linux-kernel - [PATCH v2 05/11] firmware: qcom: scm: make qcom_scm_ice_set

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Message-Id: <20230928092040.9420-6-brgl@bgdev.pl>
Date:   Thu, 28 Sep 2023 11:20:34 +0200
From:   Bartosz Golaszewski <brgl@...ev.pl>
To:     Andy Gross <agross@...nel.org>,
        Bjorn Andersson <andersson@...nel.org>,
        Konrad Dybcio <konrad.dybcio@...aro.org>,
        Maximilian Luz <luzmaximilian@...il.com>,
        Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
Cc:     linux-kernel@...r.kernel.org, linux-arm-msm@...r.kernel.org,
        kernel@...cinc.com,
        Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
Subject: [PATCH v2 05/11] firmware: qcom: scm: make qcom_scm_ice_set_key() use the SCM allocator

From: Bartosz Golaszewski <bartosz.golaszewski@...aro.org>

Let's use the new SCM memory allocator to obtain a buffer for this call
instead of using dma_alloc_coherent().

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
---
 drivers/firmware/qcom/qcom_scm.c | 20 ++++----------------
 1 file changed, 4 insertions(+), 16 deletions(-)

diff --git a/drivers/firmware/qcom/qcom_scm.c b/drivers/firmware/qcom/qcom_scm.c
index 0c532e794b92..02a773ba1383 100644
--- a/drivers/firmware/qcom/qcom_scm.c
+++ b/drivers/firmware/qcom/qcom_scm.c
@@ -1178,32 +1178,20 @@ int qcom_scm_ice_set_key(u32 index, const u8 *key, u32 key_size,
 		.args[4] = data_unit_size,
 		.owner = ARM_SMCCC_OWNER_SIP,
 	};
-	void *keybuf;
-	dma_addr_t key_phys;
+
 	int ret;
 
-	/*
-	 * 'key' may point to vmalloc()'ed memory, but we need to pass a
-	 * physical address that's been properly flushed.  The sanctioned way to
-	 * do this is by using the DMA API.  But as is best practice for crypto
-	 * keys, we also must wipe the key after use.  This makes kmemdup() +
-	 * dma_map_single() not clearly correct, since the DMA API can use
-	 * bounce buffers.  Instead, just use dma_alloc_coherent().  Programming
-	 * keys is normally rare and thus not performance-critical.
-	 */
-
-	keybuf = dma_alloc_coherent(__scm->dev, key_size, &key_phys,
-				    GFP_KERNEL);
+	void *keybuf __free(qcom_scm_mem) = qcom_scm_mem_alloc(key_size,
+							       GFP_KERNEL);
 	if (!keybuf)
 		return -ENOMEM;
 	memcpy(keybuf, key, key_size);
-	desc.args[1] = key_phys;
+	desc.args[1] = qcom_scm_mem_to_phys(keybuf);
 
 	ret = qcom_scm_call(__scm->dev, &desc, NULL);
 
 	memzero_explicit(keybuf, key_size);
 
-	dma_free_coherent(__scm->dev, key_size, keybuf, key_phys);
 	return ret;
 }
 EXPORT_SYMBOL_GPL(qcom_scm_ice_set_key);
-- 
2.39.2