linux-kernel - [tip: x86/cleanups] x86/EISA: Use memremap() to probe for the EISA BIOS signature

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <172458943207.2215.13577092392152712343.tip-bot2@tip-bot2>
Date: Sun, 25 Aug 2024 12:37:12 -0000
From: "tip-bot2 for Maciej W. Rozycki" <tip-bot2@...utronix.de>
To: linux-tip-commits@...r.kernel.org
Cc: "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
 "Maciej W. Rozycki" <macro@...am.me.uk>, Thomas Gleixner <tglx@...utronix.de>,
 x86@...nel.org, linux-kernel@...r.kernel.org
Subject: [tip: x86/cleanups] x86/EISA: Use memremap() to probe for the EISA
 BIOS signature

The following commit has been merged into the x86/cleanups branch of tip:

Commit-ID:     80a4da05642c384bc6f5b602b865ebd7e3963902
Gitweb:        https://git.kernel.org/tip/80a4da05642c384bc6f5b602b865ebd7e3963902
Author:        Maciej W. Rozycki <macro@...am.me.uk>
AuthorDate:    Sat, 24 Aug 2024 23:17:10 +01:00
Committer:     Thomas Gleixner <tglx@...utronix.de>
CommitterDate: Sun, 25 Aug 2024 14:29:38 +02:00

x86/EISA: Use memremap() to probe for the EISA BIOS signature

The area at the 0x0FFFD9 physical location in the PC memory space is
regular memory, traditionally ROM BIOS and more recently a copy of BIOS
code and data in RAM, write-protected.

Therefore use memremap() to get access to it rather than ioremap(),
avoiding issues in virtualization scenarios and complementing changes such
as commit f7750a795687 ("x86, mpparse, x86/acpi, x86/PCI, x86/dmi, SFI: Use
memremap() for RAM mappings") or commit 5997efb96756 ("x86/boot: Use
memremap() to map the MPF and MPC data").

Reported-by: Kirill A. Shutemov <kirill.shutemov@...ux.intel.com>
Signed-off-by: Maciej W. Rozycki <macro@...am.me.uk>
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Link: https://lore.kernel.org/all/alpine.DEB.2.21.2408242025210.30766@angie.orcam.me.uk
Closes: https://lore.kernel.org/r/20240822095122.736522-1-kirill.shutemov@linux.intel.com
---
 arch/x86/kernel/eisa.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kernel/eisa.c b/arch/x86/kernel/eisa.c
index 53935b4..5a4f99a 100644
--- a/arch/x86/kernel/eisa.c
+++ b/arch/x86/kernel/eisa.c
@@ -11,15 +11,15 @@

 static __init int eisa_bus_probe(void)
 {
-	void __iomem *p;
+	void *p;

 	if ((xen_pv_domain() && !xen_initial_domain()) || cc_platform_has(CC_ATTR_GUEST_SEV_SNP))
 		return 0;

-	p = ioremap(0x0FFFD9, 4);
+	p = memremap(0x0FFFD9, 4, MEMREMAP_WB);
 	if (p && readl(p) == 'E' + ('I' << 8) + ('S' << 16) + ('A' << 24))
 		EISA_bus = 1;
-	iounmap(p);
+	memunmap(p);
 	return 0;
 }
 subsys_initcall(eisa_bus_probe);