From: Bartosz Golaszewski <brgl@bgdev.pl>
To: Andy Gross <agross@kernel.org>,
Bjorn Andersson <andersson@kernel.org>,
Konrad Dybcio <konrad.dybcio@linaro.org>,
Elliot Berman <quic_eberman@quicinc.com>,
Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>,
Guru Das Srinagesh <quic_gurus@quicinc.com>,
Andrew Halaney <ahalaney@redhat.com>,
Maximilian Luz <luzmaximilian@gmail.com>,
Alex Elder <elder@linaro.org>,
Srini Kandagatla <srinivas.kandagatla@linaro.org>
Cc: linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org, kernel@quicinc.com,
Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Subject: [PATCH v5 14/15] firmware: qcom: scm: clarify the comment in qcom_scm_pas_init_image()
Date: Tue, 17 Oct 2023 11:27:31 +0200 [thread overview]
Message-ID: <20231017092732.19983-15-brgl@bgdev.pl> (raw)
In-Reply-To: <20231017092732.19983-1-brgl@bgdev.pl>
From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
The "memory protection" mechanism mentioned in the comment is the SHM
Bridge. This is also the reason why we do not convert this call to using
the TZ memory allocator.
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Tested-by: Andrew Halaney <ahalaney@redhat.com> # sc8280xp-lenovo-thinkpad-x13s
---
drivers/firmware/qcom/qcom_scm.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)
diff --git a/drivers/firmware/qcom/qcom_scm.c b/drivers/firmware/qcom/qcom_scm.c
index 839773270a21..7ba5cff6e4e7 100644
--- a/drivers/firmware/qcom/qcom_scm.c
+++ b/drivers/firmware/qcom/qcom_scm.c
@@ -563,9 +563,13 @@ int qcom_scm_pas_init_image(u32 peripheral, const void *metadata, size_t size,
struct qcom_scm_res res;
/*
- * During the scm call memory protection will be enabled for the meta
- * data blob, so make sure it's physically contiguous, 4K aligned and
- * non-cachable to avoid XPU violations.
+ * During the SCM call the hypervisor will make the buffer containing
+ * the program data into an SHM Bridge. This is why we exceptionally
+ * must not use the TrustZone memory allocator here as - depending on
+ * Kconfig - it may already use the SHM Bridge mechanism internally.
+ *
+ * If we pass a buffer that is already part of an SHM Bridge to this
+ * call, it will fail.
*/
mdata_buf = dma_alloc_coherent(__scm->dev, size, &mdata_phys,
GFP_KERNEL);
--
2.39.2
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next prev parent reply other threads:[~2023-10-17 9:28 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-17 9:27 [PATCH v5 00/15] arm64: qcom: add and enable SHM Bridge support Bartosz Golaszewski
2023-10-17 9:27 ` [PATCH v5 01/15] firmware: qcom: move Qualcomm code into its own directory Bartosz Golaszewski
2023-10-20 22:57 ` kernel test robot
2023-10-17 9:27 ` [PATCH v5 02/15] firmware: qcom: scm: add a missing forward declaration for struct device Bartosz Golaszewski
2023-10-17 9:27 ` [PATCH v5 03/15] firmware: qcom: scm: remove unneeded 'extern' specifiers Bartosz Golaszewski
2023-10-17 9:27 ` [PATCH v5 04/15] firmware: qcom: add a dedicated TrustZone buffer allocator Bartosz Golaszewski
2023-10-17 9:27 ` [PATCH v5 05/15] firmware: qcom: scm: enable the TZ mem allocator Bartosz Golaszewski
2023-10-17 9:27 ` [PATCH v5 06/15] firmware: qcom: scm: smc: switch to using the SCM allocator Bartosz Golaszewski
2023-10-17 9:27 ` [PATCH v5 07/15] firmware: qcom: scm: make qcom_scm_assign_mem() use the TZ allocator Bartosz Golaszewski
2023-10-17 9:27 ` [PATCH v5 08/15] firmware: qcom: scm: make qcom_scm_ice_set_key() " Bartosz Golaszewski
2023-10-17 9:27 ` [PATCH v5 09/15] firmware: qcom: scm: make qcom_scm_lmh_dcvsh() " Bartosz Golaszewski
2023-10-17 9:27 ` [PATCH v5 10/15] firmware: qcom: scm: make qcom_scm_qseecom_app_get_id() " Bartosz Golaszewski
2023-10-17 9:27 ` [PATCH v5 11/15] firmware: qcom: qseecom: convert to using " Bartosz Golaszewski
2023-10-17 9:27 ` [PATCH v5 12/15] firmware: qcom: scm: add support for SHM bridge operations Bartosz Golaszewski
2023-10-17 9:27 ` [PATCH v5 13/15] firmware: qcom: tzmem: enable SHM Bridge support Bartosz Golaszewski
2023-10-17 9:27 ` Bartosz Golaszewski [this message]
2023-10-17 9:27 ` [PATCH v5 15/15] arm64: defconfig: enable SHM Bridge support for the TZ memory allocator Bartosz Golaszewski
2023-10-22 16:25 ` (subset) [PATCH v5 00/15] arm64: qcom: add and enable SHM Bridge support Bjorn Andersson
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