diff mbox

[Xen-devel,v5,2/7] xen/arm: cpufeature: Provide an helper to check if a capability is supported

Message ID 1469028360-20907-3-git-send-email-julien.grall@arm.com
State Superseded
Headers show

Commit Message

Julien Grall July 20, 2016, 3:25 p.m. UTC 
The CPU capabilities will be set depending on the value found in the CPU
registers. This patch provides a generic to go through a set of capabilities
and find which one should be enabled.

The parameter "info" is used to display the kind of capability updated (e.g
workaround, feature...).

Signed-off-by: Julien Grall <julien.grall@arm.com>
Acked-by: Stefano Stabellini <sstabellini@kernel.org>

---
    Changes in v4:
        - Add Stefano's acked-by

    Changes in v3:
         - Patch added. The code was previously part of "Detect
         silicon...".
---
 xen/arch/arm/cpufeature.c        | 16 ++++++++++++++++
 xen/include/asm-arm/cpufeature.h |  9 +++++++++
 2 files changed, 25 insertions(+)

Comments

Julien Grall July 22, 2016, 3:31 p.m. UTC | #1 
Hi Konrad,

On 22/07/16 15:18, Konrad Rzeszutek Wilk wrote:
> On Wed, Jul 20, 2016 at 04:25:55PM +0100, Julien Grall wrote:
>> diff --git a/xen/arch/arm/cpufeature.c b/xen/arch/arm/cpufeature.c
>> index 7a1b56b..088625b 100644
>> --- a/xen/arch/arm/cpufeature.c
>> +++ b/xen/arch/arm/cpufeature.c
>> @@ -24,6 +24,22 @@
>>
>>  DECLARE_BITMAP(cpu_hwcaps, ARM_NCAPS);
>>
>> +void update_cpu_capabilities(const struct arm_cpu_capabilities *caps,
>> +                             const char *info)
>> +{
>> +    int i;
>> +
>> +    for ( i = 0; caps[i].matches; i++ )
>> +    {
>> +        if ( !caps[i].matches(&caps[i]) )
>
> So what if the 'struct arm_cpu_capabilitues' has '->matches' set to
> NULL?

It is the exit condition of the loop:

  for ( i = 0; caps[i].matches; i++ )

Regards,
diff mbox

Patch

diff --git a/xen/arch/arm/cpufeature.c b/xen/arch/arm/cpufeature.c
index 7a1b56b..088625b 100644
--- a/xen/arch/arm/cpufeature.c
+++ b/xen/arch/arm/cpufeature.c
@@ -24,6 +24,22 @@ 
 
 DECLARE_BITMAP(cpu_hwcaps, ARM_NCAPS);
 
+void update_cpu_capabilities(const struct arm_cpu_capabilities *caps,
+                             const char *info)
+{
+    int i;
+
+    for ( i = 0; caps[i].matches; i++ )
+    {
+        if ( !caps[i].matches(&caps[i]) )
+            continue;
+
+        if ( !cpus_have_cap(caps[i].capability) && caps[i].desc )
+            printk(XENLOG_INFO "%s: %s\n", info, caps[i].desc);
+        cpus_set_cap(caps[i].capability);
+    }
+}
+
 /*
  * Local variables:
  * mode: C
diff --git a/xen/include/asm-arm/cpufeature.h b/xen/include/asm-arm/cpufeature.h
index 2bebad1..be2414c 100644
--- a/xen/include/asm-arm/cpufeature.h
+++ b/xen/include/asm-arm/cpufeature.h
@@ -62,6 +62,15 @@  static inline void cpus_set_cap(unsigned int num)
         __set_bit(num, cpu_hwcaps);
 }
 
+struct arm_cpu_capabilities {
+    const char *desc;
+    u16 capability;
+    bool_t (*matches)(const struct arm_cpu_capabilities *);
+};
+
+void update_cpu_capabilities(const struct arm_cpu_capabilities *caps,
+                             const char *info);
+
 #endif /* __ASSEMBLY__ */
 
 #endif