kernel.git/arch/arm64/include/asm, branch linux-6.7.y

arm64/sve: Lower the maximum allocation for the SVE ptrace regset

2024-03-26T22:17:51Z

[ Upstream commit 2813926261e436d33bc74486b51cce60b76edf78 ] Doug Anderson observed that ChromeOS crashes are being reported which include failing allocations of order 7 during core dumps due to ptrace allocating storage for regsets: chrome: page allocation failure: order:7, mode:0x40dc0(GFP_KERNEL|__GFP_COMP|__GFP_ZERO), nodemask=(null),cpuset=urgent,mems_allowed=0 ... regset_get_alloc+0x1c/0x28 elf_core_dump+0x3d8/0xd8c do_coredump+0xeb8/0x1378 with further investigation showing that this is: [ 66.957385] DOUG: Allocating 279584 bytes which is the maximum size of the SVE regset. As Doug observes it is not entirely surprising that such a large allocation of contiguous memory might fail on a long running system. The SVE regset is currently sized to hold SVE registers with a VQ of SVE_VQ_MAX which is 512, substantially more than the architectural maximum of 16 which we might see even in a system emulating the limits of the architecture. Since we don't expose the size we tell the regset core externally let's define ARCH_SVE_VQ_MAX with the actual architectural maximum and use that for the regset, we'll still overallocate most of the time but much less so which will be helpful even if the core is fixed to not require contiguous allocations. Specify ARCH_SVE_VQ_MAX in terms of the maximum value that can be written into ZCR_ELx.LEN (where this is set in the hardware). For consistency update the maximum SME vector length to be specified in the same style while we are at it. We could also teach the ptrace core about runtime discoverable regset sizes but that would be a more invasive change and this is being observed in practical systems. Reported-by: Doug Anderson Signed-off-by: Mark Brown Tested-by: Douglas Anderson Link: https://lore.kernel.org/r/20240213-arm64-sve-ptrace-regset-size-v2-1-c7600ca74b9b@kernel.org Signed-off-by: Will Deacon Signed-off-by: Sasha Levin

arm64/sme: Restore SME registers on exit from suspend

2024-03-01T12:41:56Z

[ Upstream commit 9533864816fb4a6207c63b7a98396351ce1a9fae ] The fields in SMCR_EL1 and SMPRI_EL1 reset to an architecturally UNKNOWN value. Since we do not otherwise manage the traps configured in this register at runtime we need to reconfigure them after a suspend in case nothing else was kind enough to preserve them for us. The vector length will be restored as part of restoring the SME state for the next SME using task. Fixes: a1f4ccd25cc2 ("arm64/sme: Provide Kconfig for SME") Reported-by: Jackson Cooper-Driver Signed-off-by: Mark Brown Link: https://lore.kernel.org/r/20240213-arm64-sme-resume-v3-1-17e05e493471@kernel.org Signed-off-by: Will Deacon Signed-off-by: Sasha Levin

arm64: Subscribe Microsoft Azure Cobalt 100 to ARM Neoverse N2 errata

2024-02-23T08:51:53Z

commit fb091ff394792c018527b3211bbdfae93ea4ac02 upstream. Add the MIDR value of Microsoft Azure Cobalt 100, which is a Microsoft implemented CPU based on r0p0 of the ARM Neoverse N2 CPU, and therefore suffers from all the same errata. CC: stable@vger.kernel.org # 5.15+ Signed-off-by: Easwar Hariharan Reviewed-by: Anshuman Khandual Acked-by: Mark Rutland Acked-by: Marc Zyngier Reviewed-by: Oliver Upton Link: https://lore.kernel.org/r/20240214175522.2457857-1-eahariha@linux.microsoft.com Signed-off-by: Will Deacon Signed-off-by: Greg Kroah-Hartman

work around gcc bugs with 'asm goto' with outputs

2024-02-23T08:51:20Z

commit 4356e9f841f7fbb945521cef3577ba394c65f3fc upstream. We've had issues with gcc and 'asm goto' before, and we created a 'asm_volatile_goto()' macro for that in the past: see commits 3f0116c3238a ("compiler/gcc4: Add quirk for 'asm goto' miscompilation bug") and a9f180345f53 ("compiler/gcc4: Make quirk for asm_volatile_goto() unconditional"). Then, much later, we ended up removing the workaround in commit 43c249ea0b1e ("compiler-gcc.h: remove ancient workaround for gcc PR 58670") because we no longer supported building the kernel with the affected gcc versions, but we left the macro uses around. Now, Sean Christopherson reports a new version of a very similar problem, which is fixed by re-applying that ancient workaround. But the problem in question is limited to only the 'asm goto with outputs' cases, so instead of re-introducing the old workaround as-is, let's rename and limit the workaround to just that much less common case. It looks like there are at least two separate issues that all hit in this area: (a) some versions of gcc don't mark the asm goto as 'volatile' when it has outputs: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98619 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110420 which is easy to work around by just adding the 'volatile' by hand. (b) Internal compiler errors: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110422 which are worked around by adding the extra empty 'asm' as a barrier, as in the original workaround. but the problem Sean sees may be a third thing since it involves bad code generation (not an ICE) even with the manually added 'volatile'. but the same old workaround works for this case, even if this feels a bit like voodoo programming and may only be hiding the issue. Reported-and-tested-by: Sean Christopherson Link: https://lore.kernel.org/all/20240208220604.140859-1-seanjc@google.com/ Cc: Nick Desaulniers Cc: Uros Bizjak Cc: Jakub Jelinek Cc: Andrew Pinski Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

arch: consolidate arch_irq_work_raise prototypes

2024-02-05T20:16:47Z

[ Upstream commit 64bac5ea17d527872121adddfee869c7a0618f8f ] The prototype was hidden in an #ifdef on x86, which causes a warning: kernel/irq_work.c:72:13: error: no previous prototype for 'arch_irq_work_raise' [-Werror=missing-prototypes] Some architectures have a working prototype, while others don't. Fix this by providing it in only one place that is always visible. Reviewed-by: Alexander Gordeev Acked-by: Catalin Marinas Acked-by: Palmer Dabbelt Acked-by: Guo Ren Signed-off-by: Arnd Bergmann Signed-off-by: Sasha Levin

posix-timers: Get rid of [COMPAT_]SYS_NI() uses

2023-12-21T05:30:27Z

Only the posix timer system calls use this (when the posix timer support is disabled, which does not actually happen in any normal case), because they had debug code to print out a warning about missing system calls. Get rid of that special case, and just use the standard COND_SYSCALL interface that creates weak system call stubs that return -ENOSYS for when the system call does not exist. This fixes a kCFI issue with the SYS_NI() hackery: CFI failure at int80_emulation+0x67/0xb0 (target: sys_ni_posix_timers+0x0/0x70; expected type: 0xb02b34d9) WARNING: CPU: 0 PID: 48 at int80_emulation+0x67/0xb0 Reported-by: kernel test robot Reviewed-by: Sami Tolvanen Tested-by: Sami Tolvanen Cc: Thomas Gleixner Cc: Dave Hansen Cc: Borislav Petkov Signed-off-by: Linus Torvalds

arm64: mm: Always make sw-dirty PTEs hw-dirty in pte_modify

2023-12-12T16:25:26Z

It is currently possible for a userspace application to enter an infinite page fault loop when using HugeTLB pages implemented with contiguous PTEs when HAFDBS is not available. This happens because: 1. The kernel may sometimes write PTEs that are sw-dirty but hw-clean (PTE_DIRTY | PTE_RDONLY | PTE_WRITE). 2. If, during a write, the CPU uses a sw-dirty, hw-clean PTE in handling the memory access on a system without HAFDBS, we will get a page fault. 3. HugeTLB will check if it needs to update the dirty bits on the PTE. For contiguous PTEs, it will check to see if the pgprot bits need updating. In this case, HugeTLB wants to write a sequence of sw-dirty, hw-dirty PTEs, but it finds that all the PTEs it is about to overwrite are all pte_dirty() (pte_sw_dirty() => pte_dirty()), so it thinks no update is necessary. We can get the kernel to write a sw-dirty, hw-clean PTE with the following steps (showing the relevant VMA flags and pgprot bits): i. Create a valid, writable contiguous PTE. VMA vmflags: VM_SHARED | VM_READ | VM_WRITE VMA pgprot bits: PTE_RDONLY | PTE_WRITE PTE pgprot bits: PTE_DIRTY | PTE_WRITE ii. mprotect the VMA to PROT_NONE. VMA vmflags: VM_SHARED VMA pgprot bits: PTE_RDONLY PTE pgprot bits: PTE_DIRTY | PTE_RDONLY iii. mprotect the VMA back to PROT_READ | PROT_WRITE. VMA vmflags: VM_SHARED | VM_READ | VM_WRITE VMA pgprot bits: PTE_RDONLY | PTE_WRITE PTE pgprot bits: PTE_DIRTY | PTE_WRITE | PTE_RDONLY Make it impossible to create a writeable sw-dirty, hw-clean PTE with pte_modify(). Such a PTE should be impossible to create, and there may be places that assume that pte_dirty() implies pte_hw_dirty(). Signed-off-by: James Houghton Fixes: 031e6e6b4e12 ("arm64: hugetlb: Avoid unnecessary clearing in huge_ptep_set_access_flags") Cc: Acked-by: Will Deacon Reviewed-by: Ryan Roberts Link: https://lore.kernel.org/r/20231204172646.2541916-3-jthoughton@google.com Signed-off-by: Catalin Marinas

arm64: mm: Fix "rodata=on" when CONFIG_RODATA_FULL_DEFAULT_ENABLED=y

2023-11-22T18:46:05Z

When CONFIG_RODATA_FULL_DEFAULT_ENABLED=y, passing "rodata=on" on the kernel command-line (rather than "rodata=full") should turn off the "full" behaviour, leaving writable linear aliases of read-only kernel memory. Unfortunately, the option has no effect in this situation and the only way to disable the "rodata=full" behaviour is to disable rodata protection entirely by passing "rodata=off". Fix this by parsing the "on" and "off" options in the arch code, additionally enforcing that 'rodata_full' cannot be set without also setting 'rodata_enabled', allowing us to simplify a couple of checks in the process. Fixes: 2e8cff0a0eee ("arm64: fix rodata=full") Cc: Ard Biesheuvel Cc: Mark Rutland Signed-off-by: Will Deacon Reviewed-by: "Russell King (Oracle)" Reviewed-by: Ard Biesheuvel Link: https://lore.kernel.org/r/20231117131422.29663-1-will@kernel.org Signed-off-by: Catalin Marinas

Merge tag 'probes-fixes-v6.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

2023-11-11T00:35:04Z

Pull probes fixes from Masami Hiramatsu: - Documentation update: Add a note about argument and return value fetching is the best effort because it depends on the type. - objpool: Fix to make internal global variables static in test_objpool.c. - kprobes: Unify kprobes_exceptions_nofify() prototypes. There are the same prototypes in asm/kprobes.h for some architectures, but some of them are missing the prototype and it causes a warning. So move the prototype into linux/kprobes.h. - tracing: Fix to check the tracepoint event and return event at parsing stage. The tracepoint event doesn't support %return but if $retval exists, it will be converted to %return silently. This finds that case and rejects it. - tracing: Fix the order of the descriptions about the parameters of __kprobe_event_gen_cmd_start() to be consistent with the argument list of the function. * tag 'probes-fixes-v6.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: tracing/kprobes: Fix the order of argument descriptions tracing: fprobe-event: Fix to check tracepoint event and return kprobes: unify kprobes_exceptions_nofify() prototypes lib: test_objpool: make global variables static Documentation: tracing: Add a note about argument and retval access

Merge tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux

2023-11-10T20:22:14Z

Pull arm64 fixes from Catalin Marinas: "Mostly PMU fixes and a reworking of the pseudo-NMI disabling on broken MediaTek firmware: - Move the MediaTek GIC quirk handling from irqchip to core. Before the merging window commit 44bd78dd2b88 ("irqchip/gic-v3: Disable pseudo NMIs on MediaTek devices w/ firmware issues") temporarily addressed this issue. Fixed now at a deeper level in the arch code - Reject events meant for other PMUs in the CoreSight PMU driver, otherwise some of the core PMU events would disappear - Fix the Armv8 PMUv3 driver driver to not truncate 64-bit registers, causing some events to be invisible - Remove duplicate declaration of __arm64_sys##name following the patch to avoid prototype warning for syscalls - Typos in the elf_hwcap documentation" * tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: arm64/syscall: Remove duplicate declaration Revert "arm64: smp: avoid NMI IPIs with broken MediaTek FW" arm64: Move MediaTek GIC quirk handling from irqchip to core arm64/arm: arm_pmuv3: perf: Don't truncate 64-bit registers perf: arm_cspmu: Reject events meant for other PMUs Documentation/arm64: Fix typos in elf_hwcaps