From 9304d1621e6019c63497f8a4aad09d003916dbe9 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Thu, 16 Mar 2017 22:50:03 +0100 Subject: [PATCH 1/5] x86/PCI: Remove duplicate defines For some historic reason these defines are duplicated and also available in arch/x86/include/asm/pci_x86.h, Remove them. Signed-off-by: Thomas Gleixner Acked-by: Bjorn Helgaas Cc: Andi Kleen Cc: Peter Zijlstra Cc: Stephane Eranian Cc: Borislav Petkov Cc: linux-pci@vger.kernel.org Link: http://lkml.kernel.org/r/20170316215056.967808646@linutronix.de Signed-off-by: Thomas Gleixner --- arch/x86/include/asm/pci.h | 8 +------- 1 file changed, 1 insertion(+), 7 deletions(-) diff --git a/arch/x86/include/asm/pci.h b/arch/x86/include/asm/pci.h index f513cc231151..473a7295ab10 100644 --- a/arch/x86/include/asm/pci.h +++ b/arch/x86/include/asm/pci.h @@ -77,14 +77,8 @@ static inline bool is_vmd(struct pci_bus *bus) extern unsigned int pcibios_assign_all_busses(void); extern int pci_legacy_init(void); -# ifdef CONFIG_ACPI -# define x86_default_pci_init pci_acpi_init -# else -# define x86_default_pci_init pci_legacy_init -# endif #else -# define pcibios_assign_all_busses() 0 -# define x86_default_pci_init NULL +static inline int pcibios_assign_all_busses(void) { return 0; } #endif extern unsigned long pci_mem_start; From aae3e318d012e76211f34bb65754f3d4d2a8c93d Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Thu, 16 Mar 2017 22:50:04 +0100 Subject: [PATCH 2/5] x86/PCI: Abort if legacy init fails If the legacy PCI init fails, then there are no PCI config space accesors available, but the code continues and tries to scan the busses, which fails due to the lack of config space accessors. Return right away, if the last init fallback fails. Switch the few printks to pr_info while at it. Signed-off-by: Thomas Gleixner Acked-by: Bjorn Helgaas Cc: Andi Kleen Cc: Peter Zijlstra Cc: Stephane Eranian Cc: Borislav Petkov Cc: linux-pci@vger.kernel.org Link: http://lkml.kernel.org/r/20170316215057.047576516@linutronix.de Signed-off-by: Thomas Gleixner --- arch/x86/pci/legacy.c | 18 ++++++++++-------- 1 file changed, 10 insertions(+), 8 deletions(-) diff --git a/arch/x86/pci/legacy.c b/arch/x86/pci/legacy.c index ea6f3802c17b..1cb01abcb1be 100644 --- a/arch/x86/pci/legacy.c +++ b/arch/x86/pci/legacy.c @@ -24,12 +24,10 @@ static void pcibios_fixup_peer_bridges(void) int __init pci_legacy_init(void) { - if (!raw_pci_ops) { - printk("PCI: System does not support PCI\n"); - return 0; - } + if (!raw_pci_ops) + return 1; - printk("PCI: Probing PCI hardware\n"); + pr_info("PCI: Probing PCI hardware\n"); pcibios_scan_root(0); return 0; } @@ -46,7 +44,7 @@ void pcibios_scan_specific_bus(int busn) if (!raw_pci_read(0, busn, devfn, PCI_VENDOR_ID, 2, &l) && l != 0x0000 && l != 0xffff) { DBG("Found device at %02x:%02x [%04x]\n", busn, devfn, l); - printk(KERN_INFO "PCI: Discovered peer bus %02x\n", busn); + pr_info("PCI: Discovered peer bus %02x\n", busn); pcibios_scan_root(busn); return; } @@ -60,8 +58,12 @@ static int __init pci_subsys_init(void) * The init function returns an non zero value when * pci_legacy_init should be invoked. */ - if (x86_init.pci.init()) - pci_legacy_init(); + if (x86_init.pci.init()) { + if (pci_legacy_init()) { + pr_info("PCI: System does not support PCI\n"); + return -ENODEV; + } + } pcibios_fixup_peer_bridges(); x86_init.pci.init_irq(); From bb290fda879ffd1f6f6b0869bf7335554093f4bd Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Thu, 16 Mar 2017 22:50:05 +0100 Subject: [PATCH 3/5] x86/PCI/ce4100: Properly lock accessor functions x86 wants to get rid of the global pci_lock protecting the config space accessors so ECAM mode can operate completely lockless, but the CE4100 PCI code relies on that to protect the simulation registers. Restructure the code so it uses the x86 specific pci_config_lock to serialize the inner workings of the CE4100 PCI magic. That allows to remove the global locking via pci_lock later. Signed-off-by: Thomas Gleixner Acked-by: Bjorn Helgaas Cc: Andi Kleen Cc: Peter Zijlstra Cc: Stephane Eranian Cc: Borislav Petkov Cc: linux-pci@vger.kernel.org Link: http://lkml.kernel.org/r/20170316215057.126873574@linutronix.de Signed-off-by: Thomas Gleixner --- arch/x86/pci/ce4100.c | 91 ++++++++++++++++++++++++------------------- 1 file changed, 50 insertions(+), 41 deletions(-) diff --git a/arch/x86/pci/ce4100.c b/arch/x86/pci/ce4100.c index b914e20b5a00..3353b76dcff0 100644 --- a/arch/x86/pci/ce4100.c +++ b/arch/x86/pci/ce4100.c @@ -65,6 +65,9 @@ struct sim_reg_op { { PCI_DEVFN(device, func), offset, init_op, read_op, write_op,\ {0, SIZE_TO_MASK(size)} }, +/* + * All read/write functions are called with pci_config_lock held. + */ static void reg_init(struct sim_dev_reg *reg) { pci_direct_conf1.read(0, 1, reg->dev_func, reg->reg, 4, @@ -73,21 +76,13 @@ static void reg_init(struct sim_dev_reg *reg) static void reg_read(struct sim_dev_reg *reg, u32 *value) { - unsigned long flags; - - raw_spin_lock_irqsave(&pci_config_lock, flags); *value = reg->sim_reg.value; - raw_spin_unlock_irqrestore(&pci_config_lock, flags); } static void reg_write(struct sim_dev_reg *reg, u32 value) { - unsigned long flags; - - raw_spin_lock_irqsave(&pci_config_lock, flags); reg->sim_reg.value = (value & reg->sim_reg.mask) | (reg->sim_reg.value & ~reg->sim_reg.mask); - raw_spin_unlock_irqrestore(&pci_config_lock, flags); } static void sata_reg_init(struct sim_dev_reg *reg) @@ -117,12 +112,8 @@ static void sata_revid_read(struct sim_dev_reg *reg, u32 *value) static void reg_noirq_read(struct sim_dev_reg *reg, u32 *value) { - unsigned long flags; - - raw_spin_lock_irqsave(&pci_config_lock, flags); /* force interrupt pin value to 0 */ *value = reg->sim_reg.value & 0xfff00ff; - raw_spin_unlock_irqrestore(&pci_config_lock, flags); } static struct sim_dev_reg bus1_fixups[] = { @@ -265,24 +256,33 @@ int bridge_read(unsigned int devfn, int reg, int len, u32 *value) return retval; } +static int ce4100_bus1_read(unsigned int devfn, int reg, int len, u32 *value) +{ + unsigned long flags; + int i; + + for (i = 0; i < ARRAY_SIZE(bus1_fixups); i++) { + if (bus1_fixups[i].dev_func == devfn && + bus1_fixups[i].reg == (reg & ~3) && + bus1_fixups[i].read) { + + raw_spin_lock_irqsave(&pci_config_lock, flags); + bus1_fixups[i].read(&(bus1_fixups[i]), value); + raw_spin_unlock_irqrestore(&pci_config_lock, flags); + extract_bytes(value, reg, len); + return 0; + } + } + return -1; +} + static int ce4100_conf_read(unsigned int seg, unsigned int bus, unsigned int devfn, int reg, int len, u32 *value) { - int i; - WARN_ON(seg); - if (bus == 1) { - for (i = 0; i < ARRAY_SIZE(bus1_fixups); i++) { - if (bus1_fixups[i].dev_func == devfn && - bus1_fixups[i].reg == (reg & ~3) && - bus1_fixups[i].read) { - bus1_fixups[i].read(&(bus1_fixups[i]), - value); - extract_bytes(value, reg, len); - return 0; - } - } - } + + if (bus == 1 && !ce4100_bus1_read(devfn, reg, len, value)) + return 0; if (bus == 0 && (PCI_DEVFN(1, 0) == devfn) && !bridge_read(devfn, reg, len, value)) @@ -291,23 +291,32 @@ static int ce4100_conf_read(unsigned int seg, unsigned int bus, return pci_direct_conf1.read(seg, bus, devfn, reg, len, value); } +static int ce4100_bus1_write(unsigned int devfn, int reg, int len, u32 value) +{ + unsigned long flags; + int i; + + for (i = 0; i < ARRAY_SIZE(bus1_fixups); i++) { + if (bus1_fixups[i].dev_func == devfn && + bus1_fixups[i].reg == (reg & ~3) && + bus1_fixups[i].write) { + + raw_spin_lock_irqsave(&pci_config_lock, flags); + bus1_fixups[i].write(&(bus1_fixups[i]), value); + raw_spin_unlock_irqrestore(&pci_config_lock, flags); + return 0; + } + } + return -1; +} + static int ce4100_conf_write(unsigned int seg, unsigned int bus, unsigned int devfn, int reg, int len, u32 value) { - int i; - WARN_ON(seg); - if (bus == 1) { - for (i = 0; i < ARRAY_SIZE(bus1_fixups); i++) { - if (bus1_fixups[i].dev_func == devfn && - bus1_fixups[i].reg == (reg & ~3) && - bus1_fixups[i].write) { - bus1_fixups[i].write(&(bus1_fixups[i]), - value); - return 0; - } - } - } + + if (bus == 1 && !ce4100_bus1_write(devfn, reg, len, value)) + return 0; /* Discard writes to A/V bridge BAR. */ if (bus == 0 && PCI_DEVFN(1, 0) == devfn && @@ -318,8 +327,8 @@ static int ce4100_conf_write(unsigned int seg, unsigned int bus, } static const struct pci_raw_ops ce4100_pci_conf = { - .read = ce4100_conf_read, - .write = ce4100_conf_write, + .read = ce4100_conf_read, + .write = ce4100_conf_write, }; int __init ce4100_pci_init(void) From 714fe383d6c9bd95d0d2cad8cbeff3688342d025 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Thu, 16 Mar 2017 22:50:06 +0100 Subject: [PATCH 4/5] PCI: Provide Kconfig option for lockless config space accessors The generic PCI configuration space accessors are globally serialized via pci_lock. On larger systems this causes massive lock contention when the configuration space has to be accessed frequently. One such access pattern is the Intel Uncore performance counter unit. Provide a kernel config option which can be selected by an architecture when the low level PCI configuration space accessors in the architecture use their own serialization or can operate completely lockless. Signed-off-by: Thomas Gleixner Acked-by: Bjorn Helgaas Cc: Andi Kleen Cc: Peter Zijlstra Cc: Stephane Eranian Cc: Borislav Petkov Cc: linux-pci@vger.kernel.org Link: http://lkml.kernel.org/r/20170316215057.205961140@linutronix.de Signed-off-by: Thomas Gleixner --- drivers/pci/Kconfig | 3 +++ drivers/pci/access.c | 16 ++++++++++++---- 2 files changed, 15 insertions(+), 4 deletions(-) diff --git a/drivers/pci/Kconfig b/drivers/pci/Kconfig index e0cacb7b8563..c32a77fc8b03 100644 --- a/drivers/pci/Kconfig +++ b/drivers/pci/Kconfig @@ -86,6 +86,9 @@ config PCI_ATS config PCI_ECAM bool +config PCI_LOCKLESS_CONFIG + bool + config PCI_IOV bool "PCI IOV support" depends on PCI diff --git a/drivers/pci/access.c b/drivers/pci/access.c index c80e37a69305..913d6722ece9 100644 --- a/drivers/pci/access.c +++ b/drivers/pci/access.c @@ -25,6 +25,14 @@ DEFINE_RAW_SPINLOCK(pci_lock); #define PCI_word_BAD (pos & 1) #define PCI_dword_BAD (pos & 3) +#ifdef CONFIG_PCI_LOCKLESS_CONFIG +# define pci_lock_config(f) do { (void)(f); } while (0) +# define pci_unlock_config(f) do { (void)(f); } while (0) +#else +# define pci_lock_config(f) raw_spin_lock_irqsave(&pci_lock, f) +# define pci_unlock_config(f) raw_spin_unlock_irqrestore(&pci_lock, f) +#endif + #define PCI_OP_READ(size, type, len) \ int pci_bus_read_config_##size \ (struct pci_bus *bus, unsigned int devfn, int pos, type *value) \ @@ -33,10 +41,10 @@ int pci_bus_read_config_##size \ unsigned long flags; \ u32 data = 0; \ if (PCI_##size##_BAD) return PCIBIOS_BAD_REGISTER_NUMBER; \ - raw_spin_lock_irqsave(&pci_lock, flags); \ + pci_lock_config(flags); \ res = bus->ops->read(bus, devfn, pos, len, &data); \ *value = (type)data; \ - raw_spin_unlock_irqrestore(&pci_lock, flags); \ + pci_unlock_config(flags); \ return res; \ } @@ -47,9 +55,9 @@ int pci_bus_write_config_##size \ int res; \ unsigned long flags; \ if (PCI_##size##_BAD) return PCIBIOS_BAD_REGISTER_NUMBER; \ - raw_spin_lock_irqsave(&pci_lock, flags); \ + pci_lock_config(flags); \ res = bus->ops->write(bus, devfn, pos, len, value); \ - raw_spin_unlock_irqrestore(&pci_lock, flags); \ + pci_unlock_config(flags); \ return res; \ } From df65c1bcd9b7b639177a5a15da1b8dc3bee4f5fa Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Thu, 16 Mar 2017 22:50:07 +0100 Subject: [PATCH 5/5] x86/PCI: Select CONFIG_PCI_LOCKLESS_CONFIG All x86 PCI configuration space accessors have either their own serialization or can operate completely lockless (ECAM). Disable the global lock in the generic PCI configuration space accessors. Signed-off-by: Thomas Gleixner Acked-by: Bjorn Helgaas Cc: Andi Kleen Cc: Peter Zijlstra Cc: Stephane Eranian Cc: Borislav Petkov Cc: linux-pci@vger.kernel.org Link: http://lkml.kernel.org/r/20170316215057.295079391@linutronix.de Signed-off-by: Thomas Gleixner --- arch/x86/Kconfig | 1 + arch/x86/pci/common.c | 4 ++-- 2 files changed, 3 insertions(+), 2 deletions(-) diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 0efb4c9497bc..0652c9f8902e 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -166,6 +166,7 @@ config X86 select HAVE_UNSTABLE_SCHED_CLOCK select HAVE_USER_RETURN_NOTIFIER select IRQ_FORCED_THREADING + select PCI_LOCKLESS_CONFIG select PERF_EVENTS select RTC_LIB select RTC_MC146818_LIB diff --git a/arch/x86/pci/common.c b/arch/x86/pci/common.c index 190e718694b1..cfd1a89fd04e 100644 --- a/arch/x86/pci/common.c +++ b/arch/x86/pci/common.c @@ -75,8 +75,8 @@ struct pci_ops pci_root_ops = { }; /* - * This interrupt-safe spinlock protects all accesses to PCI - * configuration space. + * This interrupt-safe spinlock protects all accesses to PCI configuration + * space, except for the mmconfig (ECAM) based operations. */ DEFINE_RAW_SPINLOCK(pci_config_lock);