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From: Dan Williams <dan.j.williams@intel.com>
To: mingo@redhat.com
Cc: Will Deacon <will@kernel.org>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Ard Biesheuvel <ard.biesheuvel@linaro.org>,
	peterz@infradead.org, dave.hansen@linux.intel.com,
	x86@kernel.org, linux-acpi@vger.kernel.org,
	linux-kernel@vger.kernel.org, linux-nvdimm@lists.01.org,
	linux-efi@vger.kernel.org
Subject: [PATCH v8 06/12] arm/efi: EFI soft reservation to memblock
Date: Wed, 06 Nov 2019 17:43:21 -0800
Message-ID: <157309100134.1579826.12497928378034505817.stgit@dwillia2-desk3.amr.corp.intel.com> (raw)
In-Reply-To: <157309097008.1579826.12818463304589384434.stgit@dwillia2-desk3.amr.corp.intel.com>

UEFI 2.8 defines an EFI_MEMORY_SP attribute bit to augment the
interpretation of the EFI Memory Types as "reserved for a specific
purpose".

The proposed Linux behavior for specific purpose memory is that it is
reserved for direct-access (device-dax) by default and not available for
any kernel usage, not even as an OOM fallback.  Later, through udev
scripts or another init mechanism, these device-dax claimed ranges can
be reconfigured and hot-added to the available System-RAM with a unique
node identifier. This device-dax management scheme implements "soft" in
the "soft reserved" designation by allowing some or all of the
reservation to be recovered as typical memory. This policy can be
disabled at compile-time with CONFIG_EFI_SOFT_RESERVE=n, or runtime with
efi=nosoftreserve.

For this patch, update the ARM paths that consider
EFI_CONVENTIONAL_MEMORY to optionally take the EFI_MEMORY_SP attribute
into account as a reservation indicator. Publish the soft reservation as
IORES_DESC_SOFT_RESERVED memory, similar to x86.

(Based on an original patch by Ard)

Cc: Will Deacon <will@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
 arch/arm64/mm/mmu.c                       |    2 ++
 drivers/firmware/efi/arm-init.c           |    9 +++++++++
 drivers/firmware/efi/arm-runtime.c        |   24 ++++++++++++++++++++++++
 drivers/firmware/efi/libstub/arm32-stub.c |    5 +++++
 drivers/firmware/efi/libstub/random.c     |    4 ++++
 5 files changed, 44 insertions(+)

diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index 60c929f3683b..2c385fe05fde 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -1061,6 +1061,8 @@ int arch_add_memory(int nid, u64 start, u64 size,
 	__create_pgd_mapping(swapper_pg_dir, start, __phys_to_virt(start),
 			     size, PAGE_KERNEL, __pgd_pgtable_alloc, flags);
 
+	memblock_clear_nomap(start, size);
+
 	return __add_pages(nid, start >> PAGE_SHIFT, size >> PAGE_SHIFT,
 			   restrictions);
 }
diff --git a/drivers/firmware/efi/arm-init.c b/drivers/firmware/efi/arm-init.c
index 311cd349a862..904fa09e6a6b 100644
--- a/drivers/firmware/efi/arm-init.c
+++ b/drivers/firmware/efi/arm-init.c
@@ -163,6 +163,15 @@ static __init int is_usable_memory(efi_memory_desc_t *md)
 	case EFI_BOOT_SERVICES_DATA:
 	case EFI_CONVENTIONAL_MEMORY:
 	case EFI_PERSISTENT_MEMORY:
+		/*
+		 * Special purpose memory is 'soft reserved', which means it
+		 * is set aside initially, but can be hotplugged back in or
+		 * be assigned to the dax driver after boot.
+		 */
+		if (efi_soft_reserve_enabled() &&
+		    (md->attribute & EFI_MEMORY_SP))
+			return false;
+
 		/*
 		 * According to the spec, these regions are no longer reserved
 		 * after calling ExitBootServices(). However, we can only use
diff --git a/drivers/firmware/efi/arm-runtime.c b/drivers/firmware/efi/arm-runtime.c
index e2ac5fa5531b..899b803842bb 100644
--- a/drivers/firmware/efi/arm-runtime.c
+++ b/drivers/firmware/efi/arm-runtime.c
@@ -121,6 +121,30 @@ static int __init arm_enable_runtime_services(void)
 		return 0;
 	}
 
+	if (efi_soft_reserve_enabled()) {
+		efi_memory_desc_t *md;
+
+		for_each_efi_memory_desc(md) {
+			int md_size = md->num_pages << EFI_PAGE_SHIFT;
+			struct resource *res;
+
+			if (!(md->attribute & EFI_MEMORY_SP))
+				continue;
+
+			res = kzalloc(sizeof(*res), GFP_KERNEL);
+			if (WARN_ON(!res))
+				break;
+
+			res->start	= md->phys_addr;
+			res->end	= md->phys_addr + md_size - 1;
+			res->name	= "Soft Reserved";
+			res->flags	= IORESOURCE_MEM;
+			res->desc	= IORES_DESC_SOFT_RESERVED;
+
+			insert_resource(&iomem_resource, res);
+		}
+	}
+
 	if (efi_runtime_disabled()) {
 		pr_info("EFI runtime services will be disabled.\n");
 		return 0;
diff --git a/drivers/firmware/efi/libstub/arm32-stub.c b/drivers/firmware/efi/libstub/arm32-stub.c
index 41213bf5fcf5..4566640de650 100644
--- a/drivers/firmware/efi/libstub/arm32-stub.c
+++ b/drivers/firmware/efi/libstub/arm32-stub.c
@@ -146,6 +146,11 @@ static efi_status_t reserve_kernel_base(efi_system_table_t *sys_table_arg,
 			continue;
 
 		case EFI_CONVENTIONAL_MEMORY:
+			/* Skip soft reserved conventional memory */
+			if (efi_soft_reserve_enabled() &&
+			    (desc->attribute & EFI_MEMORY_SP))
+				continue;
+
 			/*
 			 * Reserve the intersection between this entry and the
 			 * region.
diff --git a/drivers/firmware/efi/libstub/random.c b/drivers/firmware/efi/libstub/random.c
index b4b1d1dcb5fd..6c188695e730 100644
--- a/drivers/firmware/efi/libstub/random.c
+++ b/drivers/firmware/efi/libstub/random.c
@@ -46,6 +46,10 @@ static unsigned long get_entry_num_slots(efi_memory_desc_t *md,
 	if (md->type != EFI_CONVENTIONAL_MEMORY)
 		return 0;
 
+	if (efi_soft_reserve_enabled() &&
+	    (md->attribute & EFI_MEMORY_SP))
+		return 0;
+
 	region_end = min((u64)ULONG_MAX, md->phys_addr + md->num_pages*EFI_PAGE_SIZE - 1);
 
 	first_slot = round_up(md->phys_addr, align);
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  parent reply index

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-07  1:42 [PATCH v8 00/12] EFI Specific Purpose Memory Support Dan Williams
2019-11-07  1:42 ` [PATCH v8 01/12] acpi/numa: Establish a new drivers/acpi/numa/ directory Dan Williams
2019-11-07  1:43 ` [PATCH v8 02/12] efi: Enumerate EFI_MEMORY_SP Dan Williams
2019-11-07  1:43 ` [PATCH v8 03/12] x86/efi: Push EFI_MEMMAP check into leaf routines Dan Williams
2019-11-07  1:43 ` [PATCH v8 04/12] efi: Common enable/disable infrastructure for EFI soft reservation Dan Williams
2019-11-07  1:43 ` [PATCH v8 05/12] x86/efi: EFI soft reservation to E820 enumeration Dan Williams
2019-11-07  1:43 ` Dan Williams [this message]
2019-11-07  1:43 ` [PATCH v8 07/12] x86/efi: Add efi_fake_mem support for EFI_MEMORY_SP Dan Williams
2019-11-07  1:43 ` [PATCH v8 08/12] lib: Uplevel the pmem "region" ida to a global allocator Dan Williams
2019-11-07  1:43 ` [PATCH v8 09/12] dax: Fix alloc_dax_region() compile warning Dan Williams
2019-11-07  1:43 ` [PATCH v8 10/12] device-dax: Add a driver for "hmem" devices Dan Williams
2019-11-07  1:43 ` [PATCH v8 11/12] acpi/numa/hmat: Register HMAT at device_initcall level Dan Williams
2019-11-07  1:43 ` [PATCH v8 12/12] acpi/numa/hmat: Register "soft reserved" memory as an "hmem" device Dan Williams
2019-11-07 12:46 ` [PATCH v8 00/12] EFI Specific Purpose Memory Support Rafael J. Wysocki
2019-11-07 13:48   ` Thomas Gleixner
2019-11-07 14:12     ` Rafael J. Wysocki

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