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arm64: Implement cache_line_size() based on CTR_EL0.CWG 

The hardware provides the maximum cache line size in the system via the
CTR_EL0.CWG bits. This patch implements the cache_line_size() function
to read such information, together with a sanity check if the statically
defined L1_CACHE_BYTES is smaller than the hardware value.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Will Deacon <will.deacon@arm.com>
This commit is contained in:
Catalin Marinas 2014-04-03 17:48:54 +01:00
parent 89ca3b8819
commit a41dc0e841
4 changed files with 41 additions and 1 deletions
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3
arch/arm64/Kconfig
View File

@ -242,6 +242,9 @@ config ARCH_WANT_HUGE_PMD_SHARE
config HAVE_ARCH_TRANSPARENT_HUGEPAGE
def_bool y
config ARCH_HAS_CACHE_LINE_SIZE
def_bool y
source "mm/Kconfig"
config XEN_DOM0

13
arch/arm64/include/asm/cache.h
View File

@ -16,6 +16,8 @@
#ifndef __ASM_CACHE_H
#define __ASM_CACHE_H
#include <asm/cachetype.h>
#define L1_CACHE_SHIFT 6
#define L1_CACHE_BYTES (1 << L1_CACHE_SHIFT)
@ -27,6 +29,15 @@
* the CPU.
*/
#define ARCH_DMA_MINALIGN L1_CACHE_BYTES
#define ARCH_SLAB_MINALIGN 8
#ifndef __ASSEMBLY__
static inline int cache_line_size(void)
{
u32 cwg = cache_type_cwg();
return cwg ? 4 << cwg : L1_CACHE_BYTES;
}
#endif /* __ASSEMBLY__ */
#endif

11
arch/arm64/include/asm/cachetype.h
View File

@ -20,12 +20,16 @@
#define CTR_L1IP_SHIFT 14
#define CTR_L1IP_MASK 3
#define CTR_CWG_SHIFT 24
#define CTR_CWG_MASK 15
#define ICACHE_POLICY_RESERVED 0
#define ICACHE_POLICY_AIVIVT 1
#define ICACHE_POLICY_VIPT 2
#define ICACHE_POLICY_PIPT 3
#ifndef __ASSEMBLY__
static inline u32 icache_policy(void)
{
return (read_cpuid_cachetype() >> CTR_L1IP_SHIFT) & CTR_L1IP_MASK;
@ -45,4 +49,11 @@ static inline int icache_is_aivivt(void)
return icache_policy() == ICACHE_POLICY_AIVIVT;
}
static inline u32 cache_type_cwg(void)
{
return (read_cpuid_cachetype() >> CTR_CWG_SHIFT) & CTR_CWG_MASK;
}
#endif /* __ASSEMBLY__ */
#endif /* __ASM_CACHETYPE_H */

15
arch/arm64/kernel/setup.c
View File

@ -25,6 +25,7 @@
#include <linux/utsname.h>
#include <linux/initrd.h>
#include <linux/console.h>
#include <linux/cache.h>
#include <linux/bootmem.h>
#include <linux/seq_file.h>
#include <linux/screen_info.h>
@ -198,6 +199,8 @@ static void __init setup_processor(void)
{
struct cpu_info *cpu_info;
u64 features, block;
u32 cwg;
int cls;
cpu_info = lookup_processor_type(read_cpuid_id());
if (!cpu_info) {
@ -214,6 +217,18 @@ static void __init setup_processor(void)
sprintf(init_utsname()->machine, ELF_PLATFORM);
elf_hwcap = 0;
/*
* Check for sane CTR_EL0.CWG value.
*/
cwg = cache_type_cwg();
cls = cache_line_size();
if (!cwg)
pr_warn("No Cache Writeback Granule information, assuming cache line size %d\n",
cls);
if (L1_CACHE_BYTES < cls)
pr_warn("L1_CACHE_BYTES smaller than the Cache Writeback Granule (%d < %d)\n",
L1_CACHE_BYTES, cls);
/*
* ID_AA64ISAR0_EL1 contains 4-bit wide signed feature blocks.
* The blocks we test below represent incremental functionality