6.12-stable review patch. If anyone has any objections, please let me know.
------------------
From: Krzysztof Kozlowski <krzysztof.kozlowski@xxxxxxxxxx>
[ Upstream commit 1e76b546e6fca7eb568161f408133904ca6bcf4f ]
If SCM driver fails the probe, it should not leave global '__scm'
variable assigned, because external users of this driver will assume the
probe finished successfully. For example TZMEM parts ('__scm->mempool')
are initialized later in the probe, but users of it (__scm_smc_call())
rely on the '__scm' variable.
This fixes theoretical NULL pointer exception, triggered via introducing
probe deferral in SCM driver with call trace:
qcom_tzmem_alloc+0x70/0x1ac (P)
qcom_tzmem_alloc+0x64/0x1ac (L)
qcom_scm_assign_mem+0x78/0x194
qcom_rmtfs_mem_probe+0x2d4/0x38c
platform_probe+0x68/0xc8
Fixes: 40289e35ca52 ("firmware: qcom: scm: enable the TZ mem allocator")
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20241209-qcom-scm-missing-barriers-and-all-sort-of-srap-v2-4-9061013c8d92@xxxxxxxxxx
Signed-off-by: Bjorn Andersson <andersson@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/firmware/qcom/qcom_scm.c | 42 ++++++++++++++++++++++----------
1 file changed, 29 insertions(+), 13 deletions(-)
diff --git a/drivers/firmware/qcom/qcom_scm.c b/drivers/firmware/qcom/qcom_scm.c
index 14afd68664a91..a6bdedbbf7088 100644
--- a/drivers/firmware/qcom/qcom_scm.c
+++ b/drivers/firmware/qcom/qcom_scm.c
@@ -2001,13 +2001,17 @@ static int qcom_scm_probe(struct platform_device *pdev)
irq = platform_get_irq_optional(pdev, 0);
if (irq < 0) {
- if (irq != -ENXIO)
- return irq;
+ if (irq != -ENXIO) {
+ ret = irq;
+ goto err;
+ }
} else {
ret = devm_request_threaded_irq(__scm->dev, irq, NULL, qcom_scm_irq_handler,
IRQF_ONESHOT, "qcom-scm", __scm);
- if (ret < 0)
- return dev_err_probe(scm->dev, ret, "Failed to request qcom-scm irq\n");
+ if (ret < 0) {
+ dev_err_probe(scm->dev, ret, "Failed to request qcom-scm irq\n");
+ goto err;
+ }
}
__get_convention();
@@ -2026,14 +2030,18 @@ static int qcom_scm_probe(struct platform_device *pdev)
qcom_scm_disable_sdi();
ret = of_reserved_mem_device_init(__scm->dev);
- if (ret && ret != -ENODEV)
- return dev_err_probe(__scm->dev, ret,
- "Failed to setup the reserved memory region for TZ mem\n");
+ if (ret && ret != -ENODEV) {
+ dev_err_probe(__scm->dev, ret,
+ "Failed to setup the reserved memory region for TZ mem\n");
+ goto err;
+ }
ret = qcom_tzmem_enable(__scm->dev);
- if (ret)
- return dev_err_probe(__scm->dev, ret,
- "Failed to enable the TrustZone memory allocator\n");
+ if (ret) {
+ dev_err_probe(__scm->dev, ret,
+ "Failed to enable the TrustZone memory allocator\n");
+ goto err;
+ }
memset(&pool_config, 0, sizeof(pool_config));
pool_config.initial_size = 0;
@@ -2041,9 +2049,11 @@ static int qcom_scm_probe(struct platform_device *pdev)
pool_config.max_size = SZ_256K;
__scm->mempool = devm_qcom_tzmem_pool_new(__scm->dev, &pool_config);
- if (IS_ERR(__scm->mempool))
- return dev_err_probe(__scm->dev, PTR_ERR(__scm->mempool),
- "Failed to create the SCM memory pool\n");
+ if (IS_ERR(__scm->mempool)) {
+ dev_err_probe(__scm->dev, PTR_ERR(__scm->mempool),
+ "Failed to create the SCM memory pool\n");
+ goto err;
+ }
/*
* Initialize the QSEECOM interface.
@@ -2059,6 +2069,12 @@ static int qcom_scm_probe(struct platform_device *pdev)
WARN(ret < 0, "failed to initialize qseecom: %d\n", ret);
return 0;
+
+err:
+ /* Paired with smp_load_acquire() in qcom_scm_is_available(). */
+ smp_store_release(&__scm, NULL);
+
+ return ret;
}
static void qcom_scm_shutdown(struct platform_device *pdev)
--
2.39.5
