linux-kernel - [PATCH] x86/microcode: allow non-root reading of microcode version and processor flags

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Message-Id: <20180825035039.14409-1-jacekt@dugeo.com>
Date:   Sat, 25 Aug 2018 11:50:39 +0800
From:   Jacek Tomaka <jacekt@...eo.com>
To:     Thomas Gleixner <tglx@...utronix.de>, linux-kernel@...r.kernel.org
Cc:     Jacek Tomaka <jacekt@...eo.com>,
        Jacek Tomaka <jacek.tomaka@...zta.fm>
Subject: [PATCH] x86/microcode: allow non-root reading of microcode version and processor flags

/sys/devices/system/cpu/cpuX/microcode

Before:
-r-------- processor_flags
-r-------- version

After:
-r--r--r-- processor_flags
-r--r--r-- version

Microcode version has been already readable for non root users via
/proc/cpuinfo. However it is easier to access it from
/sys/devices/system/cpu/cpuX/microcode/version

Reported-by: Tim Burgess <timb@....com>
Signed-off-by: Jacek Tomaka <jacek.tomaka@...zta.fm>
---
 arch/x86/kernel/cpu/microcode/core.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/cpu/microcode/core.c b/arch/x86/kernel/cpu/microcode/core.c
index b9bc8a1a58..2637ff09d6 100644
--- a/arch/x86/kernel/cpu/microcode/core.c
+++ b/arch/x86/kernel/cpu/microcode/core.c
@@ -666,8 +666,8 @@ static ssize_t pf_show(struct device *dev,
 }
 
 static DEVICE_ATTR_WO(reload);
-static DEVICE_ATTR(version, 0400, version_show, NULL);
-static DEVICE_ATTR(processor_flags, 0400, pf_show, NULL);
+static DEVICE_ATTR(version, 0444, version_show, NULL);
+static DEVICE_ATTR(processor_flags, 0444, pf_show, NULL);
 
 static struct attribute *mc_default_attrs[] = {
 	&dev_attr_version.attr,
-- 
2.17.0