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arm64: add helper functions to read I-cache attributes

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This adds helper functions and #defines to <asm/cachetype.h> to read the
line size and the number of sets from the level 1 instruction cache.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
This commit is contained in:
Ard Biesheuvel 2014-08-08 12:51:39 +01:00 committed by Will Deacon
parent 2ce7598c9a
commit 80c517b0ff
2 changed files with 34 additions and 0 deletions
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20
arch/arm64/include/asm/cachetype.h
View file

@ -39,6 +39,26 @@
extern unsigned long __icache_flags;
#define CCSIDR_EL1_LINESIZE_MASK 0x7
#define CCSIDR_EL1_LINESIZE(x) ((x) & CCSIDR_EL1_LINESIZE_MASK)
#define CCSIDR_EL1_NUMSETS_SHIFT 13
#define CCSIDR_EL1_NUMSETS_MASK (0x7fff << CCSIDR_EL1_NUMSETS_SHIFT)
#define CCSIDR_EL1_NUMSETS(x) \
(((x) & CCSIDR_EL1_NUMSETS_MASK) >> CCSIDR_EL1_NUMSETS_SHIFT)
extern u64 __attribute_const__ icache_get_ccsidr(void);
static inline int icache_get_linesize(void)
{
return 16 << CCSIDR_EL1_LINESIZE(icache_get_ccsidr());
}
static inline int icache_get_numsets(void)
{
return 1 + CCSIDR_EL1_NUMSETS(icache_get_ccsidr());
}
/*
* Whilst the D-side always behaves as PIPT on AArch64, aliasing is
* permitted in the I-cache.

14
arch/arm64/kernel/cpuinfo.c
View file

@ -20,8 +20,10 @@
#include <asm/cputype.h>
#include <linux/bitops.h>
#include <linux/bug.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/preempt.h>
#include <linux/printk.h>
#include <linux/smp.h>
@ -190,3 +192,15 @@ void __init cpuinfo_store_boot_cpu(void)
boot_cpu_data = *info;
}
u64 __attribute_const__ icache_get_ccsidr(void)
{
u64 ccsidr;
WARN_ON(preemptible());
/* Select L1 I-cache and read its size ID register */
asm("msr csselr_el1, %1; isb; mrs %0, ccsidr_el1"
: "=r"(ccsidr) : "r"(1L));
return ccsidr;
}