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2023-03-24Merge patch series "riscv: Add GENERIC_ENTRY support"Palmer Dabbelt
guoren@kernel.org <guoren@kernel.org> says: From: Guo Ren <guoren@linux.alibaba.com> The patches convert riscv to use the generic entry infrastructure from kernel/entry/*. Some optimization for entry.S with new .macro and merge ret_from_kernel_thread into ret_from_fork. * b4-shazam-merge: riscv: entry: Consolidate general regs saving/restoring riscv: entry: Consolidate ret_from_kernel_thread into ret_from_fork riscv: entry: Remove extra level wrappers of trace_hardirqs_{on,off} riscv: entry: Convert to generic entry riscv: entry: Add noinstr to prevent instrumentation inserted riscv: ptrace: Remove duplicate operation Link: https://lore.kernel.org/r/20230222033021.983168-1-guoren@kernel.org Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-03-23riscv: entry: Consolidate general regs saving/restoringJisheng Zhang
Consolidate the saving/restoring GPs (except zero, ra, sp, gp, tp and t0) into save_from_x6_to_x31/restore_from_x6_to_x31 macros. No functional change intended. Signed-off-by: Jisheng Zhang <jszhang@kernel.org> Reviewed-by: Guo Ren <guoren@kernel.org> Reviewed-by: Björn Töpel <bjorn@rivosinc.com> Tested-by: Guo Ren <guoren@kernel.org> Signed-off-by: Guo Ren <guoren@kernel.org> Link: https://lore.kernel.org/r/20230222033021.983168-8-guoren@kernel.org Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-03-23riscv: entry: Consolidate ret_from_kernel_thread into ret_from_forkJisheng Zhang
The ret_from_kernel_thread() behaves similarly with ret_from_fork(), the only difference is whether call the fn(arg) or not, this can be achieved by testing fn is NULL or not, I.E s0 is 0 or not. Many architectures have done the same thing, it makes entry.S more clean. Signed-off-by: Jisheng Zhang <jszhang@kernel.org> Reviewed-by: Björn Töpel <bjorn@rivosinc.com> Reviewed-by: Guo Ren <guoren@kernel.org> Tested-by: Guo Ren <guoren@kernel.org> Signed-off-by: Guo Ren <guoren@kernel.org> Link: https://lore.kernel.org/r/20230222033021.983168-7-guoren@kernel.org Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-03-23riscv: entry: Remove extra level wrappers of trace_hardirqs_{on,off}Jisheng Zhang
Since riscv is converted to generic entry, there's no need for the extra wrappers of trace_hardirqs_{on,off}. Signed-off-by: Jisheng Zhang <jszhang@kernel.org> Reviewed-by: Guo Ren <guoren@kernel.org> Reviewed-by: Björn Töpel <bjorn@rivosinc.com> Tested-by: Guo Ren <guoren@kernel.org> Signed-off-by: Guo Ren <guoren@kernel.org> Link: https://lore.kernel.org/r/20230222033021.983168-6-guoren@kernel.org Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-03-23riscv: entry: Convert to generic entryGuo Ren
This patch converts riscv to use the generic entry infrastructure from kernel/entry/*. The generic entry makes maintainers' work easier and codes more elegant. Here are the changes: - More clear entry.S with handle_exception and ret_from_exception - Get rid of complex custom signal implementation - Move syscall procedure from assembly to C, which is much more readable. - Connect ret_from_fork & ret_from_kernel_thread to generic entry. - Wrap with irqentry_enter/exit and syscall_enter/exit_from_user_mode - Use the standard preemption code instead of custom Suggested-by: Huacai Chen <chenhuacai@kernel.org> Reviewed-by: Björn Töpel <bjorn@rivosinc.com> Tested-by: Yipeng Zou <zouyipeng@huawei.com> Tested-by: Jisheng Zhang <jszhang@kernel.org> Signed-off-by: Guo Ren <guoren@linux.alibaba.com> Signed-off-by: Guo Ren <guoren@kernel.org> Cc: Ben Hutchings <ben@decadent.org.uk> Link: https://lore.kernel.org/r/20230222033021.983168-5-guoren@kernel.org Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-03-23riscv: entry: Add noinstr to prevent instrumentation insertedGuo Ren
Without noinstr the compiler is free to insert instrumentation (think all the k*SAN, KCov, GCov, ftrace etc..) which can call code we're not yet ready to run this early in the entry path, for instance it could rely on RCU which isn't on yet, or expect lockdep state. (by peterz) Link: https://lore.kernel.org/linux-riscv/YxcQ6NoPf3AH0EXe@hirez.programming.kicks-ass.net/ Reviewed-by: Björn Töpel <bjorn@rivosinc.com> Suggested-by: Peter Zijlstra <peterz@infradead.org> Tested-by: Jisheng Zhang <jszhang@kernel.org> Signed-off-by: Guo Ren <guoren@linux.alibaba.com> Signed-off-by: Guo Ren <guoren@kernel.org> Link: https://lore.kernel.org/r/20230222033021.983168-4-guoren@kernel.org Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-03-23riscv: ptrace: Remove duplicate operationGuo Ren
The TIF_SYSCALL_TRACE is controlled by a common code, see kernel/ptrace.c and include/linux/thread_info.h. clear_task_syscall_work(child, SYSCALL_TRACE); Signed-off-by: Guo Ren <guoren@linux.alibaba.com> Signed-off-by: Guo Ren <guoren@kernel.org> Reviewed-by: Oleg Nesterov <oleg@redhat.com> Reviewed-by: Björn Töpel <bjorn@rivosinc.com> Link: https://lore.kernel.org/r/20230222033021.983168-3-guoren@kernel.org Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-03-15Merge patch series "RISC-V: Apply Zicboz to clear_page"Palmer Dabbelt
Andrew Jones <ajones@ventanamicro.com> says: When the Zicboz extension is available we can more rapidly zero naturally aligned Zicboz block sized chunks of memory. As pages are always page aligned and are larger than any Zicboz block size will be, then clear_page() appears to be a good candidate for the extension. While cycle count and energy consumption should also be considered, we can be pretty certain that implementing clear_page() with the Zicboz extension is a win by comparing the new dynamic instruction count with its current count[1]. Doing so we see that the new count is just over a quarter of the old count (see patch6's commit message for more details). For those of you who reviewed v1[2], you may be looking for the memset() patches. As pointed out in v1, and a couple follow-up emails, it's not clear that patching memset() is a win yet. When I get a chance to test on real hardware with a comprehensive benchmark collection then I can post the memset() patches separately (assuming the benchmarks show it's worthwhile). * b4-shazam-merge: RISC-V: KVM: Expose Zicboz to the guest RISC-V: KVM: Provide UAPI for Zicboz block size RISC-V: Use Zicboz in clear_page when available RISC-V: cpufeatures: Put the upper 16 bits of patch ID to work RISC-V: Add Zicboz detection and block size parsing dt-bindings: riscv: Document cboz-block-size RISC-V: Factor out body of riscv_init_cbom_blocksize loop RISC-V: alternatives: Support patching multiple insns in assembly Link: https://lore.kernel.org/r/20230224162631.405473-1-ajones@ventanamicro.com Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-03-14RISC-V: KVM: Expose Zicboz to the guestAndrew Jones
Guests may use the cbo.zero instruction when the CPU has the Zicboz extension and the hypervisor sets henvcfg.CBZE. Add Zicboz support for KVM guests which may be enabled and disabled from KVM userspace using the ISA extension ONE_REG API. Signed-off-by: Andrew Jones <ajones@ventanamicro.com> Reviewed-by: Conor Dooley <conor.dooley@microchip.com> Reviewed-by: Anup Patel <anup@brainfault.org> Link: https://lore.kernel.org/r/20230224162631.405473-9-ajones@ventanamicro.com Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-03-14RISC-V: KVM: Provide UAPI for Zicboz block sizeAndrew Jones
We're about to allow guests to use the Zicboz extension. KVM userspace needs to know the cache block size in order to properly advertise it to the guest. Provide a virtual config register for userspace to get it with the GET_ONE_REG API, but setting it cannot be supported, so disallow SET_ONE_REG. Signed-off-by: Andrew Jones <ajones@ventanamicro.com> Reviewed-by: Conor Dooley <conor.dooley@microchip.com> Reviewed-by: Anup Patel <anup@brainfault.org> Link: https://lore.kernel.org/r/20230224162631.405473-8-ajones@ventanamicro.com Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-03-14RISC-V: Use Zicboz in clear_page when availableAndrew Jones
Using memset() to zero a 4K page takes 563 total instructions, where 20 are branches. clear_page(), with Zicboz and a 64 byte block size, takes 169 total instructions, where 4 are branches and 33 are nops. Even though the block size is a variable, thanks to alternatives, we can still implement a Duff device without having to do any preliminary calculations. This is achieved by using the alternatives' cpufeature value (the upper 16 bits of patch_id). The value used is the maximum zicboz block size order accepted at the patch site. This enables us to stop patching / unrolling when 4K bytes have been zeroed (we would loop and continue after 4K if the page size would be larger) For 4K pages, unrolling 16 times allows block sizes of 64 and 128 to only loop a few times and larger block sizes to not loop at all. Since cbo.zero doesn't take an offset, we also need an 'add' after each instruction, making the loop body 112 to 160 bytes. Hopefully this is small enough to not cause icache misses. Signed-off-by: Andrew Jones <ajones@ventanamicro.com> Acked-by: Conor Dooley <conor.dooley@microchip.com> Link: https://lore.kernel.org/r/20230224162631.405473-7-ajones@ventanamicro.com Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-03-14RISC-V: cpufeatures: Put the upper 16 bits of patch ID to workAndrew Jones
cpufeature IDs are consecutive integers starting at 26, so a 32-bit patch ID allows an aircraft carrier load of feature IDs. Repurposing the upper 16 bits still leaves a boat load of feature IDs and gains 16 bits which may be used to control patching on a per patch-site basis. This will be initially used in Zicboz's application to clear_page(), as Zicboz's block size must also be considered. In that case, the upper 16-bit value's role will be to convey the maximum block size which the Zicboz clear_page() implementation supports. cpufeature patch sites which need to check for the existence or absence of other cpufeatures may also be able to make use of this. Signed-off-by: Andrew Jones <ajones@ventanamicro.com> Reviewed-by: Conor Dooley <conor.dooley@microchip.com> Link: https://lore.kernel.org/r/20230224162631.405473-6-ajones@ventanamicro.com Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-03-14RISC-V: Add Zicboz detection and block size parsingAndrew Jones
Parse "riscv,cboz-block-size" from the DT by piggybacking on Zicbom's riscv_init_cbom_blocksize(). Additionally check the DT for the presence of the "zicboz" extension and, when it's present, validate the parsed cboz block size as we do Zicbom's cbom block size with riscv_isa_extension_check(). Signed-off-by: Andrew Jones <ajones@ventanamicro.com> Reviewed-by: Heiko Stuebner <heiko@sntech.de> Reviewed-by: Conor Dooley <conor.dooley@microchip.com> Link: https://lore.kernel.org/r/20230224162631.405473-5-ajones@ventanamicro.com Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-03-14RISC-V: Factor out body of riscv_init_cbom_blocksize loopAndrew Jones
Refactor riscv_init_cbom_blocksize() to prepare for it to be used for both cbom block size and cboz block size. Signed-off-by: Andrew Jones <ajones@ventanamicro.com> Reviewed-by: Heiko Stuebner <heiko@sntech.de> Reviewed-by: Conor Dooley <conor.dooley@microchip.com> Link: https://lore.kernel.org/r/20230224162631.405473-3-ajones@ventanamicro.com Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-03-14RISC-V: alternatives: Support patching multiple insns in assemblyAndrew Jones
As pointed out in commit d374a16539b1 ("RISC-V: fix compile error from deduplicated __ALTERNATIVE_CFG_2"), we need quotes around parameters passed to macros within macros to avoid spaces being interpreted as separators. ALT_NEW_CONTENT was trying to handle this by defining new_c has a vararg, but this isn't sufficient for calling ALTERNATIVE() from assembly with multiple instructions in the new/old sequences. Remove the vararg "hack" and use quotes. Signed-off-by: Andrew Jones <ajones@ventanamicro.com> Reviewed-by: Conor Dooley <conor.dooley@microchip.com> Link: https://lore.kernel.org/r/20230224162631.405473-2-ajones@ventanamicro.com Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-03-14Merge patch series "riscv: alternative/cpufeature related cleanups"Palmer Dabbelt
Andrew Jones <ajones@ventanamicro.com> says: This series has no intended functional change. These cleanups were found while renaming errata_id to patch_id in order to better convey that its purpose is larger than errata (it's also for cpufeatures). * b4-shazam-merge: riscv: cpufeature: Drop errata_list.h and other unused includes riscv: lib: Include hwcap.h directly riscv: alternatives: Rename errata_id to patch_id riscv: alternatives: Remove unnecessary define and unused struct riscv: Rename Kconfig.erratas to Kconfig.errata riscv: Clarify RISCV_ALTERNATIVE help text Link: https://lore.kernel.org/r/20230224154601.88163-1-ajones@ventanamicro.com Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-03-14riscv: cpufeature: Drop errata_list.h and other unused includesAndrew Jones
Drop errata_list.h, since cpufeature.c includes hwcap.h directly to get cpufeature IDs. And, while there, prune the rest of the unused includes too. Signed-off-by: Andrew Jones <ajones@ventanamicro.com> Reviewed-by: Conor Dooley <conor.dooley@microchip.com> Reviewed-by: Heiko Stuebner <heiko.stuebner@vrull.eu> Link: https://lore.kernel.org/r/20230224154601.88163-7-ajones@ventanamicro.com Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-03-14riscv: lib: Include hwcap.h directlyAndrew Jones
When using alternatives for cpufeatures we should include hwcap.h directly, rather than through errata_list.h. Opportunistically drop an unused include too. Signed-off-by: Andrew Jones <ajones@ventanamicro.com> Reviewed-by: Conor Dooley <conor.dooley@microchip.com> Reviewed-by: Heiko Stuebner <heiko.stuebner@vrull.eu> Link: https://lore.kernel.org/r/20230224154601.88163-6-ajones@ventanamicro.com Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-03-14riscv: alternatives: Rename errata_id to patch_idAndrew Jones
Alternatives are used for both errata and cpufeatures. Use a more generic name, 'patch_id', as in "ID of code patching site", to avoid confusion when alternatives are used for cpufeatures. Signed-off-by: Andrew Jones <ajones@ventanamicro.com> Reviewed-by: Conor Dooley <conor.dooley@microchip.com> Reviewed-by: Heiko Stuebner <heiko.stuebner@vrull.eu> Link: https://lore.kernel.org/r/20230224154601.88163-5-ajones@ventanamicro.com Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-03-14riscv: alternatives: Remove unnecessary define and unused structAndrew Jones
A define and a struct were introduced with commit 6f4eea90465a ("riscv: Introduce alternative mechanism to apply errata solution"), which introduced alternatives to RISC-V. The define is used for an arbitrary string length, specific to sifive errata, so just use the number directly there instead. The struct has never been used, so remove it. Signed-off-by: Andrew Jones <ajones@ventanamicro.com> Reviewed-by: Conor Dooley <conor.dooley@microchip.com> Reviewed-by: Heiko Stuebner <heiko.stuebner@vrull.eu> Link: https://lore.kernel.org/r/20230224154601.88163-4-ajones@ventanamicro.com Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-03-14riscv: Rename Kconfig.erratas to Kconfig.errataAndrew Jones
Errata is already plural for erratum. Rename it to make the grammar gooder. Signed-off-by: Andrew Jones <ajones@ventanamicro.com> Reviewed-by: Conor Dooley <conor.dooley@microchip.com> Reviewed-by: Heiko Stuebner <heiko.stuebner@vrull.eu> Link: https://lore.kernel.org/r/20230224154601.88163-3-ajones@ventanamicro.com Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-03-14riscv: Clarify RISCV_ALTERNATIVE help textAndrew Jones
Clarify RISCV_ALTERNATIVE's help text by pointing out that code patching is not only done at boot time, but also module load time. Also point out that this is the minimal possible overhead. Signed-off-by: Andrew Jones <ajones@ventanamicro.com> Link: https://lore.kernel.org/r/20230224154601.88163-2-ajones@ventanamicro.com Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-03-09Merge patch series "riscv, mm: detect svnapot cpu support at runtime"Palmer Dabbelt
Qinglin Pan <panqinglin00@gmail.com> says: Svnapot is a RISC-V extension for marking contiguous 4K pages as a non-4K page. This patch set is for using Svnapot in hugetlb fs and huge vmap. This patchset adds a Kconfig item for using Svnapot in "Platform type"->"SVNAPOT extension support". Its default value is on, and people can set it off if they don't allow kernel to detect Svnapot hardware support and leverage it. Tested on: - qemu rv64 with "Svnapot support" off and svnapot=true. - qemu rv64 with "Svnapot support" on and svnapot=true. - qemu rv64 with "Svnapot support" off and svnapot=false. - qemu rv64 with "Svnapot support" on and svnapot=false. * b4-shazam-merge: riscv: mm: support Svnapot in huge vmap riscv: mm: support Svnapot in hugetlb page riscv: mm: modify pte format for Svnapot Link: https://lore.kernel.org/r/20230209131647.17245-1-panqinglin00@gmail.com [Palmer: fix up the feature ordering in the merge] Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-03-07riscv: mm: support Svnapot in huge vmapQinglin Pan
As HAVE_ARCH_HUGE_VMAP and HAVE_ARCH_HUGE_VMALLOC is supported, we can implement arch_vmap_pte_range_map_size and arch_vmap_pte_supported_shift for Svnapot to support huge vmap about napot size. It can be tested by huge vmap used in pci driver. Huge vmalloc with svnapot can be tested by test_vmalloc with [1] applied, and probe this module to run fix_size_alloc_test with use_huge true. [1]https://lore.kernel.org/all/20221212055657.698420-1-panqinglin2020@iscas.ac.cn/ Signed-off-by: Qinglin Pan <panqinglin00@gmail.com> Reviewed-by: Andrew Jones <ajones@ventanamicro.com> Acked-by: Conor Dooley <conor.dooley@microchip.com> Link: https://lore.kernel.org/r/20230209131647.17245-4-panqinglin00@gmail.com Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-03-07riscv: mm: support Svnapot in hugetlb pageQinglin Pan
Svnapot can be used to support 64KB hugetlb page, so it can become a new option when using hugetlbfs. Add a basic implementation of hugetlb page, and support 64KB as a size in it by using Svnapot. For test, boot kernel with command line contains "default_hugepagesz=64K hugepagesz=64K hugepages=20" and run a simple test like this: tools/testing/selftests/vm/map_hugetlb 1 16 And it should be passed. Signed-off-by: Qinglin Pan <panqinglin00@gmail.com> Reviewed-by: Andrew Jones <ajones@ventanamicro.com> Link: https://lore.kernel.org/r/20230209131647.17245-3-panqinglin00@gmail.com Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-03-07riscv: mm: modify pte format for SvnapotQinglin Pan
Add one alternative to enable/disable svnapot support, enable this static key when "svnapot" is in the "riscv,isa" field of fdt and SVNAPOT compile option is set. It will influence the behavior of has_svnapot. All code dependent on svnapot should make sure that has_svnapot return true firstly. Modify PTE definition for Svnapot, and creates some functions in pgtable.h to mark a PTE as napot and check if it is a Svnapot PTE. Until now, only 64KB napot size is supported in spec, so some macros has only 64KB version. Signed-off-by: Qinglin Pan <panqinglin00@gmail.com> Reviewed-by: Andrew Jones <ajones@ventanamicro.com> Link: https://lore.kernel.org/r/20230209131647.17245-2-panqinglin00@gmail.com Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-03-05cpumask: re-introduce constant-sized cpumask optimizationsLinus Torvalds
Commit aa47a7c215e7 ("lib/cpumask: deprecate nr_cpumask_bits") resulted in the cpumask operations potentially becoming hugely less efficient, because suddenly the cpumask was always considered to be variable-sized. The optimization was then later added back in a limited form by commit 6f9c07be9d02 ("lib/cpumask: add FORCE_NR_CPUS config option"), but that FORCE_NR_CPUS option is not useful in a generic kernel and more of a special case for embedded situations with fixed hardware. Instead, just re-introduce the optimization, with some changes. Instead of depending on CPUMASK_OFFSTACK being false, and then always using the full constant cpumask width, this introduces three different cpumask "sizes": - the exact size (nr_cpumask_bits) remains identical to nr_cpu_ids. This is used for situations where we should use the exact size. - the "small" size (small_cpumask_bits) is the NR_CPUS constant if it fits in a single word and the bitmap operations thus end up able to trigger the "small_const_nbits()" optimizations. This is used for the operations that have optimized single-word cases that get inlined, notably the bit find and scanning functions. - the "large" size (large_cpumask_bits) is the NR_CPUS constant if it is an sufficiently small constant that makes simple "copy" and "clear" operations more efficient. This is arbitrarily set at four words or less. As a an example of this situation, without this fixed size optimization, cpumask_clear() will generate code like movl nr_cpu_ids(%rip), %edx addq $63, %rdx shrq $3, %rdx andl $-8, %edx callq memset@PLT on x86-64, because it would calculate the "exact" number of longwords that need to be cleared. In contrast, with this patch, using a MAX_CPU of 64 (which is quite a reasonable value to use), the above becomes a single movq $0,cpumask instruction instead, because instead of caring to figure out exactly how many CPU's the system has, it just knows that the cpumask will be a single word and can just clear it all. Note that this does end up tightening the rules a bit from the original version in another way: operations that set bits in the cpumask are now limited to the actual nr_cpu_ids limit, whereas we used to do the nr_cpumask_bits thing almost everywhere in the cpumask code. But if you just clear bits, or scan for bits, we can use the simpler compile-time constants. In the process, remove 'cpumask_complement()' and 'for_each_cpu_not()' which were not useful, and which fundamentally have to be limited to 'nr_cpu_ids'. Better remove them now than have somebody introduce use of them later. Of course, on x86-64 with MAXSMP there is no sane small compile-time constant for the cpumask sizes, and we end up using the actual CPU bits, and will generate the above kind of horrors regardless. Please don't use MAXSMP unless you really expect to have machines with thousands of cores. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2023-03-05Merge tag 'x86-urgent-2023-03-05' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 updates from Thomas Gleixner: "A small set of updates for x86: - Return -EIO instead of success when the certificate buffer for SEV guests is not large enough - Allow STIPB to be enabled with legacy IBSR. Legacy IBRS is cleared on return to userspace for performance reasons, but the leaves user space vulnerable to cross-thread attacks which STIBP prevents. Update the documentation accordingly" * tag 'x86-urgent-2023-03-05' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: virt/sev-guest: Return -EIO if certificate buffer is not large enough Documentation/hw-vuln: Document the interaction between IBRS and STIBP x86/speculation: Allow enabling STIBP with legacy IBRS
2023-03-05Merge tag 'pull-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfsLinus Torvalds
Pull VM_FAULT_RETRY fixes from Al Viro: "Some of the page fault handlers do not deal with the following case correctly: - handle_mm_fault() has returned VM_FAULT_RETRY - there is a pending fatal signal - fault had happened in kernel mode Correct action in such case is not "return unconditionally" - fatal signals are handled only upon return to userland and something like copy_to_user() would end up retrying the faulting instruction and triggering the same fault again and again. What we need to do in such case is to make the caller to treat that as failed uaccess attempt - handle exception if there is an exception handler for faulting instruction or oops if there isn't one. Over the years some architectures had been fixed and now are handling that case properly; some still do not. This series should fix the remaining ones. Status: - m68k, riscv, hexagon, parisc: tested/acked by maintainers. - alpha, sparc32, sparc64: tested locally - bug has been reproduced on the unpatched kernel and verified to be fixed by this series. - ia64, microblaze, nios2, openrisc: build, but otherwise completely untested" * tag 'pull-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: openrisc: fix livelock in uaccess nios2: fix livelock in uaccess microblaze: fix livelock in uaccess ia64: fix livelock in uaccess sparc: fix livelock in uaccess alpha: fix livelock in uaccess parisc: fix livelock in uaccess hexagon: fix livelock in uaccess riscv: fix livelock in uaccess m68k: fix livelock in uaccess
2023-03-05Remove Intel compiler supportMasahiro Yamada
include/linux/compiler-intel.h had no update in the past 3 years. We often forget about the third C compiler to build the kernel. For example, commit a0a12c3ed057 ("asm goto: eradicate CC_HAS_ASM_GOTO") only mentioned GCC and Clang. init/Kconfig defines CC_IS_GCC and CC_IS_CLANG but not CC_IS_ICC, and nobody has reported any issue. I guess the Intel Compiler support is broken, and nobody is caring about it. Harald Arnesen pointed out ICC (classic Intel C/C++ compiler) is deprecated: $ icc -v icc: remark #10441: The Intel(R) C++ Compiler Classic (ICC) is deprecated and will be removed from product release in the second half of 2023. The Intel(R) oneAPI DPC++/C++ Compiler (ICX) is the recommended compiler moving forward. Please transition to use this compiler. Use '-diag-disable=10441' to disable this message. icc version 2021.7.0 (gcc version 12.1.0 compatibility) Arnd Bergmann provided a link to the article, "Intel C/C++ compilers complete adoption of LLVM". lib/zstd/common/compiler.h and lib/zstd/compress/zstd_fast.c were kept untouched for better sync with https://github.com/facebook/zstd Link: https://www.intel.com/content/www/us/en/developer/articles/technical/adoption-of-llvm-complete-icx.html Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Acked-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Nathan Chancellor <nathan@kernel.org> Reviewed-by: Miguel Ojeda <ojeda@kernel.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2023-03-04Merge tag 'mm-hotfixes-stable-2023-03-04-13-12' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Pull misc fixes from Andrew Morton: "17 hotfixes. Eight are for MM and seven are for other parts of the kernel. Seven are cc:stable and eight address post-6.3 issues or were judged unsuitable for -stable backporting" * tag 'mm-hotfixes-stable-2023-03-04-13-12' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: mailmap: map Dikshita Agarwal's old address to his current one mailmap: map Vikash Garodia's old address to his current one fs/cramfs/inode.c: initialize file_ra_state fs: hfsplus: fix UAF issue in hfsplus_put_super panic: fix the panic_print NMI backtrace setting lib: parser: update documentation for match_NUMBER functions kasan, x86: don't rename memintrinsics in uninstrumented files kasan: test: fix test for new meminstrinsic instrumentation kasan: treat meminstrinsic as builtins in uninstrumented files kasan: emit different calls for instrumentable memintrinsics ocfs2: fix non-auto defrag path not working issue ocfs2: fix defrag path triggering jbd2 ASSERT mailmap: map Georgi Djakov's old Linaro address to his current one mm/hwpoison: convert TTU_IGNORE_HWPOISON to TTU_HWPOISON lib/zlib: DFLTCC deflate does not write all available bits for Z_NO_FLUSH mm/damon/paddr: fix missing folio_put() mm/mremap: fix dup_anon_vma() in vma_merge() case 4
2023-03-04Merge tag 'powerpc-6.3-2' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux Pull powerpc fixes from Michael Ellerman: - Drop orphaned VAS MAINTAINERS entry - Fix build errors with clang and KCSAN - Avoid build errors seen with LD_DEAD_CODE_DATA_ELIMINATION together with recordmcount Thanks to Nathan Chancellor. * tag 'powerpc-6.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: powerpc: Avoid dead code/data elimination when using recordmcount powerpc/vmlinux.lds: Add .text.asan/tsan sections powerpc: Drop orphaned VAS MAINTAINERS entry
2023-03-03Merge tag 's390-6.3-2' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux Pull more s390 updates from Heiko Carstens: - Add empty command line parameter handling stubs to kernel for all command line parameters which are handled in the decompressor. This avoids invalid "Unknown kernel command line parameters" messages from the kernel, and also avoids that these will be incorrectly passed to user space. This caused already confusion, therefore add the empty stubs - Add missing phys_to_virt() handling to machine check handler - Introduce and use a union to be used for zcrypt inline assemblies. This makes sure that only a register wide member of the union is passed as input and output parameter to inline assemblies, while usual C code uses other members of the union to access bit fields of it - Add and use a READ_ONCE_ALIGNED_128() macro, which can be used to atomically read a 128-bit value from memory. This replaces the (mis-)use of the 128-bit cmpxchg operation to do the same in cpum_sf code. Currently gcc does not generate the used lpq instruction if __READ_ONCE() is used for aligned 128-bit accesses, therefore use this s390 specific helper - Simplify machine check handler code if a task needs to be killed because of e.g. register corruption due to a machine malfunction - Perform CPU reset to clear pending interrupts and TLB entries on an already stopped target CPU before delegating work to it - Generate arch/s390/boot/vmlinux.map link map for the decompressor, when CONFIG_VMLINUX_MAP is enabled for debugging purposes - Fix segment type handling for dcssblk devices. It incorrectly always returned type "READ/WRITE" even for read-only segements, which can result in a kernel panic if somebody tries to write to a read-only device - Sort config S390 select list again - Fix two kprobe reenter bugs revealed by a recently added kprobe kunit test * tag 's390-6.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: s390/kprobes: fix current_kprobe never cleared after kprobes reenter s390/kprobes: fix irq mask clobbering on kprobe reenter from post_handler s390/Kconfig: sort config S390 select list again s390/extmem: return correct segment type in __segment_load() s390/decompressor: add link map saving s390/smp: perform cpu reset before delegating work to target cpu s390/mcck: cleanup user process termination path s390/cpum_sf: use READ_ONCE_ALIGNED_128() instead of 128-bit cmpxchg s390/rwonce: add READ_ONCE_ALIGNED_128() macro s390/ap,zcrypt,vfio: introduce and use ap_queue_status_reg union s390/nmi: fix virtual-physical address confusion s390/setup: do not complain about parameters handled in decompressor
2023-03-03Merge tag 'riscv-for-linus-6.3-mw2' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux Pull more RISC-V updates from Palmer Dabbelt: - Some cleanups and fixes for the Zbb-optimized string routines - Support for custom (vendor or implementation defined) perf events - COMMAND_LINE_SIZE has been increased to 1024 * tag 'riscv-for-linus-6.3-mw2' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux: riscv: Bump COMMAND_LINE_SIZE value to 1024 drivers/perf: RISC-V: Allow programming custom firmware events riscv, lib: Fix Zbb strncmp RISC-V: improve string-function assembly
2023-03-02kasan, x86: don't rename memintrinsics in uninstrumented filesMarco Elver
Now that memcpy/memset/memmove are no longer overridden by KASAN, we can just use the normal symbol names in uninstrumented files. Drop the preprocessor redefinitions. Link: https://lkml.kernel.org/r/20230224085942.1791837-4-elver@google.com Fixes: 69d4c0d32186 ("entry, kasan, x86: Disallow overriding mem*() functions") Signed-off-by: Marco Elver <elver@google.com> Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com> Cc: Alexander Potapenko <glider@google.com> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Cc: Borislav Petkov (AMD) <bp@alien8.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jakub Jelinek <jakub@redhat.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linux Kernel Functional Testing <lkft@linaro.org> Cc: Naresh Kamboju <naresh.kamboju@linaro.org> Cc: Nathan Chancellor <nathan@kernel.org> Cc: Nick Desaulniers <ndesaulniers@google.com> Cc: Nicolas Schier <nicolas@fjasle.eu> Cc: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vincenzo Frascino <vincenzo.frascino@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-03-02Merge tag 'arm64-fixes' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux Pull arm64 fixes from Catalin Marinas: - In copy_highpage(), only reset the tag of the destination pointer if KASAN_HW_TAGS is enabled so that user-space MTE does not interfere with KASAN_SW_TAGS (which relies on top-byte-ignore). - Remove warning if SME is detected without SVE, the kernel can cope with such configuration (though none in the field currently). - In cfi_handler(), pass the ESR_EL1 value to die() for consistency with other die() callers. - Disable HUGETLB_PAGE_OPTIMIZE_VMEMMAP on arm64 since the pte manipulation from the generic vmemmap_remap_pte() does not follow the required ARM break-before-make sequence (clear the pte, flush the TLBs, set the new pte). It may be re-enabled once this sequence is sorted. - Fix possible memory leak in the arm64 ACPI code if the SMCCC version and conduit checks fail. - Forbid CALL_OPS with CC_OPTIMIZE_FOR_SIZE since gcc ignores -falign-functions=N with -Os. - Don't pretend KASLR is enabled if offset < MIN_KIMG_ALIGN as no randomisation would actually take place. * tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: arm64: kaslr: don't pretend KASLR is enabled if offset < MIN_KIMG_ALIGN arm64: ftrace: forbid CALL_OPS with CC_OPTIMIZE_FOR_SIZE arm64: acpi: Fix possible memory leak of ffh_ctxt arm64: mm: hugetlb: Disable HUGETLB_PAGE_OPTIMIZE_VMEMMAP arm64: pass ESR_ELx to die() of cfi_handler arm64/fpsimd: Remove warning for SME without SVE arm64: Reset KASAN tag in copy_highpage with HW tags only
2023-03-02Merge tag 'mips_6.3_1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/mips/linux Pull more MIPS updates from Thomas Bogendoerfer: "A few more cleanups and fixes" * tag 'mips_6.3_1' of git://git.kernel.org/pub/scm/linux/kernel/git/mips/linux: MIPS: Workaround clang inline compat branch issue mips: dts: ralink: mt7621: add phandle to system controller node for watchdog mips: dts: ralink: mt7621: rename watchdog node from 'wdt' into 'watchdog' mips: ralink: make SOC_MT7621 select PINCTRL mips: remove SYS_HAS_CPU_MIPS32_R1 from RALINK MIPS: cevt-r4k: Offset the value used to clear compare interrupt MIPS: smp-cps: Don't rely on CP0_CMGCRBASE MIPS: Remove DMA_PERDEV_COHERENT
2023-03-02Merge tag 'objtool-core-2023-03-02' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull objtool updates from Ingo Molnar: - Shrink 'struct instruction', to improve objtool performance & memory footprint - Other maximum memory usage reductions - this makes the build both faster, and fixes kernel build OOM failures on allyesconfig and similar configs when they try to build the final (large) vmlinux.o - Fix ORC unwinding when a kprobe (INT3) is set on a stack-modifying single-byte instruction (PUSH/POP or LEAVE). This requires the extension of the ORC metadata structure with a 'signal' field - Misc fixes & cleanups * tag 'objtool-core-2023-03-02' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (22 commits) objtool: Fix ORC 'signal' propagation objtool: Remove instruction::list x86: Fix FILL_RETURN_BUFFER objtool: Fix overlapping alternatives objtool: Union instruction::{call_dest,jump_table} objtool: Remove instruction::reloc objtool: Shrink instruction::{type,visited} objtool: Make instruction::alts a single-linked list objtool: Make instruction::stack_ops a single-linked list objtool: Change arch_decode_instruction() signature x86/entry: Fix unwinding from kprobe on PUSH/POP instruction x86/unwind/orc: Add 'signal' field to ORC metadata objtool: Optimize layout of struct special_alt objtool: Optimize layout of struct symbol objtool: Allocate multiple structures with calloc() objtool: Make struct check_options static objtool: Make struct entries[] static and const objtool: Fix HOSTCC flag usage objtool: Properly support make V=1 objtool: Install libsubcmd in build ...
2023-03-02openrisc: fix livelock in uaccessAl Viro
openrisc equivalent of 26178ec11ef3 "x86: mm: consolidate VM_FAULT_RETRY handling" If e.g. get_user() triggers a page fault and a fatal signal is caught, we might end up with handle_mm_fault() returning VM_FAULT_RETRY and not doing anything to page tables. In such case we must *not* return to the faulting insn - that would repeat the entire thing without making any progress; what we need instead is to treat that as failed (user) memory access. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2023-03-02nios2: fix livelock in uaccessAl Viro
nios2 equivalent of 26178ec11ef3 "x86: mm: consolidate VM_FAULT_RETRY handling" If e.g. get_user() triggers a page fault and a fatal signal is caught, we might end up with handle_mm_fault() returning VM_FAULT_RETRY and not doing anything to page tables. In such case we must *not* return to the faulting insn - that would repeat the entire thing without making any progress; what we need instead is to treat that as failed (user) memory access. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2023-03-02microblaze: fix livelock in uaccessAl Viro
microblaze equivalent of 26178ec11ef3 "x86: mm: consolidate VM_FAULT_RETRY handling" If e.g. get_user() triggers a page fault and a fatal signal is caught, we might end up with handle_mm_fault() returning VM_FAULT_RETRY and not doing anything to page tables. In such case we must *not* return to the faulting insn - that would repeat the entire thing without making any progress; what we need instead is to treat that as failed (user) memory access. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2023-03-02ia64: fix livelock in uaccessAl Viro
ia64 equivalent of 26178ec11ef3 "x86: mm: consolidate VM_FAULT_RETRY handling" If e.g. get_user() triggers a page fault and a fatal signal is caught, we might end up with handle_mm_fault() returning VM_FAULT_RETRY and not doing anything to page tables. In such case we must *not* return to the faulting insn - that would repeat the entire thing without making any progress; what we need instead is to treat that as failed (user) memory access. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2023-03-02sparc: fix livelock in uaccessAl Viro
sparc equivalent of 26178ec11ef3 "x86: mm: consolidate VM_FAULT_RETRY handling" If e.g. get_user() triggers a page fault and a fatal signal is caught, we might end up with handle_mm_fault() returning VM_FAULT_RETRY and not doing anything to page tables. In such case we must *not* return to the faulting insn - that would repeat the entire thing without making any progress; what we need instead is to treat that as failed (user) memory access. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2023-03-02alpha: fix livelock in uaccessAl Viro
alpha equivalent of 26178ec11ef3 "x86: mm: consolidate VM_FAULT_RETRY handling" If e.g. get_user() triggers a page fault and a fatal signal is caught, we might end up with handle_mm_fault() returning VM_FAULT_RETRY and not doing anything to page tables. In such case we must *not* return to the faulting insn - that would repeat the entire thing without making any progress; what we need instead is to treat that as failed (user) memory access. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2023-03-02parisc: fix livelock in uaccessAl Viro
parisc equivalent of 26178ec11ef3 "x86: mm: consolidate VM_FAULT_RETRY handling" If e.g. get_user() triggers a page fault and a fatal signal is caught, we might end up with handle_mm_fault() returning VM_FAULT_RETRY and not doing anything to page tables. In such case we must *not* return to the faulting insn - that would repeat the entire thing without making any progress; what we need instead is to treat that as failed (user) memory access. Tested-by: Helge Deller <deller@gmx.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2023-03-02hexagon: fix livelock in uaccessAl Viro
hexagon equivalent of 26178ec11ef3 "x86: mm: consolidate VM_FAULT_RETRY handling" If e.g. get_user() triggers a page fault and a fatal signal is caught, we might end up with handle_mm_fault() returning VM_FAULT_RETRY and not doing anything to page tables. In such case we must *not* return to the faulting insn - that would repeat the entire thing without making any progress; what we need instead is to treat that as failed (user) memory access. Acked-by: Brian Cain <bcain@quicinc.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2023-03-02riscv: fix livelock in uaccessAl Viro
riscv equivalent of 26178ec11ef3 "x86: mm: consolidate VM_FAULT_RETRY handling" If e.g. get_user() triggers a page fault and a fatal signal is caught, we might end up with handle_mm_fault() returning VM_FAULT_RETRY and not doing anything to page tables. In such case we must *not* return to the faulting insn - that would repeat the entire thing without making any progress; what we need instead is to treat that as failed (user) memory access. Tested-by: Björn Töpel <bjorn@kernel.org> Tested-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2023-03-02m68k: fix livelock in uaccessAl Viro
m68k equivalent of 26178ec11ef3 "x86: mm: consolidate VM_FAULT_RETRY handling" If e.g. get_user() triggers a page fault and a fatal signal is caught, we might end up with handle_mm_fault() returning VM_FAULT_RETRY and not doing anything to page tables. In such case we must *not* return to the faulting insn - that would repeat the entire thing without making any progress; what we need instead is to treat that as failed (user) memory access. Tested-by: Finn Thain <fthain@linux-m68k.org> Tested-by: Geert Uytterhoeven <geert@linux-m68k.org> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2023-03-02s390/kprobes: fix current_kprobe never cleared after kprobes reenterVasily Gorbik
Recent test_kprobe_missed kprobes kunit test uncovers the following problem. Once kprobe is triggered from another kprobe (kprobe reenter), all future kprobes on this cpu are considered as kprobe reenter, thus pre_handler and post_handler are not being called and kprobes are counted as "missed". Commit b9599798f953 ("[S390] kprobes: activation and deactivation") introduced a simpler scheme for kprobes (de)activation and status tracking by using push_kprobe/pop_kprobe, which supposed to work for both initial kprobe entry as well as kprobe reentry and helps to avoid handling those two cases differently. The problem is that a sequence of calls in case of kprobes reenter: push_kprobe() <- NULL (current_kprobe) push_kprobe() <- kprobe1 (current_kprobe) pop_kprobe() -> kprobe1 (current_kprobe) pop_kprobe() -> kprobe1 (current_kprobe) leaves "kprobe1" as "current_kprobe" on this cpu, instead of setting it to NULL. In fact push_kprobe/pop_kprobe can only store a single state (there is just one prev_kprobe in kprobe_ctlblk). Which is a hack but sufficient, there is no need to have another prev_kprobe just to store NULL. To make a simple and backportable fix simply reset "prev_kprobe" when kprobe is poped from this "stack". No need to worry about "kprobe_status" in this case, because its value is only checked when current_kprobe != NULL. Cc: stable@vger.kernel.org Fixes: b9599798f953 ("[S390] kprobes: activation and deactivation") Reviewed-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2023-03-02s390/kprobes: fix irq mask clobbering on kprobe reenter from post_handlerVasily Gorbik
Recent test_kprobe_missed kprobes kunit test uncovers the following error (reported when CONFIG_DEBUG_ATOMIC_SLEEP is enabled): BUG: sleeping function called from invalid context at kernel/locking/mutex.c:580 in_atomic(): 0, irqs_disabled(): 1, non_block: 0, pid: 662, name: kunit_try_catch preempt_count: 0, expected: 0 RCU nest depth: 0, expected: 0 no locks held by kunit_try_catch/662. irq event stamp: 280 hardirqs last enabled at (279): [<00000003e60a3d42>] __do_pgm_check+0x17a/0x1c0 hardirqs last disabled at (280): [<00000003e3bd774a>] kprobe_exceptions_notify+0x27a/0x318 softirqs last enabled at (0): [<00000003e3c5c890>] copy_process+0x14a8/0x4c80 softirqs last disabled at (0): [<0000000000000000>] 0x0 CPU: 46 PID: 662 Comm: kunit_try_catch Tainted: G N 6.2.0-173644-g44c18d77f0c0 #2 Hardware name: IBM 3931 A01 704 (LPAR) Call Trace: [<00000003e60a3a00>] dump_stack_lvl+0x120/0x198 [<00000003e3d02e82>] __might_resched+0x60a/0x668 [<00000003e60b9908>] __mutex_lock+0xc0/0x14e0 [<00000003e60bad5a>] mutex_lock_nested+0x32/0x40 [<00000003e3f7b460>] unregister_kprobe+0x30/0xd8 [<00000003e51b2602>] test_kprobe_missed+0xf2/0x268 [<00000003e51b5406>] kunit_try_run_case+0x10e/0x290 [<00000003e51b7dfa>] kunit_generic_run_threadfn_adapter+0x62/0xb8 [<00000003e3ce30f8>] kthread+0x2d0/0x398 [<00000003e3b96afa>] __ret_from_fork+0x8a/0xe8 [<00000003e60ccada>] ret_from_fork+0xa/0x40 The reason for this error report is that kprobes handling code failed to restore irqs. The problem is that when kprobe is triggered from another kprobe post_handler current sequence of enable_singlestep / disable_singlestep is the following: enable_singlestep <- original kprobe (saves kprobe_saved_imask) enable_singlestep <- kprobe triggered from post_handler (clobbers kprobe_saved_imask) disable_singlestep <- kprobe triggered from post_handler (restores kprobe_saved_imask) disable_singlestep <- original kprobe (restores wrong clobbered kprobe_saved_imask) There is just one kprobe_ctlblk per cpu and both calls saves and loads irq mask to kprobe_saved_imask. To fix the problem simply move resume_execution (which calls disable_singlestep) before calling post_handler. This also fixes the problem that post_handler is called with pt_regs which were not yet adjusted after single-stepping. Cc: stable@vger.kernel.org Fixes: 4ba069b802c2 ("[S390] add kprobes support.") Reviewed-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>