[PATCH v2] libnvdimm, e820: make CONFIG_X86_PMEM_LEGACY a tristate option
From: Dan Williams
Date: Wed Aug 19 2015 - 00:51:04 EST
We currently register a platform device for e820 type-12 memory and
register a nvdimm bus beneath it. Registering the platform device
triggers the device-core machinery to probe for a driver, but that
search currently comes up empty. Building the nvdimm-bus registration
into the e820_pmem platform device registration in this way forces
libnvdimm to be built-in. Instead, convert the built-in portion of
CONFIG_X86_PMEM_LEGACY to simply register a platform device and move the
rest of the logic to the driver for e820_pmem, for the following
reasons:
1/ Letting e820_pmem support be a module allows building and testing
libnvdimm.ko changes without rebooting
2/ All the normal policy around modules can be applied to e820_pmem
(unbind to disable and/or blacklisting the module from loading by
default)
3/ Moving the driver to a generic location and converting it to scan
"iomem_resource" rather than "e820.map" means any other architecture can
take advantage of this simple nvdimm resource discovery mechanism by
registering a resource named "Persistent Memory (legacy)"
Cc: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
---
No code changes since v1, just a revised changelog.
arch/x86/Kconfig | 6 ++-
arch/x86/include/uapi/asm/e820.h | 2 -
arch/x86/kernel/Makefile | 2 -
arch/x86/kernel/pmem.c | 79 ++++-------------------------------
drivers/nvdimm/Makefile | 3 +
drivers/nvdimm/e820.c | 86 ++++++++++++++++++++++++++++++++++++++
tools/testing/nvdimm/Kbuild | 4 ++
7 files changed, 108 insertions(+), 74 deletions(-)
create mode 100644 drivers/nvdimm/e820.c
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index b3a1a5d77d92..76c61154ed50 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1426,10 +1426,14 @@ config ILLEGAL_POINTER_VALUE
source "mm/Kconfig"
+config X86_PMEM_LEGACY_DEVICE
+ bool
+
config X86_PMEM_LEGACY
- bool "Support non-standard NVDIMMs and ADR protected memory"
+ tristate "Support non-standard NVDIMMs and ADR protected memory"
depends on PHYS_ADDR_T_64BIT
depends on BLK_DEV
+ select X86_PMEM_LEGACY_DEVICE
select LIBNVDIMM
help
Treat memory marked using the non-standard e820 type of 12 as used
diff --git a/arch/x86/include/uapi/asm/e820.h b/arch/x86/include/uapi/asm/e820.h
index 0f457e6eab18..9dafe59cf6e2 100644
--- a/arch/x86/include/uapi/asm/e820.h
+++ b/arch/x86/include/uapi/asm/e820.h
@@ -37,7 +37,7 @@
/*
* This is a non-standardized way to represent ADR or NVDIMM regions that
* persist over a reboot. The kernel will ignore their special capabilities
- * unless the CONFIG_X86_PMEM_LEGACY=y option is set.
+ * unless the CONFIG_X86_PMEM_LEGACY option is set.
*
* ( Note that older platforms also used 6 for the same type of memory,
* but newer versions switched to 12 as 6 was assigned differently. Some
diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index 0f15af41bd80..ac2bb7e28ba2 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -92,7 +92,7 @@ obj-$(CONFIG_KVM_GUEST) += kvm.o kvmclock.o
obj-$(CONFIG_PARAVIRT) += paravirt.o paravirt_patch_$(BITS).o
obj-$(CONFIG_PARAVIRT_SPINLOCKS)+= paravirt-spinlocks.o
obj-$(CONFIG_PARAVIRT_CLOCK) += pvclock.o
-obj-$(CONFIG_X86_PMEM_LEGACY) += pmem.o
+obj-$(CONFIG_X86_PMEM_LEGACY_DEVICE) += pmem.o
obj-$(CONFIG_PCSPKR_PLATFORM) += pcspeaker.o
diff --git a/arch/x86/kernel/pmem.c b/arch/x86/kernel/pmem.c
index 64f90f53bb85..4f00b63d7ff3 100644
--- a/arch/x86/kernel/pmem.c
+++ b/arch/x86/kernel/pmem.c
@@ -3,80 +3,17 @@
* Copyright (c) 2015, Intel Corporation.
*/
#include <linux/platform_device.h>
-#include <linux/libnvdimm.h>
#include <linux/module.h>
-#include <asm/e820.h>
-
-static void e820_pmem_release(struct device *dev)
-{
- struct nvdimm_bus *nvdimm_bus = dev->platform_data;
-
- if (nvdimm_bus)
- nvdimm_bus_unregister(nvdimm_bus);
-}
-
-static struct platform_device e820_pmem = {
- .name = "e820_pmem",
- .id = -1,
- .dev = {
- .release = e820_pmem_release,
- },
-};
-
-static const struct attribute_group *e820_pmem_attribute_groups[] = {
- &nvdimm_bus_attribute_group,
- NULL,
-};
-
-static const struct attribute_group *e820_pmem_region_attribute_groups[] = {
- &nd_region_attribute_group,
- &nd_device_attribute_group,
- NULL,
-};
static __init int register_e820_pmem(void)
{
- static struct nvdimm_bus_descriptor nd_desc;
- struct device *dev = &e820_pmem.dev;
- struct nvdimm_bus *nvdimm_bus;
- int rc, i;
-
- rc = platform_device_register(&e820_pmem);
- if (rc)
- return rc;
-
- nd_desc.attr_groups = e820_pmem_attribute_groups;
- nd_desc.provider_name = "e820";
- nvdimm_bus = nvdimm_bus_register(dev, &nd_desc);
- if (!nvdimm_bus)
- goto err;
- dev->platform_data = nvdimm_bus;
-
- for (i = 0; i < e820.nr_map; i++) {
- struct e820entry *ei = &e820.map[i];
- struct resource res = {
- .flags = IORESOURCE_MEM,
- .start = ei->addr,
- .end = ei->addr + ei->size - 1,
- };
- struct nd_region_desc ndr_desc;
-
- if (ei->type != E820_PRAM)
- continue;
-
- memset(&ndr_desc, 0, sizeof(ndr_desc));
- ndr_desc.res = &res;
- ndr_desc.attr_groups = e820_pmem_region_attribute_groups;
- ndr_desc.numa_node = NUMA_NO_NODE;
- if (!nvdimm_pmem_region_create(nvdimm_bus, &ndr_desc))
- goto err;
- }
-
- return 0;
-
- err:
- dev_err(dev, "failed to register legacy persistent memory ranges\n");
- platform_device_unregister(&e820_pmem);
- return -ENXIO;
+ struct platform_device *pdev;
+
+ /*
+ * See drivers/nvdimm/e820.c for the implementation, this is
+ * simply here to trigger the module to load on demand.
+ */
+ pdev = platform_device_alloc("e820_pmem", -1);
+ return platform_device_add(pdev);
}
device_initcall(register_e820_pmem);
diff --git a/drivers/nvdimm/Makefile b/drivers/nvdimm/Makefile
index 594bb97c867a..9bf15db52dee 100644
--- a/drivers/nvdimm/Makefile
+++ b/drivers/nvdimm/Makefile
@@ -2,6 +2,7 @@ obj-$(CONFIG_LIBNVDIMM) += libnvdimm.o
obj-$(CONFIG_BLK_DEV_PMEM) += nd_pmem.o
obj-$(CONFIG_ND_BTT) += nd_btt.o
obj-$(CONFIG_ND_BLK) += nd_blk.o
+obj-$(CONFIG_X86_PMEM_LEGACY) += nd_e820.o
nd_pmem-y := pmem.o
@@ -9,6 +10,8 @@ nd_btt-y := btt.o
nd_blk-y := blk.o
+nd_e820-y := e820.o
+
libnvdimm-y := core.o
libnvdimm-y += bus.o
libnvdimm-y += dimm_devs.o
diff --git a/drivers/nvdimm/e820.c b/drivers/nvdimm/e820.c
new file mode 100644
index 000000000000..1b5743ad92db
--- /dev/null
+++ b/drivers/nvdimm/e820.c
@@ -0,0 +1,86 @@
+/*
+ * Copyright (c) 2015, Christoph Hellwig.
+ * Copyright (c) 2015, Intel Corporation.
+ */
+#include <linux/platform_device.h>
+#include <linux/libnvdimm.h>
+#include <linux/module.h>
+
+static const struct attribute_group *e820_pmem_attribute_groups[] = {
+ &nvdimm_bus_attribute_group,
+ NULL,
+};
+
+static const struct attribute_group *e820_pmem_region_attribute_groups[] = {
+ &nd_region_attribute_group,
+ &nd_device_attribute_group,
+ NULL,
+};
+
+static int e820_pmem_remove(struct platform_device *pdev)
+{
+ struct nvdimm_bus *nvdimm_bus = platform_get_drvdata(pdev);
+
+ nvdimm_bus_unregister(nvdimm_bus);
+ return 0;
+}
+
+static int e820_pmem_probe(struct platform_device *pdev)
+{
+ static struct nvdimm_bus_descriptor nd_desc;
+ struct device *dev = &pdev->dev;
+ struct nvdimm_bus *nvdimm_bus;
+ struct resource *p;
+
+ nd_desc.attr_groups = e820_pmem_attribute_groups;
+ nd_desc.provider_name = "e820";
+ nvdimm_bus = nvdimm_bus_register(dev, &nd_desc);
+ if (!nvdimm_bus)
+ goto err;
+ platform_set_drvdata(pdev, nvdimm_bus);
+
+ for (p = iomem_resource.child; p ; p = p->sibling) {
+ struct nd_region_desc ndr_desc;
+
+ if (strncmp(p->name, "Persistent Memory (legacy)", 26) != 0)
+ continue;
+
+ memset(&ndr_desc, 0, sizeof(ndr_desc));
+ ndr_desc.res = p;
+ ndr_desc.attr_groups = e820_pmem_region_attribute_groups;
+ ndr_desc.numa_node = NUMA_NO_NODE;
+ if (!nvdimm_pmem_region_create(nvdimm_bus, &ndr_desc))
+ goto err;
+ }
+
+ return 0;
+
+ err:
+ nvdimm_bus_unregister(nvdimm_bus);
+ dev_err(dev, "failed to register legacy persistent memory ranges\n");
+ return -ENXIO;
+}
+
+static struct platform_driver e820_pmem_driver = {
+ .probe = e820_pmem_probe,
+ .remove = e820_pmem_remove,
+ .driver = {
+ .name = "e820_pmem",
+ },
+};
+
+static __init int e820_pmem_init(void)
+{
+ return platform_driver_register(&e820_pmem_driver);
+}
+
+static __exit void e820_pmem_exit(void)
+{
+ platform_driver_unregister(&e820_pmem_driver);
+}
+
+MODULE_ALIAS("platform:e820_pmem*");
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Intel Corporation");
+module_init(e820_pmem_init);
+module_exit(e820_pmem_exit);
diff --git a/tools/testing/nvdimm/Kbuild b/tools/testing/nvdimm/Kbuild
index f56914c7929b..d7c136a96346 100644
--- a/tools/testing/nvdimm/Kbuild
+++ b/tools/testing/nvdimm/Kbuild
@@ -15,6 +15,7 @@ obj-$(CONFIG_LIBNVDIMM) += libnvdimm.o
obj-$(CONFIG_BLK_DEV_PMEM) += nd_pmem.o
obj-$(CONFIG_ND_BTT) += nd_btt.o
obj-$(CONFIG_ND_BLK) += nd_blk.o
+obj-$(CONFIG_X86_PMEM_LEGACY) += nd_e820.o
obj-$(CONFIG_ACPI_NFIT) += nfit.o
nfit-y := $(ACPI_SRC)/nfit.o
@@ -29,6 +30,9 @@ nd_btt-y += config_check.o
nd_blk-y := $(NVDIMM_SRC)/blk.o
nd_blk-y += config_check.o
+nd_e820-y := $(NVDIMM_SRC)/e820.o
+nd_e820-y += config_check.o
+
libnvdimm-y := $(NVDIMM_SRC)/core.o
libnvdimm-y += $(NVDIMM_SRC)/bus.o
libnvdimm-y += $(NVDIMM_SRC)/dimm_devs.o
--
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