irqchip/gic-v3: Make gic_enable_sre an inline function

In order for gic_enable_sre to be used by the arm64 core code,
move it to arm-gic-v3.h. As a bonus, we now also check if
system registers have been already enabled, and return early
if they have.

In all cases, the function now returns a boolean indicating if
the enabling has been successful.

Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

diff --git a/drivers/irqchip/irq-gic-v3.c b/drivers/irqchip/irq-gic-v3.c
index 149e3c6..936da87 100644 (file)
--- a/drivers/irqchip/irq-gic-v3.c
+++ b/drivers/irqchip/irq-gic-v3.c
@@ -171,27 +171,6 @@ static void __maybe_unused gic_write_sgi1r(u64 val)
        asm volatile("msr_s " __stringify(ICC_SGI1R_EL1) ", %0" : : "r" (val));
 }
 
-static void gic_enable_sre(void)
-{
-       u64 val;
-
-       asm volatile("mrs_s %0, " __stringify(ICC_SRE_EL1) : "=r" (val));
-       val |= ICC_SRE_EL1_SRE;
-       asm volatile("msr_s " __stringify(ICC_SRE_EL1) ", %0" : : "r" (val));
-       isb();
-
-       /*
-        * Need to check that the SRE bit has actually been set. If
-        * not, it means that SRE is disabled at EL2. We're going to
-        * die painfully, and there is nothing we can do about it.
-        *
-        * Kindly inform the luser.
-        */
-       asm volatile("mrs_s %0, " __stringify(ICC_SRE_EL1) : "=r" (val));
-       if (!(val & ICC_SRE_EL1_SRE))
-               pr_err("GIC: unable to set SRE (disabled at EL2), panic ahead\n");
-}
-
 static void gic_enable_redist(bool enable)
 {
        void __iomem *rbase;
@@ -525,8 +504,15 @@ static int gic_populate_rdist(void)
 
 static void gic_cpu_sys_reg_init(void)
 {
-       /* Enable system registers */
-       gic_enable_sre();
+       /*
+        * Need to check that the SRE bit has actually been set. If
+        * not, it means that SRE is disabled at EL2. We're going to
+        * die painfully, and there is nothing we can do about it.
+        *
+        * Kindly inform the luser.
+        */
+       if (!gic_enable_sre())
+               pr_err("GIC: unable to set SRE (disabled at EL2), panic ahead\n");
 
        /* Set priority mask register */
        gic_write_pmr(DEFAULT_PMR_VALUE);

diff --git a/include/linux/irqchip/arm-gic-v3.h b/include/linux/irqchip/arm-gic-v3.h
index c0c8a2e..9001b0b 100644 (file)
--- a/include/linux/irqchip/arm-gic-v3.h
+++ b/include/linux/irqchip/arm-gic-v3.h
@@ -398,6 +398,22 @@ static inline void gic_write_dir(u64 irq)
        isb();
 }
 
+static inline bool gic_enable_sre(void)
+{
+       u64 val;
+
+       asm volatile("mrs_s %0, " __stringify(ICC_SRE_EL1) : "=r" (val));
+       if (val & ICC_SRE_EL1_SRE)
+               return true;
+
+       val |= ICC_SRE_EL1_SRE;
+       asm volatile("msr_s " __stringify(ICC_SRE_EL1) ", %0" : : "r" (val));
+       isb();
+       asm volatile("mrs_s %0, " __stringify(ICC_SRE_EL1) : "=r" (val));
+
+       return !!(val & ICC_SRE_EL1_SRE);
+}
+
 struct irq_domain;
 int its_cpu_init(void);
 int its_init(struct device_node *node, struct rdists *rdists,