arm: move GIC SGI kicking into separate function

Currently we unconditionally send SGIs to all cores on SMP bringup.

Those SGIs (software generated interrupts) are to push a secondary core
through a gate in the Xen bring up code to filter the right CPU. This gate is
necessary on platforms which do not allow us to wake up a specific secondary
processor and will trap all but the CPU we are trying to wake up.

With PSCI we can explicitly specify the core to startup, so we don't need the
kick here because the CPU will fall straight through Xen's gate.

So we move the GIC kick into a function and call it explicitly from the
platforms that need it. This gets us get rid of the empty cpu_up() platform
functions in ARM32 and the comment in there.

Signed-off-by: Andre Przywara <andre.przywara@linaro.org>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
[ ijc -- explain more about the Xen gate in the commit message ]

diff --git a/xen/arch/arm/arm64/smpboot.c b/xen/arch/arm/arm64/smpboot.c
index 8696ed6a795cc4115ba34ddd4ee2c03da5d6a219..6a34bd4b5a4937cebefc87a78c34ca6c940da1f0 100644 (file)
--- a/xen/arch/arm/arm64/smpboot.c
+++ b/xen/arch/arm/arm64/smpboot.c
@@ -38,7 +38,7 @@ static int __init smp_spin_table_cpu_up(int cpu)
 
     sev();
 
-    return 0;
+    return cpu_up_send_sgi(cpu);
 }
 
 static void __init smp_spin_table_init(int cpu, struct dt_device_node *dn)

diff --git a/xen/arch/arm/platform.c b/xen/arch/arm/platform.c
index 5ed8eb269c1f5e17390a4dfe5ea77be4456baf0a..e13a354cd5a61238e0fdb6ec0569401c2801dd98 100644 (file)
--- a/xen/arch/arm/platform.c
+++ b/xen/arch/arm/platform.c
@@ -112,7 +112,7 @@ int __init platform_cpu_up(int cpu)
     if ( platform && platform->cpu_up )
         return platform->cpu_up(cpu);
 
-    return -EAGAIN;
+    return -ENODEV;
 }
 
 int __init platform_smp_init(void)

diff --git a/xen/arch/arm/platforms/exynos5.c b/xen/arch/arm/platforms/exynos5.c
index fa6b46542c60756b4c2ffac0365fadd3db882892..65e584f73ab51dd5d2ea93db5986768ae68e90ea 100644 (file)
--- a/xen/arch/arm/platforms/exynos5.c
+++ b/xen/arch/arm/platforms/exynos5.c
@@ -85,15 +85,6 @@ static int __init exynos5_smp_init(void)
     return 0;
 }
 
-static int __init exynos5_cpu_up(int cpu)
-{
-    /* Nothing to do here, the generic sev() will suffice to kick CPUs
-     * out of either the firmware or our own smp_up_cpu gate,
-     * depending on where they have ended up. */
-
-    return 0;
-}
-
 static void exynos5_reset(void)
 {
     void __iomem *pmu;
@@ -132,7 +123,7 @@ PLATFORM_START(exynos5, "SAMSUNG EXYNOS5")
     .init_time = exynos5_init_time,
     .specific_mapping = exynos5_specific_mapping,
     .smp_init = exynos5_smp_init,
-    .cpu_up = exynos5_cpu_up,
+    .cpu_up = cpu_up_send_sgi,
     .reset = exynos5_reset,
     .blacklist_dev = exynos5_blacklist_dev,
 PLATFORM_END

diff --git a/xen/arch/arm/platforms/omap5.c b/xen/arch/arm/platforms/omap5.c
index 3a3b16b0bd2ea852b6e4b63ef638090cd3f1bc22..423d11b144e4136e58034c2c9ce9b1803fec34d9 100644 (file)
--- a/xen/arch/arm/platforms/omap5.c
+++ b/xen/arch/arm/platforms/omap5.c
@@ -144,15 +144,6 @@ static int __init omap5_smp_init(void)
     return 0;
 }
 
-static int __init omap5_cpu_up(int cpu)
-{
-    /* Nothing to do here, the generic sev() will suffice to kick CPUs
-     * out of either the firmware or our own smp_up_cpu gate,
-     * depending on where they have ended up. */
-
-    return 0;
-}
-
 static const char const *omap5_dt_compat[] __initconst =
 {
     "ti,omap5",
@@ -164,7 +155,7 @@ PLATFORM_START(omap5, "TI OMAP5")
     .init_time = omap5_init_time,
     .specific_mapping = omap5_specific_mapping,
     .smp_init = omap5_smp_init,
-    .cpu_up = omap5_cpu_up,
+    .cpu_up = cpu_up_send_sgi,
 PLATFORM_END
 
 /*

diff --git a/xen/arch/arm/platforms/vexpress.c b/xen/arch/arm/platforms/vexpress.c
index 9056366428d913cf48cd742c6795c5aa450a1c66..613205637a37b26ff537c8eaab289db1e1a8ee89 100644 (file)
--- a/xen/arch/arm/platforms/vexpress.c
+++ b/xen/arch/arm/platforms/vexpress.c
@@ -144,14 +144,6 @@ static int __init vexpress_smp_init(void)
     return 0;
 }
 
-static int __init vexpress_cpu_up(int cpu)
-{
-    /* Nothing to do here, the generic sev() will suffice to kick CPUs
-     * out of either the firmware or our own smp_up_cpu gate,
-     * depending on where they have ended up. */
-
-    return 0;
-}
 #endif
 
 static const char * const vexpress_dt_compat[] __initconst =
@@ -180,7 +172,7 @@ PLATFORM_START(vexpress, "VERSATILE EXPRESS")
     .compatible = vexpress_dt_compat,
 #ifdef CONFIG_ARM_32
     .smp_init = vexpress_smp_init,
-    .cpu_up = vexpress_cpu_up,
+    .cpu_up = cpu_up_send_sgi,
 #endif
     .reset = vexpress_reset,
     .blacklist_dev = vexpress_blacklist_dev,

diff --git a/xen/arch/arm/smpboot.c b/xen/arch/arm/smpboot.c
index bd76d141e4b24736c91de0489e0c5a44af413412..8d96c17983c68e3a7f364a4a0ca80bcaf11eb3d6 100644 (file)
--- a/xen/arch/arm/smpboot.c
+++ b/xen/arch/arm/smpboot.c
@@ -343,6 +343,16 @@ void stop_cpu(void)
         wfi();
 }
 
+int __init cpu_up_send_sgi(int cpu)
+{
+    /* We don't know the GIC ID of the CPU until it has woken up, so just
+     * signal everyone and rely on our own smp_up_cpu gate to ensure only
+     * the one we want gets through. */
+    send_SGI_allbutself(GIC_SGI_EVENT_CHECK);
+
+    return 0;
+}
+
 /* Bring up a remote CPU */
 int __cpu_up(unsigned int cpu)
 {
@@ -376,11 +386,6 @@ int __cpu_up(unsigned int cpu)
         return rc;
     }
 
-    /* We don't know the GIC ID of the CPU until it has woken up, so just signal
-     * everyone and rely on our own smp_up_cpu gate to ensure only the one we
-     * want gets through. */
-    send_SGI_allbutself(GIC_SGI_EVENT_CHECK);
-
     while ( !cpu_online(cpu) )
     {
         cpu_relax();

diff --git a/xen/include/asm-arm/smp.h b/xen/include/asm-arm/smp.h
index 1485cc64d3b3f383c81fa31a05e420bb548f2872..a1de03c32d1b36b9079ea868d95e36cc528dd38f 100644 (file)
--- a/xen/include/asm-arm/smp.h
+++ b/xen/include/asm-arm/smp.h
@@ -21,6 +21,8 @@ extern int arch_smp_init(void);
 extern int arch_cpu_init(int cpu, struct dt_device_node *dn);
 extern int arch_cpu_up(int cpu);
 
+int cpu_up_send_sgi(int cpu);
+
 /* Secondary CPU entry point */
 extern void init_secondary(void);