469 lines
16 KiB
C
469 lines
16 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
|
|
#ifndef __LINUX_ENTRYCOMMON_H
|
|
#define __LINUX_ENTRYCOMMON_H
|
|
|
|
#include <linux/static_call_types.h>
|
|
#include <linux/ptrace.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_PATCH_PENDING
|
|
# define _TIF_PATCH_PENDING (0)
|
|
#endif
|
|
|
|
#ifndef _TIF_UPROBE
|
|
# define _TIF_UPROBE (0)
|
|
#endif
|
|
|
|
/*
|
|
* SYSCALL_WORK flags handled in syscall_enter_from_user_mode()
|
|
*/
|
|
#ifndef ARCH_SYSCALL_WORK_ENTER
|
|
# define ARCH_SYSCALL_WORK_ENTER (0)
|
|
#endif
|
|
|
|
/*
|
|
* SYSCALL_WORK flags handled in syscall_exit_to_user_mode()
|
|
*/
|
|
#ifndef ARCH_SYSCALL_WORK_EXIT
|
|
# define ARCH_SYSCALL_WORK_EXIT (0)
|
|
#endif
|
|
|
|
#define SYSCALL_WORK_ENTER (SYSCALL_WORK_SECCOMP | \
|
|
SYSCALL_WORK_SYSCALL_TRACEPOINT | \
|
|
SYSCALL_WORK_SYSCALL_TRACE | \
|
|
SYSCALL_WORK_SYSCALL_EMU | \
|
|
SYSCALL_WORK_SYSCALL_AUDIT | \
|
|
SYSCALL_WORK_SYSCALL_USER_DISPATCH | \
|
|
ARCH_SYSCALL_WORK_ENTER)
|
|
#define SYSCALL_WORK_EXIT (SYSCALL_WORK_SYSCALL_TRACEPOINT | \
|
|
SYSCALL_WORK_SYSCALL_TRACE | \
|
|
SYSCALL_WORK_SYSCALL_AUDIT | \
|
|
SYSCALL_WORK_SYSCALL_USER_DISPATCH | \
|
|
SYSCALL_WORK_SYSCALL_EXIT_TRAP | \
|
|
ARCH_SYSCALL_WORK_EXIT)
|
|
|
|
/*
|
|
* 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 | _TIF_NOTIFY_SIGNAL | \
|
|
ARCH_EXIT_TO_USER_MODE_WORK)
|
|
|
|
/**
|
|
* arch_enter_from_user_mode - 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_enter_from_user_mode(struct pt_regs *regs);
|
|
|
|
#ifndef arch_enter_from_user_mode
|
|
static __always_inline void arch_enter_from_user_mode(struct pt_regs *regs) {}
|
|
#endif
|
|
|
|
/**
|
|
* enter_from_user_mode - Establish state when coming from user mode
|
|
*
|
|
* Syscall/interrupt entry disables interrupts, but user mode is traced as
|
|
* interrupts enabled. Also with NO_HZ_FULL RCU might be idle.
|
|
*
|
|
* 1) Tell lockdep that interrupts are disabled
|
|
* 2) Invoke context tracking if enabled to reactivate RCU
|
|
* 3) Trace interrupts off state
|
|
*
|
|
* 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 interrupts are still
|
|
* disabled. The subsequent functions can be instrumented.
|
|
*
|
|
* This is invoked when there is architecture specific functionality to be
|
|
* done between establishing state and enabling interrupts. The caller must
|
|
* enable interrupts before invoking syscall_enter_from_user_mode_work().
|
|
*/
|
|
void enter_from_user_mode(struct pt_regs *regs);
|
|
|
|
/**
|
|
* syscall_enter_from_user_mode_prepare - Establish state and enable interrupts
|
|
* @regs: Pointer to currents pt_regs
|
|
*
|
|
* 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, interrupts are enabled and the
|
|
* subsequent functions can be instrumented.
|
|
*
|
|
* This handles lockdep, RCU (context tracking) and tracing state, i.e.
|
|
* the functionality provided by enter_from_user_mode().
|
|
*
|
|
* This is invoked when there is extra architecture specific functionality
|
|
* to be done between establishing state and handling user mode entry work.
|
|
*/
|
|
void syscall_enter_from_user_mode_prepare(struct pt_regs *regs);
|
|
|
|
/**
|
|
* syscall_enter_from_user_mode_work - 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
|
|
* enabled after invoking syscall_enter_from_user_mode_prepare() and extra
|
|
* architecture specific work.
|
|
*
|
|
* 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.
|
|
*
|
|
* It handles the following work items:
|
|
*
|
|
* 1) syscall_work flag dependent invocations of
|
|
* ptrace_report_syscall_entry(), __secure_computing(), trace_sys_enter()
|
|
* 2) Invocation of audit_syscall_entry()
|
|
*/
|
|
long syscall_enter_from_user_mode_work(struct pt_regs *regs, long syscall);
|
|
|
|
/**
|
|
* syscall_enter_from_user_mode - Establish state and 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, interrupts are enabled and the
|
|
* subsequent functions can be instrumented.
|
|
*
|
|
* This is combination of syscall_enter_from_user_mode_prepare() and
|
|
* syscall_enter_from_user_mode_work().
|
|
*
|
|
* Returns: The original or a modified syscall number. See
|
|
* syscall_enter_from_user_mode_work() for further explanation.
|
|
*/
|
|
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_or_restart - Architecture specific signal delivery function
|
|
* @regs: Pointer to currents pt_regs
|
|
*
|
|
* Invoked from exit_to_user_mode_loop().
|
|
*/
|
|
void arch_do_signal_or_restart(struct pt_regs *regs);
|
|
|
|
/**
|
|
* exit_to_user_mode - Fixup state when exiting to user mode
|
|
*
|
|
* Syscall/interrupt exit enables interrupts, but the kernel state is
|
|
* interrupts disabled when this is invoked. Also tell RCU about it.
|
|
*
|
|
* 1) Trace interrupts on state
|
|
* 2) Invoke context tracking if enabled to adjust RCU state
|
|
* 3) Invoke architecture specific last minute exit code, e.g. speculation
|
|
* mitigations, etc.: arch_exit_to_user_mode()
|
|
* 4) Tell lockdep that interrupts are enabled
|
|
*
|
|
* Invoked from architecture specific code when syscall_exit_to_user_mode()
|
|
* is not suitable as the last step before returning to userspace. Must be
|
|
* invoked with interrupts disabled and the caller must be
|
|
* non-instrumentable.
|
|
* The caller has to invoke syscall_exit_to_user_mode_work() before this.
|
|
*/
|
|
void exit_to_user_mode(void);
|
|
|
|
/**
|
|
* syscall_exit_to_user_mode_work - Handle work before returning to user mode
|
|
* @regs: Pointer to currents pt_regs
|
|
*
|
|
* Same as step 1 and 2 of syscall_exit_to_user_mode() but without calling
|
|
* exit_to_user_mode() to perform the final transition to user mode.
|
|
*
|
|
* Calling convention is the same as for syscall_exit_to_user_mode() and it
|
|
* returns with all work handled and interrupts disabled. The caller must
|
|
* invoke exit_to_user_mode() before actually switching to user mode to
|
|
* make the final state transitions. Interrupts must stay disabled between
|
|
* return from this function and the invocation of exit_to_user_mode().
|
|
*/
|
|
void syscall_exit_to_user_mode_work(struct pt_regs *regs);
|
|
|
|
/**
|
|
* 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
|
|
* - ptrace (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), i.e. the
|
|
* functionality in exit_to_user_mode().
|
|
*
|
|
* This is a combination of syscall_exit_to_user_mode_work() (1,2) and
|
|
* exit_to_user_mode(). This function is preferred unless there is a
|
|
* compelling architectural reason to use the separate functions.
|
|
*/
|
|
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 disabled 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
|
|
/**
|
|
* struct irqentry_state - Opaque object for exception state storage
|
|
* @exit_rcu: Used exclusively in the irqentry_*() calls; signals whether the
|
|
* exit path has to invoke ct_irq_exit().
|
|
* @lockdep: Used exclusively in the irqentry_nmi_*() calls; ensures that
|
|
* lockdep state is restored correctly on exit from nmi.
|
|
*
|
|
* This opaque object is filled in by the irqentry_*_enter() functions and
|
|
* must be passed back into the corresponding irqentry_*_exit() functions
|
|
* when the exception is complete.
|
|
*
|
|
* Callers of irqentry_*_[enter|exit]() must consider this structure opaque
|
|
* and all members private. Descriptions of the members are provided to aid in
|
|
* the maintenance of the irqentry_*() functions.
|
|
*/
|
|
typedef struct irqentry_state {
|
|
union {
|
|
bool exit_rcu;
|
|
bool lockdep;
|
|
};
|
|
} 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 ct_irq_enter() has to be
|
|
* invoked on entry and ct_irq_exit() on exit.
|
|
*
|
|
* Avoiding the ct_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 ct_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 raw_irqentry_exit_cond_resched(void);
|
|
#ifdef CONFIG_PREEMPT_DYNAMIC
|
|
#if defined(CONFIG_HAVE_PREEMPT_DYNAMIC_CALL)
|
|
#define irqentry_exit_cond_resched_dynamic_enabled raw_irqentry_exit_cond_resched
|
|
#define irqentry_exit_cond_resched_dynamic_disabled NULL
|
|
DECLARE_STATIC_CALL(irqentry_exit_cond_resched, raw_irqentry_exit_cond_resched);
|
|
#define irqentry_exit_cond_resched() static_call(irqentry_exit_cond_resched)()
|
|
#elif defined(CONFIG_HAVE_PREEMPT_DYNAMIC_KEY)
|
|
DECLARE_STATIC_KEY_TRUE(sk_dynamic_irqentry_exit_cond_resched);
|
|
void dynamic_irqentry_exit_cond_resched(void);
|
|
#define irqentry_exit_cond_resched() dynamic_irqentry_exit_cond_resched()
|
|
#endif
|
|
#else /* CONFIG_PREEMPT_DYNAMIC */
|
|
#define irqentry_exit_cond_resched() raw_irqentry_exit_cond_resched()
|
|
#endif /* CONFIG_PREEMPT_DYNAMIC */
|
|
|
|
/**
|
|
* 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 required 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);
|
|
|
|
/**
|
|
* irqentry_nmi_enter - Handle NMI entry
|
|
* @regs: Pointer to currents pt_regs
|
|
*
|
|
* Similar to irqentry_enter() but taking care of the NMI constraints.
|
|
*/
|
|
irqentry_state_t noinstr irqentry_nmi_enter(struct pt_regs *regs);
|
|
|
|
/**
|
|
* irqentry_nmi_exit - Handle return from NMI handling
|
|
* @regs: Pointer to pt_regs (NMI entry regs)
|
|
* @irq_state: Return value from matching call to irqentry_nmi_enter()
|
|
*
|
|
* Last action before returning to the low level assembly code.
|
|
*
|
|
* Counterpart to irqentry_nmi_enter().
|
|
*/
|
|
void noinstr irqentry_nmi_exit(struct pt_regs *regs, irqentry_state_t irq_state);
|
|
|
|
#endif
|