From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-13.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D622DC433EF for ; Thu, 23 Sep 2021 12:26:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AC43860FA0 for ; Thu, 23 Sep 2021 12:26:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240838AbhIWM2N (ORCPT ); Thu, 23 Sep 2021 08:28:13 -0400 Received: from sibelius.xs4all.nl ([83.163.83.176]:52962 "EHLO sibelius.xs4all.nl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240787AbhIWM2M (ORCPT ); Thu, 23 Sep 2021 08:28:12 -0400 Received: from localhost (bloch.sibelius.xs4all.nl [local]) by bloch.sibelius.xs4all.nl (OpenSMTPD) with ESMTPA id fc8383ed; Thu, 23 Sep 2021 14:26:39 +0200 (CEST) Date: Thu, 23 Sep 2021 14:26:39 +0200 (CEST) From: Mark Kettenis To: "Rafael J. Wysocki" Cc: lorenzo.pieralisi@arm.com, justin.he@arm.com, harb@amperecomputing.com, will@kernel.org, lenb@kernel.org, robert.moore@intel.com, erik.kaneda@intel.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org, devel@acpica.org, ardb@kernel.org, guohanjun@huawei.com, catalin.marinas@arm.com, rafael.j.wysocki@intel.com In-Reply-To: (rafael@kernel.org) Subject: Re: [PATCH v2] Revert "ACPI: Add memory semantics to acpi_os_map_memory()" References: <20210910122820.26886-1-justin.he@arm.com> <20210910143223.6705-1-justin.he@arm.com> <20210922163336.GA24633@lpieralisi> <56147a0b8b9fba46@bloch.sibelius.xs4all.nl> <20210923094031.GA6454@lpieralisi> Message-ID: <56147c6e73afe9f6@bloch.sibelius.xs4all.nl> Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org > From: "Rafael J. Wysocki" > Date: Thu, 23 Sep 2021 13:05:05 +0200 > > On Thu, Sep 23, 2021 at 11:40 AM Lorenzo Pieralisi > wrote: > > > > On Thu, Sep 23, 2021 at 01:09:58AM +0200, Mark Kettenis wrote: > > > > Date: Wed, 22 Sep 2021 17:33:36 +0100 > > > > From: Lorenzo Pieralisi > > > > > > > > On Fri, Sep 10, 2021 at 10:32:23PM +0800, Jia He wrote: > > > > > This reverts commit 437b38c51162f8b87beb28a833c4d5dc85fa864e. > > > > > > > > > > After this commit, a boot panic is alway hit on an Ampere EMAG server > > > > > with call trace as follows: > > > > > Internal error: synchronous external abort: 96000410 [#1] SMP > > > > > Modules linked in: > > > > > CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.14.0+ #462 > > > > > Hardware name: MiTAC RAPTOR EV-883832-X3-0001/RAPTOR, BIOS 0.14 02/22/2019 > > > > > pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--) > > > > > [...snip...] > > > > > Call trace: > > > > > acpi_ex_system_memory_space_handler+0x26c/0x2c8 > > > > > acpi_ev_address_space_dispatch+0x228/0x2c4 > > > > > acpi_ex_access_region+0x114/0x268 > > > > > acpi_ex_field_datum_io+0x128/0x1b8 > > > > > acpi_ex_extract_from_field+0x14c/0x2ac > > > > > acpi_ex_read_data_from_field+0x190/0x1b8 > > > > > acpi_ex_resolve_node_to_value+0x1ec/0x288 > > > > > acpi_ex_resolve_to_value+0x250/0x274 > > > > > acpi_ds_evaluate_name_path+0xac/0x124 > > > > > acpi_ds_exec_end_op+0x90/0x410 > > > > > acpi_ps_parse_loop+0x4ac/0x5d8 > > > > > acpi_ps_parse_aml+0xe0/0x2c8 > > > > > acpi_ps_execute_method+0x19c/0x1ac > > > > > acpi_ns_evaluate+0x1f8/0x26c > > > > > acpi_ns_init_one_device+0x104/0x140 > > > > > acpi_ns_walk_namespace+0x158/0x1d0 > > > > > acpi_ns_initialize_devices+0x194/0x218 > > > > > acpi_initialize_objects+0x48/0x50 > > > > > acpi_init+0xe0/0x498 > > > > > > > > > > As mentioned by Lorenzo: > > > > > "We are forcing memory semantics mappings to PROT_NORMAL_NC, which > > > > > eMAG does not like at all and I'd need to understand why. It looks > > > > > like the issue happen in SystemMemory Opregion handler." > > > > > > > > > > Hence just revert it before everything is clear. > > > > > > > > > > Fixes: 437b38c51162 ("ACPI: Add memory semantics to acpi_os_map_memory()") > > > > > Cc: Lorenzo Pieralisi > > > > > Cc: Ard Biesheuvel > > > > > Cc: Hanjun Guo > > > > > Cc: Catalin Marinas > > > > > Cc: Rafael J. Wysocki > > > > > Cc: Harb Abdulhamid > > > > > > > > > > Signed-off-by: Jia He > > > > > > > > Rewrote the commit log, please take the patch below and repost > > > > it as a v3. > > > > > > > > It would still be great if Ampere can help us understand why > > > > the NormalNC attributes trigger a sync abort on the opregion > > > > before merging it. > > > > > > To be honest, I don't think you really need an explanation from Ampere > > > here. Mapping a part of the address space that doesn't provide memory > > > semantics with NormalNC attributes is wrong and triggering a sync > > > abort in that case is way better than silently ignoring the access. > > > > That's understood and that's what I explained in the revert commit > > log, no question about it. > > > > I was just asking to confirm if that's what's actually happening. > > > > > Putting my OpenBSD hat on (where we have our own ACPI OSPM > > > implementation) I must say that we always interpreted SystemMemory as > > > memory mapped IO and I think that is a logical choice as SystemIO is > > > used for (non-memory mapped) IO. And I'd say that the ACPI OSPM code > > > should make sure that it uses properly aligned access to any Field > > > object that doesn't use AnyAcc as its access type. Even on x86! And > > > I'd say that AML that uses AnyAcc fields for SystemMemory OpRegions on > > > arm64 is buggy. > > > > > > But maybe relaxing this when the EFI memory map indicates that the > > > address space in question does provide memory semantics does make > > > sense. That should defenitely be documented in the ACPI standard > > > though. > > > > Mapping SystemMemory Opregions as "memory" does not make sense > > at all to me. Still, that's what Linux ACPICA code does (*if* > > that's what acpi_os_map_memory() is supposed to mean). > > > > https://lore.kernel.org/linux-acpi/20210916160827.GA4525@lpieralisi > > It doesn't need to do that, though, if there are good enough arguments > to change the current behavior (and the argument here is that it may > be an MMIO region, so mapping it as memory doesn't really work, but it > also may be a region in memory - there is no rule in the spec by which > SystemMemory Opregions cannot be "memory" AFAICS) and if that change > doesn't introduce regressions in the installed base. > > > Where do we go from here, to be defined, we still have a bug > > to fix after the revert is applied. > > > > drivers/acpi/sysfs.c > > > > maps BERT error regions with acpi_os_map_memory(). > > That mechanism is basically used for exporting ACPI tables to user > space and they are known to reside in memory. Whether or not BERT > regions should be mapped in the same way is a good question. It is not inconceivable that BERT regions actually live in memory of the BMC that is exposed over a bus that doesn't implement memory semantics is it? > > If the BERT error > > region is not in the EFI memory map, we map that memory as device-nGnRnE > > and we execute memory semantics operation on it. > > > > https://lore.kernel.org/linux-acpi/e548e72c-83a4-2366-dd57-3e746040fea9@arm.com > > > > I could change that code to map those regions as ioremap_wc() because > > supposedly we *know* that's memory but this is becoming a slippery > > slope to follow IMO. > > > > > > -- >8 -- > > > > Subject: [PATCH] Revert "ACPI: Add memory semantics to acpi_os_map_memory()" > > > > > > > > This reverts commit 437b38c51162f8b87beb28a833c4d5dc85fa864e. > > > > > > > > The memory semantics added in commit 437b38c51162 causes SystemMemory > > > > Operation region, whose address range is not described in the EFI memory > > > > map to be mapped as NormalNC memory on arm64 platforms (through > > > > acpi_os_map_memory() in acpi_ex_system_memory_space_handler()). > > > > > > > > This triggers the following abort on an ARM64 Ampere eMAG machine, > > > > because presumably the physical address range area backing the Opregion > > > > does not support NormalNC memory attributes driven on the bus. > > > > > > > > Internal error: synchronous external abort: 96000410 [#1] SMP > > > > Modules linked in: > > > > CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.14.0+ #462 > > > > Hardware name: MiTAC RAPTOR EV-883832-X3-0001/RAPTOR, BIOS 0.14 02/22/2019 > > > > pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--) > > > > [...snip...] > > > > Call trace: > > > > acpi_ex_system_memory_space_handler+0x26c/0x2c8 > > > > acpi_ev_address_space_dispatch+0x228/0x2c4 > > > > acpi_ex_access_region+0x114/0x268 > > > > acpi_ex_field_datum_io+0x128/0x1b8 > > > > acpi_ex_extract_from_field+0x14c/0x2ac > > > > acpi_ex_read_data_from_field+0x190/0x1b8 > > > > acpi_ex_resolve_node_to_value+0x1ec/0x288 > > > > acpi_ex_resolve_to_value+0x250/0x274 > > > > acpi_ds_evaluate_name_path+0xac/0x124 > > > > acpi_ds_exec_end_op+0x90/0x410 > > > > acpi_ps_parse_loop+0x4ac/0x5d8 > > > > acpi_ps_parse_aml+0xe0/0x2c8 > > > > acpi_ps_execute_method+0x19c/0x1ac > > > > acpi_ns_evaluate+0x1f8/0x26c > > > > acpi_ns_init_one_device+0x104/0x140 > > > > acpi_ns_walk_namespace+0x158/0x1d0 > > > > acpi_ns_initialize_devices+0x194/0x218 > > > > acpi_initialize_objects+0x48/0x50 > > > > acpi_init+0xe0/0x498 > > > > > > > > If the Opregion address range is not present in the EFI memory map there > > > > is no way for us to determine the memory attributes to use to map it - > > > > defaulting to NormalNC does not work (and it is not correct on a memory > > > > region that may have read side-effects) and therefore commit > > > > 437b38c51162 should be reverted, which means reverting back to the > > > > original behavior whereby address ranges that are mapped using > > > > acpi_os_map_memory() default to the safe devicenGnRnE attributes on > > > > ARM64 if the mapped address range is not defined in the EFI memory map. > > > > > > > > Fixes: 437b38c51162 ("ACPI: Add memory semantics to acpi_os_map_memory()") > > > > Signed-off-by: Jia He > > > > Cc: Lorenzo Pieralisi > > > > Cc: Ard Biesheuvel > > > > Cc: Hanjun Guo > > > > Cc: Catalin Marinas > > > > Cc: Rafael J. Wysocki > > > > Cc: Harb Abdulhamid > > > > --- > > > > arch/arm64/include/asm/acpi.h | 3 --- > > > > arch/arm64/kernel/acpi.c | 19 +++---------------- > > > > drivers/acpi/osl.c | 23 +++++++---------------- > > > > include/acpi/acpi_io.h | 8 -------- > > > > 4 files changed, 10 insertions(+), 43 deletions(-) > > > > > > > > diff --git a/arch/arm64/include/asm/acpi.h b/arch/arm64/include/asm/acpi.h > > > > index 7535dc7cc5aa..bd68e1b7f29f 100644 > > > > --- a/arch/arm64/include/asm/acpi.h > > > > +++ b/arch/arm64/include/asm/acpi.h > > > > @@ -50,9 +50,6 @@ pgprot_t __acpi_get_mem_attribute(phys_addr_t addr); > > > > void __iomem *acpi_os_ioremap(acpi_physical_address phys, acpi_size size); > > > > #define acpi_os_ioremap acpi_os_ioremap > > > > > > > > -void __iomem *acpi_os_memmap(acpi_physical_address phys, acpi_size size); > > > > -#define acpi_os_memmap acpi_os_memmap > > > > - > > > > typedef u64 phys_cpuid_t; > > > > #define PHYS_CPUID_INVALID INVALID_HWID > > > > > > > > diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c > > > > index 1c9c2f7a1c04..f3851724fe35 100644 > > > > --- a/arch/arm64/kernel/acpi.c > > > > +++ b/arch/arm64/kernel/acpi.c > > > > @@ -273,8 +273,7 @@ pgprot_t __acpi_get_mem_attribute(phys_addr_t addr) > > > > return __pgprot(PROT_DEVICE_nGnRnE); > > > > } > > > > > > > > -static void __iomem *__acpi_os_ioremap(acpi_physical_address phys, > > > > - acpi_size size, bool memory) > > > > +void __iomem *acpi_os_ioremap(acpi_physical_address phys, acpi_size size) > > > > { > > > > efi_memory_desc_t *md, *region = NULL; > > > > pgprot_t prot; > > > > @@ -300,11 +299,9 @@ static void __iomem *__acpi_os_ioremap(acpi_physical_address phys, > > > > * It is fine for AML to remap regions that are not represented in the > > > > * EFI memory map at all, as it only describes normal memory, and MMIO > > > > * regions that require a virtual mapping to make them accessible to > > > > - * the EFI runtime services. Determine the region default > > > > - * attributes by checking the requested memory semantics. > > > > + * the EFI runtime services. > > > > */ > > > > - prot = memory ? __pgprot(PROT_NORMAL_NC) : > > > > - __pgprot(PROT_DEVICE_nGnRnE); > > > > + prot = __pgprot(PROT_DEVICE_nGnRnE); > > > > if (region) { > > > > switch (region->type) { > > > > case EFI_LOADER_CODE: > > > > @@ -364,16 +361,6 @@ static void __iomem *__acpi_os_ioremap(acpi_physical_address phys, > > > > return __ioremap(phys, size, prot); > > > > } > > > > > > > > -void __iomem *acpi_os_ioremap(acpi_physical_address phys, acpi_size size) > > > > -{ > > > > - return __acpi_os_ioremap(phys, size, false); > > > > -} > > > > - > > > > -void __iomem *acpi_os_memmap(acpi_physical_address phys, acpi_size size) > > > > -{ > > > > - return __acpi_os_ioremap(phys, size, true); > > > > -} > > > > - > > > > /* > > > > * Claim Synchronous External Aborts as a firmware first notification. > > > > * > > > > diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c > > > > index a43f1521efe6..45c5c0e45e33 100644 > > > > --- a/drivers/acpi/osl.c > > > > +++ b/drivers/acpi/osl.c > > > > @@ -284,8 +284,7 @@ acpi_map_lookup_virt(void __iomem *virt, acpi_size size) > > > > #define should_use_kmap(pfn) page_is_ram(pfn) > > > > #endif > > > > > > > > -static void __iomem *acpi_map(acpi_physical_address pg_off, unsigned long pg_sz, > > > > - bool memory) > > > > +static void __iomem *acpi_map(acpi_physical_address pg_off, unsigned long pg_sz) > > > > { > > > > unsigned long pfn; > > > > > > > > @@ -295,8 +294,7 @@ static void __iomem *acpi_map(acpi_physical_address pg_off, unsigned long pg_sz, > > > > return NULL; > > > > return (void __iomem __force *)kmap(pfn_to_page(pfn)); > > > > } else > > > > - return memory ? acpi_os_memmap(pg_off, pg_sz) : > > > > - acpi_os_ioremap(pg_off, pg_sz); > > > > + return acpi_os_ioremap(pg_off, pg_sz); > > > > } > > > > > > > > static void acpi_unmap(acpi_physical_address pg_off, void __iomem *vaddr) > > > > @@ -311,10 +309,9 @@ static void acpi_unmap(acpi_physical_address pg_off, void __iomem *vaddr) > > > > } > > > > > > > > /** > > > > - * __acpi_os_map_iomem - Get a virtual address for a given physical address range. > > > > + * acpi_os_map_iomem - Get a virtual address for a given physical address range. > > > > * @phys: Start of the physical address range to map. > > > > * @size: Size of the physical address range to map. > > > > - * @memory: true if remapping memory, false if IO > > > > * > > > > * Look up the given physical address range in the list of existing ACPI memory > > > > * mappings. If found, get a reference to it and return a pointer to it (its > > > > @@ -324,8 +321,8 @@ static void acpi_unmap(acpi_physical_address pg_off, void __iomem *vaddr) > > > > * During early init (when acpi_permanent_mmap has not been set yet) this > > > > * routine simply calls __acpi_map_table() to get the job done. > > > > */ > > > > -static void __iomem __ref > > > > -*__acpi_os_map_iomem(acpi_physical_address phys, acpi_size size, bool memory) > > > > +void __iomem __ref > > > > +*acpi_os_map_iomem(acpi_physical_address phys, acpi_size size) > > > > { > > > > struct acpi_ioremap *map; > > > > void __iomem *virt; > > > > @@ -356,7 +353,7 @@ static void __iomem __ref > > > > > > > > pg_off = round_down(phys, PAGE_SIZE); > > > > pg_sz = round_up(phys + size, PAGE_SIZE) - pg_off; > > > > - virt = acpi_map(phys, size, memory); > > > > + virt = acpi_map(phys, size); > > > > if (!virt) { > > > > mutex_unlock(&acpi_ioremap_lock); > > > > kfree(map); > > > > @@ -375,17 +372,11 @@ static void __iomem __ref > > > > mutex_unlock(&acpi_ioremap_lock); > > > > return map->virt + (phys - map->phys); > > > > } > > > > - > > > > -void __iomem *__ref > > > > -acpi_os_map_iomem(acpi_physical_address phys, acpi_size size) > > > > -{ > > > > - return __acpi_os_map_iomem(phys, size, false); > > > > -} > > > > EXPORT_SYMBOL_GPL(acpi_os_map_iomem); > > > > > > > > void *__ref acpi_os_map_memory(acpi_physical_address phys, acpi_size size) > > > > { > > > > - return (void *)__acpi_os_map_iomem(phys, size, true); > > > > + return (void *)acpi_os_map_iomem(phys, size); > > > > } > > > > EXPORT_SYMBOL_GPL(acpi_os_map_memory); > > > > > > > > diff --git a/include/acpi/acpi_io.h b/include/acpi/acpi_io.h > > > > index a0212e67d6f4..027faa8883aa 100644 > > > > --- a/include/acpi/acpi_io.h > > > > +++ b/include/acpi/acpi_io.h > > > > @@ -14,14 +14,6 @@ static inline void __iomem *acpi_os_ioremap(acpi_physical_address phys, > > > > } > > > > #endif > > > > > > > > -#ifndef acpi_os_memmap > > > > -static inline void __iomem *acpi_os_memmap(acpi_physical_address phys, > > > > - acpi_size size) > > > > -{ > > > > - return ioremap_cache(phys, size); > > > > -} > > > > -#endif > > > > - > > > > extern bool acpi_permanent_mmap; > > > > > > > > void __iomem __ref > > > > -- > > > > 2.31.0 > > > > > > > > _______________________________________________ > > > > linux-arm-kernel mailing list > > > > linux-arm-kernel@lists.infradead.org > > > > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel > > > > >