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Violators will be prosecuted for from ; Fri, 6 Jul 2018 04:29:27 -0400 From: "Aneesh Kumar K.V" Subject: [RFC PATCH 2/2] mm/pmem: Add memblock based e820 platform driver Date: Fri, 6 Jul 2018 13:59:11 +0530 In-Reply-To: <20180706082911.13405-1-aneesh.kumar@linux.ibm.com> References: <20180706082911.13405-1-aneesh.kumar@linux.ibm.com> Message-Id: <20180706082911.13405-2-aneesh.kumar@linux.ibm.com> Sender: owner-linux-mm@kvack.org List-ID: To: akpm@linux-foundation.org, Dan Williams , Oliver Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, "Aneesh Kumar K.V" This patch steal system RAM and use that to emulate pmem device using the e820 platform driver. This adds a new kernel command line 'pmemmap' which takes the format to allocate memory early in the boot. This memory is later registered as persistent memory range. Based on original patch from Oliver OHalloran Not-Signed-off-by: Aneesh Kumar K.V --- drivers/nvdimm/Kconfig | 13 ++++ drivers/nvdimm/Makefile | 1 + drivers/nvdimm/memblockpmem.c | 115 ++++++++++++++++++++++++++++++++++ 3 files changed, 129 insertions(+) create mode 100644 drivers/nvdimm/memblockpmem.c diff --git a/drivers/nvdimm/Kconfig b/drivers/nvdimm/Kconfig index 50d2a33de441..cbbbcbd4506b 100644 --- a/drivers/nvdimm/Kconfig +++ b/drivers/nvdimm/Kconfig @@ -115,4 +115,17 @@ config OF_PMEM config PMEM_PLATFORM_DEVICE bool +config MEMBLOCK_PMEM + bool "pmemmap= parameter support" + default y + depends on HAVE_MEMBLOCK + select PMEM_PLATFORM_DEVICE + help + Add support for the pmemmap= kernel command line parameter. This is similar + to the memmap= parameter available on ACPI platforms, but it uses generic + kernel facilities (the memblock allocator) to reserve memory rather than adding + to the e820 table. + + Select Y if unsure. + endif diff --git a/drivers/nvdimm/Makefile b/drivers/nvdimm/Makefile index 94f7f29146ce..0215ce0182e9 100644 --- a/drivers/nvdimm/Makefile +++ b/drivers/nvdimm/Makefile @@ -5,6 +5,7 @@ obj-$(CONFIG_ND_BTT) += nd_btt.o obj-$(CONFIG_ND_BLK) += nd_blk.o obj-$(CONFIG_PMEM_PLATFORM_DEVICE) += nd_e820.o obj-$(CONFIG_OF_PMEM) += of_pmem.o +obj-$(CONFIG_MEMBLOCK_PMEM) += memblockpmem.o nd_pmem-y := pmem.o diff --git a/drivers/nvdimm/memblockpmem.c b/drivers/nvdimm/memblockpmem.c new file mode 100644 index 000000000000..d39772b75fcd --- /dev/null +++ b/drivers/nvdimm/memblockpmem.c @@ -0,0 +1,115 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * Copyright (c) 2018 IBM Corporation + */ + +#define pr_fmt(fmt) "memblock pmem: " fmt + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +/* + * Align pmem reservations to the section size so we don't have issues with + * memory hotplug + */ +#ifdef CONFIG_SPARSEMEM +#define BOOTPMEM_ALIGN (1UL << SECTION_SIZE_BITS) +#else +#define BOOTPMEM_ALIGN PFN_DEFAULT_ALIGNMENT +#endif + +static __initdata u64 pmem_size; +static __initdata phys_addr_t pmem_stolen_memory; + +static void alloc_pmem_from_memblock(void) +{ + + pmem_stolen_memory = memblock_alloc_base(pmem_size, + BOOTPMEM_ALIGN, + MEMBLOCK_ALLOC_ACCESSIBLE); + if (!pmem_stolen_memory) { + pr_err("Failed to allocate memory for PMEM from memblock\n"); + return; + } + + /* + * Remove from the memblock reserved range + */ + memblock_free(pmem_stolen_memory, pmem_size); + + /* + * Remove from the memblock memory range. + */ + memblock_remove(pmem_stolen_memory, pmem_size); + pr_info("Allocated %ld memory at 0x%lx\n", (unsigned long)pmem_size, + (unsigned long)pmem_stolen_memory); + return; +} + +/* + * pmemmap=ss[KMG] + * + * This is similar to the memremap=offset[KMG]!size[KMG] paramater + * for adding a legacy pmem range to the e820 map on x86, but it's + * platform agnostic. + * + * e.g. pmemmap=16G allocates 16G pmem region + */ +static int __init parse_pmemmap(char *p) +{ + char *old_p = p; + + if (!p) + return -EINVAL; + + pmem_size = memparse(p, &p); + if (p == old_p) + return -EINVAL; + + alloc_pmem_from_memblock(); + return 0; +} +early_param("pmemmap", parse_pmemmap); + +static __init int register_e820_pmem(void) +{ + struct resource *res, *conflict; + struct platform_device *pdev; + + if (!pmem_stolen_memory) + return 0; + + res = kzalloc(sizeof(*res), GFP_KERNEL); + if (!res) + return -1; + + memset(res, 0, sizeof(*res)); + res->start = pmem_stolen_memory; + res->end = pmem_stolen_memory + pmem_size - 1; + res->name = "Persistent Memory (legacy)"; + res->desc = IORES_DESC_PERSISTENT_MEMORY_LEGACY; + res->flags = IORESOURCE_MEM; + + conflict = insert_resource_conflict(&iomem_resource, res); + if (conflict) { + pr_err("%pR conflicts, try insert below %pR\n", res, conflict); + kfree(res); + return -1; + } + /* + * 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); -- 2.17.1