From: Orlando Chamberlain <redecorating@protonmail.com>
To: Ard Biesheuvel <ardb@kernel.org>
Cc: Aditya Garg <gargaditya08@live.com>,
"jk@ozlabs.org" <jk@ozlabs.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
"linux-efi@vger.kernel.org" <linux-efi@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Aun-Ali Zaidi <admin@kodeit.net>
Subject: Re: [BUG][SEVERE] Enabling EFI runtime services causes panics in the T2 security chip on Macs equipped with it.
Date: Wed, 12 Jan 2022 09:06:02 +0000 [thread overview]
Message-ID: <20220112090554.1b279c4e@localhost> (raw)
In-Reply-To: <CAMj1kXExPTyxSaioSmwhz+bTYwLjQJQ5PHRJKY11cX9M71STSQ@mail.gmail.com>
On Wed, 12 Jan 2022 19:21:55 +1100
"Ard Biesheuvel" <ardb@kernel.org> wrote:
> What we might do is just use EFI 1.10 for all Apple x86 EFI machines.
I have found logs of pre-T2 x86 Macs that have EFI v2.40 but I haven't
heard of them having the issue with writing to nvram:
[ 0.000000] efi: EFI v2.40 by Apple
[ 0.000000] efi: ACPI=0x88ffe000 ACPI 2.0=0x88ffe014 SMBIOS=0x88f00000 SMBIOS 3.0=0x88efe000
[ 0.000000] secureboot: Secure boot disabled
[ 0.000000] SMBIOS 3.0.0 present.
[ 0.000000] DMI: Apple Inc. MacBookPro14,1/Mac-B4831CEBD52A0C4C, BIOS XXX.XXX.XXX.XXX.0 04/24/2020
MacBookPro14,1 [1], and MacBookPro13,1 [2] have EFI v2.40, but
MacBookPro12,1 [3] has v1.10
[1] https://linux-hardware.org/?probe=b1b965bcfa&log=dmesg
[2] https://linux-hardware.org/?probe=df102d9c8c&log=dmesg
[3] https://linux-hardware.org/?probe=ef5195a62e&log=dmesg
I don't know if this would mean the other Macs with EFI v2.40 would lose
any functionality due to a patch like this (I'm not familiar with what
was added to the runtime services between v1.10 and v2.40).
> Please try the below:
>
> diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
> index ae79c3300129..2303f9b06412 100644
> --- a/drivers/firmware/efi/efi.c
> +++ b/drivers/firmware/efi/efi.c
> @@ -722,6 +722,13 @@ void __init efi_systab_report_header(const
> efi_table_hdr_t *systab_hdr,
> systab_hdr->revision >> 16,
> systab_hdr->revision & 0xffff,
> vendor);
> +
> + if (IS_ENABLED(CONFIG_X86_64) &&
> + systab_hdr->revision > EFI_1_10_SYSTEM_TABLE_REVISION &&
> + !strcmp(vendor, "Apple")) {
> + pr_info("Apple EFI Mac detected, using EFI v1.10
> runtime services only\n");
> + efi.runtime_version = EFI_1_10_SYSTEM_TABLE_REVISION;
> + }
> }
>
> static __initdata char memory_type_name[][13] = {
This patch makes writing to nvram work for me on MacBookPro16,1
--
next prev parent reply other threads:[~2022-01-12 9:06 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-10 15:37 [BUG][SEVERE] Enabling EFI runtime services causes panics in the T2 security chip on Macs equipped with it Aditya Garg
2022-01-10 16:02 ` Ard Biesheuvel
2022-01-10 16:27 ` Aditya Garg
2022-01-10 16:37 ` Ard Biesheuvel
2022-01-10 17:45 ` Ard Biesheuvel
2022-01-11 5:17 ` Orlando Chamberlain
2022-01-11 7:35 ` Aditya Garg
2022-01-11 7:32 ` Aditya Garg
2022-01-12 6:23 ` Aditya Garg
2022-01-12 8:21 ` Ard Biesheuvel
2022-01-12 9:06 ` Orlando Chamberlain [this message]
2022-01-12 9:13 ` Ard Biesheuvel
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