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From: Jarkko Sakkinen <jarkko@kernel.org>
To: Atharva Tiwari <atharvatiwarilinuxdev@gmail.com>
Cc: "Bjorn Helgaas" <bhelgaas@google.com>,
	"Thomas Gleixner" <tglx@kernel.org>,
	"Ingo Molnar" <mingo@redhat.com>,
	"Borislav Petkov" <bp@alien8.de>,
	"Dave Hansen" <dave.hansen@linux.intel.com>,
	x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
	"Andreas Noever" <andreas.noever@gmail.com>,
	"Mika Westerberg" <westeri@kernel.org>,
	"Yehezkel Bernat" <YehezkelShB@gmail.com>,
	"Hans de Goede" <hansg@kernel.org>,
	"Ilpo Järvinen" <ilpo.jarvinen@linux.intel.com>,
	"Mimi Zohar" <zohar@linux.ibm.com>,
	"Roberto Sassu" <roberto.sassu@huawei.com>,
	"Dmitry Kasatkin" <dmitry.kasatkin@gmail.com>,
	"Eric Snowberg" <eric.snowberg@oracle.com>,
	"Paul Moore" <paul@paul-moore.com>,
	"James Morris" <jmorris@namei.org>,
	"Serge E. Hallyn" <serge@hallyn.com>,
	linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-usb@vger.kernel.org, platform-driver-x86@vger.kernel.org,
	linux-integrity@vger.kernel.org, keyrings@vger.kernel.org,
	linux-security-module@vger.kernel.org
Subject: Re: [PATCH v3 1/2] treewide: Add a flag to detect the Apple T2 chip
Date: Tue, 21 Jul 2026 13:57:07 +0300	[thread overview]
Message-ID: <al9Qg-0o0XNlo_Z6@kernel.org> (raw)
In-Reply-To: <20260721063412.11588-2-atharvatiwarilinuxdev@gmail.com>

On Tue, Jul 21, 2026 at 02:34:06AM -0400, Atharva Tiwari wrote:
> Add a flag to detect Apple T2 chips on Intel Macs.
> Cache the result to avoid repeated checks. That will
> be used in upcoming patches.
> 
> Signed-off-by: Atharva Tiwari <atharvatiwarilinuxdev@gmail.com>
> ---
>  arch/x86/kernel/quirks.c                      | 105 ++++++++++++++++++
>  include/linux/platform_data/x86/apple.h       |   5 +
>  .../platform_certs/keyring_handler.h          |   8 --
>  security/integrity/platform_certs/load_uefi.c |  38 ++-----
>  4 files changed, 118 insertions(+), 38 deletions(-)
> 
> diff --git a/arch/x86/kernel/quirks.c b/arch/x86/kernel/quirks.c
> index a92f18db9610..300d6436060d 100644
> --- a/arch/x86/kernel/quirks.c
> +++ b/arch/x86/kernel/quirks.c
> @@ -664,8 +664,113 @@ DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, 0x2083, quirk_intel_purley_xeon_ras
>  bool x86_apple_machine;
>  EXPORT_SYMBOL(x86_apple_machine);
>  
> +bool has_apple_t2_chip;
> +EXPORT_SYMBOL(has_apple_t2_chip);
> +
> +static const struct dmi_system_id apple_t2_devices[] __initconst = {
> +	{
> +		.matches = {
> +			DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
> +			DMI_MATCH(DMI_PRODUCT_NAME, "MacBookPro15,1"),
> +		},
> +	},
> +	{
> +		.matches = {
> +			DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
> +			DMI_MATCH(DMI_PRODUCT_NAME, "MacBookPro15,2"),
> +		},
> +	},
> +	{
> +		.matches = {
> +			DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
> +			DMI_MATCH(DMI_PRODUCT_NAME, "MacBookPro15,3"),
> +		},
> +	},
> +	{
> +		.matches = {
> +			DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
> +			DMI_MATCH(DMI_PRODUCT_NAME, "MacBookPro15,4"),
> +		},
> +	},
> +	{
> +		.matches = {
> +			DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
> +			DMI_MATCH(DMI_PRODUCT_NAME, "MacBookPro16,1"),
> +		},
> +	},
> +	{
> +		.matches = {
> +			DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
> +			DMI_MATCH(DMI_PRODUCT_NAME, "MacBookPro16,2"),
> +		},
> +	},
> +	{
> +		.matches = {
> +			DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
> +			DMI_MATCH(DMI_PRODUCT_NAME, "MacBookPro16,3"),
> +		},
> +	},
> +	{
> +		.matches = {
> +			DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
> +			DMI_MATCH(DMI_PRODUCT_NAME, "MacBookPro16,4"),
> +		},
> +	},
> +	{
> +		.matches = {
> +			DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
> +			DMI_MATCH(DMI_PRODUCT_NAME, "MacBookAir8,1"),
> +		},
> +	},
> +	{
> +		.matches = {
> +			DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
> +			DMI_MATCH(DMI_PRODUCT_NAME, "MacBookAir8,2"),
> +		},
> +	},
> +	{
> +		.matches = {
> +			DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
> +			DMI_MATCH(DMI_PRODUCT_NAME, "MacBookAir9,1"),
> +		},
> +	},
> +	{
> +		.matches = {
> +			DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
> +			DMI_MATCH(DMI_PRODUCT_NAME, "Macmini8,1"),
> +		},
> +	},
> +	{
> +		.matches = {
> +			DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
> +			DMI_MATCH(DMI_PRODUCT_NAME, "MacPro7,1"),
> +		},
> +	},
> +	{
> +		.matches = {
> +			DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
> +			DMI_MATCH(DMI_PRODUCT_NAME, "iMac20,1"),
> +		},
> +	},
> +	{
> +		.matches = {
> +			DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
> +			DMI_MATCH(DMI_PRODUCT_NAME, "iMac20,2"),
> +		},
> +	},
> +	{
> +		.matches = {
> +			DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
> +			DMI_MATCH(DMI_PRODUCT_NAME, "iMacPro1,1"),
> +		},
> +	},
> +	{ }
> +};
> +
>  void __init early_platform_quirks(void)
>  {
>  	x86_apple_machine = dmi_match(DMI_SYS_VENDOR, "Apple Inc.") ||
>  			    dmi_match(DMI_SYS_VENDOR, "Apple Computer, Inc.");
> +
> +	has_apple_t2_chip = dmi_check_system(apple_t2_devices);
>  }
> diff --git a/include/linux/platform_data/x86/apple.h b/include/linux/platform_data/x86/apple.h
> index 079e816c3c21..47b27dceab18 100644
> --- a/include/linux/platform_data/x86/apple.h
> +++ b/include/linux/platform_data/x86/apple.h
> @@ -6,8 +6,13 @@
>   * x86_apple_machine - whether the machine is an x86 Apple Macintosh
>   */
>  extern bool x86_apple_machine;
> +/**
> + * has_apple_t2_chip - whether the machine has the Apple T2 chip
> + */
> +extern bool has_apple_t2_chip;
>  #else
>  #define x86_apple_machine false
> +#define has_apple_t2_chip false
>  #endif
>  
>  #endif
> diff --git a/security/integrity/platform_certs/keyring_handler.h b/security/integrity/platform_certs/keyring_handler.h
> index f92895cc50f6..a355f4400179 100644
> --- a/security/integrity/platform_certs/keyring_handler.h
> +++ b/security/integrity/platform_certs/keyring_handler.h
> @@ -45,11 +45,3 @@ efi_element_handler_t get_handler_for_code_signing_keys(const efi_guid_t *sig_ty
>  efi_element_handler_t get_handler_for_dbx(const efi_guid_t *sig_type);
>  
>  #endif
> -
> -#ifndef UEFI_QUIRK_SKIP_CERT
> -#define UEFI_QUIRK_SKIP_CERT(vendor, product) \
> -		 .matches = { \
> -			DMI_MATCH(DMI_BOARD_VENDOR, vendor), \
> -			DMI_MATCH(DMI_PRODUCT_NAME, product), \
> -		},
> -#endif
> diff --git a/security/integrity/platform_certs/load_uefi.c b/security/integrity/platform_certs/load_uefi.c
> index c0d6948446c3..b4096d4c828d 100644
> --- a/security/integrity/platform_certs/load_uefi.c
> +++ b/security/integrity/platform_certs/load_uefi.c
> @@ -3,42 +3,16 @@
>  #include <linux/kernel.h>
>  #include <linux/sched.h>
>  #include <linux/cred.h>
> -#include <linux/dmi.h>
>  #include <linux/err.h>
>  #include <linux/efi.h>
>  #include <linux/slab.h>
>  #include <linux/ima.h>
> +#include <linux/platform_data/x86/apple.h>
>  #include <keys/asymmetric-type.h>
>  #include <keys/system_keyring.h>
>  #include "../integrity.h"
>  #include "keyring_handler.h"
>  
> -/*
> - * On T2 Macs reading the db and dbx efi variables to load UEFI Secure Boot
> - * certificates causes occurrence of a page fault in Apple's firmware and
> - * a crash disabling EFI runtime services. The following quirk skips reading
> - * these variables.
> - */
> -static const struct dmi_system_id uefi_skip_cert[] = {
> -	{ UEFI_QUIRK_SKIP_CERT("Apple Inc.", "MacBookPro15,1") },
> -	{ UEFI_QUIRK_SKIP_CERT("Apple Inc.", "MacBookPro15,2") },
> -	{ UEFI_QUIRK_SKIP_CERT("Apple Inc.", "MacBookPro15,3") },
> -	{ UEFI_QUIRK_SKIP_CERT("Apple Inc.", "MacBookPro15,4") },
> -	{ UEFI_QUIRK_SKIP_CERT("Apple Inc.", "MacBookPro16,1") },
> -	{ UEFI_QUIRK_SKIP_CERT("Apple Inc.", "MacBookPro16,2") },
> -	{ UEFI_QUIRK_SKIP_CERT("Apple Inc.", "MacBookPro16,3") },
> -	{ UEFI_QUIRK_SKIP_CERT("Apple Inc.", "MacBookPro16,4") },
> -	{ UEFI_QUIRK_SKIP_CERT("Apple Inc.", "MacBookAir8,1") },
> -	{ UEFI_QUIRK_SKIP_CERT("Apple Inc.", "MacBookAir8,2") },
> -	{ UEFI_QUIRK_SKIP_CERT("Apple Inc.", "MacBookAir9,1") },
> -	{ UEFI_QUIRK_SKIP_CERT("Apple Inc.", "Macmini8,1") },
> -	{ UEFI_QUIRK_SKIP_CERT("Apple Inc.", "MacPro7,1") },
> -	{ UEFI_QUIRK_SKIP_CERT("Apple Inc.", "iMac20,1") },
> -	{ UEFI_QUIRK_SKIP_CERT("Apple Inc.", "iMac20,2") },
> -	{ UEFI_QUIRK_SKIP_CERT("Apple Inc.", "iMacPro1,1") },
> -	{ }
> -};
> -
>  /*
>   * Look to see if a UEFI variable called MokIgnoreDB exists and return true if
>   * it does.
> @@ -165,10 +139,14 @@ static int __init load_uefi_certs(void)
>  	unsigned long dbsize = 0, dbxsize = 0, mokxsize = 0;
>  	efi_status_t status;
>  	int rc = 0;
> -	const struct dmi_system_id *dmi_id;
>  
> -	dmi_id = dmi_first_match(uefi_skip_cert);
> -	if (dmi_id) {
> +	/*
> +	 * On T2 Macs reading the db and dbx efi variables to load UEFI Secure Boot
> +	 * certificates causes occurrence of a page fault in Apple's firmware and
> +	 * a crash disabling EFI runtime services. The following quirk skips reading
> +	 * these variables.
> +	 */
> +	if (has_apple_t2_chip) {
>  		pr_err("Reading UEFI Secure Boot Certs is not supported on T2 Macs.\n");
>  		return false;
>  	}
> -- 
> 2.43.0
> 


Acked-by: Jarkko Sakkinen <jarkko@kernel.org>

BR, Jarkko

  parent reply	other threads:[~2026-07-21 10:57 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-07-21  6:34 [PATCH v3 0/2] Add Apple T2 NHI device links Atharva Tiwari
2026-07-21  6:34 ` [PATCH v3 1/2] treewide: Add a flag to detect the Apple T2 chip Atharva Tiwari
2026-07-21  6:44   ` sashiko-bot
2026-07-21 10:57   ` Jarkko Sakkinen [this message]
2026-07-21 15:29   ` Hans de Goede
2026-07-21  6:34 ` [PATCH v3 2/2] thunderbolt: Add device links for Apple T2 NHI Atharva Tiwari
2026-07-21  8:59   ` sashiko-bot
2026-07-21  9:03   ` Ilpo Järvinen

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