diff options
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/entry-common.h | 372 | ||||
| -rw-r--r-- | include/linux/entry-kvm.h | 80 | ||||
| -rw-r--r-- | include/linux/kvm_host.h | 8 | ||||
| -rw-r--r-- | include/linux/seccomp.h | 2 |
4 files changed, 462 insertions, 0 deletions
diff --git a/include/linux/entry-common.h b/include/linux/entry-common.h new file mode 100644 index 000000000000..efebbffcd5cc --- /dev/null +++ b/include/linux/entry-common.h @@ -0,0 +1,372 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __LINUX_ENTRYCOMMON_H +#define __LINUX_ENTRYCOMMON_H + +#include <linux/tracehook.h> +#include <linux/syscalls.h> +#include <linux/seccomp.h> +#include <linux/sched.h> + +#include <asm/entry-common.h> + +/* + * Define dummy _TIF work flags if not defined by the architecture or for + * disabled functionality. + */ +#ifndef _TIF_SYSCALL_EMU +# define _TIF_SYSCALL_EMU (0) +#endif + +#ifndef _TIF_SYSCALL_TRACEPOINT +# define _TIF_SYSCALL_TRACEPOINT (0) +#endif + +#ifndef _TIF_SECCOMP +# define _TIF_SECCOMP (0) +#endif + +#ifndef _TIF_SYSCALL_AUDIT +# define _TIF_SYSCALL_AUDIT (0) +#endif + +#ifndef _TIF_PATCH_PENDING +# define _TIF_PATCH_PENDING (0) +#endif + +#ifndef _TIF_UPROBE +# define _TIF_UPROBE (0) +#endif + +/* + * TIF flags handled in syscall_enter_from_usermode() + */ +#ifndef ARCH_SYSCALL_ENTER_WORK +# define ARCH_SYSCALL_ENTER_WORK (0) +#endif + +#define SYSCALL_ENTER_WORK \ + (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | _TIF_SECCOMP | \ + _TIF_SYSCALL_TRACEPOINT | _TIF_SYSCALL_EMU | \ + ARCH_SYSCALL_ENTER_WORK) + +/* + * TIF flags handled in syscall_exit_to_user_mode() + */ +#ifndef ARCH_SYSCALL_EXIT_WORK +# define ARCH_SYSCALL_EXIT_WORK (0) +#endif + +#define SYSCALL_EXIT_WORK \ + (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | \ + _TIF_SYSCALL_TRACEPOINT | ARCH_SYSCALL_EXIT_WORK) + +/* + * TIF flags handled in exit_to_user_mode_loop() + */ +#ifndef ARCH_EXIT_TO_USER_MODE_WORK +# define ARCH_EXIT_TO_USER_MODE_WORK (0) +#endif + +#define EXIT_TO_USER_MODE_WORK \ + (_TIF_SIGPENDING | _TIF_NOTIFY_RESUME | _TIF_UPROBE | \ + _TIF_NEED_RESCHED | _TIF_PATCH_PENDING | \ + ARCH_EXIT_TO_USER_MODE_WORK) + +/** + * arch_check_user_regs - Architecture specific sanity check for user mode regs + * @regs: Pointer to currents pt_regs + * + * Defaults to an empty implementation. Can be replaced by architecture + * specific code. + * + * Invoked from syscall_enter_from_user_mode() in the non-instrumentable + * section. Use __always_inline so the compiler cannot push it out of line + * and make it instrumentable. + */ +static __always_inline void arch_check_user_regs(struct pt_regs *regs); + +#ifndef arch_check_user_regs +static __always_inline void arch_check_user_regs(struct pt_regs *regs) {} +#endif + +/** + * arch_syscall_enter_tracehook - Wrapper around tracehook_report_syscall_entry() + * @regs: Pointer to currents pt_regs + * + * Returns: 0 on success or an error code to skip the syscall. + * + * Defaults to tracehook_report_syscall_entry(). Can be replaced by + * architecture specific code. + * + * Invoked from syscall_enter_from_user_mode() + */ +static inline __must_check int arch_syscall_enter_tracehook(struct pt_regs *regs); + +#ifndef arch_syscall_enter_tracehook +static inline __must_check int arch_syscall_enter_tracehook(struct pt_regs *regs) +{ + return tracehook_report_syscall_entry(regs); +} +#endif + +/** + * syscall_enter_from_user_mode - Check and handle work before invoking + * a syscall + * @regs: Pointer to currents pt_regs + * @syscall: The syscall number + * + * Invoked from architecture specific syscall entry code with interrupts + * disabled. The calling code has to be non-instrumentable. When the + * function returns all state is correct and the subsequent functions can be + * instrumented. + * + * Returns: The original or a modified syscall number + * + * If the returned syscall number is -1 then the syscall should be + * skipped. In this case the caller may invoke syscall_set_error() or + * syscall_set_return_value() first. If neither of those are called and -1 + * is returned, then the syscall will fail with ENOSYS. + * + * The following functionality is handled here: + * + * 1) Establish state (lockdep, RCU (context tracking), tracing) + * 2) TIF flag dependent invocations of arch_syscall_enter_tracehook(), + * __secure_computing(), trace_sys_enter() + * 3) Invocation of audit_syscall_entry() + */ +long syscall_enter_from_user_mode(struct pt_regs *regs, long syscall); + +/** + * local_irq_enable_exit_to_user - Exit to user variant of local_irq_enable() + * @ti_work: Cached TIF flags gathered with interrupts disabled + * + * Defaults to local_irq_enable(). Can be supplied by architecture specific + * code. + */ +static inline void local_irq_enable_exit_to_user(unsigned long ti_work); + +#ifndef local_irq_enable_exit_to_user +static inline void local_irq_enable_exit_to_user(unsigned long ti_work) +{ + local_irq_enable(); +} +#endif + +/** + * local_irq_disable_exit_to_user - Exit to user variant of local_irq_disable() + * + * Defaults to local_irq_disable(). Can be supplied by architecture specific + * code. + */ +static inline void local_irq_disable_exit_to_user(void); + +#ifndef local_irq_disable_exit_to_user +static inline void local_irq_disable_exit_to_user(void) +{ + local_irq_disable(); +} +#endif + +/** + * arch_exit_to_user_mode_work - Architecture specific TIF work for exit + * to user mode. + * @regs: Pointer to currents pt_regs + * @ti_work: Cached TIF flags gathered with interrupts disabled + * + * Invoked from exit_to_user_mode_loop() with interrupt enabled + * + * Defaults to NOOP. Can be supplied by architecture specific code. + */ +static inline void arch_exit_to_user_mode_work(struct pt_regs *regs, + unsigned long ti_work); + +#ifndef arch_exit_to_user_mode_work +static inline void arch_exit_to_user_mode_work(struct pt_regs *regs, + unsigned long ti_work) +{ +} +#endif + +/** + * arch_exit_to_user_mode_prepare - Architecture specific preparation for + * exit to user mode. + * @regs: Pointer to currents pt_regs + * @ti_work: Cached TIF flags gathered with interrupts disabled + * + * Invoked from exit_to_user_mode_prepare() with interrupt disabled as the last + * function before return. Defaults to NOOP. + */ +static inline void arch_exit_to_user_mode_prepare(struct pt_regs *regs, + unsigned long ti_work); + +#ifndef arch_exit_to_user_mode_prepare +static inline void arch_exit_to_user_mode_prepare(struct pt_regs *regs, + unsigned long ti_work) +{ +} +#endif + +/** + * arch_exit_to_user_mode - Architecture specific final work before + * exit to user mode. + * + * Invoked from exit_to_user_mode() with interrupt disabled as the last + * function before return. Defaults to NOOP. + * + * This needs to be __always_inline because it is non-instrumentable code + * invoked after context tracking switched to user mode. + * + * An architecture implementation must not do anything complex, no locking + * etc. The main purpose is for speculation mitigations. + */ +static __always_inline void arch_exit_to_user_mode(void); + +#ifndef arch_exit_to_user_mode +static __always_inline void arch_exit_to_user_mode(void) { } +#endif + +/** + * arch_do_signal - Architecture specific signal delivery function + * @regs: Pointer to currents pt_regs + * + * Invoked from exit_to_user_mode_loop(). + */ +void arch_do_signal(struct pt_regs *regs); + +/** + * arch_syscall_exit_tracehook - Wrapper around tracehook_report_syscall_exit() + * @regs: Pointer to currents pt_regs + * @step: Indicator for single step + * + * Defaults to tracehook_report_syscall_exit(). Can be replaced by + * architecture specific code. + * + * Invoked from syscall_exit_to_user_mode() + */ +static inline void arch_syscall_exit_tracehook(struct pt_regs *regs, bool step); + +#ifndef arch_syscall_exit_tracehook +static inline void arch_syscall_exit_tracehook(struct pt_regs *regs, bool step) +{ + tracehook_report_syscall_exit(regs, step); +} +#endif + +/** + * syscall_exit_to_user_mode - Handle work before returning to user mode + * @regs: Pointer to currents pt_regs + * + * Invoked with interrupts enabled and fully valid regs. Returns with all + * work handled, interrupts disabled such that the caller can immediately + * switch to user mode. Called from architecture specific syscall and ret + * from fork code. + * + * The call order is: + * 1) One-time syscall exit work: + * - rseq syscall exit + * - audit + * - syscall tracing + * - tracehook (single stepping) + * + * 2) Preparatory work + * - Exit to user mode loop (common TIF handling). Invokes + * arch_exit_to_user_mode_work() for architecture specific TIF work + * - Architecture specific one time work arch_exit_to_user_mode_prepare() + * - Address limit and lockdep checks + * + * 3) Final transition (lockdep, tracing, context tracking, RCU). Invokes + * arch_exit_to_user_mode() to handle e.g. speculation mitigations + */ +void syscall_exit_to_user_mode(struct pt_regs *regs); + +/** + * irqentry_enter_from_user_mode - Establish state before invoking the irq handler + * @regs: Pointer to currents pt_regs + * + * Invoked from architecture specific entry code with interrupts disabled. + * Can only be called when the interrupt entry came from user mode. The + * calling code must be non-instrumentable. When the function returns all + * state is correct and the subsequent functions can be instrumented. + * + * The function establishes state (lockdep, RCU (context tracking), tracing) + */ +void irqentry_enter_from_user_mode(struct pt_regs *regs); + +/** + * irqentry_exit_to_user_mode - Interrupt exit work + * @regs: Pointer to current's pt_regs + * + * Invoked with interrupts disbled and fully valid regs. Returns with all + * work handled, interrupts disabled such that the caller can immediately + * switch to user mode. Called from architecture specific interrupt + * handling code. + * + * The call order is #2 and #3 as described in syscall_exit_to_user_mode(). + * Interrupt exit is not invoking #1 which is the syscall specific one time + * work. + */ +void irqentry_exit_to_user_mode(struct pt_regs *regs); + +#ifndef irqentry_state +typedef struct irqentry_state { + bool exit_rcu; +} irqentry_state_t; +#endif + +/** + * irqentry_enter - Handle state tracking on ordinary interrupt entries + * @regs: Pointer to pt_regs of interrupted context + * + * Invokes: + * - lockdep irqflag state tracking as low level ASM entry disabled + * interrupts. + * + * - Context tracking if the exception hit user mode. + * + * - The hardirq tracer to keep the state consistent as low level ASM + * entry disabled interrupts. + * + * As a precondition, this requires that the entry came from user mode, + * idle, or a kernel context in which RCU is watching. + * + * For kernel mode entries RCU handling is done conditional. If RCU is + * watching then the only RCU requirement is to check whether the tick has + * to be restarted. If RCU is not watching then rcu_irq_enter() has to be + * invoked on entry and rcu_irq_exit() on exit. + * + * Avoiding the rcu_irq_enter/exit() calls is an optimization but also + * solves the problem of kernel mode pagefaults which can schedule, which + * is not possible after invoking rcu_irq_enter() without undoing it. + * + * For user mode entries irqentry_enter_from_user_mode() is invoked to + * establish the proper context for NOHZ_FULL. Otherwise scheduling on exit + * would not be possible. + * + * Returns: An opaque object that must be passed to idtentry_exit() + */ +irqentry_state_t noinstr irqentry_enter(struct pt_regs *regs); + +/** + * irqentry_exit_cond_resched - Conditionally reschedule on return from interrupt + * + * Conditional reschedule with additional sanity checks. + */ +void irqentry_exit_cond_resched(void); + +/** + * irqentry_exit - Handle return from exception that used irqentry_enter() + * @regs: Pointer to pt_regs (exception entry regs) + * @state: Return value from matching call to irqentry_enter() + * + * Depending on the return target (kernel/user) this runs the necessary + * preemption and work checks if possible and reguired and returns to + * the caller with interrupts disabled and no further work pending. + * + * This is the last action before returning to the low level ASM code which + * just needs to return to the appropriate context. + * + * Counterpart to irqentry_enter(). + */ +void noinstr irqentry_exit(struct pt_regs *regs, irqentry_state_t state); + +#endif diff --git a/include/linux/entry-kvm.h b/include/linux/entry-kvm.h new file mode 100644 index 000000000000..0cef17afb41a --- /dev/null +++ b/include/linux/entry-kvm.h @@ -0,0 +1,80 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __LINUX_ENTRYKVM_H +#define __LINUX_ENTRYKVM_H + +#include <linux/entry-common.h> + +/* Transfer to guest mode work */ +#ifdef CONFIG_KVM_XFER_TO_GUEST_WORK + +#ifndef ARCH_XFER_TO_GUEST_MODE_WORK +# define ARCH_XFER_TO_GUEST_MODE_WORK (0) +#endif + +#define XFER_TO_GUEST_MODE_WORK \ + (_TIF_NEED_RESCHED | _TIF_SIGPENDING | \ + _TIF_NOTIFY_RESUME | ARCH_XFER_TO_GUEST_MODE_WORK) + +struct kvm_vcpu; + +/** + * arch_xfer_to_guest_mode_handle_work - Architecture specific xfer to guest + * mode work handling function. + * @vcpu: Pointer to current's VCPU data + * @ti_work: Cached TIF flags gathered in xfer_to_guest_mode_handle_work() + * + * Invoked from xfer_to_guest_mode_handle_work(). Defaults to NOOP. Can be + * replaced by architecture specific code. + */ +static inline int arch_xfer_to_guest_mode_handle_work(struct kvm_vcpu *vcpu, + unsigned long ti_work); + +#ifndef arch_xfer_to_guest_mode_work +static inline int arch_xfer_to_guest_mode_handle_work(struct kvm_vcpu *vcpu, + unsigned long ti_work) +{ + return 0; +} +#endif + +/** + * xfer_to_guest_mode_handle_work - Check and handle pending work which needs + * to be handled before going to guest mode + * @vcpu: Pointer to current's VCPU data + * + * Returns: 0 or an error code + */ +int xfer_to_guest_mode_handle_work(struct kvm_vcpu *vcpu); + +/** + * __xfer_to_guest_mode_work_pending - Check if work is pending + * + * Returns: True if work pending, False otherwise. + * + * Bare variant of xfer_to_guest_mode_work_pending(). Can be called from + * interrupt enabled code for racy quick checks with care. + */ +static inline bool __xfer_to_guest_mode_work_pending(void) +{ + unsigned long ti_work = READ_ONCE(current_thread_info()->flags); + + return !!(ti_work & XFER_TO_GUEST_MODE_WORK); +} + +/** + * xfer_to_guest_mode_work_pending - Check if work is pending which needs to be + * handled before returning to guest mode + * + * Returns: True if work pending, False otherwise. + * + * Has to be invoked with interrupts disabled before the transition to + * guest mode. + */ +static inline bool xfer_to_guest_mode_work_pending(void) +{ + lockdep_assert_irqs_disabled(); + return __xfer_to_guest_mode_work_pending(); +} +#endif /* CONFIG_KVM_XFER_TO_GUEST_WORK */ + +#endif diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index d564855243d8..ac83e9c1d82c 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -1439,4 +1439,12 @@ int kvm_vm_create_worker_thread(struct kvm *kvm, kvm_vm_thread_fn_t thread_fn, uintptr_t data, const char *name, struct task_struct **thread_ptr); +#ifdef CONFIG_KVM_XFER_TO_GUEST_WORK +static inline void kvm_handle_signal_exit(struct kvm_vcpu *vcpu) +{ + vcpu->run->exit_reason = KVM_EXIT_INTR; + vcpu->stat.signal_exits++; +} +#endif /* CONFIG_KVM_XFER_TO_GUEST_WORK */ + #endif diff --git a/include/linux/seccomp.h b/include/linux/seccomp.h index 881c90b6aa25..02aef2844c38 100644 --- a/include/linux/seccomp.h +++ b/include/linux/seccomp.h @@ -64,9 +64,11 @@ static inline int seccomp_mode(struct seccomp *s) struct seccomp { }; struct seccomp_filter { }; +struct seccomp_data; #ifdef CONFIG_HAVE_ARCH_SECCOMP_FILTER static inline int secure_computing(void) { return 0; } +static inline int __secure_computing(const struct seccomp_data *sd) { return 0; } #else static inline void secure_computing_strict(int this_syscall) { return; } #endif |