From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail.kernel.org ([198.145.29.99]) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1icW12-0006vt-Gb for kexec@lists.infradead.org; Wed, 04 Dec 2019 14:52:38 +0000 From: Ard Biesheuvel Subject: [PATCH] efi/memreserve: register reservations as 'reserved' in /proc/iomem Date: Wed, 4 Dec 2019 14:52:33 +0000 Message-Id: <20191204145233.11962-1-ardb@kernel.org> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "kexec" Errors-To: kexec-bounces+dwmw2=infradead.org@lists.infradead.org To: linux-efi@vger.kernel.org Cc: mark.rutland@arm.com, Masayoshi Mizuma , kexec@lists.infradead.org, d.hatayama@fujitsu.com, james.morse@arm.com, Ard Biesheuvel Memory regions that are reserved using efi_mem_reserve_persistent() are recorded in a special EFI config table which survives kexec, allowing the incoming kernel to honour them as well. However, such reservations are not visible in /proc/iomem, and so the kexec tools that load the incoming kernel and its initrd into memory may overwrite these reserved regions before the incoming kernel has a chance to reserve them from further use. So add these reservations to /proc/iomem as they are created. Note that reservations that are inherited from a previous kernel are memblock_reserve()'d early on, so they are already visible in /proc/iomem. Cc: Masayoshi Mizuma Cc: d.hatayama@fujitsu.com Cc: kexec@lists.infradead.org Signed-off-by: Ard Biesheuvel --- drivers/firmware/efi/efi.c | 29 ++++++++++++++++++-- 1 file changed, 26 insertions(+), 3 deletions(-) diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c index d101f072c8f8..fcd82dde23c8 100644 --- a/drivers/firmware/efi/efi.c +++ b/drivers/firmware/efi/efi.c @@ -979,6 +979,24 @@ static int __init efi_memreserve_map_root(void) return 0; } +static int efi_mem_reserve_iomem(phys_addr_t addr, u64 size) +{ + struct resource *res, *parent; + + res = kzalloc(sizeof(struct resource), GFP_ATOMIC); + if (!res) + return -ENOMEM; + + res->name = "reserved"; + res->flags = IORESOURCE_MEM; + res->start = addr; + res->end = addr + size - 1; + + /* we expect a conflict with a 'System RAM' region */ + parent = request_resource_conflict(&iomem_resource, res); + return parent ? request_resource(parent, res) : 0; +} + int __ref efi_mem_reserve_persistent(phys_addr_t addr, u64 size) { struct linux_efi_memreserve *rsv; @@ -1001,9 +1019,8 @@ int __ref efi_mem_reserve_persistent(phys_addr_t addr, u64 size) if (index < rsv->size) { rsv->entry[index].base = addr; rsv->entry[index].size = size; - memunmap(rsv); - return 0; + return efi_mem_reserve_iomem(addr, size); } memunmap(rsv); } @@ -1013,6 +1030,12 @@ int __ref efi_mem_reserve_persistent(phys_addr_t addr, u64 size) if (!rsv) return -ENOMEM; + rc = efi_mem_reserve_iomem(__pa(rsv), SZ_4K); + if (rc) { + free_page(rsv); + return rc; + } + /* * The memremap() call above assumes that a linux_efi_memreserve entry * never crosses a page boundary, so let's ensure that this remains true @@ -1029,7 +1052,7 @@ int __ref efi_mem_reserve_persistent(phys_addr_t addr, u64 size) efi_memreserve_root->next = __pa(rsv); spin_unlock(&efi_mem_reserve_persistent_lock); - return 0; + return efi_mem_reserve_iomem(addr, size); } static int __init efi_memreserve_root_init(void) -- 2.17.1 _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec