10 files changed, 40 insertions, 6 deletions

diff --git a/arch/ia64/Kconfig b/arch/ia64/Kconfig
index 5b4ec80bf586..7ff5b3bbf160 100644
--- a/arch/ia64/Kconfig
+++ b/arch/ia64/Kconfig
@@ -56,6 +56,7 @@ config IA64
 	select NEED_DMA_MAP_STATE
 	select NEED_SG_DMA_LENGTH
 	select NUMA if !FLATMEM
+	select PCI_MSI_ARCH_FALLBACKS
 	default y
 	help
 	  The Itanium Processor Family is Intel's 64-bit successor to
diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index c95fa3a2484c..3690582eb61f 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -86,6 +86,7 @@ config MIPS
 	select MODULES_USE_ELF_REL if MODULES
 	select MODULES_USE_ELF_RELA if MODULES && 64BIT
 	select PERF_USE_VMALLOC
+	select PCI_MSI_ARCH_FALLBACKS
 	select RTC_LIB
 	select SYSCTL_EXCEPTION_TRACE
 	select VIRT_TO_BUS
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 65bed1fdeaad..9e66ca1376af 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -246,6 +246,7 @@ config PPC
 	select OLD_SIGACTION			if PPC32
 	select OLD_SIGSUSPEND
 	select PCI_DOMAINS			if PCI
+	select PCI_MSI_ARCH_FALLBACKS
 	select PCI_SYSCALL			if PCI
 	select PPC_DAWR				if PPC64
 	select RTC_LIB
diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index b29fcc66ec39..63dd5a0aa252 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -185,6 +185,7 @@ config S390
 	select OLD_SIGSUSPEND3
 	select PCI_DOMAINS		if PCI
 	select PCI_MSI			if PCI
+	select PCI_MSI_ARCH_FALLBACKS
 	select SPARSE_IRQ
 	select SYSCTL_EXCEPTION_TRACE
 	select THREAD_INFO_IN_TASK
diff --git a/arch/sparc/Kconfig b/arch/sparc/Kconfig
index efeff2c896a5..21a3239870c0 100644
--- a/arch/sparc/Kconfig
+++ b/arch/sparc/Kconfig
@@ -43,6 +43,7 @@ config SPARC
 	select GENERIC_STRNLEN_USER
 	select MODULES_USE_ELF_RELA
 	select PCI_SYSCALL if PCI
+	select PCI_MSI_ARCH_FALLBACKS
 	select ODD_RT_SIGACTION
 	select OLD_SIGSUSPEND
 	select CPU_NO_EFFICIENT_FFS
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 7101ac64bb20..196e0688ec3c 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -225,6 +225,7 @@ config X86
 	select NEED_SG_DMA_LENGTH
 	select PCI_DOMAINS			if PCI
 	select PCI_LOCKLESS_CONFIG		if PCI
+	select PCI_MSI_ARCH_FALLBACKS
 	select PERF_EVENTS
 	select RTC_LIB
 	select RTC_MC146818_LIB
diff --git a/drivers/pci/Kconfig b/drivers/pci/Kconfig
index 4bef5c2bae9f..438a792d2cf7 100644
--- a/drivers/pci/Kconfig
+++ b/drivers/pci/Kconfig
@@ -56,6 +56,9 @@ config PCI_MSI_IRQ_DOMAIN
 	depends on PCI_MSI
 	select GENERIC_MSI_IRQ_DOMAIN
 
+config PCI_MSI_ARCH_FALLBACKS
+	bool
+
 config PCI_QUIRKS
 	default y
 	bool "Enable PCI quirk workarounds" if EXPERT
diff --git a/drivers/pci/controller/Kconfig b/drivers/pci/controller/Kconfig
index f18c3725ef80..4a7afbe189f8 100644
--- a/drivers/pci/controller/Kconfig
+++ b/drivers/pci/controller/Kconfig
@@ -41,6 +41,7 @@ config PCI_TEGRA
 	bool "NVIDIA Tegra PCIe controller"
 	depends on ARCH_TEGRA || COMPILE_TEST
 	depends on PCI_MSI_IRQ_DOMAIN
+	select PCI_MSI_ARCH_FALLBACKS
 	help
 	  Say Y here if you want support for the PCIe host controller found
 	  on NVIDIA Tegra SoCs.
@@ -67,6 +68,7 @@ config PCIE_RCAR_HOST
 	bool "Renesas R-Car PCIe host controller"
 	depends on ARCH_RENESAS || COMPILE_TEST
 	depends on PCI_MSI_IRQ_DOMAIN
+	select PCI_MSI_ARCH_FALLBACKS
 	help
 	  Say Y here if you want PCIe controller support on R-Car SoCs in host
 	  mode.
@@ -95,6 +97,7 @@ config PCI_HOST_GENERIC
 config PCIE_XILINX
 	bool "Xilinx AXI PCIe host bridge support"
 	depends on OF || COMPILE_TEST
+	select PCI_MSI_ARCH_FALLBACKS
 	help
 	  Say 'Y' here if you want kernel to support the Xilinx AXI PCIe
 	  Host Bridge driver.
diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
index a2f00d181016..d52d118979a6 100644
--- a/drivers/pci/msi.c
+++ b/drivers/pci/msi.c
@@ -58,8 +58,8 @@ static void pci_msi_teardown_msi_irqs(struct pci_dev *dev)
 #define pci_msi_teardown_msi_irqs	arch_teardown_msi_irqs
 #endif
 
+#ifdef CONFIG_PCI_MSI_ARCH_FALLBACKS
 /* Arch hooks */
-
 int __weak arch_setup_msi_irq(struct pci_dev *dev, struct msi_desc *desc)
 {
 	struct msi_controller *chip = dev->bus->msi;
@@ -132,6 +132,7 @@ void __weak arch_teardown_msi_irqs(struct pci_dev *dev)
 {
 	return default_teardown_msi_irqs(dev);
 }
+#endif /* CONFIG_PCI_MSI_ARCH_FALLBACKS */
 
 static void default_restore_msi_irq(struct pci_dev *dev, int irq)
 {
diff --git a/include/linux/msi.h b/include/linux/msi.h
index 0180534b5428..6b584cc4757c 100644
--- a/include/linux/msi.h
+++ b/include/linux/msi.h
@@ -193,17 +193,38 @@ void pci_msi_mask_irq(struct irq_data *data);
 void pci_msi_unmask_irq(struct irq_data *data);
 
 /*
- * The arch hooks to setup up msi irqs. Those functions are
- * implemented as weak symbols so that they /can/ be overriden by
- * architecture specific code if needed.
+ * The arch hooks to setup up msi irqs. Default functions are implemented
+ * as weak symbols so that they /can/ be overriden by architecture specific
+ * code if needed. These hooks must be enabled by the architecture or by
+ * drivers which depend on them via msi_controller based MSI handling.
+ *
+ * If CONFIG_PCI_MSI_ARCH_FALLBACKS is not selected they are replaced by
+ * stubs with warnings.
  */
+#ifdef CONFIG_PCI_MSI_ARCH_FALLBACKS
 int arch_setup_msi_irq(struct pci_dev *dev, struct msi_desc *desc);
 void arch_teardown_msi_irq(unsigned int irq);
 int arch_setup_msi_irqs(struct pci_dev *dev, int nvec, int type);
 void arch_teardown_msi_irqs(struct pci_dev *dev);
-void arch_restore_msi_irqs(struct pci_dev *dev);
-
 void default_teardown_msi_irqs(struct pci_dev *dev);
+#else
+static inline int arch_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
+{
+	WARN_ON_ONCE(1);
+	return -ENODEV;
+}
+
+static inline void arch_teardown_msi_irqs(struct pci_dev *dev)
+{
+	WARN_ON_ONCE(1);
+}
+#endif
+
+/*
+ * The restore hooks are still available as they are useful even
+ * for fully irq domain based setups. Courtesy to XEN/X86.
+ */
+void arch_restore_msi_irqs(struct pci_dev *dev);
 void default_restore_msi_irqs(struct pci_dev *dev);
 
 struct msi_controller {