arm64: Add hypervisor safe helper for checking constant capabilities

The hypervisor may not have full access to the kernel data structures
and hence cannot safely use cpus_have_cap() helper for checking the
system capability. Add a safe helper for hypervisors to check a constant
system capability, which *doesn't* fall back to checking the bitmap
maintained by the kernel. With this, make the cpus_have_cap() only
check the bitmask and force constant cap checks to use the new API
for quicker checks.

Cc: Robert Ritcher <rritcher@cavium.com>
Cc: Tirumalesh Chalamarla <tchalamarla@cavium.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

1 files changed, 1 insertions, 12 deletions

diff --git a/drivers/irqchip/irq-gic-v3.c b/drivers/irqchip/irq-gic-v3.c
index 19d642eae096..26e1d7fafb1e 100644
--- a/drivers/irqchip/irq-gic-v3.c
+++ b/drivers/irqchip/irq-gic-v3.c
@@ -120,11 +120,10 @@ static void gic_redist_wait_for_rwp(void)
 }
 
 #ifdef CONFIG_ARM64
-static DEFINE_STATIC_KEY_FALSE(is_cavium_thunderx);
 
 static u64 __maybe_unused gic_read_iar(void)
 {
-        if (static_branch_unlikely(&is_cavium_thunderx))
+        if (cpus_have_const_cap(ARM64_WORKAROUND_CAVIUM_23154))
                 return gic_read_iar_cavium_thunderx();
         else
                 return gic_read_iar_common();
@@ -905,14 +904,6 @@ static const struct irq_domain_ops partition_domain_ops = {
         .select = gic_irq_domain_select,
 };
 
-static void gicv3_enable_quirks(void)
-{
-#ifdef CONFIG_ARM64
-        if (cpus_have_cap(ARM64_WORKAROUND_CAVIUM_23154))
-                static_branch_enable(&is_cavium_thunderx);
-#endif
-}
-
 static int __init gic_init_bases(void __iomem *dist_base,
                                  struct redist_region *rdist_regs,
                                  u32 nr_redist_regions,
@@ -935,8 +926,6 @@ static int __init gic_init_bases(void __iomem *dist_base,
         gic_data.nr_redist_regions = nr_redist_regions;
         gic_data.redist_stride = redist_stride;
 
-        gicv3_enable_quirks();
-
         /*
          * Find out how many interrupts are supported.
          * The GIC only supports up to 1020 interrupt sources (SGI+PPI+SPI)