[Xen-changelog] [xen stable-4.6] xen/arm: cpufeature: Provide an helper to check if a capability is supported

[patchbot@xxxxxxx]

commit 225e9c7050e8f2694df3dc92c95b06a46e57130e
Author:     Julien Grall <julien.grall@xxxxxxx>
AuthorDate: Wed Jul 27 17:37:06 2016 +0100
Commit:     Stefano Stabellini <sstabellini@xxxxxxxxxx>
CommitDate: Fri Feb 16 16:34:47 2018 -0800

    xen/arm: cpufeature: Provide an helper to check if a capability is supported
    
    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@xxxxxxx>
    Acked-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>
    Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
    Signed-off-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>
    (cherry picked from commit 64eb606000f1258267f27e6819c59848e2226773)
---
 xen/arch/arm/cpufeature.c        | 16 ++++++++++++++++
 xen/include/asm-arm/cpufeature.h |  9 +++++++++
 2 files changed, 25 insertions(+)

diff --git a/xen/arch/arm/cpufeature.c b/xen/arch/arm/cpufeature.c
index 7a1b56b67e..088625bbac 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 2bebad16cd..be2414c671 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
--
generated by git-patchbot for /home/xen/git/xen.git#stable-4.6

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