Linux-EFI Archive on lore.kernel.org
 help / color / Atom feed
From: Ard Biesheuvel <ard.biesheuvel@linaro.org>
To: linux-efi@vger.kernel.org, Ingo Molnar <mingo@kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>,
	linux-kernel@vger.kernel.org,
	Ben Dooks <ben.dooks@codethink.co.uk>,
	Dave Young <dyoung@redhat.com>,
	Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>,
	Jerry Snitselaar <jsnitsel@redhat.com>,
	linux-integrity@vger.kernel.org, Lukas Wunner <lukas@wunner.de>,
	Lyude Paul <lyude@redhat.com>, Matthew Garrett <mjg59@google.com>,
	Octavian Purdila <octavian.purdila@intel.com>,
	Peter Jones <pjones@redhat.com>, Scott Talbert <swt@techie.net>
Subject: [PATCH 2/7] efivar/ssdt: don't iterate over EFI vars if no SSDT override was specified
Date: Wed,  2 Oct 2019 18:58:59 +0200
Message-ID: <20191002165904.8819-3-ard.biesheuvel@linaro.org> (raw)
In-Reply-To: <20191002165904.8819-1-ard.biesheuvel@linaro.org>

The kernel command line option efivar_ssdt= allows the name to be
specified of an EFI variable containing an ACPI SSDT table that should
be loaded into memory by the OS, and treated as if it was provided by
the firmware.

Currently, that code will always iterate over the EFI variables and
compare each name with the provided name, even if the command line
option wasn't set to begin with.

So bail early when no variable name was provided. This works around a
boot regression on the 2012 Mac Pro, as reported by Scott.

Fixes: 475fb4e8b2f4 ("efi / ACPI: load SSTDs from EFI variables")
Cc: <stable@vger.kernel.org> # v4.9+
Cc: Octavian Purdila <octavian.purdila@intel.com>
Tested-by: Scott Talbert <swt@techie.net>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
 drivers/firmware/efi/efi.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
index 8d3e778e988b..69f00f7453a3 100644
--- a/drivers/firmware/efi/efi.c
+++ b/drivers/firmware/efi/efi.c
@@ -267,6 +267,9 @@ static __init int efivar_ssdt_load(void)
 	void *data;
 	int ret;
 
+	if (!efivar_ssdt[0])
+		return 0;
+
 	ret = efivar_init(efivar_ssdt_iter, &entries, true, &entries);
 
 	list_for_each_entry_safe(entry, aux, &entries, list) {
-- 
2.20.1


  parent reply index

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-02 16:58 [GIT PULL 0/7] EFI fixes for v5.4 Ard Biesheuvel
2019-10-02 16:58 ` [PATCH 1/7] efi: cper: Fix endianness of PCIe class code Ard Biesheuvel
2019-10-07 14:49   ` [tip: efi/urgent] efi/cper: " tip-bot2 for Lukas Wunner
2019-10-02 16:58 ` Ard Biesheuvel [this message]
2019-10-07 14:49   ` [tip: efi/urgent] efivar/ssdt: Don't iterate over EFI vars if no SSDT override was specified tip-bot2 for Ard Biesheuvel
2019-10-02 16:59 ` [PATCH 3/7] efi/tpm: Don't access event->count when it isn't mapped Ard Biesheuvel
2019-10-07 14:49   ` [tip: efi/urgent] " tip-bot2 for Peter Jones
2019-10-02 16:59 ` [PATCH 4/7] efi/tpm: don't traverse an event log with no events Ard Biesheuvel
2019-10-07 14:49   ` [tip: efi/urgent] efi/tpm: Don't " tip-bot2 for Peter Jones
2019-10-02 16:59 ` [PATCH 5/7] efi/tpm: only set efi_tpm_final_log_size after successful event log parsing Ard Biesheuvel
2019-10-07 14:49   ` [tip: efi/urgent] efi/tpm: Only set 'efi_tpm_final_log_size' " tip-bot2 for Jerry Snitselaar
2019-10-02 16:59 ` [PATCH 6/7] efi: make unexported efi_rci2_sysfs_init static Ard Biesheuvel
2019-10-07 14:49   ` [tip: efi/urgent] efi: Make unexported efi_rci2_sysfs_init() static tip-bot2 for Ben Dooks
2019-10-02 16:59 ` [PATCH 7/7] efi/x86: do not clean dummy variable in kexec path Ard Biesheuvel
2019-10-07 14:49   ` [tip: efi/urgent] efi/x86: Do " tip-bot2 for Dave Young

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20191002165904.8819-3-ard.biesheuvel@linaro.org \
    --to=ard.biesheuvel@linaro.org \
    --cc=ben.dooks@codethink.co.uk \
    --cc=dyoung@redhat.com \
    --cc=jarkko.sakkinen@linux.intel.com \
    --cc=jsnitsel@redhat.com \
    --cc=linux-efi@vger.kernel.org \
    --cc=linux-integrity@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=lukas@wunner.de \
    --cc=lyude@redhat.com \
    --cc=mingo@kernel.org \
    --cc=mjg59@google.com \
    --cc=octavian.purdila@intel.com \
    --cc=pjones@redhat.com \
    --cc=swt@techie.net \
    --cc=tglx@linutronix.de \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

Linux-EFI Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-efi/0 linux-efi/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-efi linux-efi/ https://lore.kernel.org/linux-efi \
		linux-efi@vger.kernel.org
	public-inbox-index linux-efi

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-efi


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git