On Thu, Jun 29, 2017 at 07:06:44PM +0100, Sudeep Holla wrote:
> We already have various macros related to cache type and bitfields in
> CLIDR system register. We can replace some of the hardcoded values
> here using those existing macros.
>
> This patch reuses those existing cache type/info related macros and
> replaces the hardcorded values. It also removes some of the comments
> that become trivial with the macro names.
>
> Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
> Cc: Will Deacon <will.deacon@xxxxxxx>
> Cc: Christoffer Dall <christoffer.dall@xxxxxxxxxx>
> Cc: Marc Zyngier <marc.zyngier@xxxxxxx>
> Signed-off-by: Sudeep Holla <sudeep.holla@xxxxxxx>
> ---
> arch/arm64/include/asm/cache.h | 7 +++++++
> arch/arm64/kernel/cacheinfo.c | 7 -------
> arch/arm64/kvm/sys_regs.c | 29 +++++++++++++++--------------
> 3 files changed, 22 insertions(+), 21 deletions(-)
>
> Hi,
>
> I dropped the support for 64bit format CCSIDR after Will's commit a8d4636f96ad
> ("arm64: cacheinfo: Remove CCSIDR-based cache information probing"). However
> I forgot to follow up on this patch which can be still applied. So just
> reposting it.
>
> Regards,
> Sudeep
>
> diff --git a/arch/arm64/include/asm/cache.h b/arch/arm64/include/asm/cache.h
> index ea9bb4e0e9bb..70fd4357ed38 100644
> --- a/arch/arm64/include/asm/cache.h
> +++ b/arch/arm64/include/asm/cache.h
> @@ -49,6 +49,13 @@
> #define ICACHEF_VPIPT 1
> extern unsigned long __icache_flags;
>
> +#define MAX_CACHE_LEVEL 7 /* Max 7 level supported */
> +/* Ctypen, bits[3(n - 1) + 2 : 3(n - 1)], for n = 1 to 7 */
> +#define CLIDR_CTYPE_SHIFT(level) (3 * (level - 1))
> +#define CLIDR_CTYPE_MASK(level) (7 << CLIDR_CTYPE_SHIFT(level))
> +#define CLIDR_CTYPE(clidr, level) \
> + (((clidr) & CLIDR_CTYPE_MASK(level)) >> CLIDR_CTYPE_SHIFT(level))
> +
> /*
> * Whilst the D-side always behaves as PIPT on AArch64, aliasing is
> * permitted in the I-cache.
> diff --git a/arch/arm64/kernel/cacheinfo.c b/arch/arm64/kernel/cacheinfo.c
> index 380f2e2fbed5..4798aa4bc17b 100644
> --- a/arch/arm64/kernel/cacheinfo.c
> +++ b/arch/arm64/kernel/cacheinfo.c
> @@ -20,13 +20,6 @@
> #include <linux/cacheinfo.h>
> #include <linux/of.h>
>
> -#define MAX_CACHE_LEVEL 7 /* Max 7 level supported */
> -/* Ctypen, bits[3(n - 1) + 2 : 3(n - 1)], for n = 1 to 7 */
> -#define CLIDR_CTYPE_SHIFT(level) (3 * (level - 1))
> -#define CLIDR_CTYPE_MASK(level) (7 << CLIDR_CTYPE_SHIFT(level))
> -#define CLIDR_CTYPE(clidr, level) \
> - (((clidr) & CLIDR_CTYPE_MASK(level)) >> CLIDR_CTYPE_SHIFT(level))
> -
> static inline enum cache_type get_cache_type(int level)
> {
> u64 clidr;
> diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
> index 0fe27024a2e1..e4107047f405 100644
> --- a/arch/arm64/kvm/sys_regs.c
> +++ b/arch/arm64/kvm/sys_regs.c
> @@ -21,11 +21,13 @@
> */
>
> #include <linux/bsearch.h>
> +#include <linux/cacheinfo.h>
> #include <linux/kvm_host.h>
> #include <linux/mm.h>
> #include <linux/uaccess.h>
>
> #include <asm/cacheflush.h>
> +#include <asm/cache.h>
> #include <asm/cputype.h>
> #include <asm/debug-monitors.h>
> #include <asm/esr.h>
> @@ -68,7 +70,7 @@ static bool read_from_write_only(struct kvm_vcpu *vcpu,
> static u32 cache_levels;
>
> /* CSSELR values; used to index KVM_REG_ARM_DEMUX_ID_CCSIDR */
> -#define CSSELR_MAX 12
> +#define CSSELR_MAX ((MAX_CACHE_LEVEL - 1) << 1)
>
> /* Which cache CCSIDR represents depends on CSSELR value. */
> static u32 get_ccsidr(u32 csselr)
> @@ -1894,19 +1896,18 @@ static bool is_valid_cache(u32 val)
> return false;
>
> /* Bottom bit is Instruction or Data bit. Next 3 bits are level. */
> - level = (val >> 1);
> - ctype = (cache_levels >> (level * 3)) & 7;
> + level = (val >> 1) + 1;
> + ctype = CLIDR_CTYPE(cache_levels, level);
>
> switch (ctype) {
> - case 0: /* No cache */
> - return false;
> - case 1: /* Instruction cache only */
> - return (val & 1);
> - case 2: /* Data cache only */
> - case 4: /* Unified cache */
> - return !(val & 1);
> - case 3: /* Separate instruction and data caches */
> + case CACHE_TYPE_INST:
> + return (val & CACHE_TYPE_INST);
> + case CACHE_TYPE_DATA:
> + case CACHE_TYPE_UNIFIED:
> + return !(val & CACHE_TYPE_INST);
> + case CACHE_TYPE_SEPARATE:
> return true;
> + case CACHE_TYPE_NOCACHE:
> default: /* Reserved: we can't know instruction or data. */
> return false;
> }
These defines seem to be arch-generic concepts defined in
include/linux/cacheinfo.h. Are they guaranteed to not change and
therefore always match the format of ARM registers?
Otherwise, this looks good to me.
Thanks,
-Christoffer
> @@ -2173,11 +2174,11 @@ void kvm_sys_reg_table_init(void)
> */
> get_clidr_el1(NULL, &clidr); /* Ugly... */
> cache_levels = clidr.val;
> - for (i = 0; i < 7; i++)
> - if (((cache_levels >> (i*3)) & 7) == 0)
> + for (i = 1; i <= MAX_CACHE_LEVEL; i++)
> + if (CLIDR_CTYPE(cache_levels, i) == CACHE_TYPE_NOCACHE)
> break;
> /* Clear all higher bits. */
> - cache_levels &= (1 << (i*3))-1;
> + cache_levels &= (1 << CLIDR_CTYPE_SHIFT(i)) - 1;
> }
>
> /**
> --
> 2.7.4
>
