kernel/git/stable/linux.git/arch/powerpc/include, branch linux-7.2.y

powerpc/syscall: Fix syscall skip handling for seccomp and ptrace

2026-09-14T11:40:12+00:00

[ Upstream commit 69cb2be898be6d5826cacd1a628f6945a24480b6 ] After enabling GENERIC_ENTRY on PowerPC, syscall_enter_from_user_mode() returns -1 as a sentinel to signal that seccomp or ptrace has intercepted the syscall and already set a return value via syscall_set_return_value(). system_call_exception() was not handling this sentinel, and since -1UL is >= NR_syscalls, the code fell into the out-of-range path and returned -ENOSYS, overwriting the errno already placed in regs->gpr[3]. The naive fix of checking r0 == -1L before the NR_syscalls bounds check is ambiguous: a user legitimately calling syscall(-1) also produces r0 == -1L, and a tracer intercepting such a call would have its injected return value silently discarded. Fix this by introducing a thread flag that is set whenever syscall_set_return_value() explicitly updates the return value. In system_call_exception(), check and clear this flag before dispatching the syscall, and return the preset value directly when it is present. This ensures that an explicitly supplied return value always suppresses syscall execution, regardless of the syscall number. This handles all seccomp actions correctly: - SECCOMP_RET_ERRNO, SECCOMP_RET_TRACE (no tracer), SECCOMP_RET_USER_NOTIF: all call syscall_set_return_value(), flag is set, injected value returned. - SECCOMP_RET_TRAP, SECCOMP_RET_KILL: call syscall_rollback() and deliver a signal; flag is not set, but the process is dying so the return value is irrelevant. The fix covers both ppc32 and ppc64 with no #ifdefs. Fixes: bee25f97ad24 ("powerpc: Enable GENERIC_ENTRY feature") Reported-by: Michal Suchánek Closes: https://lore.kernel.org/all/ajpp-_XnbF3UTM_E@kunlun.suse.cz/ Tested-by: Michal Suchánek Reviewed-by: Michal Suchánek Signed-off-by: Mukesh Kumar Chaurasiya (IBM) Signed-off-by: Madhavan Srinivasan Link: https://patch.msgid.link/20260731081521.1852133-1-mkchauras@gmail.com Signed-off-by: Sasha Levin

powerpc/xive: add error return value to xive_smp_probe()

2026-09-14T11:40:12+00:00

[ Upstream commit ab5ae5dceb86614f6c9e7488f91b652000edfdc5 ] xive_smp_probe() calls xive_init_ipis() which can fail, but its return value is currently ignored. Change xive_smp_probe() to return int so that errors can be propagated to callers. This is a preparatory patch for the next one. No functional change yet; the return value is always 0 at this point. Signed-off-by: Gou Hao Reviewed-by: Wentao Guan Reviewed-by: jiazhenyuan Reviewed-by: Cédric Le Goater Signed-off-by: Madhavan Srinivasan Link: https://patch.msgid.link/20260727104215.184786-3-gouhao@uniontech.com Stable-dep-of: 411a3c016e7a ("powerpc/xive: propagate IPI init errors to prevent use-after-free") Signed-off-by: Sasha Levin

KVM: PPC: Book3S HV: Validate arch_compat against host compatibility mode

2026-09-11T09:51:06+00:00

commit 884ea0283f4effac97ee8f451464a7d1be480d7c upstream. On IBM POWER systems, newer processor generations can operate in compatibility modes corresponding to earlier generations. This becomes relevant for nested virtualization, where nested KVM guests may need to run with a specific processor compatibility level. Currently, when running a nested KVM guest (L2) inside a Power11 pSeries logical partition (L1) booted in Power10 compatibility mode, the guest fails to boot while setting 'arch_compat'. This happens because the CPU class is derived from the hardware PVR (via mfspr()), which reflects the physical processor generation (Power11), rather than the effective compatibility mode (Power10). As a result, userspace may request a Power11 arch_compat for the L2 guest. However, the L1 partition, running in Power10 compatibility, has only negotiated support up to Power10 with the Power Hypervisor (L0). When H_GUEST_SET_STATE is invoked with a Power11 Logical PVR, the hypervisor rejects the request, leading to a late guest boot failure: KVM-NESTEDv2: couldn't set guest wide elements [..KVM reg dump..] This situation should be detected earlier and rejected by KVM. Without proper validation, if userspace ignores the error, the guest may continue to boot in Power11 raw mode on a Power10 compatibility host, which should not be allowed. Introduce a validation mechanism that detects unsupported arch_compat values early in the guest initialization path. When an unsupported arch_compat is requested (e.g., Power11 on a Power10 compatibility mode host), kvmppc_set_arch_compat() uses cpu_has_feature(CPU_FTR_P11_PVR) to detect the mismatch and sets arch_compat to PVR_ARCH_INVALID (0xffffffff). This sentinel value is architecturally safe: PAPR specifies that valid logical PVR values must have 0x0f as the first byte, ensuring 0xffffffff lies permanently outside the specification-defined range. Setting this value triggers kvmppc_sanity_check() to mark the vCPU as invalid by setting vcpu->arch.sane to false. On the next vCPU run, kvmppc_vcpu_run_hv() checks this flag and returns -EINVAL, preventing the guest from running with an invalid processor compatibility configuration. With this, when a Power11 arch_compat is requested on a Power10 compatibility mode host, the guest fails early during boot with: error: kvm run failed Invalid argument This provides a much clearer failure mode compared to the previous behavior where the guest could boot in Power11 raw mode (if userspace ignored the error) or fail late during H_GUEST_SET_STATE. Suggested-by: Vaibhav Jain Reviewed-by: Vaibhav Jain Tested-by: Anushree Mathur Acked-by: Gautam Menghani Cc: stable@vger.kernel.org # v6.13+ Reviewed-by: Ritesh Harjani (IBM) Reviewed-by: Mukesh Kumar Chaurasiya (IBM) Signed-off-by: Amit Machhiwal Signed-off-by: Madhavan Srinivasan Link: https://patch.msgid.link/20260714175432.86388-1-amachhiw@linux.ibm.com Signed-off-by: Greg Kroah-Hartman

powerpc/crash: stop watchdogs before booting kdump kernel

2026-09-11T09:50:56+00:00

commit fb43ba4256543ce18ca0540fc37022bda438a293 upstream. On pseries LPAR systems, watchdog timers configured from userspace can remain active after a kernel panic. When a panic triggers kdump, the crashing kernel jumps directly to the kdump kernel without stopping active watchdogs. As a result, the watchdogs remain active after the kdump kernel starts. If dump capture takes longer than the watchdog timeout, PHYP resets the LPAR before the dump is fully captured, causing dump capture to fail. Fix this by issuing the `H_WATCHDOG` hcall during the crash shutdown sequence to stop all active watchdogs before booting the kdump kernel. Cc: stable@vger.kernel.org Fixes: 69472ffa6575 ("watchdog/pseries-wdt: initial support for H_WATCHDOG-based watchdog timers") Reported-by: Mahesh Kumar G Suggested-by: Ritesh Harjani (IBM) Reviewed-by: Ritesh Harjani (IBM) Signed-off-by: Sourabh Jain Signed-off-by: Madhavan Srinivasan Link: https://patch.msgid.link/20260727053416.276317-4-sourabhjain@linux.ibm.com Signed-off-by: Greg Kroah-Hartman

powerpc/pseries: Move H_WATCHDOG definitions to a common header

2026-09-11T09:50:56+00:00

commit 516a254918453ec99660201263d01189c082332c upstream. The H_WATCHDOG input and output definitions are currently local to the pseries watchdog driver. The next patch in this series also needs these definitions to issue H_WATCHDOG hypercalls outside the watchdog driver. Move the H_WATCHDOG definitions to a new common header, asm/papr-watchdog.h, so they can be shared without duplicating the PAPR watchdog definitions. No functional changes. Cc: stable@vger.kernel.org Suggested-by: Ritesh Harjani (IBM) Signed-off-by: Sourabh Jain Signed-off-by: Madhavan Srinivasan Link: https://patch.msgid.link/20260727053416.276317-2-sourabhjain@linux.ibm.com Signed-off-by: Greg Kroah-Hartman

powerpc/serial: Fix include guard comment

2026-07-28T04:53:32+00:00

Replace _PPC64_SERIAL_H with _ASM_POWERPC_SERIAL_H to match the actual macro name. Remove an empty comment while at it. Signed-off-by: Thorsten Blum Reviewed-by: Mukesh Kumar Chaurasiya (IBM) Signed-off-by: Madhavan Srinivasan Link: https://patch.msgid.link/20260623153825.403819-2-thorsten.blum@linux.dev

powerpc: Fix exit_flags field placement in pt_regs for ptrace

2026-07-28T04:53:31+00:00

Commit d7a6797e0bc1 ("powerpc: add exit_flags field in pt_regs") added the exit_flags field to struct pt_regs to pass internal exit control flags (e.g. _TIF_RESTOREALL) from syscall_exit_prepare() to the low-level assembly exit path. However, the field was placed in a way that was visible to userspace tools such as strace via PTRACE_GETREGS, or caused a struct layout or size regression observable through ptrace. The field is purely kernel-internal and must not be exposed beyond the user_pt_regs boundary. Move exit_flags into struct thread_info where it is only accessible to the kernel, and keep it out of the ptrace-visible register window entirely. Fixes: d7a6797e0bc1 ("powerpc: add exit_flags field in pt_regs") Reported-by: Dmitry V. Levin Closes: https://lore.kernel.org/all/20260722070155.GA11808@strace.io/ Signed-off-by: Mukesh Kumar Chaurasiya (IBM) Signed-off-by: Madhavan Srinivasan Link: https://patch.msgid.link/20260723194809.4046600-1-mkchauras@gmail.com

powerpc/970: fix nap return address corruption on async interrupt exit

2026-07-28T04:53:31+00:00

On PowerMac G5 (PPC970, CONFIG_PPC_970_NAP) the system panics shortly after boot with symptoms including instruction fetch faults, kernel data access faults, and stack corruption, predominantly on SMP and always somewhere inside softirq processing. The PPC970 idle path works by setting _TLF_NAPPING in the current thread's local flags before entering the MSR_POW nap loop. When any async interrupt wakes the CPU, nap_adjust_return() is expected to detect _TLF_NAPPING, clear it, and rewrite regs->NIP to power4_idle_nap_return so that the interrupt returns cleanly to the caller of power4_idle_nap() rather than back into the nap spin loop. DEFINE_INTERRUPT_HANDLER_ASYNC generates the following sequence: irq_enter_rcu(); ____func(regs); /* timer_interrupt / do_IRQ body */ irq_exit_rcu(); /* softirqs run here, irqs re-enabled */ arch_interrupt_async_exit_prepare(regs); /* nap_adjust_return was here */ irqentry_exit(regs, state); irq_exit_rcu() calls invoke_softirq() -> do_softirq_own_stack(), which runs softirqs with hardware interrupts re-enabled. A nested async interrupt can therefore arrive while _TLF_NAPPING is still set. That nested interrupt reaches nap_adjust_return() in its own arch_interrupt_async_exit_prepare() call, finds _TLF_NAPPING set, and redirects *its own* regs->NIP to power4_idle_nap_return. Returning via that blr with an unrelated LR on the softirq stack jumps to a garbage address, causing the observed crashes. The comment that previously lived in arch_interrupt_async_exit_prepare() even described this exact hazard ("must come before irq_exit()"), but nap_adjust_return() was placed after irq_exit_rcu() in the macro, so the protection was never effective. Fix this by calling nap_adjust_return() inside DEFINE_INTERRUPT_HANDLER_ASYNC immediately before irq_exit_rcu(), ensuring _TLF_NAPPING is cleared and regs->NIP is adjusted before any code that can re-enable interrupts or invoke softirqs runs. Move the explanatory comment into nap_adjust_return() itself and remove it from arch_interrupt_async_exit_prepare(). Fixes: bee25f97ad24 ("powerpc: Enable GENERIC_ENTRY feature") Closes: https://lore.kernel.org/all/87wlvazrdy.fsf@igel.home/ Reported-by: Andreas Schwab Signed-off-by: Mukesh Kumar Chaurasiya (IBM) Tested-by: John Ogness Signed-off-by: Madhavan Srinivasan Link: https://patch.msgid.link/20260707172430.790040-1-mkchauras@gmail.com

powerpc: Remove dead non-preemption code

2026-07-15T02:34:13+00:00

Since commit 7dadeaa6e851 ("sched: Further restrict the preemption modes"), powerpc always has CONFIG_PREEMPTION because only CONFIG_PREEMPT and CONFIG_PREEMPT_LAZY are possible, even in dynamic preemption mode (see sched_dynamic_mode). As a consequence, need_irq_preemption() is always true and can be removed. And because commit bee25f97ad24 ("powerpc: Enable GENERIC_ENTRY feature") includes linux/irq-entry-common.h which already declares sk_dynamic_irqentry_exit_cond_resched static key, asm/preempt.h becauses useless and can be removed. Signed-off-by: Christophe Leroy (CS GROUP) Reviewed-by: Shrikanth Hegde Signed-off-by: Madhavan Srinivasan Link: https://patch.msgid.link/2bf10a0afffefb6aca44bf2f864cc17471a80e31.1781870889.git.chleroy@kernel.org

powerpc/uaccess: correct check for CONFIG_PPC_E500 in mask_user_address()

2026-07-15T02:34:13+00:00

mask_user_address() incorrectly checks for CONFIG_E500 instead of CONFIG_PPC_E500, causing mask_user_address_isel() to not be used on E500 hardware. Fix the check to use the correct name. Fixes: 861574d51bbd ("powerpc/uaccess: Implement masked user access") Cc: stable@vger.kernel.org # 7.0+ Signed-off-by: Ethan Nelson-Moore Fixes: 861574d51bbd ("powerpc/uaccess: Implement masked user access") Reviewed-by: Christophe Leroy (CS GROUP) Signed-off-by: Madhavan Srinivasan Link: https://patch.msgid.link/20260615233729.29386-1-enelsonmoore@gmail.com