1  /* SPDX-License-Identifier: GPL-2.0-only */
 2  
 3  #ifndef CPU_X86_CACHE
 4  #define CPU_X86_CACHE
 5  
 6  #include <cpu/x86/cr.h>
 7  
 8  #define CR0_CacheDisable	(CR0_CD)
 9  #define CR0_NoWriteThrough	(CR0_NW)
10  
11  #define CPUID_FEATURE_CLFLUSH_BIT 19
12  #define CPUID_FEATURE_SELF_SNOOP_BIT 27
13  
14  #if !defined(__ASSEMBLER__)
15  
16  #include <arch/cpuid.h>
17  #include <stdbool.h>
18  #include <stddef.h>
19  
20  static inline void wbinvd(void)
21  {
22  	asm volatile ("wbinvd" ::: "memory");
23  }
24  
25  static inline void invd(void)
26  {
27  	asm volatile("invd" ::: "memory");
28  }
29  
30  static inline void clflush(void *addr)
31  {
32  	asm volatile ("clflush (%0)"::"r" (addr));
33  }
34  
35  bool clflush_supported(void);
36  void clflush_region(const uintptr_t start, const size_t size);
37  
38  /* The following functions require the __always_inline due to AMD
39   * function STOP_CAR_AND_CPU that disables cache as
40   * RAM, the cache as RAM stack can no longer be used. Called
41   * functions must be inlined to avoid stack usage. Also, the
42   * compiler must keep local variables register based and not
43   * allocated them from the stack. With gcc 4.5.0, some functions
44   * declared as inline are not being inlined. This patch forces
45   * these functions to always be inlined by adding the qualifier
46   * __always_inline to their declaration.
47   */
48  static __always_inline void enable_cache(void)
49  {
50  	write_cr0(read_cr0() & ~(CR0_CD | CR0_NW));
51  }
52  
53  /*
54   * Cache flushing is the most time-consuming step when programming the MTRRs.
55   * However, if the processor supports cache self-snooping (ss), we can skip
56   * this step and save time.
57   */
58  static __always_inline bool self_snooping_supported(void)
59  {
60  	return (cpuid_edx(1) >> CPUID_FEATURE_SELF_SNOOP_BIT) & 1;
61  }
62  
63  static __always_inline void disable_cache(void)
64  {
65  	/* Disable and write back the cache */
66  	write_cr0(read_cr0() | CR0_CD);
67  	if (!self_snooping_supported())
68  		wbinvd();
69  }
70  
71  #endif /* !__ASSEMBLER__ */
72  #endif /* CPU_X86_CACHE */