// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (c) 2010-2020, The Linux Foundation. All rights reserved.
 */

#include <linux/slab.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/errno.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/delay.h>

#include <asm/cacheflush.h>
#include <asm/compiler.h>

#include <soc/qcom/scm.h>
#include <soc/qcom/qtee_shmbridge.h>

#define CREATE_TRACE_POINTS
#include <trace/events/scm.h>

#define SCM_ENOMEM		-9
#define SCM_EINVAL_ADDR		-3
#define SCM_EINVAL_ARG		-2
#define SCM_ERROR		-1
#define SCM_INTERRUPTED		1
#define SCM_V2_EBUSY		-12

static DEFINE_MUTEX(scm_lock);

/*
 * MSM8996 V2 requires a lock to protect against
 * concurrent accesses between the limits management
 * driver and the clock controller
 */
DEFINE_MUTEX(scm_lmh_lock);

#define SCM_EBUSY_WAIT_MS 30
#define SCM_EBUSY_MAX_RETRY 67

#define N_EXT_SCM_ARGS 7
#define FIRST_EXT_ARG_IDX 3
#define SMC_ATOMIC_SYSCALL 31
#define N_REGISTER_ARGS (MAX_SCM_ARGS - N_EXT_SCM_ARGS + 1)
#define SMC64_MASK 0x40000000
#define SMC_ATOMIC_MASK 0x80000000
#define IS_CALL_AVAIL_CMD 1

#ifdef CONFIG_ARM64

#define R0_STR "x0"
#define R1_STR "x1"
#define R2_STR "x2"
#define R3_STR "x3"
#define R4_STR "x4"
#define R5_STR "x5"
#define R6_STR "x6"

/* Outer caches unsupported on ARM64 platforms */
#define outer_inv_range(x, y)
#define outer_flush_range(x, y)

#define __cpuc_flush_dcache_area __flush_dcache_area

#else

#define R0_STR "r0"
#define R1_STR "r1"
#define R2_STR "r2"
#define R3_STR "r3"
#define R4_STR "r4"
#define R5_STR "r5"
#define R6_STR "r6"

#endif

static int scm_remap_error(int err)
{
	switch (err) {
	case SCM_ERROR:
		return -EOPNOTSUPP;
	case SCM_EINVAL_ADDR:
	case SCM_EINVAL_ARG:
		return -EINVAL;
	case SCM_ENOMEM:
		return -ENOMEM;
	case SCM_V2_EBUSY:
		return -EBUSY;
	}
	return -EINVAL;
}

#ifdef CONFIG_ARM64

static int __scm_call_armv8_64(u64 x0, u64 x1, u64 x2, u64 x3, u64 x4, u64 x5,
				u64 *ret1, u64 *ret2, u64 *ret3)
{
	register u64 r0 asm("x0") = x0;
	register u64 r1 asm("x1") = x1;
	register u64 r2 asm("x2") = x2;
	register u64 r3 asm("x3") = x3;
	register u64 r4 asm("x4") = x4;
	register u64 r5 asm("x5") = x5;
	register u64 r6 asm("x6") = 0;

	do {
		asm volatile(
			__asmeq("%0", R0_STR)
			__asmeq("%1", R1_STR)
			__asmeq("%2", R2_STR)
			__asmeq("%3", R3_STR)
			__asmeq("%4", R4_STR)
			__asmeq("%5", R5_STR)
			__asmeq("%6", R6_STR)
			__asmeq("%7", R0_STR)
			__asmeq("%8", R1_STR)
			__asmeq("%9", R2_STR)
			__asmeq("%10", R3_STR)
			__asmeq("%11", R4_STR)
			__asmeq("%12", R5_STR)
			__asmeq("%13", R6_STR)
#ifdef REQUIRES_SEC
			".arch_extension sec\n"
#endif
			"smc	#0\n"
			: "=r" (r0), "=r" (r1), "=r" (r2), "=r" (r3),
			  "=r" (r4), "=r" (r5), "=r" (r6)
			: "r" (r0), "r" (r1), "r" (r2), "r" (r3), "r" (r4),
			  "r" (r5), "r" (r6)
			: "x7", "x8", "x9", "x10", "x11", "x12", "x13",
			  "x14", "x15", "x16", "x17");
	} while (r0 == SCM_INTERRUPTED);

	if (ret1)
		*ret1 = r1;
	if (ret2)
		*ret2 = r2;
	if (ret3)
		*ret3 = r3;

	return r0;
}

static int __scm_call_armv8_32(u32 w0, u32 w1, u32 w2, u32 w3, u32 w4, u32 w5,
				u64 *ret1, u64 *ret2, u64 *ret3)
{
	register u32 r0 asm("w0") = w0;
	register u32 r1 asm("w1") = w1;
	register u32 r2 asm("w2") = w2;
	register u32 r3 asm("w3") = w3;
	register u32 r4 asm("w4") = w4;
	register u32 r5 asm("w5") = w5;
	register u32 r6 asm("w6") = 0;

	do {
		asm volatile(
			__asmeq("%0", R0_STR)
			__asmeq("%1", R1_STR)
			__asmeq("%2", R2_STR)
			__asmeq("%3", R3_STR)
			__asmeq("%4", R4_STR)
			__asmeq("%5", R5_STR)
			__asmeq("%6", R6_STR)
			__asmeq("%7", R0_STR)
			__asmeq("%8", R1_STR)
			__asmeq("%9", R2_STR)
			__asmeq("%10", R3_STR)
			__asmeq("%11", R4_STR)
			__asmeq("%12", R5_STR)
			__asmeq("%13", R6_STR)
#ifdef REQUIRES_SEC
			".arch_extension sec\n"
#endif
			"smc	#0\n"
			: "=r" (r0), "=r" (r1), "=r" (r2), "=r" (r3),
			  "=r" (r4), "=r" (r5), "=r" (r6)
			: "r" (r0), "r" (r1), "r" (r2), "r" (r3), "r" (r4),
			  "r" (r5), "r" (r6)
			: "x7", "x8", "x9", "x10", "x11", "x12", "x13",
			"x14", "x15", "x16", "x17");

	} while (r0 == SCM_INTERRUPTED);

	if (ret1)
		*ret1 = r1;
	if (ret2)
		*ret2 = r2;
	if (ret3)
		*ret3 = r3;

	return r0;
}

#else

static int __scm_call_armv8_32(u32 w0, u32 w1, u32 w2, u32 w3, u32 w4, u32 w5,
				u64 *ret1, u64 *ret2, u64 *ret3)
{
	register u32 r0 asm("r0") = w0;
	register u32 r1 asm("r1") = w1;
	register u32 r2 asm("r2") = w2;
	register u32 r3 asm("r3") = w3;
	register u32 r4 asm("r4") = w4;
	register u32 r5 asm("r5") = w5;
	register u32 r6 asm("r6") = 0;

	do {
		asm volatile(
			__asmeq("%0", R0_STR)
			__asmeq("%1", R1_STR)
			__asmeq("%2", R2_STR)
			__asmeq("%3", R3_STR)
			__asmeq("%4", R4_STR)
			__asmeq("%5", R5_STR)
			__asmeq("%6", R6_STR)
			__asmeq("%7", R0_STR)
			__asmeq("%8", R1_STR)
			__asmeq("%9", R2_STR)
			__asmeq("%10", R3_STR)
			__asmeq("%11", R4_STR)
			__asmeq("%12", R5_STR)
			__asmeq("%13", R6_STR)
#ifdef REQUIRES_SEC
			".arch_extension sec\n"
#endif
			"smc	#0\n"
			: "=r" (r0), "=r" (r1), "=r" (r2), "=r" (r3),
			  "=r" (r4), "=r" (r5), "=r" (r6)
			: "r" (r0), "r" (r1), "r" (r2), "r" (r3), "r" (r4),
			 "r" (r5), "r" (r6));

	} while (r0 == SCM_INTERRUPTED);

	if (ret1)
		*ret1 = r1;
	if (ret2)
		*ret2 = r2;
	if (ret3)
		*ret3 = r3;

	return r0;
}

static int __scm_call_armv8_64(u64 x0, u64 x1, u64 x2, u64 x3, u64 x4, u64 x5,
				u64 *ret1, u64 *ret2, u64 *ret3)
{
	return 0;
}
#endif

struct scm_extra_arg {
	union {
		u32 args32[N_EXT_SCM_ARGS];
		u64 args64[N_EXT_SCM_ARGS];
	};
};

static enum scm_interface_version {
	SCM_UNKNOWN,
	SCM_LEGACY,
	SCM_ARMV8_32,
	SCM_ARMV8_64,
} scm_version = SCM_UNKNOWN;

/* This will be set to specify SMC32 or SMC64 */
static u32 scm_version_mask;

bool is_scm_armv8(void)
{
	int ret;
	u64 ret1, x0;

	if (likely(scm_version != SCM_UNKNOWN))
		return (scm_version == SCM_ARMV8_32) ||
			(scm_version == SCM_ARMV8_64);
	/*
	 * This is a one time check that runs on the first ever
	 * invocation of is_scm_armv8. We might be called in atomic
	 * context so no mutexes etc. Also, we can't use the scm_call2
	 * or scm_call2_APIs directly since they depend on this init.
	 */

	/* First try a SMC64 call */
	scm_version = SCM_ARMV8_64;
	ret1 = 0;
	x0 = SCM_SIP_FNID(SCM_SVC_INFO, IS_CALL_AVAIL_CMD) | SMC_ATOMIC_MASK;
	ret = __scm_call_armv8_64(x0 | SMC64_MASK, SCM_ARGS(1), x0, 0, 0, 0,
				  &ret1, NULL, NULL);
	if (ret || !ret1) {
		/* Try SMC32 call */
		ret1 = 0;
		ret = __scm_call_armv8_32(x0, SCM_ARGS(1), x0, 0, 0, 0,
					  &ret1, NULL, NULL);
		if (ret || !ret1)
			scm_version = SCM_LEGACY;
		else
			scm_version = SCM_ARMV8_32;
	} else
		scm_version_mask = SMC64_MASK;

	pr_debug("scm_call: scm version is %x, mask is %x\n", scm_version,
		  scm_version_mask);

	return (scm_version == SCM_ARMV8_32) ||
			(scm_version == SCM_ARMV8_64);
}

/*
 * If there are more than N_REGISTER_ARGS, allocate a buffer and place
 * the additional arguments in it. The extra argument buffer will be
 * pointed to by X5.
 */
static int allocate_extra_arg_buffer(struct scm_desc *desc, gfp_t flags)
{
	int i, j;
	int rc;
	struct scm_extra_arg *argbuf;
	int arglen = desc->arginfo & 0xf;
	struct qtee_shm shm;
	size_t argbuflen = PAGE_ALIGN(sizeof(struct scm_extra_arg));

	desc->x5 = desc->args[FIRST_EXT_ARG_IDX];

	if (likely(arglen <= N_REGISTER_ARGS))
		return 0;

	rc = qtee_shmbridge_allocate_shm(argbuflen, &shm);
	if (rc)
		return rc;

	desc->shm = shm;
	argbuf = shm.vaddr;

	j = FIRST_EXT_ARG_IDX;
	if (scm_version == SCM_ARMV8_64)
		for (i = 0; i < N_EXT_SCM_ARGS; i++)
			argbuf->args64[i] = desc->args[j++];
	else
		for (i = 0; i < N_EXT_SCM_ARGS; i++)
			argbuf->args32[i] = desc->args[j++];

	desc->x5 = shm.paddr;
	__cpuc_flush_dcache_area(argbuf, argbuflen);
	outer_flush_range(shm.paddr, shm.paddr + argbuflen);

	return 0;
}

static int __scm_call2(u32 fn_id, struct scm_desc *desc, bool retry)
{
	int arglen = desc->arginfo & 0xf;
	int ret, retry_count = 0;
	u64 x0;

	if (unlikely(!is_scm_armv8()))
		return -ENODEV;

	ret = allocate_extra_arg_buffer(desc, GFP_NOIO);
	if (ret)
		return ret;

	x0 = fn_id | scm_version_mask;

	trace_scm_call_start(x0, desc);
	do {
		mutex_lock(&scm_lock);

		if (SCM_SVC_ID(fn_id) == SCM_SVC_LMH)
			mutex_lock(&scm_lmh_lock);

		desc->ret[0] = desc->ret[1] = desc->ret[2] = 0;

		if (scm_version == SCM_ARMV8_64)
			ret = __scm_call_armv8_64(x0, desc->arginfo,
						  desc->args[0], desc->args[1],
						  desc->args[2], desc->x5,
						  &desc->ret[0], &desc->ret[1],
						  &desc->ret[2]);
		else
			ret = __scm_call_armv8_32(x0, desc->arginfo,
						  desc->args[0], desc->args[1],
						  desc->args[2], desc->x5,
						  &desc->ret[0], &desc->ret[1],
						  &desc->ret[2]);

		if (SCM_SVC_ID(fn_id) == SCM_SVC_LMH)
			mutex_unlock(&scm_lmh_lock);

		mutex_unlock(&scm_lock);
		if (!retry)
			goto out;

		if (ret == SCM_V2_EBUSY)
			msleep(SCM_EBUSY_WAIT_MS);
		if (retry_count == 33)
			pr_warn("scm: secure world has been busy for 1 second!\n");
	} while (ret == SCM_V2_EBUSY && (retry_count++ < SCM_EBUSY_MAX_RETRY));
out:
	trace_scm_call_end(desc);
	if (ret < 0)
		pr_err("scm_call failed: func id %#llx, ret: %d, syscall returns: %#llx, %#llx, %#llx\n",
			x0, ret, desc->ret[0], desc->ret[1], desc->ret[2]);

	if (arglen > N_REGISTER_ARGS)
		qtee_shmbridge_free_shm(&desc->shm);
	if (ret < 0)
		return scm_remap_error(ret);
	return 0;
}

/**
 * scm_call2() - Invoke a syscall in the secure world
 * @fn_id: The function ID for this syscall
 * @desc: Descriptor structure containing arguments and return values
 *
 * Sends a command to the SCM and waits for the command to finish processing.
 * This should *only* be called in pre-emptible context.
 *
 * A note on cache maintenance:
 * Note that any buffers that are expected to be accessed by the secure world
 * must be flushed before invoking scm_call and invalidated in the cache
 * immediately after scm_call returns. An important point that must be noted
 * is that on ARMV8 architectures, invalidation actually also causes a dirty
 * cache line to be cleaned (flushed + unset-dirty-bit). Therefore it is of
 * paramount importance that the buffer be flushed before invoking scm_call2,
 * even if you don't care about the contents of that buffer.
 *
 * Note that cache maintenance on the argument buffer (desc->args) is taken care
 * of by scm_call2; however, callers are responsible for any other cached
 * buffers passed over to the secure world.
 */
int scm_call2(u32 fn_id, struct scm_desc *desc)
{
	return __scm_call2(fn_id, desc, true);
}
EXPORT_SYMBOL(scm_call2);

/**
 * scm_call2_noretry() - Invoke a syscall in the secure world
 *
 * Similar to scm_call2 except that there is no retry mechanism
 * implemented.
 */
int scm_call2_noretry(u32 fn_id, struct scm_desc *desc)
{
	return __scm_call2(fn_id, desc, false);
}
EXPORT_SYMBOL(scm_call2_noretry);

/**
 * scm_call2_atomic() - Invoke a syscall in the secure world
 *
 * Similar to scm_call2 except that this can be invoked in atomic context.
 * There is also no retry mechanism implemented. Please ensure that the
 * secure world syscall can be executed in such a context and can complete
 * in a timely manner.
 */
int scm_call2_atomic(u32 fn_id, struct scm_desc *desc)
{
	int arglen = desc->arginfo & 0xf;
	int ret;
	u64 x0;

	if (unlikely(!is_scm_armv8()))
		return -ENODEV;

	ret = allocate_extra_arg_buffer(desc, GFP_ATOMIC);
	if (ret)
		return ret;

	x0 = fn_id | BIT(SMC_ATOMIC_SYSCALL) | scm_version_mask;

	trace_scm_call_start(x0, desc);
	if (scm_version == SCM_ARMV8_64)
		ret = __scm_call_armv8_64(x0, desc->arginfo, desc->args[0],
					  desc->args[1], desc->args[2],
					  desc->x5, &desc->ret[0],
					  &desc->ret[1], &desc->ret[2]);
	else
		ret = __scm_call_armv8_32(x0, desc->arginfo, desc->args[0],
					  desc->args[1], desc->args[2],
					  desc->x5, &desc->ret[0],
					  &desc->ret[1], &desc->ret[2]);
	trace_scm_call_end(desc);
	if (ret < 0)
		pr_err("scm_call failed: func id %#llx, ret: %d, syscall returns: %#llx, %#llx, %#llx\n",
			x0, ret, desc->ret[0],
			desc->ret[1], desc->ret[2]);

	if (arglen > N_REGISTER_ARGS)
		qtee_shmbridge_free_shm(&desc->shm);
	if (ret < 0)
		return scm_remap_error(ret);
	return ret;
}
EXPORT_SYMBOL(scm_call2_atomic);

u32 scm_get_version(void)
{
	int context_id;
	static u32 version = -1;

	register u32 r0 asm(R0_STR);
	register u32 r1 asm(R1_STR);

	if (version != -1)
		return version;

	mutex_lock(&scm_lock);

	r0 = 0x1 << 8;
	r1 = (uintptr_t)&context_id;
	do {
		asm volatile(
			__asmeq("%0", R0_STR)
			__asmeq("%1", R1_STR)
			__asmeq("%2", R0_STR)
			__asmeq("%3", R1_STR)
#ifdef REQUIRES_SEC
			".arch_extension sec\n"
#endif
			"smc	#0\n"
			: "=r" (r0), "=r" (r1)
			: "r" (r0), "r" (r1)
			: R2_STR, R3_STR);
	} while (r0 == SCM_INTERRUPTED);

	version = r1;
	mutex_unlock(&scm_lock);

	return version;
}
EXPORT_SYMBOL(scm_get_version);

#define SCM_IO_READ	0x1
#define SCM_IO_WRITE	0x2

u32 scm_io_read(phys_addr_t address)
{
	struct scm_desc desc = {
		.args[0] = address,
		.arginfo = SCM_ARGS(1),
	};

	scm_call2_atomic(SCM_SIP_FNID(SCM_SVC_IO, SCM_IO_READ), &desc);
	return desc.ret[0];
}
EXPORT_SYMBOL(scm_io_read);

int scm_io_write(phys_addr_t address, u32 val)
{
	int ret;
	struct scm_desc desc = {
		.args[0] = address,
		.args[1] = val,
		.arginfo = SCM_ARGS(2),
	};

	ret = scm_call2_atomic(SCM_SIP_FNID(SCM_SVC_IO, SCM_IO_WRITE),
					&desc);
	return ret;
}
EXPORT_SYMBOL(scm_io_write);

int scm_is_call_available(u32 svc_id, u32 cmd_id)
{
	int ret;
	struct scm_desc desc = {0};

	desc.arginfo = SCM_ARGS(1);
	desc.args[0] = SCM_SIP_FNID(svc_id, cmd_id);
	ret = scm_call2(SCM_SIP_FNID(SCM_SVC_INFO, IS_CALL_AVAIL_CMD), &desc);
	if (ret)
		return ret;

	return desc.ret[0];
}
EXPORT_SYMBOL(scm_is_call_available);

#define GET_FEAT_VERSION_CMD	3
int scm_get_feat_version(u32 feat)
{
	struct scm_desc desc = {0};
	int ret;

	ret = scm_is_call_available(SCM_SVC_INFO, GET_FEAT_VERSION_CMD);
	if (ret <= 0)
		return 0;

	desc.args[0] = feat;
	desc.arginfo = SCM_ARGS(1);
	ret = scm_call2(SCM_SIP_FNID(SCM_SVC_INFO, GET_FEAT_VERSION_CMD),
			&desc);
	if (!ret)
		return desc.ret[0];

	return 0;
}
EXPORT_SYMBOL(scm_get_feat_version);

#define RESTORE_SEC_CFG    2
int scm_restore_sec_cfg(u32 device_id, u32 spare, int *scm_ret)
{
	struct scm_desc desc = {0};
	int ret;
	struct restore_sec_cfg {
		u32 device_id;
		u32 spare;
	} cfg;

	cfg.device_id = device_id;
	cfg.spare = spare;

	if (IS_ERR_OR_NULL(scm_ret))
		return -EINVAL;

	desc.args[0] = device_id;
	desc.args[1] = spare;
	desc.arginfo = SCM_ARGS(2);

	ret = scm_call2(SCM_SIP_FNID(SCM_SVC_MP, RESTORE_SEC_CFG), &desc);
	if (ret)
		return ret;

	*scm_ret = desc.ret[0];
	return 0;
}
EXPORT_SYMBOL(scm_restore_sec_cfg);

/*
 * SCM call command ID to check secure mode
 * Return zero for secure device.
 * Return one for non secure device or secure
 * device with debug enabled device.
 */
#define TZ_INFO_GET_SECURE_STATE	0x4
bool scm_is_secure_device(void)
{
	struct scm_desc desc = {0};
	int ret = 0, resp;

	desc.args[0] = 0;
	desc.arginfo = 0;
	ret = scm_call2(SCM_SIP_FNID(SCM_SVC_INFO,
			TZ_INFO_GET_SECURE_STATE),
			&desc);
	resp = desc.ret[0];

	if (ret) {
		pr_err("%s: SCM call failed\n", __func__);
		return false;
	}

	if ((resp & BIT(0)) || (resp & BIT(2)))
		return true;
	else
		return false;
}
EXPORT_SYMBOL(scm_is_secure_device);

#ifdef CONFIG_ARM64

#define TZ_HLOS_NOTIFY_CORE_KERNEL_BOOTUP 0x7
int  scm_mem_protection_init_do_qrks(void)
{
	uint32_t pid_offset = 0;
	uint32_t task_name_offset = 0;
	struct scm_desc desc = {0};
	int ret = 0, resp;

	pid_offset = offsetof(struct task_struct, pid);
	task_name_offset = offsetof(struct task_struct, comm);
	pr_debug("offset of pid is %zu, offset of comm is %zu\n",
		pid_offset, task_name_offset);
	desc.args[0] = pid_offset;
	desc.args[1] = task_name_offset;
	desc.arginfo = 2;
	ret = scm_call2(SCM_SIP_FNID(SCM_SVC_RTIC,
			TZ_HLOS_NOTIFY_CORE_KERNEL_BOOTUP),
			&desc);
	resp = desc.ret[0];

	if (ret == -1) {
		pr_err("%s: SCM call not supported\n", __func__);
		return ret;
	} else if (ret || resp) {
		pr_err("%s: SCM call failed\n", __func__);
		if (ret)
			return ret;
		else
			return resp;
	}

	return resp;
}

/*
 * SCM call command ID to protect kernel memory
 * in Hyp Stage 2 page tables.
 * Return zero for success.
 * Return non-zero for failure.
 */
#define TZ_RTIC_ENABLE_MEM_PROTECTION	0x4
#if IS_ENABLED(CONFIG_QCOM_QHEE_ENABLE_MEM_PROTECTION)
static int __init scm_mem_protection_init(void)
{
	struct scm_desc desc = {0};
	int ret = 0, resp;

	scm_mem_protection_init_do_qrks();
	desc.args[0] = 0;
	desc.arginfo = 0;
	ret = scm_call2(SCM_SIP_FNID(SCM_SVC_RTIC,
			TZ_RTIC_ENABLE_MEM_PROTECTION),
			&desc);
	resp = desc.ret[0];

	if (ret == -1) {
		pr_err("%s: SCM call not supported\n", __func__);
		return ret;
	} else if (ret || resp) {
		pr_err("%s: SCM call failed\n", __func__);
		if (ret)
			return ret;
		else
			return resp;
	}

	return resp;
}

early_initcall(scm_mem_protection_init);
#endif

#endif