Commit 543904cd authored by Ahmed S. Darwish's avatar Ahmed S. Darwish Committed by Ingo Molnar
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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:

  fe3944fb ("fs: Move enum rw_hint into a new header file")

for the core SCSI code.

Signed-off-by: default avatarAhmed S. Darwish <darwi@linutronix.de>
Signed-off-by: default avatarIngo 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
parent e1e6b571

arch/x86/include/asm/cpuid/types.h

+31 −0
Original line number Diff line number Diff line
@@ -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 */

arch/x86/kernel/cpu/intel.c

+3 −25
Original line number Diff line number Diff line
@@ -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);