[PATCH] arm64: add pmem module for kernel update

From: Zhuling
Date: Thu Dec 31 2020 - 01:47:23 EST

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Category: feature
Bugzilla: NA
CVE: NA

Use reserved memory to create a pmem device to store the
processes information that dumped before kernel update.
When you want to use this feature you need to declare by
"pmemmem=pmem_size:pmem_phystart" in cmdline.
(exp: pmemmem=100M:0x202000000000)

Signed-off-by: Zhuling <zhuling8@xxxxxxxxxx>
---
arch/arm64/kernel/setup.c | 5 +++
arch/arm64/mm/init.c | 90 +++++++++++++++++++++++++++++++++++++++
drivers/nvdimm/Kconfig | 11 +++++
drivers/nvdimm/Makefile | 3 ++
drivers/nvdimm/kup_pmem.c | 106 ++++++++++++++++++++++++++++++++++++++++++++++
include/linux/ioport.h | 1 +
include/linux/mm.h | 4 ++
lib/Kconfig | 6 +++
8 files changed, 226 insertions(+)
create mode 100644 drivers/nvdimm/kup_pmem.c

diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
index 133257f..0bd9429 100644
--- a/arch/arm64/kernel/setup.c
+++ b/arch/arm64/kernel/setup.c
@@ -237,6 +237,11 @@ static void __init request_standard_resources(void)
if (kernel_data.start >= res->start &&
kernel_data.end <= res->end)
request_resource(res, &kernel_data);
+#ifdef CONFIG_KUP_PMEM_MEMORY
+ if (pmem_res.end)
+ insert_resource(&iomem_resource, &pmem_res);
+#endif
+
#ifdef CONFIG_KEXEC_CORE
/* Userspace will find "Crash kernel" region in /proc/iomem. */
if (crashk_res.end && crashk_res.start >= res->start &&
diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index 0955406..9d1395e 100644
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c
@@ -62,6 +62,18 @@ EXPORT_SYMBOL(memstart_addr);
phys_addr_t arm64_dma_phys_limit __ro_after_init;
static phys_addr_t arm64_dma32_phys_limit __ro_after_init;

+#ifdef CONFIG_KUP_PMEM_MEMORY
+static unsigned long long pmem_size, pmem_phystart;
+
+struct resource pmem_res = {
+ .name = "Kpmem Dev",
+ .start = 0,
+ .end = 0,
+ .flags = IORESOURCE_MEM,
+ .desc = IORES_DESC_KPMEM_DEV
+};
+#endif
+
#ifdef CONFIG_KEXEC_CORE
/*
* reserve_crashkernel() - reserves memory for crash kernel
@@ -123,6 +135,80 @@ static void __init reserve_crashkernel(void)
}
#endif /* CONFIG_KEXEC_CORE */

+#ifdef CONFIG_KUP_PMEM_MEMORY
+/*
+ * reserve_pmem() - reserves memory for pmem
+ *
+ * This function reserves memory area given in "pmemmem=" kernel command
+ * line parameter. The memory reserved is used by pmem restore progress
+ * when kernel update.
+ */
+static int __init parse_pmem(char *par)
+{
+ char *cur = par;
+
+ if (!par)
+ return 0;
+
+ pmem_size = 0;
+ pmem_phystart = 0;
+
+ pmem_size = memparse(par, &cur);
+ if (par == cur) {
+ pr_warn("pmem: memory value expected\n");
+ return -EINVAL;
+ }
+
+ if (*cur == ':')
+ pmem_phystart = memparse(cur+1, &cur);
+ else if (*cur != ' ' && *cur != '\0') {
+ pr_warn("pmem: unrecognized char %c\n", *cur);
+ return -EINVAL;
+ }
+
+ return 0;
+}
+early_param("pmemmem", parse_pmem);
+
+static void __init reserve_pmem(void)
+{
+ if (!pmem_size || !pmem_phystart) {
+ return;
+ }
+
+ pmem_size = PAGE_ALIGN(pmem_size);
+
+ if (!memblock_is_region_memory(pmem_phystart, pmem_size)) {
+ pr_warn("cannot reserve pmem: region is not memory!\n");
+ return;
+ }
+
+ if (memblock_is_region_reserved(pmem_phystart, pmem_size)) {
+ pr_warn("cannot reserve pmem: region overlaps reserved memory!\n");
+ return;
+ }
+
+ if (!IS_ALIGNED(pmem_phystart, SZ_2M)) {
+ pr_warn("cannot reserve pmem: base address is not 2MB aligned\n");
+ return;
+ }
+ memblock_reserve(pmem_phystart, pmem_size);
+ memblock_remove(pmem_phystart, pmem_size);
+ pr_info("pmem reserved: 0x%016llx - 0x%016llx (%lld MB)\n",
+ pmem_phystart, pmem_phystart + pmem_size, pmem_size >> 20);
+
+ pmem_res.start = pmem_phystart;
+ pmem_res.end = pmem_phystart + pmem_size - 1;
+}
+#else
+static void __init reserve_pmem(void)
+{
+}
+static void __init reserve_pmem_pages(void)
+{
+}
+#endif /*CONFIG_KUP_PMEM_MEMORY*/
+
#ifdef CONFIG_CRASH_DUMP
static int __init early_init_dt_scan_elfcorehdr(unsigned long node,
const char *uname, int depth, void *data)
@@ -390,6 +476,10 @@ void __init arm64_memblock_init(void)

reserve_elfcorehdr();

+#ifdef CONFIG_KUP_PMEM_MEMORY
+ reserve_pmem();
+#endif
+
high_memory = __va(memblock_end_of_DRAM() - 1) + 1;

dma_contiguous_reserve(arm64_dma32_phys_limit);
diff --git a/drivers/nvdimm/Kconfig b/drivers/nvdimm/Kconfig
index b7d1eb3..7f5fa22 100644
--- a/drivers/nvdimm/Kconfig
+++ b/drivers/nvdimm/Kconfig
@@ -119,6 +119,17 @@ config NVDIMM_KEYS
depends on ENCRYPTED_KEYS
depends on (LIBNVDIMM=ENCRYPTED_KEYS) || LIBNVDIMM=m

+config KUP_PMEM
+ tristate "Persistent memory for kernel update"
+ depends on LIBNVDIMM
+ depends on KUP_PMEM_MEMORY
+ default LIBNVDIMM
+ help
+ Allows regions of persistent memory to be described in the
+ device-tree.
+
+ Select Y if unsure.
+
config NVDIMM_TEST_BUILD
tristate "Build the unit test core"
depends on m
diff --git a/drivers/nvdimm/Makefile b/drivers/nvdimm/Makefile
index 29203f3..39fabc3 100644
--- a/drivers/nvdimm/Makefile
+++ b/drivers/nvdimm/Makefile
@@ -6,6 +6,7 @@ obj-$(CONFIG_ND_BLK) += nd_blk.o
obj-$(CONFIG_X86_PMEM_LEGACY) += nd_e820.o
obj-$(CONFIG_OF_PMEM) += of_pmem.o
obj-$(CONFIG_VIRTIO_PMEM) += virtio_pmem.o nd_virtio.o
+obj-$(CONFIG_KUP_PMEM) += nd_kup_pmem.o

nd_pmem-y := pmem.o

@@ -15,6 +16,8 @@ nd_blk-y := blk.o

nd_e820-y := e820.o

+nd_kup_pmem-y := kup_pmem.o
+
libnvdimm-y := core.o
libnvdimm-y += bus.o
libnvdimm-y += dimm_devs.o
diff --git a/drivers/nvdimm/kup_pmem.c b/drivers/nvdimm/kup_pmem.c
new file mode 100644
index 0000000..eadf95a
--- /dev/null
+++ b/drivers/nvdimm/kup_pmem.c
@@ -0,0 +1,106 @@
+/*
+ * Copyright (c) Huawei Technologies Co., Ltd. 2020. All rights reserved.
+ *
+ * This source code is licensed under the GNU General Public License,
+ * Version 2. See the file COPYING for more details.
+ *
+ * kup_pmem.c - kernel update support code.
+ * create a pmem device to store the processes information that is dumped
+ * when we want to kernel update.
+ */
+
+#include <linux/platform_device.h>
+#include <linux/memory_hotplug.h>
+#include <linux/libnvdimm.h>
+#include <linux/module.h>
+#include <asm/io.h>
+
+static const struct attribute_group *kup_pmem_attribute_groups[] = {
+ &nvdimm_bus_attribute_group,
+ NULL,
+};
+
+static const struct attribute_group *kup_pmem_region_attribute_groups[] = {
+ &nd_region_attribute_group,
+ &nd_device_attribute_group,
+ NULL,
+};
+
+static int kup_pmem_remove(struct platform_device *pdev)
+{
+ struct nvdimm_bus *nvdimm_bus = platform_get_drvdata(pdev);
+
+ nvdimm_bus_unregister(nvdimm_bus);
+
+ return 0;
+}
+
+static int kup_register_one(struct resource *res, void *data)
+{
+ struct nd_region_desc ndr_desc;
+ struct nvdimm_bus *nvdimm_bus = data;
+
+ memset(&ndr_desc, 0, sizeof(ndr_desc));
+ ndr_desc.res = res;
+ ndr_desc.attr_groups = kup_pmem_region_attribute_groups;
+ ndr_desc.numa_node = NUMA_NO_NODE;
+ set_bit(ND_REGION_PAGEMAP, &ndr_desc.flags);
+ if (!nvdimm_pmem_region_create(nvdimm_bus, &ndr_desc))
+ return -ENXIO;
+ return 0;
+}
+
+static int kup_pmem_probe(struct platform_device *pdev)
+{
+ static struct nvdimm_bus_descriptor nd_desc;
+ struct device *dev = &pdev->dev;
+ struct nvdimm_bus *nvdimm_bus;
+ int rc = -ENXIO;
+
+ nd_desc.attr_groups = kup_pmem_attribute_groups;
+ nd_desc.provider_name = "kup_pmem";
+ nd_desc.module = THIS_MODULE;
+ nvdimm_bus = nvdimm_bus_register(dev, &nd_desc);
+ if (!nvdimm_bus)
+ goto err;
+ platform_set_drvdata(pdev, nvdimm_bus);
+
+ rc = walk_iomem_res_desc(IORES_DESC_KPMEM_DEV,
+ IORESOURCE_MEM, 0, -1, nvdimm_bus, kup_register_one);
+ if (rc)
+ goto err;
+
+ return 0;
+err:
+ nvdimm_bus_unregister(nvdimm_bus);
+ dev_err(dev, "kup_pmem: failed to register legacy persistent memory ranges\n");
+ return rc;
+}
+
+static struct platform_driver kup_pmem_driver = {
+ .probe = kup_pmem_probe,
+ .remove = kup_pmem_remove,
+ .driver = {
+ .name = "kup_pmem",
+ },
+};
+static struct platform_device *pdev;
+
+static __init int register_kup_pmem(void)
+{
+ platform_driver_register(&kup_pmem_driver);
+ pdev = platform_device_alloc("kup_pmem", -1);
+
+ return platform_device_add(pdev);
+}
+
+static __exit void unregister_kup_pmem(void)
+{
+ platform_device_del(pdev);
+ platform_driver_unregister(&kup_pmem_driver);
+}
+
+module_init(register_kup_pmem);
+module_exit(unregister_kup_pmem);
+MODULE_ALIAS("platform:kup_pmem*");
+MODULE_LICENSE("GPL v2");
diff --git a/include/linux/ioport.h b/include/linux/ioport.h
index 5135d4b..bba36f2 100644
--- a/include/linux/ioport.h
+++ b/include/linux/ioport.h
@@ -139,6 +139,7 @@ enum {
IORES_DESC_DEVICE_PRIVATE_MEMORY = 6,
IORES_DESC_RESERVED = 7,
IORES_DESC_SOFT_RESERVED = 8,
+ IORES_DESC_KPMEM_DEV = 9,
};

/*
diff --git a/include/linux/mm.h b/include/linux/mm.h
index db6ae4d..2b2a94c 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -45,6 +45,10 @@ extern int sysctl_page_lock_unfairness;

void init_mm_internals(void);

+#ifdef CONFIG_KUP_PMEM_MEMORY
+extern struct resource pmem_res;
+#endif
+
#ifndef CONFIG_NEED_MULTIPLE_NODES /* Don't use mapnrs, do it properly */
extern unsigned long max_mapnr;

diff --git a/lib/Kconfig b/lib/Kconfig
index b46a9fd..ff5677c 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -689,3 +689,9 @@ config GENERIC_LIB_UCMPDI2
config PLDMFW
bool
default n
+
+config KUP_PMEM_MEMORY
+ bool "reserve memory for kup pmem to store image"
+ default y
+ help
+ Say y here to enable this feature
--
2.9.5

Next message: Shenming Lu: "[PATCH RFC] KVM: arm64: vgic: Decouple the check of the EnableLPIs bit from the ITS LPI translation"
Previous message: Kai-Heng Feng: "[PATCH] PM: sleep: core: Resume suspended device if direct-complete is disabled"
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