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ARM: 7062/1: cache: detect PIPT I-cache using CTR 

The Cache Type Register L1Ip field identifies I-caches with a PIPT
policy using the encoding 11b.

This patch extends the cache policy parsing to identify PIPT I-caches
correctly and prevent them from being treated as VIPT aliasing in cases
where they are sufficiently large.

Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Will Deacon 2011-08-23 22:22:11 +01:00 committed by Russell King
parent 0744a3ee37
commit 7f94e9cc5e
2 changed files with 17 additions and 3 deletions
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5
arch/arm/include/asm/cachetype.h
View File

@ -7,6 +7,7 @@
#define CACHEID_VIPT (CACHEID_VIPT_ALIASING|CACHEID_VIPT_NONALIASING)
#define CACHEID_ASID_TAGGED (1 << 3)
#define CACHEID_VIPT_I_ALIASING (1 << 4)
#define CACHEID_PIPT (1 << 5)
extern unsigned int cacheid;
@ -16,6 +17,7 @@ extern unsigned int cacheid;
#define cache_is_vipt_aliasing() cacheid_is(CACHEID_VIPT_ALIASING)
#define icache_is_vivt_asid_tagged() cacheid_is(CACHEID_ASID_TAGGED)
#define icache_is_vipt_aliasing() cacheid_is(CACHEID_VIPT_I_ALIASING)
#define icache_is_pipt() cacheid_is(CACHEID_PIPT)
/*
* __LINUX_ARM_ARCH__ is the minimum supported CPU architecture
@ -26,7 +28,8 @@ extern unsigned int cacheid;
#if __LINUX_ARM_ARCH__ >= 7
#define __CACHEID_ARCH_MIN (CACHEID_VIPT_NONALIASING |\
CACHEID_ASID_TAGGED |\
CACHEID_VIPT_I_ALIASING)
CACHEID_VIPT_I_ALIASING |\
CACHEID_PIPT)
#elif __LINUX_ARM_ARCH__ >= 6
#define __CACHEID_ARCH_MIN (~CACHEID_VIVT)
#else

15
arch/arm/kernel/setup.c
View File

@ -265,6 +265,10 @@ static int cpu_has_aliasing_icache(unsigned int arch)
int aliasing_icache;
unsigned int id_reg, num_sets, line_size;
/* PIPT caches never alias. */
if (icache_is_pipt())
return 0;
/* arch specifies the register format */
switch (arch) {
case CPU_ARCH_ARMv7:
@ -299,8 +303,14 @@ static void __init cacheid_init(void)
/* ARMv7 register format */
arch = CPU_ARCH_ARMv7;
cacheid = CACHEID_VIPT_NONALIASING;
if ((cachetype & (3 << 14)) == 1 << 14)
switch (cachetype & (3 << 14)) {
case (1 << 14):
cacheid |= CACHEID_ASID_TAGGED;
break;
case (3 << 14):
cacheid |= CACHEID_PIPT;
break;
}
} else {
arch = CPU_ARCH_ARMv6;
if (cachetype & (1 << 23))
@ -317,10 +327,11 @@ static void __init cacheid_init(void)
printk("CPU: %s data cache, %s instruction cache\n",
cache_is_vivt() ? "VIVT" :
cache_is_vipt_aliasing() ? "VIPT aliasing" :
cache_is_vipt_nonaliasing() ? "VIPT nonaliasing" : "unknown",
cache_is_vipt_nonaliasing() ? "PIPT / VIPT nonaliasing" : "unknown",
cache_is_vivt() ? "VIVT" :
icache_is_vivt_asid_tagged() ? "VIVT ASID tagged" :
icache_is_vipt_aliasing() ? "VIPT aliasing" :
icache_is_pipt() ? "PIPT" :
cache_is_vipt_nonaliasing() ? "VIPT nonaliasing" : "unknown");
}