nuttx/arch/arm/include/armv8-m/irq.h

/****************************************************************************
 * arch/arm/include/armv8-m/irq.h
 *
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.  The
 * ASF licenses this file to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance with the
 * License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
 * License for the specific language governing permissions and limitations
 * under the License.
 *
 ****************************************************************************/

/* This file should never be included directly but, rather, only indirectly
 * through nuttx/irq.h
 */

#ifndef __ARCH_ARM_INCLUDE_ARMV8_M_IRQ_H
#define __ARCH_ARM_INCLUDE_ARMV8_M_IRQ_H

/****************************************************************************
 * Included Files
 ****************************************************************************/

#include <nuttx/config.h>

#include <nuttx/irq.h>
#ifndef __ASSEMBLY__
#  include <nuttx/compiler.h>
#  include <arch/armv8-m/nvicpri.h>
#  include <stdint.h>
#endif

/* Included implementation-dependent register save structure layouts */

#ifndef CONFIG_ARMV8M_LAZYFPU
#  include <arch/armv8-m/irq_cmnvector.h>
#else
#  include <arch/armv8-m/irq_lazyfpu.h>
#endif

/****************************************************************************
 * Pre-processor Prototypes
 ****************************************************************************/

/* Configuration ************************************************************/

/* If this is a kernel build, how many nested system calls should we
 * support?
 */

#ifndef CONFIG_SYS_NNEST
#  define CONFIG_SYS_NNEST 2
#endif

/* Alternate register names *************************************************/

#define REG_A1              REG_R0
#define REG_A2              REG_R1
#define REG_A3              REG_R2
#define REG_A4              REG_R3
#define REG_V1              REG_R4
#define REG_V2              REG_R5
#define REG_V3              REG_R6
#define REG_V4              REG_R7
#define REG_V5              REG_R8
#define REG_V6              REG_R9
#define REG_V7              REG_R10
#define REG_SB              REG_R9
#define REG_SL              REG_R10
#define REG_FP              REG_R7
#define REG_IP              REG_R12
#define REG_SP              REG_R13
#define REG_LR              REG_R14
#define REG_PC              REG_R15

/* The PIC register is usually R10. It can be R9 is stack checking is enabled
 * or if the user changes it with -mpic-register on the GCC command line.
 */

#define REG_PIC             REG_R10

/* CONTROL register */

#define CONTROL_UPAC_EN     (1 << 7) /* Bit 7: Unprivileged pointer authentication enable */
#define CONTROL_PAC_EN      (1 << 6) /* Bit 6: Privileged pointer authentication enable */
#define CONTROL_UBTI_EN     (1 << 5) /* Bit 5: Unprivileged branch target identification enable */
#define CONTROL_BTI_EN      (1 << 4) /* Bit 4: Privileged branch target identification enable */
#define CONTROL_SFPA        (1 << 3) /* Bit 3: Secure Floating-point active */
#define CONTROL_FPCA        (1 << 2) /* Bit 2: Floating-point context active */
#define CONTROL_SPSEL       (1 << 1) /* Bit 1: Stack-pointer select */
#define CONTROL_NPRIV       (1 << 0) /* Bit 0: Not privileged */

/****************************************************************************
 * Public Types
 ****************************************************************************/
#ifndef __ASSEMBLY__

/* This structure represents the return state from a system call */

#ifdef CONFIG_LIB_SYSCALL
struct xcpt_syscall_s
{
  uint32_t excreturn;   /* The EXC_RETURN value */
  uint32_t sysreturn;   /* The return PC */
};
#endif

/* The following structure is included in the TCB and defines the complete
 * state of the thread.
 */

struct xcptcontext
{
  /* The following function pointer is non-zero if there
   * are pending signals to be processed.
   */

  FAR void *sigdeliver; /* Actual type is sig_deliver_t */

  /* These are saved copies of LR, PRIMASK, and xPSR used during
   * signal processing.
   *
   * REVISIT:  Because there is only one copy of these save areas,
   * only a single signal handler can be active.  This precludes
   * queuing of signal actions.  As a result, signals received while
   * another signal handler is executing will be ignored!
   */

  uint32_t saved_pc;
#ifdef CONFIG_ARMV8M_USEBASEPRI
  uint32_t saved_basepri;
#else
  uint32_t saved_primask;
#endif
  uint32_t saved_xpsr;
#ifdef CONFIG_BUILD_PROTECTED
  uint32_t saved_lr;

  /* This is the saved address to use when returning from a user-space
   * signal handler.
   */

  uint32_t sigreturn;

#endif

#ifdef CONFIG_LIB_SYSCALL
  /* The following array holds the return address and the exc_return value
   * needed to return from each nested system call.
   */

  uint8_t nsyscalls;
  struct xcpt_syscall_s syscall[CONFIG_SYS_NNEST];

#endif

  /* Register save area */

  uint32_t regs[XCPTCONTEXT_REGS];
};
#endif

/****************************************************************************
 * Inline functions
 ****************************************************************************/

#ifndef __ASSEMBLY__

/* Name: up_irq_save, up_irq_restore, and friends.
 *
 * NOTE: This function should never be called from application code and,
 * as a general rule unless you really know what you are doing, this
 * function should not be called directly from operation system code either:
 * Typically, the wrapper functions, enter_critical_section() and
 * leave_critical section(), are probably what you really want.
 */

/* Get/set the PRIMASK register */

static inline uint8_t getprimask(void) inline_function;
static inline uint8_t getprimask(void)
{
  uint32_t primask;
  __asm__ __volatile__
    (
     "\tmrs  %0, primask\n"
     : "=r" (primask)
     :
     : "memory");

  return (uint8_t)primask;
}

static inline void setprimask(uint32_t primask) inline_function;
static inline void setprimask(uint32_t primask)
{
  __asm__ __volatile__
    (
      "\tmsr primask, %0\n"
      :
      : "r" (primask)
      : "memory");
}

static inline void cpsie(void) inline_function;
static inline void cpsie(void)
{
  __asm__ __volatile__ ("\tcpsie  i\n");
}

static inline void cpsid(void) inline_function;
static inline void cpsid(void)
{
  __asm__ __volatile__ ("\tcpsid  i\n");
}

/* Get/set the BASEPRI register.  The BASEPRI register defines the minimum
 * priority for exception processing. When BASEPRI is set to a nonzero
 * value, it prevents the activation of all exceptions with the same or
 * lower priority level as the BASEPRI value.
 */

static inline uint8_t getbasepri(void) inline_function;
static inline uint8_t getbasepri(void)
{
  uint32_t basepri;

  __asm__ __volatile__
    (
     "\tmrs  %0, basepri\n"
     : "=r" (basepri)
     :
     : "memory");

  return (uint8_t)basepri;
}

static inline void setbasepri(uint32_t basepri) inline_function;
static inline void setbasepri(uint32_t basepri)
{
  __asm__ __volatile__
    (
      "\tmsr basepri, %0\n"
      :
      : "r" (basepri)
      : "memory");
}

#  define raisebasepri(b) setbasepri(b);

/* Disable IRQs */

static inline void up_irq_disable(void) inline_function;
static inline void up_irq_disable(void)
{
#ifdef CONFIG_ARMV8M_USEBASEPRI
  /* Probably raising priority */

  raisebasepri(NVIC_SYSH_DISABLE_PRIORITY);
#else
  __asm__ __volatile__ ("\tcpsid  i\n");
#endif
}

/* Save the current primask state & disable IRQs */

static inline irqstate_t up_irq_save(void) inline_function;
static inline irqstate_t up_irq_save(void)
{
#ifdef CONFIG_ARMV8M_USEBASEPRI
  /* Probably raising priority */

  uint8_t basepri = getbasepri();
  raisebasepri(NVIC_SYSH_DISABLE_PRIORITY);
  return (irqstate_t)basepri;

#else

  unsigned short primask;

  /* Return the current value of primask register and set
   * bit 0 of the primask register to disable interrupts
   */

  __asm__ __volatile__
    (
     "\tmrs    %0, primask\n"
     "\tcpsid  i\n"
     : "=r" (primask)
     :
     : "memory");

  return primask;
#endif
}

/* Enable IRQs */

static inline void up_irq_enable(void) inline_function;
static inline void up_irq_enable(void)
{
  /* In this case, we are always retaining or lowering the priority value */

  setbasepri(NVIC_SYSH_PRIORITY_MIN);
  __asm__ __volatile__ ("\tcpsie  i\n");
}

/* Restore saved primask state */

static inline void up_irq_restore(irqstate_t flags) inline_function;
static inline void up_irq_restore(irqstate_t flags)
{
#ifdef CONFIG_ARMV8M_USEBASEPRI
  /* In this case, we are always retaining or lowering the priority value */

  setbasepri((uint32_t)flags);

#else
  /* If bit 0 of the primask is 0, then we need to restore
   * interrupts.
   */

  __asm__ __volatile__
    (
      "\ttst    %0, #1\n"
      "\tbne.n  1f\n"
      "\tcpsie  i\n"
      "1:\n"
      :
      : "r" (flags)
      : "memory");

#endif
}

/* Get/set IPSR */

static inline uint32_t getipsr(void) inline_function;
static inline uint32_t getipsr(void)
{
  uint32_t ipsr;
  __asm__ __volatile__
    (
     "\tmrs  %0, ipsr\n"
     : "=r" (ipsr)
     :
     : "memory");

  return ipsr;
}

/* Get/set CONTROL */

static inline uint32_t getcontrol(void) inline_function;
static inline uint32_t getcontrol(void)
{
  uint32_t control;
  __asm__ __volatile__
    (
     "\tmrs  %0, control\n"
     : "=r" (control)
     :
     : "memory");

  return control;
}

static inline void setcontrol(uint32_t control) inline_function;
static inline void setcontrol(uint32_t control)
{
  __asm__ __volatile__
    (
      "\tmsr control, %0\n"
      :
      : "r" (control)
      : "memory");
}

#endif /* __ASSEMBLY__ */

/****************************************************************************
 * Public Data
 ****************************************************************************/

/****************************************************************************
 * Public Function Prototypes
 ****************************************************************************/

#ifndef __ASSEMBLY__
#ifdef __cplusplus
#define EXTERN extern "C"
extern "C"
{
#else
#define EXTERN extern
#endif

#undef EXTERN
#ifdef __cplusplus
}
#endif
#endif

#endif /* __ARCH_ARM_INCLUDE_ARMV8_M_IRQ_H */