From af1996ef59dbcb36fe4878df7c717a02eb89d07a Mon Sep 17 00:00:00 2001 From: Toshi Kani Date: Wed, 9 Mar 2016 12:47:06 -0700 Subject: [PATCH] ACPI: Change NFIT driver to insert new resource ACPI 6 defines persistent memory (PMEM) ranges in multiple firmware interfaces, e820, EFI, and ACPI NFIT table. This EFI change, however, leads to hit a bug in the grub bootloader, which treats EFI_PERSISTENT_MEMORY type as regular memory and corrupts stored user data [1]. Therefore, BIOS may set generic reserved type in e820 and EFI to cover PMEM ranges. The kernel can initialize PMEM ranges from ACPI NFIT table alone. This scheme causes a problem in the iomem table, though. On x86, for instance, e820_reserve_resources() initializes top-level entries (iomem_resource.child) from the e820 table at early boot-time. This creates "reserved" entry for a PMEM range, which does not allow region_intersects() to check with PMEM type. Change acpi_nfit_register_region() to call acpi_nfit_insert_resource(), which calls insert_resource() to insert a PMEM entry from NFIT when the iomem table does not have a PMEM entry already. That is, when a PMEM range is marked as reserved type in e820, it inserts "Persistent Memory" entry, which results as follows. + "Persistent Memory" + "reserved" This allows the EINJ driver, which calls region_intersects() to check PMEM ranges, to work continuously even if BIOS sets reserved type (or sets nothing) to PMEM ranges in e820 and EFI. [1]: https://lists.gnu.org/archive/html/grub-devel/2015-11/msg00209.html Signed-off-by: Toshi Kani Cc: Rafael J. Wysocki Cc: Dan Williams Cc: Ingo Molnar Cc: Borislav Petkov Cc: Andrew Morton Signed-off-by: Dan Williams --- drivers/acpi/nfit.c | 48 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 48 insertions(+) diff --git a/drivers/acpi/nfit.c b/drivers/acpi/nfit.c index fb53db187854..269de5f75d98 100644 --- a/drivers/acpi/nfit.c +++ b/drivers/acpi/nfit.c @@ -1571,6 +1571,48 @@ static int ars_status_process_records(struct nvdimm_bus *nvdimm_bus, return 0; } +static void acpi_nfit_remove_resource(void *data) +{ + struct resource *res = data; + + remove_resource(res); +} + +static int acpi_nfit_insert_resource(struct acpi_nfit_desc *acpi_desc, + struct nd_region_desc *ndr_desc) +{ + struct resource *res, *nd_res = ndr_desc->res; + int is_pmem, ret; + + /* No operation if the region is already registered as PMEM */ + is_pmem = region_intersects(nd_res->start, resource_size(nd_res), + IORESOURCE_MEM, IORES_DESC_PERSISTENT_MEMORY); + if (is_pmem == REGION_INTERSECTS) + return 0; + + res = devm_kzalloc(acpi_desc->dev, sizeof(*res), GFP_KERNEL); + if (!res) + return -ENOMEM; + + res->name = "Persistent Memory"; + res->start = nd_res->start; + res->end = nd_res->end; + res->flags = IORESOURCE_MEM; + res->desc = IORES_DESC_PERSISTENT_MEMORY; + + ret = insert_resource(&iomem_resource, res); + if (ret) + return ret; + + ret = devm_add_action(acpi_desc->dev, acpi_nfit_remove_resource, res); + if (ret) { + remove_resource(res); + return ret; + } + + return 0; +} + static int acpi_nfit_find_poison(struct acpi_nfit_desc *acpi_desc, struct nd_region_desc *ndr_desc) { @@ -1781,6 +1823,12 @@ static int acpi_nfit_register_region(struct acpi_nfit_desc *acpi_desc, nvdimm_bus = acpi_desc->nvdimm_bus; if (nfit_spa_type(spa) == NFIT_SPA_PM) { + rc = acpi_nfit_insert_resource(acpi_desc, ndr_desc); + if (rc) + dev_warn(acpi_desc->dev, + "failed to insert pmem resource to iomem: %d\n", + rc); + rc = acpi_nfit_find_poison(acpi_desc, ndr_desc); if (rc) { dev_err(acpi_desc->dev, -- 2.20.1