[PATCH] arm64: kvm: reuse existing cache type/info related macros

[Sudeep Holla]

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 <***@arm.com>
Cc: Will Deacon <***@arm.com>
Cc: Christoffer Dall <***@linaro.org>
Cc: Marc Zyngier <***@arm.com>
Signed-off-by: Sudeep Holla <***@arm.com>
---
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;
}
@@ -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;
}

/**

[Christoffer Dall]

Post by Sudeep Holla
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.
---
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 */
+ return (val & CACHE_TYPE_INST);
+ return !(val & CACHE_TYPE_INST);
return true;
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

Post by Sudeep Holla
@@ -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

[Sudeep Holla]

Post by Christoffer Dall

Post by Sudeep Holla
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.
---
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(-)

[...]

Post by Christoffer Dall

Post by Sudeep Holla
/* 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 */
+ return (val & CACHE_TYPE_INST);
+ return !(val & CACHE_TYPE_INST);
return true;
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?

Indeed, I have added the mapping code for other architectures which
doesn't match. We can do the same when ARM deviates :)

Post by Christoffer Dall
Otherwise, this looks good to me.

Thanks, Will/Marc had requested to repost after -rc1, will do that ASAP.