Re: [PATCH OLK-5.10] arm64: Add memmap parameter and register pmem

整体上，

1. 补丁至少拆成2个，1个pmem.c共享，包括kconfig设计

2. cmdline支持

On 2022/1/7 19:03, Zhuling wrote:

hulk inclusion category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/I4O31I?from=project-issue CVE: NA

---

Register pmem in arm64: Use memmap(memmap=nn[KMG]!ss[KMG]) reserve memory and e820(driver/nvdimm/e820.c) function to register persistent memory in arm64. when the kernel restart or update, the data in PMEM will not be lost and can be loaded faster. this is a general features.

driver/nvdimm/e820.c: The function of this file is scan "iomem_resource" and take advantage of nvdimm resource discovery mechanism by registering a resource named "Persistent Memory (legacy)", this function doesn't depend on architecture.

We will push the feature to linux kernel community and discuss to modify the file name. because people have a mistaken notion that the e820.c is depend on x86.

If you want use this features, you need do as follows: 1.Reserve memory: add memmap to reserve memory in grub.cfg memmap=nn[KMG]!ss[KMG] exp:memmap=100K!0x1a0000000. 2.Insmod nd_e820.ko: modprobe nd_e820. 3.Check pmem device in /dev exp: /dev/pmem0

Signed-off-by: Zhuling zhuling8@huawei.com

arch/arm64/Kconfig | 22 ++++++++++++++++ arch/arm64/kernel/Makefile | 1 + arch/arm64/kernel/pmem.c | 36 ++++++++++++++++++++++++++ arch/arm64/kernel/setup.c | 11 ++++++++ arch/arm64/mm/init.c | 63 ++++++++++++++++++++++++++++++++++++++++++++++ drivers/nvdimm/Kconfig | 6 +++++ drivers/nvdimm/Makefile | 1 + 7 files changed, 140 insertions(+) create mode 100644 arch/arm64/kernel/pmem.c

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 405e5ce..2231eac 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -1322,6 +1322,28 @@ config RODATA_FULL_DEFAULT_ENABLED This requires the linear region to be mapped down to pages, which may adversely affect performance in some cases.

+config ARM64_PMEM_RESERVE

• bool "Reserve memory for persistent storage"
• default n
• help

•  Use memmap=nn[KMG]!ss[KMG](memmap=100K!0x1a0000000) reserve
  

•  memory for persistent storage.
  

•  Say y here to enable this feature.
  

+config ARM64_PMEM_LEGACY_DEVICE

• bool "Create persistent storage"
• depends on BLK_DEV
• depends on LIBNVDIMM
• select ARM64_PMEM_RESERVE
• help

•  Use reserved memory for persistent storage when the kernel
  

•  restart or update. the data in PMEM will not be lost and
  

•  can be loaded faster.
  

•  Say y if unsure.
  

• config ARM64_SW_TTBR0_PAN bool "Emulate Privileged Access Never using TTBR0_EL1 switching" help

diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile index 169d90f..f615325 100644 --- a/arch/arm64/kernel/Makefile +++ b/arch/arm64/kernel/Makefile @@ -68,6 +68,7 @@ obj-$(CONFIG_ARM64_PTR_AUTH) += pointer_auth.o obj-$(CONFIG_SHADOW_CALL_STACK) += scs.o obj-$(CONFIG_ARM64_MTE) += mte.o obj-$(CONFIG_MPAM) += mpam/ +obj-$(CONFIG_ARM64_PMEM_LEGACY_DEVICE) += pmem.o

obj-y += vdso/ probes/ obj-$(CONFIG_COMPAT_VDSO) += vdso32/ diff --git a/arch/arm64/kernel/pmem.c b/arch/arm64/kernel/pmem.c new file mode 100644 index 0000000..d1efdc8 --- /dev/null +++ b/arch/arm64/kernel/pmem.c @@ -0,0 +1,36 @@ +// SPDX-License-Identifier: GPL-2.0 +/*

• • Copyright(c) 2021 Huawei Technologies Co., Ltd
• • Derived from x86 and arm64 implement PMEM.
• */

+#include <linux/platform_device.h> +#include <linux/init.h> +#include <linux/ioport.h> +#include <linux/module.h>

+static int found(struct resource *res, void *data) +{

• return 1;

+}

+static int __init register_e820_pmem(void) +{

• struct platform_device *pdev;
• int rc;
• rc = walk_iomem_res_desc(IORES_DESC_PERSISTENT_MEMORY_LEGACY,

• 		 IORESOURCE_MEM, 0, -1, NULL, found);
  

• if (rc <= 0)

• return 0;
  

• /*

• * 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);

1. 这个跟x86的 pmem.c 有什么区别，如果没有区别，应该先抽取一个补丁放到公共目录，而不是简单的copy

这个作为单独的补丁

diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c index 92d75e3..1a8a4d2 100644 --- a/arch/arm64/kernel/setup.c +++ b/arch/arm64/kernel/setup.c @@ -70,6 +70,11 @@ static int __init arm64_enable_cpu0_hotplug(char *str) __setup("arm64_cpu0_hotplug", arm64_enable_cpu0_hotplug); #endif

+#ifdef CONFIG_ARM64_PMEM_RESERVE +extern struct resource pmem_res; +#endif

这个只支持一个pmem，从实际情况，可以有很多pmem，cmdline也是支持的；

这块代码放到单独文件

• phys_addr_t __fdt_pointer __initdata;

  /*

@@ -305,6 +310,12 @@ static void __init request_standard_resources(void) } }

+#ifdef CONFIG_ARM64_PMEM_RESERVE

• if (pmem_res.end && pmem_res.start)

• request_resource(&iomem_resource, &pmem_res);
  

+#endif

• static int __init reserve_memblock_reserved_regions(void) { u64 i, j;

diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c index 6ebfabd..3b6907f 100644 --- a/arch/arm64/mm/init.c +++ b/arch/arm64/mm/init.c @@ -56,6 +56,8 @@ s64 memstart_addr __ro_after_init = -1; EXPORT_SYMBOL(memstart_addr);

+phys_addr_t start_at, mem_size;

• #ifdef CONFIG_PIN_MEMORY struct resource pin_memory_resource = { .name = "Pin memory",

@@ -111,6 +113,18 @@ static void __init reserve_pin_memory_res(void) */ phys_addr_t arm64_dma_phys_limit __ro_after_init;

上面pin_memory的代码也是一样的问题；

+static unsigned long long pmem_size, pmem_start;

+#ifdef CONFIG_ARM64_PMEM_RESERVE +struct resource pmem_res = {

• .name = "Persistent Memory (legacy)",
• .start = 0,
• .end = 0,
• .flags = IORESOURCE_MEM,
• .desc = IORES_DESC_PERSISTENT_MEMORY_LEGACY

+}; +#endif

放到独立文件吧

• #ifndef CONFIG_KEXEC_CORE static void __init reserve_crashkernel(void) {

@@ -403,6 +417,26 @@ static int __init reserve_park_mem(void) return -EINVAL; } #endif +static bool __init is_mem_valid(unsigned long long mem_size, unsigned long long mem_start) +{

• if (!memblock_is_region_memory(mem_start, mem_size)) {

• pr_warn("cannot reserve mem: region is not memory!\n");
  

• return false;
  

• }
• if (memblock_is_region_reserved(mem_start, mem_size)) {

• pr_warn("cannot reserve mem: region overlaps reserved memory!\n");
  

• return false;
  

• }
• if (!IS_ALIGNED(mem_start, SZ_2M)) {

• pr_warn("cannot reserve mem: base address is not 2MB aligned!\n");
  

• return false;
  

• }
• return true;

+}

同上

static int need_remove_real_memblock __initdata;

@@ -442,7 +476,17 @@ static int __init parse_memmap_one(char *p) start_at = memparse(p + 1, &p); memblock_reserve(start_at, mem_size); memblock_mark_memmap(start_at, mem_size); +<<<<<<< HEAD

• } else if (*p == '!') {

• start_at = memparse(p+1, &p);
  

• pmem_start = start_at;
  

• pmem_size = mem_size;
  

有冲突； cmdline可以有多次，这样写有问题；后面会覆盖前面

• }else

+======= } else +>>>>>>> 374db2be8805428b4f54b5ef793b0d3f5069c5f9 pr_info("Unrecognized memmap option, please check the parameter.\n");

return *p == '\0' ? 0 : -EINVAL; @@ -464,6 +508,20 @@ static int __init parse_memmap_opt(char *str) } early_param("memmap", parse_memmap_opt);

+#ifdef CONFIG_ARM64_PMEM_RESERVE +static void __init reserve_pmem(void) +{

• if (!is_mem_valid(mem_size, start_at))

• return;
  

• memblock_remove(pmem_start, pmem_size);
• pr_info("pmem reserved: 0x%016llx - 0x%016llx (%lld MB)\n",

• pmem_start, pmem_start + pmem_size, pmem_size >> 20);
  

• pmem_res.start = pmem_start;
• pmem_res.end = pmem_start + pmem_size - 1;

+} +#endif

放到独立文件

• void __init arm64_memblock_init(void) { const s64 linear_region_size = BIT(vabits_actual - 1);

@@ -638,6 +696,11 @@ void __init bootmem_init(void) reserve_quick_kexec(); #endif

+#ifdef CONFIG_ARM64_PMEM_RESERVE

• reserve_pmem();

+#endif

• reserve_pin_memory_res();

  memblock_dump_all();

diff --git a/drivers/nvdimm/Kconfig b/drivers/nvdimm/Kconfig index b7d1eb3..9567cca 100644 --- a/drivers/nvdimm/Kconfig +++ b/drivers/nvdimm/Kconfig @@ -132,3 +132,9 @@ config NVDIMM_TEST_BUILD infrastructure.

endif

+config PMEM_LEGACY

• tristate "Pmem_legacy"

• select X86_PMEM_LEGACY if X86
• select ARM64_PMEM_LEGACY_DEVICE if ARM64

这个不对等，而且不合理；X86_PMEM_LEGACY是  tristate的，由用户控制，

所以这个PMEM_LEGGACY应该是替代x86_pmem_legacy的

diff --git a/drivers/nvdimm/Makefile b/drivers/nvdimm/Makefile index 0407753..6f8dc92 100644 --- a/drivers/nvdimm/Makefile +++ b/drivers/nvdimm/Makefile @@ -3,6 +3,7 @@ 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-$(CONFIG_PMEM_LEGACY) += nd_e820.o obj-$(CONFIG_OF_PMEM) += of_pmem.o obj-$(CONFIG_VIRTIO_PMEM) += virtio_pmem.o nd_virtio.o