x86/cpu: Use enums for TLB descriptor types

The leaf 0x2 one-byte TLB descriptor types:

	TLB_INST_4K
	TLB_INST_4M
	TLB_INST_2M_4M
	...

are just discriminators to be used within the intel_tlb_table[] mapping.
Their specific values are irrelevant.

Use enums for such types.

Make the enum packed and static assert that its values remain within a
single byte so that the intel_tlb_table[] size do not go out of hand.

Use a __CHECKER__ guard for the static_assert(sizeof(enum) == 1) line as
sparse ignores the __packed annotation on enums.

This is similar to:

  fe3944fb245a ("fs: Move enum rw_hint into a new header file")

for the core SCSI code.

Signed-off-by: Ahmed S. Darwish <darwi@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/Z9rsTirs9lLfEPD9@lx-t490
Link: https://lore.kernel.org/r/20250324133324.23458-20-darwi@linutronix.de

diff --git a/arch/x86/include/asm/cpuid/types.h b/arch/x86/include/asm/cpuid/types.h
index 39c3c79c081b56e5b57f529911c21df65d5aae7f..e756327f8e020cbfd0d45f15d45924580d98f7e8 100644 (file)
--- a/arch/x86/include/asm/cpuid/types.h
+++ b/arch/x86/include/asm/cpuid/types.h
@@ -60,4 +60,35 @@ enum _cache_table_type {
 static_assert(sizeof(enum _cache_table_type) == 1);
 #endif
 
+/*
+ * Leaf 0x2 1-byte descriptors' TLB types
+ * To be used for their mappings at intel_tlb_table[]
+ *
+ * Start at 1 since type 0 is reserved for HW byte descriptors which are
+ * not recognized by the kernel; i.e., those without an explicit mapping.
+ */
+enum _tlb_table_type {
+       TLB_INST_4K             = 1,
+       TLB_INST_4M,
+       TLB_INST_2M_4M,
+       TLB_INST_ALL,
+
+       TLB_DATA_4K,
+       TLB_DATA_4M,
+       TLB_DATA_2M_4M,
+       TLB_DATA_4K_4M,
+       TLB_DATA_1G,
+       TLB_DATA_1G_2M_4M,
+
+       TLB_DATA0_4K,
+       TLB_DATA0_4M,
+       TLB_DATA0_2M_4M,
+
+       STLB_4K,
+       STLB_4K_2M,
+} __packed;
+#ifndef __CHECKER__
+static_assert(sizeof(enum _tlb_table_type) == 1);
+#endif
+
 #endif /* _ASM_X86_CPUID_TYPES_H */

diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c
index aeb7d6d48379241137ec59bb48069d58dd7206f6..def433e0081f68d45ea2ab268ca7160c8ff5bd10 100644 (file)
--- a/arch/x86/kernel/cpu/intel.c
+++ b/arch/x86/kernel/cpu/intel.c
@@ -626,28 +626,6 @@ static unsigned int intel_size_cache(struct cpuinfo_x86 *c, unsigned int size)
 }
 #endif
 
-#define TLB_INST_4K            0x01
-#define TLB_INST_4M            0x02
-#define TLB_INST_2M_4M         0x03
-
-#define TLB_INST_ALL           0x05
-#define TLB_INST_1G            0x06
-
-#define TLB_DATA_4K            0x11
-#define TLB_DATA_4M            0x12
-#define TLB_DATA_2M_4M         0x13
-#define TLB_DATA_4K_4M         0x14
-
-#define TLB_DATA_1G            0x16
-#define TLB_DATA_1G_2M_4M      0x17
-
-#define TLB_DATA0_4K           0x21
-#define TLB_DATA0_4M           0x22
-#define TLB_DATA0_2M_4M                0x23
-
-#define STLB_4K                        0x41
-#define STLB_4K_2M             0x42
-
 /*
  * All of leaf 0x2's one-byte TLB descriptors implies the same number of
  * entries for their respective TLB types.  The 0x63 descriptor is an
@@ -660,7 +638,7 @@ static unsigned int intel_size_cache(struct cpuinfo_x86 *c, unsigned int size)
 
 struct _tlb_table {
        unsigned char descriptor;
-       char tlb_type;
+       enum _tlb_table_type type;
        unsigned int entries;
 };
 
@@ -718,11 +696,11 @@ static void intel_tlb_lookup(const unsigned char desc)
             intel_tlb_table[k].descriptor != 0; k++)
                ;
 
-       if (intel_tlb_table[k].tlb_type == 0)
+       if (intel_tlb_table[k].type == 0)
                return;
 
        entries = intel_tlb_table[k].entries;
-       switch (intel_tlb_table[k].tlb_type) {
+       switch (intel_tlb_table[k].type) {
        case STLB_4K:
                tlb_lli_4k = max(tlb_lli_4k, entries);
                tlb_lld_4k = max(tlb_lld_4k, entries);