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From:   Michal Suchanek <msuchanek@suse.de>
To:     linuxppc-dev@lists.ozlabs.org
Cc:     Michal Suchanek <msuchanek@suse.de>,
        Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        Paul Mackerras <paulus@samba.org>,
        Michael Ellerman <mpe@ellerman.id.au>,
        Diana Craciun <diana.craciun@nxp.com>,
        Josh Poimboeuf <jpoimboe@redhat.com>,
        Anthony Steinhauser <asteinhauser@google.com>,
        "Gustavo L. F. Walbon" <gwalbon@linux.ibm.com>,
        YueHaibing <yuehaibing@huawei.com>,
        Geert Uytterhoeven <geert+renesas@glider.be>,
        "Christopher M. Riedl" <cmr@informatik.wtf>,
        linux-kernel@vger.kernel.org
Subject: [PATCH] powerpc: add link stack flush mitigation status in debugfs.
Date:   Wed, 27 Nov 2019 23:09:59 +0100
Message-Id: <20191127220959.6208-1-msuchanek@suse.de>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

The link stack flush status is not visible in debugfs. It can be enabled
even when count cache flush is disabled. Add separate file for its
status.

Signed-off-by: Michal Suchanek <msuchanek@suse.de>
---
 arch/powerpc/kernel/security.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/arch/powerpc/kernel/security.c b/arch/powerpc/kernel/security.c
index 7d4b2080a658..56dce4798a4d 100644
--- a/arch/powerpc/kernel/security.c
+++ b/arch/powerpc/kernel/security.c
@@ -446,14 +446,26 @@ static int count_cache_flush_get(void *data, u64 *val)
 	return 0;
 }
 
+static int link_stack_flush_get(void *data, u64 *val)
+{
+	*val = link_stack_flush_enabled;
+
+	return 0;
+}
+
 DEFINE_DEBUGFS_ATTRIBUTE(fops_count_cache_flush, count_cache_flush_get,
 			 count_cache_flush_set, "%llu\n");
+DEFINE_DEBUGFS_ATTRIBUTE(fops_link_stack_flush, link_stack_flush_get,
+			 count_cache_flush_set, "%llu\n");
 
 static __init int count_cache_flush_debugfs_init(void)
 {
 	debugfs_create_file_unsafe("count_cache_flush", 0600,
 				   powerpc_debugfs_root, NULL,
 				   &fops_count_cache_flush);
+	debugfs_create_file_unsafe("link_stack_flush", 0600,
+				   powerpc_debugfs_root, NULL,
+				   &fops_link_stack_flush);
 	return 0;
 }
 device_initcall(count_cache_flush_debugfs_init);
-- 
2.23.0