From patchwork Mon Jun 22 14:01:55 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Rafael J. Wysocki" X-Patchwork-Id: 11617865 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 3CC07161F for ; Mon, 22 Jun 2020 14:03:23 +0000 (UTC) Received: from ml01.01.org (ml01.01.org [198.145.21.10]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 259F8206E2 for ; Mon, 22 Jun 2020 14:03:23 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 259F8206E2 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=rjwysocki.net Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-nvdimm-bounces@lists.01.org Received: from ml01.vlan13.01.org (localhost [IPv6:::1]) by ml01.01.org (Postfix) with ESMTP id 8CEAF10FCB710; Mon, 22 Jun 2020 07:03:22 -0700 (PDT) Received-SPF: Pass (mailfrom) identity=mailfrom; client-ip=79.96.170.134; helo=cloudserver094114.home.pl; envelope-from=rjw@rjwysocki.net; receiver= Received: from cloudserver094114.home.pl (cloudserver094114.home.pl [79.96.170.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id CDBB310FC729B for ; Mon, 22 Jun 2020 07:03:19 -0700 (PDT) Received: from 89-64-85-91.dynamic.chello.pl (89.64.85.91) (HELO kreacher.localnet) by serwer1319399.home.pl (79.96.170.134) with SMTP (IdeaSmtpServer 0.83.415) id 053a9db2a1335a90; Mon, 22 Jun 2020 16:03:17 +0200 From: "Rafael J. Wysocki" To: Dan Williams , Erik Kaneda Subject: [RFT][PATCH v2 3/4] ACPICA: Preserve memory opregion mappings if supported by OS Date: Mon, 22 Jun 2020 16:01:55 +0200 Message-ID: <13749323.0m2ImmhSHx@kreacher> In-Reply-To: <2713141.s8EVnczdoM@kreacher> References: <158889473309.2292982.18007035454673387731.stgit@dwillia2-desk3.amr.corp.intel.com> <2713141.s8EVnczdoM@kreacher> MIME-Version: 1.0 Message-ID-Hash: LMYATE65NJSNLT7SO5OFU57MAFZEUXZT X-Message-ID-Hash: LMYATE65NJSNLT7SO5OFU57MAFZEUXZT X-MailFrom: rjw@rjwysocki.net X-Mailman-Rule-Hits: nonmember-moderation X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; emergency; loop; banned-address; member-moderation CC: rafael.j.wysocki@intel.com, Len Brown , Borislav Petkov , James Morse , Myron Stowe , Andy Shevchenko , linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org, linux-nvdimm@lists.01.org, Bob Moore X-Mailman-Version: 3.1.1 Precedence: list List-Id: "Linux-nvdimm developer list." Archived-At: List-Archive: List-Help: List-Post: List-Subscribe: List-Unsubscribe: From: "Rafael J. Wysocki" The ACPICA's strategy with respect to the handling of memory mappings associated with memory operation regions is to avoid mapping the entire region at once which may be problematic at least in principle (for example, it may lead to conflicts with overlapping mappings having different attributes created by drivers). It may also be wasteful, because memory opregions on some systems take up vast chunks of address space while the fields in those regions actually accessed by AML are sparsely distributed. For this reason, a one-page "window" is mapped for a given opregion on the first memory access through it and if that "window" does not cover an address range accessed through that opregion subsequently, it is unmapped and a new "window" is mapped to replace it. Next, if the new "window" is not sufficient to access memory through the opregion in question in the future, it will be replaced with yet another "window" and so on. That may lead to a suboptimal sequence of memory mapping and unmapping operations, for example if two fields in one opregion separated from each other by a sufficiently wide chunk of unused address space are accessed in an alternating pattern. The situation may still be suboptimal if the deferred unmapping introduced previously is supported by the OS layer. For instance, the alternating memory access pattern mentioned above may produce a relatively long list of mappings to release with substantial duplication among the entries in it, which could be avoided if acpi_ex_system_memory_space_handler() did not release the mapping used by it previously as soon as the current access was not covered by it. In order to improve that, modify acpi_ex_system_memory_space_handler() to take advantage of the memory mappings reference counting at the OS level if a suitable interface is provided. Namely, if ACPI_USE_FAST_PATH_MAPPING is set, the OS is expected to implement acpi_os_map_memory_fast_path() that will return NULL if there is no mapping covering the given address range known to it. If such a mapping is there, however, its reference counter will be incremented and a pointer representing the requested virtual address will be returned right away without any additional consequences. That allows acpi_ex_system_memory_space_handler() to acquire additional references to all new memory mappings with the help of acpi_os_map_memory_fast_path() so as to retain them until the memory opregions associated with them go away. The function will still use a new "window" mapping if the current one does not cover the address range at hand, but it will avoid unmapping the current one right away by adding it to a list of "known" mappings associated with the given memory opregion which will be deleted at the opregion deactivation time. The mappings in that list can be used every time a "new window" is needed so as to avoid overhead related to the mapping and unmapping of memory. Signed-off-by: Rafael J. Wysocki --- drivers/acpi/acpica/acinterp.h | 4 + drivers/acpi/acpica/evrgnini.c | 7 +- drivers/acpi/acpica/exregion.c | 159 ++++++++++++++++++++++++++++++++- 3 files changed, 162 insertions(+), 8 deletions(-) diff --git a/drivers/acpi/acpica/acinterp.h b/drivers/acpi/acpica/acinterp.h index 1f1026fb06e9..db9c279baa2e 100644 --- a/drivers/acpi/acpica/acinterp.h +++ b/drivers/acpi/acpica/acinterp.h @@ -479,8 +479,12 @@ void acpi_ex_pci_cls_to_string(char *dest, u8 class_code[3]); u8 acpi_is_valid_space_id(u8 space_id); +struct acpi_mem_space_context *acpi_ex_alloc_mem_space_context(void); + void acpi_ex_unmap_region_memory(struct acpi_mem_space_context *mem_info); +void acpi_ex_unmap_all_region_mappings(struct acpi_mem_space_context *mem_info); + /* * exregion - default op_region handlers */ diff --git a/drivers/acpi/acpica/evrgnini.c b/drivers/acpi/acpica/evrgnini.c index 9f33114a74ca..f6c5feea10bc 100644 --- a/drivers/acpi/acpica/evrgnini.c +++ b/drivers/acpi/acpica/evrgnini.c @@ -46,10 +46,10 @@ acpi_ev_system_memory_region_setup(acpi_handle handle, local_region_context = (struct acpi_mem_space_context *)*region_context; - /* Delete a cached mapping if present */ + /* Delete memory mappings if present */ if (local_region_context->mapped_length) { - acpi_ex_unmap_region_memory(local_region_context); + acpi_ex_unmap_all_region_mappings(local_region_context); } ACPI_FREE(local_region_context); *region_context = NULL; @@ -59,8 +59,7 @@ acpi_ev_system_memory_region_setup(acpi_handle handle, /* Create a new context */ - local_region_context = - ACPI_ALLOCATE_ZEROED(sizeof(struct acpi_mem_space_context)); + local_region_context = acpi_ex_alloc_mem_space_context(); if (!(local_region_context)) { return_ACPI_STATUS(AE_NO_MEMORY); } diff --git a/drivers/acpi/acpica/exregion.c b/drivers/acpi/acpica/exregion.c index af777b7fccb0..9d97b6a67074 100644 --- a/drivers/acpi/acpica/exregion.c +++ b/drivers/acpi/acpica/exregion.c @@ -14,6 +14,40 @@ #define _COMPONENT ACPI_EXECUTER ACPI_MODULE_NAME("exregion") +struct acpi_mem_mapping { + acpi_physical_address physical_address; + u8 *logical_address; + acpi_size length; + struct acpi_mem_mapping *next_mm; +}; + +struct acpi_mm_context { + struct acpi_mem_space_context mem_info; + struct acpi_mem_mapping *first_mm; +}; + +/***************************************************************************** + * + * FUNCTION: acpi_ex_alloc_mem_space_context + * + * PARAMETERS: None + * + * RETURN: Pointer to a new region context object. + * + * DESCRIPTION: Allocate memory for memory operation region representation. + * + ****************************************************************************/ +struct acpi_mem_space_context *acpi_ex_alloc_mem_space_context(void) +{ + ACPI_FUNCTION_TRACE(acpi_ex_alloc_mem_space_context); + +#ifdef ACPI_USE_FAST_PATH_MAPPING + return ACPI_ALLOCATE_ZEROED(sizeof(struct acpi_mm_context)); +#else + return ACPI_ALLOCATE_ZEROED(sizeof(struct acpi_mem_space_context)); +#endif +} + /***************************************************************************** * * FUNCTION: acpi_ex_unmap_region_memory @@ -40,6 +74,44 @@ void acpi_ex_unmap_region_memory(struct acpi_mem_space_context *mem_info) return_VOID; } +/***************************************************************************** + * + * FUNCTION: acpi_ex_unmap_all_region_mappings + * + * PARAMETERS: mem_info - Region specific context + * + * RETURN: None + * + * DESCRIPTION: Unmap all mappings associated with a memory operation region. + * + ****************************************************************************/ +void acpi_ex_unmap_all_region_mappings(struct acpi_mem_space_context *mem_info) +{ +#ifdef ACPI_USE_FAST_PATH_MAPPING + struct acpi_mm_context *mm_context = (struct acpi_mm_context *)mem_info; + struct acpi_mem_mapping *mm; +#endif + + ACPI_FUNCTION_TRACE(acpi_ex_unmap_all_region_mappings); + + acpi_ex_unmap_region_memory(mem_info); + +#ifdef ACPI_USE_FAST_PATH_MAPPING + while (mm_context->first_mm) { + mm = mm_context->first_mm; + mm_context->first_mm = mm->next_mm; +#ifdef ACPI_USE_DEFERRED_UNMAPPING + acpi_os_unmap_deferred(mm->logical_address, mm->length); +#else + acpi_os_unmap_memory(mm->logical_address, mm->length); +#endif + ACPI_FREE(mm); + } +#endif /* ACPI_USE_FAST_PATH_MAPPING */ + + return_VOID; +} + /******************************************************************************* * * FUNCTION: acpi_ex_system_memory_space_handler @@ -70,6 +142,10 @@ acpi_ex_system_memory_space_handler(u32 function, u32 length; acpi_size map_length; acpi_size page_boundary_map_length; +#ifdef ACPI_USE_FAST_PATH_MAPPING + struct acpi_mm_context *mm_context = (struct acpi_mm_context *)mem_info; + struct acpi_mem_mapping *mm; +#endif #ifdef ACPI_MISALIGNMENT_NOT_SUPPORTED u32 remainder; #endif @@ -128,7 +204,7 @@ acpi_ex_system_memory_space_handler(u32 function, mem_info->mapped_length))) { /* * The request cannot be resolved by the current memory mapping; - * Delete the existing mapping and create a new one. + * Delete the current cached mapping and get a new one. */ if (mem_info->mapped_length) { @@ -137,6 +213,36 @@ acpi_ex_system_memory_space_handler(u32 function, acpi_ex_unmap_region_memory(mem_info); } +#ifdef ACPI_USE_FAST_PATH_MAPPING + /* + * Look for an existing saved mapping matching the address range + * at hand. If found, make the OS layer bump up the reference + * counter of that mapping, cache it and carry out the access. + */ + for (mm = mm_context->first_mm; mm; mm = mm->next_mm) { + if (address < mm->physical_address) + continue; + + if ((u64)address + length > + (u64)mm->physical_address + mm->length) + continue; + + /* + * When called on a known-existing memory mapping, + * acpi_os_map_memory_fast_path() must return the same + * logical address as before or NULL. + */ + if (!acpi_os_map_memory_fast_path(mm->physical_address, + mm->length)) + continue; + + mem_info->mapped_logical_address = mm->logical_address; + mem_info->mapped_physical_address = mm->physical_address; + mem_info->mapped_length = mm->length; + goto access; + } +#endif /* ACPI_USE_FAST_PATH_MAPPING */ + /* * October 2009: Attempt to map from the requested address to the * end of the region. However, we will never map more than one @@ -168,9 +274,8 @@ acpi_ex_system_memory_space_handler(u32 function, /* Create a new mapping starting at the address given */ - mem_info->mapped_logical_address = - acpi_os_map_memory(address, map_length); - if (!mem_info->mapped_logical_address) { + logical_addr_ptr = acpi_os_map_memory(address, map_length); + if (!logical_addr_ptr) { ACPI_ERROR((AE_INFO, "Could not map memory at 0x%8.8X%8.8X, size %u", ACPI_FORMAT_UINT64(address), @@ -181,10 +286,56 @@ acpi_ex_system_memory_space_handler(u32 function, /* Save the physical address and mapping size */ + mem_info->mapped_logical_address = logical_addr_ptr; mem_info->mapped_physical_address = address; mem_info->mapped_length = map_length; + +#ifdef ACPI_USE_FAST_PATH_MAPPING + /* + * Create a new mm list entry to save the new mapping for + * removal at the operation region deactivation time. + */ + mm = ACPI_ALLOCATE_ZEROED(sizeof(*mm)); + if (!mm) { + /* + * No room to save the new mapping, but this is not + * critical. Just log the error and carry out the + * access as requested. + */ + ACPI_ERROR((AE_INFO, + "Not enough memory to save memory mapping at 0x%8.8X%8.8X, size %u", + ACPI_FORMAT_UINT64(address), + (u32)map_length)); + goto access; + } + /* + * Bump up the new mapping's reference counter in the OS layer + * to prevent it from getting dropped prematurely. + */ + if (!acpi_os_map_memory_fast_path(address, map_length)) { + /* + * Something has gone wrong, but this is not critical. + * Log the error, free the mm list entry that won't be + * used and carry out the access as requested. + */ + ACPI_ERROR((AE_INFO, + "Unable to save memory mapping at 0x%8.8X%8.8X, size %u", + ACPI_FORMAT_UINT64(address), + (u32)map_length)); + ACPI_FREE(mm); + goto access; + } + mm->physical_address = address; + mm->logical_address = logical_addr_ptr; + mm->length = map_length; + mm->next_mm = mm_context->first_mm; + mm_context->first_mm = mm; } +access: +#else /* !ACPI_USE_FAST_PATH_MAPPING */ + } +#endif /* !ACPI_USE_FAST_PATH_MAPPING */ /* * Generate a logical pointer corresponding to the address we want to * access