linux-kernel - [PATCH v2 2/2] crypto: ccp: Get a free page to use while fetching initial nonce

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Message-ID: <20230824221932.2807-2-mario.limonciello@amd.com>
Date:   Thu, 24 Aug 2023 17:19:32 -0500
From:   Mario Limonciello <mario.limonciello@....com>
To:     <thomas.lendacky@....com>, <herbert@...dor.apana.org.au>
CC:     <john.allen@....com>, <davem@...emloft.net>,
        <linux-crypto@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        "Mario Limonciello" <mario.limonciello@....com>
Subject: [PATCH v2 2/2] crypto: ccp: Get a free page to use while fetching initial nonce

dbc_dev_init() gets a free page from `GFP_KERNEL`, but if that page has
any data in it the first nonce request will fail.
This prevents dynamic boost control from probing. To fix this, explicitly
request a zeroed page with `__GFP_ZERO` to ensure first nonce fetch works.

Fixes: c04cf9e14f10 ("crypto: ccp - Add support for fetching a nonce for dynamic boost control")
Signed-off-by: Mario Limonciello <mario.limonciello@....com>
---
v1->v2:
 * Use GFP_KERNEL | __GFP_ZERO to ensure accounting works properly

 drivers/crypto/ccp/dbc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/crypto/ccp/dbc.c b/drivers/crypto/ccp/dbc.c
index 839ea14b9a85..a99b8f02153a 100644
--- a/drivers/crypto/ccp/dbc.c
+++ b/drivers/crypto/ccp/dbc.c
@@ -205,7 +205,7 @@ int dbc_dev_init(struct psp_device *psp)
 		return -ENOMEM;
 
 	BUILD_BUG_ON(sizeof(union dbc_buffer) > PAGE_SIZE);
-	dbc_dev->mbox = (void *)devm_get_free_pages(dev, GFP_KERNEL, 0);
+	dbc_dev->mbox = (void *)devm_get_free_pages(dev, GFP_KERNEL | __GFP_ZERO, 0);
 	if (!dbc_dev->mbox) {
 		ret = -ENOMEM;
 		goto cleanup_dev;
-- 
2.34.1