text: /* SPDX-License-Identifier: GPL-2.0 */
  #ifndef _MPX_HW_H
  #define _MPX_HW_H
  
  #include <assert.h>
  
  /* Describe the MPX Hardware Layout in here */
  
  #define NR_MPX_BOUNDS_REGISTERS 4
  
  #ifdef __i386__
  
  #define MPX_BOUNDS_TABLE_ENTRY_SIZE_BYTES	16 /* 4 * 32-bits */
  #define MPX_BOUNDS_TABLE_SIZE_BYTES		(1ULL << 14) /* 16k */
  #define MPX_BOUNDS_DIR_ENTRY_SIZE_BYTES		4
  #define MPX_BOUNDS_DIR_SIZE_BYTES		(1ULL << 22) /* 4MB */
  
  #define MPX_BOUNDS_TABLE_BOTTOM_BIT		2
  #define MPX_BOUNDS_TABLE_TOP_BIT		11
  #define MPX_BOUNDS_DIR_BOTTOM_BIT		12
  #define MPX_BOUNDS_DIR_TOP_BIT			31
  
  #else
  
  /*
   * Linear Address of "pointer" (LAp)
   *   0 ->  2: ignored
   *   3 -> 19: index in to bounds table
   *  20 -> 47: index in to bounds directory
   *  48 -> 63: ignored
   */
  
  #define MPX_BOUNDS_TABLE_ENTRY_SIZE_BYTES	32
  #define MPX_BOUNDS_TABLE_SIZE_BYTES		(1ULL << 22) /* 4MB */
  #define MPX_BOUNDS_DIR_ENTRY_SIZE_BYTES		8
  #define MPX_BOUNDS_DIR_SIZE_BYTES		(1ULL << 31) /* 2GB */
  
  #define MPX_BOUNDS_TABLE_BOTTOM_BIT		3
  #define MPX_BOUNDS_TABLE_TOP_BIT		19
  #define MPX_BOUNDS_DIR_BOTTOM_BIT		20
  #define MPX_BOUNDS_DIR_TOP_BIT			47
  
  #endif
  
  #define MPX_BOUNDS_DIR_NR_ENTRIES	\
  	(MPX_BOUNDS_DIR_SIZE_BYTES/MPX_BOUNDS_DIR_ENTRY_SIZE_BYTES)
  #define MPX_BOUNDS_TABLE_NR_ENTRIES	\
  	(MPX_BOUNDS_TABLE_SIZE_BYTES/MPX_BOUNDS_TABLE_ENTRY_SIZE_BYTES)
  
  #define MPX_BOUNDS_TABLE_ENTRY_VALID_BIT	0x1
  
  struct mpx_bd_entry {
  	union {
  		char x[MPX_BOUNDS_DIR_ENTRY_SIZE_BYTES];
  		void *contents[0];
  	};
  } __attribute__((packed));
  
  struct mpx_bt_entry {
  	union {
  		char x[MPX_BOUNDS_TABLE_ENTRY_SIZE_BYTES];
  		unsigned long contents[0];
  	};
  } __attribute__((packed));
  
  struct mpx_bounds_dir {
  	struct mpx_bd_entry entries[MPX_BOUNDS_DIR_NR_ENTRIES];
  } __attribute__((packed));
  
  struct mpx_bounds_table {
  	struct mpx_bt_entry entries[MPX_BOUNDS_TABLE_NR_ENTRIES];
  } __attribute__((packed));
  
  static inline unsigned long GET_BITS(unsigned long val, int bottombit, int topbit)
  {
  	int total_nr_bits = topbit - bottombit;
  	unsigned long mask = (1UL << total_nr_bits)-1;
  	return (val >> bottombit) & mask;
  }
  
  static inline unsigned long __vaddr_bounds_table_index(void *vaddr)
  {
  	return GET_BITS((unsigned long)vaddr, MPX_BOUNDS_TABLE_BOTTOM_BIT,
  					      MPX_BOUNDS_TABLE_TOP_BIT);
  }
  
  static inline unsigned long __vaddr_bounds_directory_index(void *vaddr)
  {
  	return GET_BITS((unsigned long)vaddr, MPX_BOUNDS_DIR_BOTTOM_BIT,
  					      MPX_BOUNDS_DIR_TOP_BIT);
  }
  
  static inline struct mpx_bd_entry *mpx_vaddr_to_bd_entry(void *vaddr,
  		struct mpx_bounds_dir *bounds_dir)
  {
  	unsigned long index = __vaddr_bounds_directory_index(vaddr);
  	return &bounds_dir->entries[index];
  }
  
  static inline int bd_entry_valid(struct mpx_bd_entry *bounds_dir_entry)
  {
  	unsigned long __bd_entry = (unsigned long)bounds_dir_entry->contents;
  	return (__bd_entry & MPX_BOUNDS_TABLE_ENTRY_VALID_BIT);
  }
  
  static inline struct mpx_bounds_table *
  __bd_entry_to_bounds_table(struct mpx_bd_entry *bounds_dir_entry)
  {
  	unsigned long __bd_entry = (unsigned long)bounds_dir_entry->contents;
  	assert(__bd_entry & MPX_BOUNDS_TABLE_ENTRY_VALID_BIT);
  	__bd_entry &= ~MPX_BOUNDS_TABLE_ENTRY_VALID_BIT;
  	return (struct mpx_bounds_table *)__bd_entry;
  }
  
  static inline struct mpx_bt_entry *
  mpx_vaddr_to_bt_entry(void *vaddr, struct mpx_bounds_dir *bounds_dir)
  {
  	struct mpx_bd_entry *bde = mpx_vaddr_to_bd_entry(vaddr, bounds_dir);
  	struct mpx_bounds_table *bt = __bd_entry_to_bounds_table(bde);
  	unsigned long index = __vaddr_bounds_table_index(vaddr);
  	return &bt->entries[index];
  }
  
  #endif /* _MPX_HW_H */
  