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 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 64B91C4332F for ; Thu, 10 Nov 2022 14:38:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=zBjeXGLRabUgGEEZPWGaBEclAi/S3rfsqj48IvCGWJY=; b=KZbQlbKo4LT9Sc sW5uZvzGg4EpUSsgCBYPzs0Nl9SsKE+2q/lTSAOJ+zv+sDicAvxGKQKQLCLcH5425dG+W6YKK6Dqa V6t6l2Dv4+cqxSQZtCIKiqwOHOx62dx2EDHwdAf2on8zXMwima24Aci554LICNIQmEM7+2mEiWP7e 5h/aLuzJu+BxntU818rKIEZMot8fvWhwIvatfpb+9zN2bdob93MLP8OPMK7CqrNfdqzi3VMYYTcxo xIuhoxvCNp/NOwXi24TxNx7sud+HRRueRj0RoTpJgI6GDq5Bk9YCsUaPh9hdrnFXzBlmcUDY0U4+7 DEK1/OSP7dRSnJu9KTsw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1ot8ga-006Qai-ER; Thu, 10 Nov 2022 14:37:44 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1ot8gV-006QYY-IM for linux-arm-kernel@lists.infradead.org; Thu, 10 Nov 2022 14:37:41 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 7CD931FB; Thu, 10 Nov 2022 06:37:43 -0800 (PST) Received: from monolith.localdoman (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 96FCB3F703; Thu, 10 Nov 2022 06:37:36 -0800 (PST) Date: Thu, 10 Nov 2022 14:37:33 +0000 From: Alexandru Elisei To: Ard Biesheuvel Cc: linux-efi@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH] arm64: efi: Force the use of SetVirtualAddressMap() on Altra machines Message-ID: References: <20221110094951.2963479-1-ardb@kernel.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20221110094951.2963479-1-ardb@kernel.org> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20221110_063739_744294_97C8D624 X-CRM114-Status: GOOD ( 35.84 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi, On Thu, Nov 10, 2022 at 10:49:51AM +0100, Ard Biesheuvel wrote: > Ampere Altra machines are reported to misbehave when the SetTime() EFI > runtime service is called after ExitBootServices() but before calling > SetVirtualAddressMap(). Given that the latter is horrid, pointless and > explicitly documented as optional by the EFI spec, we no longer invoke > it at boot if the configured size of the VA space guarantees that the > EFI runtime memory regions can remain mapped 1:1 like they are at boot > time. > > This means that SetTime() calls on Ampere Altra machines issued by the > rtc-efi driver now trigger a synchronous exception during boot. We can > now recover from those without bringing down the system entirely, due to > commit 23715a26c8d81291 ("arm64: efi: Recover from synchronous > exceptions occurring in firmware"). However, it would be better to avoid > this completely, given that the firmware appears to remain in a funny > state after this. > > So attempt to identify these machines based on the 'family' field in the > type #1 SMBIOS record, and call SetVirtualAddressMap() unconditionally > in that case. This works for my machine. Tested with this patch on top of the patch [1] that disables only the misbehaving services, not runtime services altogether (can test other configurations, if you feel it's necessary): Tested-by: Alexandru Elisei [1] https://lore.kernel.org/all/20221108151509.2250968-1-ardb@kernel.org/ Thanks, Alex > > Signed-off-by: Ard Biesheuvel > --- > drivers/firmware/efi/libstub/Makefile | 2 +- > drivers/firmware/efi/libstub/arm64-stub.c | 17 ++++++- > drivers/firmware/efi/libstub/efistub.h | 28 ++++++++++ > drivers/firmware/efi/libstub/smbios.c | 62 +++++++++++++++++++++++ > include/linux/efi.h | 1 + > 5 files changed, 108 insertions(+), 2 deletions(-) > create mode 100644 drivers/firmware/efi/libstub/smbios.c > > diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile > index b1601aad7e1a8d66..ef5045a53ce09653 100644 > --- a/drivers/firmware/efi/libstub/Makefile > +++ b/drivers/firmware/efi/libstub/Makefile > @@ -82,7 +82,7 @@ $(obj)/lib-%.o: $(srctree)/lib/%.c FORCE > lib-$(CONFIG_EFI_GENERIC_STUB) += efi-stub.o string.o intrinsics.o systable.o > > lib-$(CONFIG_ARM) += arm32-stub.o > -lib-$(CONFIG_ARM64) += arm64-stub.o > +lib-$(CONFIG_ARM64) += arm64-stub.o smbios.o > lib-$(CONFIG_X86) += x86-stub.o > lib-$(CONFIG_RISCV) += riscv-stub.o > lib-$(CONFIG_LOONGARCH) += loongarch-stub.o > diff --git a/drivers/firmware/efi/libstub/arm64-stub.c b/drivers/firmware/efi/libstub/arm64-stub.c > index 259e4b852d63276d..f9de5217ea65ed93 100644 > --- a/drivers/firmware/efi/libstub/arm64-stub.c > +++ b/drivers/firmware/efi/libstub/arm64-stub.c > @@ -15,6 +15,21 @@ > > #include "efistub.h" > > +static bool system_needs_vamap(void) > +{ > + const u8 *type1_family = efi_get_smbios_string(1, family); > + > + /* > + * Ampere Altra machines crash in SetTime() if SetVirtualAddressMap() > + * has not been called prior. > + */ > + if (!type1_family || strcmp(type1_family, "Altra")) > + return false; > + > + efi_warn("Working around broken SetVirtualAddressMap()\n"); > + return true; > +} > + > efi_status_t check_platform_features(void) > { > u64 tg; > @@ -24,7 +39,7 @@ efi_status_t check_platform_features(void) > * UEFI runtime regions 1:1 and so calling SetVirtualAddressMap() is > * unnecessary. > */ > - if (VA_BITS_MIN >= 48) > + if (VA_BITS_MIN >= 48 && !system_needs_vamap()) > efi_novamap = true; > > /* UEFI mandates support for 4 KB granularity, no need to check */ > diff --git a/drivers/firmware/efi/libstub/efistub.h b/drivers/firmware/efi/libstub/efistub.h > index a30fb5d8ef05ae9c..eb03d5a9aac88e84 100644 > --- a/drivers/firmware/efi/libstub/efistub.h > +++ b/drivers/firmware/efi/libstub/efistub.h > @@ -975,4 +975,32 @@ efi_enable_reset_attack_mitigation(void) { } > > void efi_retrieve_tpm2_eventlog(void); > > +struct efi_smbios_record { > + u8 type; > + u8 length; > + u16 handle; > +}; > + > +struct efi_smbios_type1_record { > + struct efi_smbios_record header; > + > + u8 manufacturer; > + u8 product_name; > + u8 version; > + u8 serial_number; > + efi_guid_t uuid; > + u8 wakeup_type; > + u8 sku_number; > + u8 family; > +}; > + > +#define efi_get_smbios_string(__type, __name) ({ \ > + int size = sizeof(struct efi_smbios_type ## __type ## _record); \ > + int off = offsetof(struct efi_smbios_type ## __type ## _record, \ > + __name); \ > + __efi_get_smbios_string(__type, off, size); \ > +}) > + > +const u8 *__efi_get_smbios_string(u8 type, int offset, int recsize); > + > #endif > diff --git a/drivers/firmware/efi/libstub/smbios.c b/drivers/firmware/efi/libstub/smbios.c > new file mode 100644 > index 0000000000000000..0b7fbd85cc2f6b4b > --- /dev/null > +++ b/drivers/firmware/efi/libstub/smbios.c > @@ -0,0 +1,62 @@ > +// SPDX-License-Identifier: GPL-2.0-only > +// Copyright 2022 Google LLC > +// Author: Ard Biesheuvel > + > +#include > + > +#include "efistub.h" > + > +typedef union efi_smbios_protocol efi_smbios_protocol_t; > + > +union efi_smbios_protocol { > + struct { > + efi_status_t (__efiapi *add)(efi_smbios_protocol_t *, > + efi_handle_t, u16 *, > + struct efi_smbios_record *); > + efi_status_t (__efiapi *update_string)(efi_smbios_protocol_t *, > + u16 *, unsigned long *, > + u8 *); > + efi_status_t (__efiapi *remove)(efi_smbios_protocol_t *, u16); > + efi_status_t (__efiapi *get_next)(efi_smbios_protocol_t *, > + u16 *, u8 *, > + struct efi_smbios_record **, > + efi_handle_t *); > + > + u8 major_version; > + u8 minor_version; > + }; > + struct { > + u32 add; > + u32 update_string; > + u32 remove; > + u32 get_next; > + > + u8 major_version; > + u8 minor_version; > + } mixed_mode; > +}; > + > +const u8 *__efi_get_smbios_string(u8 type, int offset, int recsize) > +{ > + struct efi_smbios_record *record; > + efi_smbios_protocol_t *smbios; > + efi_status_t status; > + u16 handle = 0xfffe; > + const u8 *strtable; > + > + status = efi_bs_call(locate_protocol, &EFI_SMBIOS_PROTOCOL_GUID, NULL, > + (void **)&smbios) ?: > + efi_call_proto(smbios, get_next, &handle, &type, &record, NULL); > + if (status != EFI_SUCCESS) > + return NULL; > + > + strtable = (u8 *)record + recsize; > + for (int i = 1; i < ((u8 *)record)[offset]; i++) { > + int len = strlen(strtable); > + > + if (!len) > + return NULL; > + strtable += len + 1; > + } > + return strtable; > +} > diff --git a/include/linux/efi.h b/include/linux/efi.h > index 61b252386d61cc4d..cf88dda630649f87 100644 > --- a/include/linux/efi.h > +++ b/include/linux/efi.h > @@ -389,6 +389,7 @@ void efi_native_runtime_setup(void); > #define EFI_LOAD_FILE2_PROTOCOL_GUID EFI_GUID(0x4006c0c1, 0xfcb3, 0x403e, 0x99, 0x6d, 0x4a, 0x6c, 0x87, 0x24, 0xe0, 0x6d) > #define EFI_RT_PROPERTIES_TABLE_GUID EFI_GUID(0xeb66918a, 0x7eef, 0x402a, 0x84, 0x2e, 0x93, 0x1d, 0x21, 0xc3, 0x8a, 0xe9) > #define EFI_DXE_SERVICES_TABLE_GUID EFI_GUID(0x05ad34ba, 0x6f02, 0x4214, 0x95, 0x2e, 0x4d, 0xa0, 0x39, 0x8e, 0x2b, 0xb9) > +#define EFI_SMBIOS_PROTOCOL_GUID EFI_GUID(0x03583ff6, 0xcb36, 0x4940, 0x94, 0x7e, 0xb9, 0xb3, 0x9f, 0x4a, 0xfa, 0xf7) > > #define EFI_IMAGE_SECURITY_DATABASE_GUID EFI_GUID(0xd719b2cb, 0x3d3a, 0x4596, 0xa3, 0xbc, 0xda, 0xd0, 0x0e, 0x67, 0x65, 0x6f) > #define EFI_SHIM_LOCK_GUID EFI_GUID(0x605dab50, 0xe046, 0x4300, 0xab, 0xb6, 0x3d, 0xd8, 0x10, 0xdd, 0x8b, 0x23) > -- > 2.35.1 > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel