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Date: Tue, 28 Apr 2015 13:49:35 -0700 From: Andy Lutomirski <luto@...capital.net> To: Dan Williams <dan.j.williams@...el.com> Cc: linux-nvdimm <linux-nvdimm@...ts.01.org>, Ingo Molnar <mingo@...nel.org>, Boaz Harrosh <boaz@...xistor.com>, Andrew Morton <akpm@...ux-foundation.org>, "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>, Christoph Hellwig <hch@....de>, Jens Axboe <axboe@...com>, Borislav Petkov <bp@...en8.de>, "H. Peter Anvin" <hpa@...or.com>, Matthew Wilcox <willy@...ux.intel.com>, Thomas Gleixner <tglx@...utronix.de>, Linus Torvalds <torvalds@...ux-foundation.org>, Ross Zwisler <ross.zwisler@...ux.intel.com> Subject: Re: [PATCH v2 01/20] e820, efi: add ACPI 6.0 persistent memory types On Tue, Apr 28, 2015 at 11:24 AM, Dan Williams <dan.j.williams@...el.com> wrote: > ACPI 6.0 formalizes e820-type-7 and efi-type-14 as persistent memory. > Mark it "reserved" and allow it to be claimed by a persistent memory > device driver. > > This definition is in addition to the Linux kernel's existing type-12 > definition that was recently added in support of shipping platforms with > NVDIMM support that predate ACPI 6.0 (which now classifies type-12 as > OEM reserved). We may choose to exploit this wealth of definitions for > NVDIMMs to differentiate E820_PRAM (type-12) from E820_PMEM (type-7). > One potential differentiation is that PMEM is not backed by struct page > by default in contrast to PRAM. For now, they are effectively treated > as aliases by the mm. > > Note, /proc/iomem can be consulted for differentiating legacy > "Persistent RAM" E820_PRAM vs standard "Persistent I/O Memory" > E820_PMEM. > > Cc: Boaz Harrosh <boaz@...xistor.com> > Cc: Ingo Molnar <mingo@...nel.org> > Cc: Christoph Hellwig <hch@....de> > Cc: Andrew Morton <akpm@...ux-foundation.org> > Cc: Borislav Petkov <bp@...en8.de> > Cc: H. Peter Anvin <hpa@...or.com> > Cc: Jens Axboe <axboe@...com> > Cc: Linus Torvalds <torvalds@...ux-foundation.org> > Cc: Matthew Wilcox <willy@...ux.intel.com> > Cc: Thomas Gleixner <tglx@...utronix.de> > Acked-by: Andy Lutomirski <luto@...capital.net> > Reviewed-by: Ross Zwisler <ross.zwisler@...ux.intel.com> > Signed-off-by: Dan Williams <dan.j.williams@...el.com> > --- > arch/arm64/kernel/efi.c | 1 + > arch/ia64/kernel/efi.c | 4 ++++ > arch/x86/boot/compressed/eboot.c | 4 ++++ > arch/x86/include/uapi/asm/e820.h | 1 + > arch/x86/kernel/e820.c | 26 +++++++++++++++++++++++--- > arch/x86/platform/efi/efi.c | 3 +++ > include/linux/efi.h | 3 ++- > 7 files changed, 38 insertions(+), 4 deletions(-) > > diff --git a/arch/arm64/kernel/efi.c b/arch/arm64/kernel/efi.c > index ab21e0d58278..9d4aa18f2a82 100644 > --- a/arch/arm64/kernel/efi.c > +++ b/arch/arm64/kernel/efi.c > @@ -158,6 +158,7 @@ static __init int is_reserve_region(efi_memory_desc_t *md) > case EFI_BOOT_SERVICES_CODE: > case EFI_BOOT_SERVICES_DATA: > case EFI_CONVENTIONAL_MEMORY: > + case EFI_PERSISTENT_MEMORY: > return 0; > default: > break; > diff --git a/arch/ia64/kernel/efi.c b/arch/ia64/kernel/efi.c > index c52d7540dc05..9028bc268cd7 100644 > --- a/arch/ia64/kernel/efi.c > +++ b/arch/ia64/kernel/efi.c > @@ -1223,6 +1223,10 @@ efi_initialize_iomem_resources(struct resource *code_resource, > flags |= IORESOURCE_DISABLED; > break; > > + case EFI_PERSISTENT_MEMORY: > + name = "persistent"; > + break; > + > case EFI_RESERVED_TYPE: > case EFI_RUNTIME_SERVICES_CODE: > case EFI_RUNTIME_SERVICES_DATA: > diff --git a/arch/x86/boot/compressed/eboot.c b/arch/x86/boot/compressed/eboot.c > index ef17683484e9..dde5bf7726f4 100644 > --- a/arch/x86/boot/compressed/eboot.c > +++ b/arch/x86/boot/compressed/eboot.c > @@ -1222,6 +1222,10 @@ static efi_status_t setup_e820(struct boot_params *params, > e820_type = E820_NVS; > break; > > + case EFI_PERSISTENT_MEMORY: > + e820_type = E820_PMEM; > + break; > + > default: > continue; > } > diff --git a/arch/x86/include/uapi/asm/e820.h b/arch/x86/include/uapi/asm/e820.h > index 960a8a9dc4ab..0f457e6eab18 100644 > --- a/arch/x86/include/uapi/asm/e820.h > +++ b/arch/x86/include/uapi/asm/e820.h > @@ -32,6 +32,7 @@ > #define E820_ACPI 3 > #define E820_NVS 4 > #define E820_UNUSABLE 5 > +#define E820_PMEM 7 > > /* > * This is a non-standardized way to represent ADR or NVDIMM regions that > diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c > index 11cc7d54ec3f..d38b53a7e9b2 100644 > --- a/arch/x86/kernel/e820.c > +++ b/arch/x86/kernel/e820.c > @@ -149,6 +149,7 @@ static void __init e820_print_type(u32 type) > case E820_UNUSABLE: > printk(KERN_CONT "unusable"); > break; > + case E820_PMEM: > case E820_PRAM: > printk(KERN_CONT "persistent (type %u)", type); > break; I'd kind of like to make it more clear what's going on here. It doesn't help that the spec chose poor names. How about "NVDIMM physical aperture" for E820_PMEM and "legacy persistent RAM" for E820_PRAM? Otherwise this looks generaly sensible, although I don't really understand why e820_type_to_string and e820_print_type are different. --Andy -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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