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linux/drivers/firmware/qcom/qcom_scm-smc.c
Murali Nalajala 9960085a3a firmware: qcom: scm: Mark get_wq_ctx() as atomic call
Currently get_wq_ctx() is wrongly configured as a standard call. When two
SMC calls are in sleep and one SMC wakes up, it calls get_wq_ctx() to
resume the corresponding sleeping thread. But if get_wq_ctx() is
interrupted, goes to sleep and another SMC call is waiting to be allocated
a waitq context, it leads to a deadlock.

To avoid this get_wq_ctx() must be an atomic call and can't be a standard
SMC call. Hence mark get_wq_ctx() as a fast call.

Fixes: 6bf3259922 ("firmware: qcom: scm: Add wait-queue handling logic")
Cc: stable@vger.kernel.org
Signed-off-by: Murali Nalajala <quic_mnalajal@quicinc.com>
Signed-off-by: Unnathi Chalicheemala <quic_uchalich@quicinc.com>
Reviewed-by: Elliot Berman <quic_eberman@quicinc.com>
Link: https://lore.kernel.org/r/20240814223244.40081-1-quic_uchalich@quicinc.com
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
2024-08-14 22:08:28 -05:00

212 lines
5.2 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/* 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>
#include <linux/mutex.h>
#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>
#include "qcom_scm.h"
/**
* struct arm_smccc_args
* @args: The array of values used in registers in smc instruction
*/
struct arm_smccc_args {
unsigned long args[8];
};
static DEFINE_MUTEX(qcom_scm_lock);
#define QCOM_SCM_EBUSY_WAIT_MS 30
#define QCOM_SCM_EBUSY_MAX_RETRY 20
#define SCM_SMC_N_REG_ARGS 4
#define SCM_SMC_FIRST_EXT_IDX (SCM_SMC_N_REG_ARGS - 1)
#define SCM_SMC_N_EXT_ARGS (MAX_QCOM_SCM_ARGS - SCM_SMC_N_REG_ARGS + 1)
#define SCM_SMC_FIRST_REG_IDX 2
#define SCM_SMC_LAST_REG_IDX (SCM_SMC_FIRST_REG_IDX + SCM_SMC_N_REG_ARGS - 1)
static void __scm_smc_do_quirk(const struct arm_smccc_args *smc,
struct arm_smccc_res *res)
{
unsigned long a0 = smc->args[0];
struct arm_smccc_quirk quirk = { .id = ARM_SMCCC_QUIRK_QCOM_A6 };
quirk.state.a6 = 0;
do {
arm_smccc_smc_quirk(a0, smc->args[1], smc->args[2],
smc->args[3], smc->args[4], smc->args[5],
quirk.state.a6, smc->args[7], res, &quirk);
if (res->a0 == QCOM_SCM_INTERRUPTED)
a0 = res->a0;
} while (res->a0 == QCOM_SCM_INTERRUPTED);
}
static void fill_wq_resume_args(struct arm_smccc_args *resume, u32 smc_call_ctx)
{
memset(resume->args, 0, sizeof(resume->args[0]) * ARRAY_SIZE(resume->args));
resume->args[0] = ARM_SMCCC_CALL_VAL(ARM_SMCCC_STD_CALL,
ARM_SMCCC_SMC_64, ARM_SMCCC_OWNER_SIP,
SCM_SMC_FNID(QCOM_SCM_SVC_WAITQ, QCOM_SCM_WAITQ_RESUME));
resume->args[1] = QCOM_SCM_ARGS(1);
resume->args[2] = smc_call_ctx;
}
int scm_get_wq_ctx(u32 *wq_ctx, u32 *flags, u32 *more_pending)
{
int ret;
struct arm_smccc_res get_wq_res;
struct arm_smccc_args get_wq_ctx = {0};
get_wq_ctx.args[0] = ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL,
ARM_SMCCC_SMC_64, ARM_SMCCC_OWNER_SIP,
SCM_SMC_FNID(QCOM_SCM_SVC_WAITQ, QCOM_SCM_WAITQ_GET_WQ_CTX));
/* Guaranteed to return only success or error, no WAITQ_* */
__scm_smc_do_quirk(&get_wq_ctx, &get_wq_res);
ret = get_wq_res.a0;
if (ret)
return ret;
*wq_ctx = get_wq_res.a1;
*flags = get_wq_res.a2;
*more_pending = get_wq_res.a3;
return 0;
}
static int __scm_smc_do_quirk_handle_waitq(struct device *dev, struct arm_smccc_args *waitq,
struct arm_smccc_res *res)
{
int ret;
u32 wq_ctx, smc_call_ctx;
struct arm_smccc_args resume;
struct arm_smccc_args *smc = waitq;
do {
__scm_smc_do_quirk(smc, res);
if (res->a0 == QCOM_SCM_WAITQ_SLEEP) {
wq_ctx = res->a1;
smc_call_ctx = res->a2;
ret = qcom_scm_wait_for_wq_completion(wq_ctx);
if (ret)
return ret;
fill_wq_resume_args(&resume, smc_call_ctx);
smc = &resume;
}
} while (res->a0 == QCOM_SCM_WAITQ_SLEEP);
return 0;
}
static int __scm_smc_do(struct device *dev, struct arm_smccc_args *smc,
struct arm_smccc_res *res, bool atomic)
{
int ret, retry_count = 0;
if (atomic) {
__scm_smc_do_quirk(smc, res);
return 0;
}
do {
mutex_lock(&qcom_scm_lock);
ret = __scm_smc_do_quirk_handle_waitq(dev, smc, res);
mutex_unlock(&qcom_scm_lock);
if (ret)
return ret;
if (res->a0 == QCOM_SCM_V2_EBUSY) {
if (retry_count++ > QCOM_SCM_EBUSY_MAX_RETRY)
break;
msleep(QCOM_SCM_EBUSY_WAIT_MS);
}
} while (res->a0 == QCOM_SCM_V2_EBUSY);
return 0;
}
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;
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) ?
ARM_SMCCC_SMC_32 : ARM_SMCCC_SMC_64;
struct arm_smccc_res smc_res;
struct arm_smccc_args smc = {0};
smc.args[0] = ARM_SMCCC_CALL_VAL(
smccc_call_type,
qcom_smccc_convention,
desc->owner,
SCM_SMC_FNID(desc->svc, desc->cmd));
smc.args[1] = desc->arginfo;
for (i = 0; i < SCM_SMC_N_REG_ARGS; i++)
smc.args[i + SCM_SMC_FIRST_REG_IDX] = desc->args[i];
if (unlikely(arglen > SCM_SMC_N_REG_ARGS)) {
args_virt = qcom_tzmem_alloc(mempool,
SCM_SMC_N_EXT_ARGS * sizeof(u64),
flag);
if (!args_virt)
return -ENOMEM;
if (qcom_smccc_convention == ARM_SMCCC_SMC_32) {
__le32 *args = args_virt;
for (i = 0; i < SCM_SMC_N_EXT_ARGS; i++)
args[i] = cpu_to_le32(desc->args[i +
SCM_SMC_FIRST_EXT_IDX]);
} else {
__le64 *args = args_virt;
for (i = 0; i < SCM_SMC_N_EXT_ARGS; i++)
args[i] = cpu_to_le64(desc->args[i +
SCM_SMC_FIRST_EXT_IDX]);
}
smc.args[SCM_SMC_LAST_REG_IDX] = qcom_tzmem_to_phys(args_virt);
}
ret = __scm_smc_do(dev, &smc, &smc_res, atomic);
if (ret)
return ret;
if (res) {
res->result[0] = smc_res.a1;
res->result[1] = smc_res.a2;
res->result[2] = smc_res.a3;
}
return (long)smc_res.a0 ? qcom_scm_remap_error(smc_res.a0) : 0;
}