[RESEND PATCH v6 03/12] firmware: qcom: scm: smc: switch to using the SCM allocator

Bartosz Golaszewski
2024-01-22T10:22:10Z

We need to allocate, map and pass a buffer to the trustzone if we have
more than 4 arguments for a given SCM calls. Let's use the new TrustZone
allocator for that memory and shrink the code in process.

As this code lives in a different compilation unit than the rest of the
SCM code, we need to provide a helper in the form of
qcom_scm_get_tzmem_pool() that allows the SMC low-level routines to
access the SCM memory pool.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Reviewed-by: Andrew Halaney <ahalaney@redhat.com>
Tested-by: Andrew Halaney <ahalaney@redhat.com> # sc8280xp-lenovo-thinkpad-x13s
Tested-by: Deepti Jaggi <quic_djaggi@quicinc.com> #sa8775p-ride
Reviewed-by: Elliot Berman <quic_eberman@quicinc.com>
---
drivers/firmware/qcom/qcom_scm-smc.c | 30 ++++++++--------------------
drivers/firmware/qcom/qcom_scm.c | 5 +++++
drivers/firmware/qcom/qcom_scm.h | 3 +++
3 files changed, 16 insertions(+), 22 deletions(-)

diff --git a/drivers/firmware/qcom/qcom_scm-smc.c b/drivers/firmware/qcom/qcom_scm-smc.c
index 16cf88acfa8e..dca5f3f1883b 100644
--- a/drivers/firmware/qcom/qcom_scm-smc.c
+++ b/drivers/firmware/qcom/qcom_scm-smc.c
@@ -2,6 +2,7 @@
/* Copyright (c) 2015,2019 The Linux Foundation. All rights reserved.
*/

+#include <linux/cleanup.h>
#include <linux/io.h>
#include <linux/errno.h>
#include <linux/delay.h>
@@ -9,6 +10,7 @@
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/firmware/qcom/qcom_scm.h>
+#include <linux/firmware/qcom/qcom_tzmem.h>
#include <linux/arm-smccc.h>
#include <linux/dma-mapping.h>

@@ -150,11 +152,10 @@ int __scm_smc_call(struct device *dev, const struct qcom_scm_desc *desc,
enum qcom_scm_convention qcom_convention,
struct qcom_scm_res *res, bool atomic)
{
+ struct qcom_tzmem_pool *mempool = qcom_scm_get_tzmem_pool();
int arglen = desc->arginfo & 0xf;
int i, ret;
- dma_addr_t args_phys = 0;
- void *args_virt = NULL;
- size_t alloc_len;
+ void *args_virt __free(qcom_tzmem) = NULL;
gfp_t flag = atomic ? GFP_ATOMIC : GFP_KERNEL;
u32 smccc_call_type = atomic ? ARM_SMCCC_FAST_CALL : ARM_SMCCC_STD_CALL;
u32 qcom_smccc_convention = (qcom_convention == SMC_CONVENTION_ARM_32) ?
@@ -172,9 +173,9 @@ int __scm_smc_call(struct device *dev, const struct qcom_scm_desc *desc,
smc.args[i + SCM_SMC_FIRST_REG_IDX] = desc->args[i];

if (unlikely(arglen > SCM_SMC_N_REG_ARGS)) {
- alloc_len = SCM_SMC_N_EXT_ARGS * sizeof(u64);
- args_virt = kzalloc(PAGE_ALIGN(alloc_len), flag);
-
+ args_virt = qcom_tzmem_alloc(mempool,
+ SCM_SMC_N_EXT_ARGS * sizeof(u64),
+ flag);
if (!args_virt)
return -ENOMEM;

@@ -192,25 +193,10 @@ int __scm_smc_call(struct device *dev, const struct qcom_scm_desc *desc,
SCM_SMC_FIRST_EXT_IDX]);
}

- args_phys = dma_map_single(dev, args_virt, alloc_len,
- DMA_TO_DEVICE);
-
- if (dma_mapping_error(dev, args_phys)) {
- kfree(args_virt);
- return -ENOMEM;
- }
-
- smc.args[SCM_SMC_LAST_REG_IDX] = args_phys;
+ smc.args[SCM_SMC_LAST_REG_IDX] = qcom_tzmem_to_phys(args_virt);
}

- /* ret error check follows after args_virt cleanup*/
ret = __scm_smc_do(dev, &smc, &smc_res, atomic);
-
- if (args_virt) {
- dma_unmap_single(dev, args_phys, alloc_len, DMA_TO_DEVICE);
- kfree(args_virt);
- }
-
if (ret)
return ret;

diff --git a/drivers/firmware/qcom/qcom_scm.c b/drivers/firmware/qcom/qcom_scm.c
index 0d4c028be0c1..71e98b666391 100644
--- a/drivers/firmware/qcom/qcom_scm.c
+++ b/drivers/firmware/qcom/qcom_scm.c
@@ -201,6 +201,11 @@ static void qcom_scm_bw_disable(void)
enum qcom_scm_convention qcom_scm_convention = SMC_CONVENTION_UNKNOWN;
static DEFINE_SPINLOCK(scm_query_lock);

+struct qcom_tzmem_pool *qcom_scm_get_tzmem_pool(void)
+{
+ return __scm->mempool;
+}
+
static enum qcom_scm_convention __get_convention(void)
{
unsigned long flags;
diff --git a/drivers/firmware/qcom/qcom_scm.h b/drivers/firmware/qcom/qcom_scm.h
index 4532907e8489..aa7d06939f8e 100644
--- a/drivers/firmware/qcom/qcom_scm.h
+++ b/drivers/firmware/qcom/qcom_scm.h
@@ -5,6 +5,7 @@
#define __QCOM_SCM_INT_H

struct device;
+struct qcom_tzmem_pool;

enum qcom_scm_convention {
SMC_CONVENTION_UNKNOWN,
@@ -78,6 +79,8 @@ int scm_legacy_call_atomic(struct device *dev, const struct qcom_scm_desc *desc,
int scm_legacy_call(struct device *dev, const struct qcom_scm_desc *desc,
struct qcom_scm_res *res);

+struct qcom_tzmem_pool *qcom_scm_get_tzmem_pool(void);
+
#define QCOM_SCM_SVC_BOOT 0x01
#define QCOM_SCM_BOOT_SET_ADDR 0x01
#define QCOM_SCM_BOOT_TERMINATE_PC 0x02
--
2.40.1