deacon <will.deacon@arm.com>
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由 Suzuki K Poulose 提交于
On systems with mismatched i/d cache min line sizes, we need to use the smallest size possible across all CPUs. This will be done by fetching the system wide safe value from CPU feature infrastructure. However the some special users(e.g kexec, hibernate) would need the line size on the CPU (rather than the system wide), when either the system wide feature may not be accessible or it is guranteed that the caller executes with a gurantee of no migration. Provide another helper which will fetch cache line size on the current CPU. Cc: Mark Rutland <mark.rutland@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Acked-by: NJames Morse <james.morse@arm.com> Reviewed-by: NGeoff Levand <geoff@infradead.org> Signed-off-by: NSuzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: NWill Deacon <will.deacon@arm.com>
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由 Suzuki K Poulose 提交于
Adds helpers for decoding/encoding the PC relative addresses for adrp. This will be used for handling dynamic patching of 'adrp' instructions in alternative code patching. Cc: Mark Rutland <mark.rutland@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: NSuzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: NWill Deacon <will.deacon@arm.com>
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由 Suzuki K Poulose 提交于
Right now we run through the work around checks on a CPU from __cpuinfo_store_cpu. There are some problems with that: 1) We initialise the system wide CPU feature registers only after the Boot CPU updates its cpuinfo. Now, if a work around depends on the variance of a CPU ID feature (e.g, check for Cache Line size mismatch), we have no way of performing it cleanly for the boot CPU. 2) It is out of place, invoked from __cpuinfo_store_cpu() in cpuinfo.c. It is not an obvious place for that. This patch rearranges the CPU specific capability(aka work around) checks. 1) At the moment we use verify_local_cpu_capabilities() to check if a new CPU has all the system advertised features. Use this for the secondary CPUs to perform the work around check. For that we rename verify_local_cpu_capabilities() => check_local_cpu_capabilities() which: If the system wide capabilities haven't been initialised (i.e, the CPU is activated at the boot), update the system wide detected work arounds. Otherwise (i.e a CPU hotplugged in later) verify that this CPU conforms to the system wide capabilities. 2) Boot CPU updates the work arounds from smp_prepare_boot_cpu() after we have initialised the system wide CPU feature values. Cc: Mark Rutland <mark.rutland@arm.com> Cc: Andre Przywara <andre.przywara@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: NSuzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: NWill Deacon <will.deacon@arm.com>
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由 Suzuki K Poulose 提交于
This is a cosmetic change to rename the functions dealing with the errata work arounds to be more consistent with their naming. 1) check_local_cpu_errata() => update_cpu_errata_workarounds() check_local_cpu_errata() actually updates the system's errata work arounds. So rename it to reflect the same. 2) verify_local_cpu_errata() => verify_local_cpu_errata_workarounds() Use errata_workarounds instead of _errata. Cc: Mark Rutland <mark.rutland@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Acked-by: NAndre Przywara <andre.przywara@arm.com> Signed-off-by: NSuzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: NWill Deacon <will.deacon@arm.com>
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由 Suzuki K Poulose 提交于
Right now we use 0 as the safe value for CTR_EL0:L1Ip, which is not defined at the moment. The safer value for the L1Ip should be the weakest of the policies, which happens to be AIVIVT. While at it, fix the comment about safe_val. Cc: Mark Rutland <mark.rutland@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: NSuzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: NWill Deacon <will.deacon@arm.com>
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由 Mark Rutland 提交于
When CONFIG_PID_IN_CONTEXTIDR is not selected, we use an empty stub definition of contextidr_thread_switch(). As everything we rely upon exists regardless of CONFIG_PID_IN_CONTEXTIDR, we don't strictly require an empty stub. By using IS_ENABLED() rather than ifdeffery, we avoid duplication, and get compiler coverage on all the code even when CONFIG_PID_IN_CONTEXTIDR is not selected and the code is optimised away. Signed-off-by: NMark Rutland <mark.rutland@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: NWill Deacon <will.deacon@arm.com>
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由 Mark Rutland 提交于
A while back we added {read,write}_sysreg accessors to handle accesses to system registers, without the usual boilerplate asm volatile, temporary variable, etc. This patch makes use of these across arm64 to make code shorter and clearer. For sequences with a trailing ISB, the existing isb() macro is also used so that asm blocks can be removed entirely. A few uses of inline assembly for msr/mrs are left as-is. Those manipulating sp_el0 for the current thread_info value have special clobber requiremends. Signed-off-by: NMark Rutland <mark.rutland@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: NWill Deacon <will.deacon@arm.com>
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由 Mark Rutland 提交于
A while back we added {read,write}_sysreg accessors to handle accesses to system registers, without the usual boilerplate asm volatile, temporary variable, etc. This patch makes use of these in the arm64 KVM code to make the code shorter and clearer. At the same time, a comment style violation next to a system register access is fixed up in reset_pmcr, and comments describing whether operations are reads or writes are removed as this is now painfully obvious. Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Marc Zyngier <marc.zyngier@arm.com> Cc: Will Deacon <will.deacon@arm.com> Acked-by: NChristoffer Dall <christoffer.dall@linaro.org> Signed-off-by: NMark Rutland <mark.rutland@arm.com> Signed-off-by: NWill Deacon <will.deacon@arm.com>
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由 Mark Rutland 提交于
A while back we added {read,write}_sysreg accessors to handle accesses to system registers, without the usual boilerplate asm volatile, temporary variable, etc. This patch makes use of these in the arm64 DCC accessors to make the code shorter and clearer. Signed-off-by: NMark Rutland <mark.rutland@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: NWill Deacon <will.deacon@arm.com>
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由 Mark Rutland 提交于
A while back we added {read,write}_sysreg accessors to handle accesses to system registers, without the usual boilerplate asm volatile, temporary variable, etc. This patch makes use of these in the arm64 arch timer accessors to make the code shorter and clearer. Signed-off-by: NMark Rutland <mark.rutland@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Marc Zyngier <marc.zyngier@arm.com> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: NWill Deacon <will.deacon@arm.com>
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由 Mark Rutland 提交于
Currently write_sysreg has to allocate a temporary register to write zero to a system register, which is unfortunate given that the MSR instruction accepts XZR as an operand. Allow XZR to be used when appropriate by fiddling with the assembly constraints. Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Marc Zyngier <marc.zyngier@arm.com> Cc: Suzuki K Poulose <suzuki.poulose@arm.com> Reviewed-by: NRobin Murphy <robin.murphy@arm.com> Signed-off-by: NMark Rutland <mark.rutland@arm.com> Signed-off-by: NWill Deacon <will.deacon@arm.com>
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- 08 9月, 2016 1 次提交
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由 Robin Murphy 提交于
When zeroing an I/O location, the current accessors are forced to allocate a temporary register to store the zero for the write. By tweaking the assembly constraints, we can allow the compiler to use the zero register directly in such cases, and save some juggling. Compiling a representative kernel configuration with GCC 6 shows that 2.3KB worth of code can be wasted just on that! text data bss dec hex filename 13316776 3248256 18176769 34741801 2121e29 vmlinux.o.new 13319140 3248256 18176769 34744165 2122765 vmlinux.o.old Acked-by: NMark Rutland <mark.rutland@arm.com> Signed-off-by: NRobin Murphy <robin.murphy@arm.com> Signed-off-by: NWill Deacon <will.deacon@arm.com>
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- 07 9月, 2016 1 次提交
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由 Catalin Marinas 提交于
This patch adds static keys transparently for all the cpu_hwcaps features by implementing an array of default-false static keys and enabling them when detected. The cpus_have_cap() check uses the static keys if the feature being checked is a constant, otherwise the compiler generates the bitmap test. Because of the early call to static_branch_enable() via check_local_cpu_errata() -> update_cpu_capabilities(), the jump labels are initialised in cpuinfo_store_boot_cpu(). Cc: Will Deacon <will.deacon@arm.com> Cc: Suzuki K. Poulose <Suzuki.Poulose@arm.com> Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com> Signed-off-by: NWill Deacon <will.deacon@arm.com>
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- 05 9月, 2016 1 次提交
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由 James Morse 提交于
The code that provides /dev/mem uses xlate_dev_mem_{k,}ptr() to avoid making a cachable mapping of a non-cachable area on ia64. On arm64 we do this via phys_mem_access_prot() instead, but provide dummy versions of xlate_dev_mem_{k,}ptr(). These are the same as those in asm-generic/io.h, which we include from asm/io.h Signed-off-by: NJames Morse <james.morse@arm.com> Signed-off-by: NWill Deacon <will.deacon@arm.com>
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- 01 9月, 2016 1 次提交
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由 zijun_hu 提交于
remove duplicate macro __KERNEL__ check Signed-off-by: Nzijun_hu <zijun_hu@htc.com> Signed-off-by: NWill Deacon <will.deacon@arm.com>
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- 31 8月, 2016 4 次提交
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由 Ard Biesheuvel 提交于
Expose the arm64_ftr_reg struct covering CTR_EL0 outside of cpufeature.o so that other code can refer to it directly (i.e., without performing the binary search) Reviewed-by: NSuzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: NArd Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: NWill Deacon <will.deacon@arm.com>
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由 Ard Biesheuvel 提交于
Constify the arm64_ftr_regs array, by moving the mutable arm64_ftr_reg fields out of the array itself. This also streamlines the bsearch, since the entire array can be covered by fewer cachelines. Moving the payload out of the array also allows us to have special explicitly defined struct instance in case other code needs to refer to it directly. Note that this replaces the runtime sorting of the array with a runtime BUG() check whether the array is sorted correctly in the code. Reviewed-by: NSuzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: NArd Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: NWill Deacon <will.deacon@arm.com>
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由 Ard Biesheuvel 提交于
The arm64_ftr_bits structures are never modified, so make them read-only. Reviewed-by: NSuzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: NArd Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: NWill Deacon <will.deacon@arm.com>
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由 Kefeng Wang 提交于
The UDBG_UNDEFINED/SYSCALL/BADABORT/SEGV are only used to show verbose user fault messages in arm, not arm64, drop them. Signed-off-by: NKefeng Wang <wangkefeng.wang@huawei.com> Signed-off-by: NWill Deacon <will.deacon@arm.com>
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- 26 8月, 2016 6 次提交
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由 James Morse 提交于
disable_nonboot_cpus() assumes that the lowest numbered online CPU is the boot CPU, and that this is the correct CPU to run any power management code on. On arm64 CPU0 can be taken offline. For hibernate/resume this means we may hibernate on a CPU other than CPU0. If the system is rebooted with kexec 'CPU0' will be assigned to a different CPU. This complicates hibernate/resume as now we can't trust the CPU numbers. We currently forbid hibernate if CPU0 has been hotplugged out to avoid this situation without kexec. Save the MPIDR of the CPU we hibernated on in the hibernate arch-header, use hibernate_resume_nonboot_cpu_disable() to direct which CPU we should resume on based on the MPIDR of the CPU we hibernated on. This allows us to hibernate/resume on any CPU, even if the logical numbers have been shuffled by kexec. Signed-off-by: NJames Morse <james.morse@arm.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Reviewed-by: NCatalin Marinas <catalin.marinas@arm.com> Signed-off-by: NWill Deacon <will.deacon@arm.com>
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由 AKASHI Takahiro 提交于
Kdump(kexec-tools) parses /proc/iomem to identify all the memory regions on the system. Since the current kernel names "nomap" regions, like UEFI runtime services code/data, as "System RAM," kexec-tools sets up elf core header to include them in a crash dump file (/proc/vmcore). Then crash dump kernel parses UEFI memory map again, re-marks those regions as "nomap" and does not create a memory mapping for them unlike the other areas of System RAM. In this case, copying /proc/vmcore through copy_oldmem_page() on crash dump kernel will end up with a kernel abort, as reported in [1]. This patch names all the "nomap" regions explicitly as "reserved" so that we can exclude them from a crash dump file. acpi_os_ioremap() must also be modified because those regions have WB attributes [2]. Apart from kdump, this change also matches x86's use of acpi (and /proc/iomem). [1] http://lists.infradead.org/pipermail/linux-arm-kernel/2016-August/448186.html [2] http://lists.infradead.org/pipermail/linux-arm-kernel/2016-August/450089.htmlReviewed-by: NCatalin Marinas <catalin.marinas@arm.com> Tested-by: NJames Morse <james.morse@arm.com> Reviewed-by: NJames Morse <james.morse@arm.com> Signed-off-by: NAKASHI Takahiro <takahiro.akashi@linaro.org> Signed-off-by: NWill Deacon <will.deacon@arm.com>
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由 James Morse 提交于
DEBUG_PAGEALLOC removes the valid bit of page table entries to prevent any access to unallocated memory. Hibernate uses this as a hint that those pages don't need to be saved/restored. This patch adds the kernel_page_present() function it uses. hibernate.c copies the resume kernel's linear map for use during restore. Add _copy_pte() to fill-in the holes made by DEBUG_PAGEALLOC in the resume kernel, so we can restore data the original kernel had at these addresses. Finally, DEBUG_PAGEALLOC means the linear-map alias of KERNEL_START to KERNEL_END may have holes in it, so we can't lazily clean this whole area to the PoC. Only clean the new mmuoff region, and the kernel/kvm idmaps. This reverts commit da24eb1f. Reported-by: NWill Deacon <will.deacon@arm.com> Signed-off-by: NJames Morse <james.morse@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Reviewed-by: NCatalin Marinas <catalin.marinas@arm.com> Signed-off-by: NWill Deacon <will.deacon@arm.com>
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由 James Morse 提交于
Resume from hibernate needs to clean any text executed by the kernel with the MMU off to the PoC. Collect these functions together into the .idmap.text section as all this code is tightly coupled and also needs the same cleaning after resume. Data is more complicated, secondary_holding_pen_release is written with the MMU on, clean and invalidated, then read with the MMU off. In contrast __boot_cpu_mode is written with the MMU off, the corresponding cache line is invalidated, so when we read it with the MMU on we don't get stale data. These cache maintenance operations conflict with each other if the values are within a Cache Writeback Granule (CWG) of each other. Collect the data into two sections .mmuoff.data.read and .mmuoff.data.write, the linker script ensures mmuoff.data.write section is aligned to the architectural maximum CWG of 2KB. Signed-off-by: NJames Morse <james.morse@arm.com> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Mark Rutland <mark.rutland@arm.com> Reviewed-by: NCatalin Marinas <catalin.marinas@arm.com> Signed-off-by: NWill Deacon <will.deacon@arm.com>
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由 James Morse 提交于
Each time new section markers are added, kernel/vmlinux.ld.S is updated, and new extern char __start_foo[] definitions are scattered through the tree. Create asm/include/sections.h to collect these definitions (and include the existing asm-generic version). Signed-off-by: NJames Morse <james.morse@arm.com> Reviewed-by: NMark Rutland <mark.rutland@arm.com> Tested-by: NMark Rutland <mark.rutland@arm.com> Reviewed-by: NCatalin Marinas <catalin.marinas@arm.com> Signed-off-by: NWill Deacon <will.deacon@arm.com>
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由 Catalin Marinas 提交于
The ARMv8 architecture allows execute-only user permissions by clearing the PTE_UXN and PTE_USER bits. However, the kernel running on a CPU implementation without User Access Override (ARMv8.2 onwards) can still access such page, so execute-only page permission does not protect against read(2)/write(2) etc. accesses. Systems requiring such protection must enable features like SECCOMP. This patch changes the arm64 __P100 and __S100 protection_map[] macros to the new __PAGE_EXECONLY attributes. A side effect is that pte_user() no longer triggers for __PAGE_EXECONLY since PTE_USER isn't set. To work around this, the check is done on the PTE_NG bit via the pte_ng() macro. VM_READ is also checked now for page faults. Reviewed-by: NWill Deacon <will.deacon@arm.com> Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com> Signed-off-by: NWill Deacon <will.deacon@arm.com>
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- 22 8月, 2016 2 次提交
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由 Mark Rutland 提交于
Even though perf_ops_bp was removed/renamed back in commit b0a873eb ("perf: Register PMU implementations"), as part of v2.6.37, its definition still lives on in some arch headers. This patch removes the vestigal definition from arm64. Signed-off-by: NMark Rutland <mark.rutland@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: NWill Deacon <will.deacon@arm.com>
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由 Kwangwoo Lee 提交于
__dma_* routines have been converted to use start and size instread of start and end addresses. The patch was origianlly for adding __clean_dcache_area_poc() which will be used in pmem driver to clean dcache to the PoC(Point of Coherency) in arch_wb_cache_pmem(). The functionality of __clean_dcache_area_poc() was equivalent to __dma_clean_range(). The difference was __dma_clean_range() uses the end address, but __clean_dcache_area_poc() uses the size to clean. Thus, __clean_dcache_area_poc() has been revised with a fallthrough function of __dma_clean_range() after the change that __dma_* routines use start and size instead of using start and end. As a consequence of using start and size, the name of __dma_* routines has also been altered following the terminology below: area: takes a start and size range: takes a start and end Reviewed-by: NRobin Murphy <robin.murphy@arm.com> Signed-off-by: NKwangwoo Lee <kwangwoo.lee@sk.com> Signed-off-by: NWill Deacon <will.deacon@arm.com>
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- 12 8月, 2016 1 次提交
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由 David A. Long 提交于
Because the arm64 calling standard allows stacked function arguments to be anywhere in the stack frame, do not attempt to duplicate the stack frame for jprobes handler functions. Documentation changes to describe this issue have been broken out into a separate patch in order to simultaneously address them in other architecture(s). Signed-off-by: NDavid A. Long <dave.long@linaro.org> Acked-by: NMasami Hiramatsu <mhiramat@kernel.org> Acked-by: NMarc Zyngier <marc.zyngier@arm.com> Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>
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- 04 8月, 2016 1 次提交
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由 Steve Capper 提交于
set_pte_at(.) will set or unset the PTE_RDONLY hardware bit before writing the entry to the table. This can cause problems with the copy-on-write logic in hugetlb_cow: *) hugetlb_cow(.) called to handle a write fault on read only pte, *) Before the copy-on-write updates the new page table a call is made to pte_same(huge_ptep_get(ptep), pte)), to check for a race, *) Because set_pte_at(.) changed the pte, *ptep != pte, and the hugetlb_cow(.) code erroneously assumes that it lost the race, *) The new page is subsequently freed without being used. On arm64 this problem only becomes apparent when we apply: 67961f9d mm/hugetlb: fix huge page reserve accounting for private mappings When one runs the libhugetlbfs test suite, there are allocation errors and hugetlbfs pages become erroneously locked in memory as reserved. (There is a high HugePages_Rsvd: count). In this patch we introduce pte_same which ignores the PTE_RDONLY bit, allowing for the libhugetlbfs test suite to pass as expected and without leaking any reserved HugeTLB pages. Reported-by: NHuang Shijie <shijie.huang@arm.com> Signed-off-by: NSteve Capper <steve.capper@arm.com> Signed-off-by: NWill Deacon <will.deacon@arm.com>
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- 29 7月, 2016 1 次提交
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由 James Hogan 提交于
AT_VECTOR_SIZE_ARCH should be defined with the maximum number of NEW_AUX_ENT entries that ARCH_DLINFO can contain, but it wasn't defined for arm64 at all even though ARCH_DLINFO will contain one NEW_AUX_ENT for the VDSO address. This shouldn't be a problem as AT_VECTOR_SIZE_BASE includes space for AT_BASE_PLATFORM which arm64 doesn't use, but lets define it now and add the comment above ARCH_DLINFO as found in several other architectures to remind future modifiers of ARCH_DLINFO to keep AT_VECTOR_SIZE_ARCH up to date. Fixes: f668cd16 ("arm64: ELF definitions") Signed-off-by: NJames Hogan <james.hogan@imgtec.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: linux-arm-kernel@lists.infradead.org Signed-off-by: NWill Deacon <will.deacon@arm.com>
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- 27 7月, 2016 2 次提交
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由 Catalin Marinas 提交于
Commit 0a8ea52c ("arm64: Add HAVE_REGS_AND_STACK_ACCESS_API feature") inadvertently removed the arch/arm prototype instead of the arm64 one introduced by the original patch. There should not be any bisection issues since this function is not called from anywhere else (it could as well be removed from arch/arm at some point). Fixes: 0a8ea52c ("arm64: Add HAVE_REGS_AND_STACK_ACCESS_API feature") Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>
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由 Kees Cook 提交于
Enables CONFIG_HARDENED_USERCOPY checks on arm64. As done by KASAN in -next, renames the low-level functions to __arch_copy_*_user() so a static inline can do additional work before the copy. Signed-off-by: NKees Cook <keescook@chromium.org>
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- 19 7月, 2016 7 次提交
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由 Will Deacon 提交于
The debug enable/disable macros are not used anywhere in the kernel, so remove them from irqflags.h Reported-by: NRobin Murphy <robin.murphy@arm.com> Signed-off-by: NWill Deacon <will.deacon@arm.com> Acked-by: NMark Rutland <mark.rutland@arm.com> Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>
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由 Vladimir Murzin 提交于
...and do not confuse source navigation tools ;) Signed-off-by: NVladimir Murzin <vladimir.murzin@arm.com> Acked-by: NWill Deacon <will.deacon@arm.com> Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>
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由 William Cohen 提交于
The trampoline code is used by kretprobes to capture a return from a probed function. This is done by saving the registers, calling the handler, and restoring the registers. The code then returns to the original saved caller return address. It is necessary to do this directly instead of using a software breakpoint because the code used in processing that breakpoint could itself be kprobe'd and cause a problematic reentry into the debug exception handler. Signed-off-by: NWilliam Cohen <wcohen@redhat.com> Signed-off-by: NDavid A. Long <dave.long@linaro.org> Acked-by: NMasami Hiramatsu <mhiramat@kernel.org> [catalin.marinas@arm.com: removed unnecessary masking of the PSTATE bits] Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>
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由 Sandeepa Prabhu 提交于
Kprobes needs simulation of instructions that cannot be stepped from a different memory location, e.g.: those instructions that uses PC-relative addressing. In simulation, the behaviour of the instruction is implemented using a copy of pt_regs. The following instruction categories are simulated: - All branching instructions(conditional, register, and immediate) - Literal access instructions(load-literal, adr/adrp) Conditional execution is limited to branching instructions in ARM v8. If conditions at PSTATE do not match the condition fields of opcode, the instruction is effectively NOP. Thanks to Will Cohen for assorted suggested changes. Signed-off-by: NSandeepa Prabhu <sandeepa.s.prabhu@gmail.com> Signed-off-by: NWilliam Cohen <wcohen@redhat.com> Signed-off-by: NDavid A. Long <dave.long@linaro.org> Acked-by: NMasami Hiramatsu <mhiramat@kernel.org> [catalin.marinas@arm.com: removed linux/module.h include] Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>
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由 Sandeepa Prabhu 提交于
Add support for basic kernel probes(kprobes) and jump probes (jprobes) for ARM64. Kprobes utilizes software breakpoint and single step debug exceptions supported on ARM v8. A software breakpoint is placed at the probe address to trap the kernel execution into the kprobe handler. ARM v8 supports enabling single stepping before the break exception return (ERET), with next PC in exception return address (ELR_EL1). The kprobe handler prepares an executable memory slot for out-of-line execution with a copy of the original instruction being probed, and enables single stepping. The PC is set to the out-of-line slot address before the ERET. With this scheme, the instruction is executed with the exact same register context except for the PC (and DAIF) registers. Debug mask (PSTATE.D) is enabled only when single stepping a recursive kprobe, e.g.: during kprobes reenter so that probed instruction can be single stepped within the kprobe handler -exception- context. The recursion depth of kprobe is always 2, i.e. upon probe re-entry, any further re-entry is prevented by not calling handlers and the case counted as a missed kprobe). Single stepping from the x-o-l slot has a drawback for PC-relative accesses like branching and symbolic literals access as the offset from the new PC (slot address) may not be ensured to fit in the immediate value of the opcode. Such instructions need simulation, so reject probing them. Instructions generating exceptions or cpu mode change are rejected for probing. Exclusive load/store instructions are rejected too. Additionally, the code is checked to see if it is inside an exclusive load/store sequence (code from Pratyush). System instructions are mostly enabled for stepping, except MSR/MRS accesses to "DAIF" flags in PSTATE, which are not safe for probing. This also changes arch/arm64/include/asm/ptrace.h to use include/asm-generic/ptrace.h. Thanks to Steve Capper and Pratyush Anand for several suggested Changes. Signed-off-by: NSandeepa Prabhu <sandeepa.s.prabhu@gmail.com> Signed-off-by: NDavid A. Long <dave.long@linaro.org> Signed-off-by: NPratyush Anand <panand@redhat.com> Acked-by: NMasami Hiramatsu <mhiramat@kernel.org> Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>
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由 David A. Long 提交于
Cease using the arm32 arm_check_condition() function and replace it with a local version for use in deprecated instruction support on arm64. Also make the function table used by this available for future use by kprobes and/or uprobes. This function is derived from code written by Sandeepa Prabhu. Signed-off-by: NSandeepa Prabhu <sandeepa.s.prabhu@gmail.com> Signed-off-by: NDavid A. Long <dave.long@linaro.org> Acked-by: NMasami Hiramatsu <mhiramat@kernel.org> Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>
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由 David A. Long 提交于
Certain instructions are hard to execute correctly out-of-line (as in kprobes). Test functions are added to insn.[hc] to identify these. The instructions include any that use PC-relative addressing, change the PC, or change interrupt masking. For efficiency and simplicity test functions are also added for small collections of related instructions. Signed-off-by: NDavid A. Long <dave.long@linaro.org> Acked-by: NMasami Hiramatsu <mhiramat@kernel.org> Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>
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