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smc_call.md

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zx_smc_call

NAME

smc_call - Make Secure Monitor Call (SMC) from user space

SYNOPSIS

#include <zircon/syscalls.h>
#include <zircon/syscalls/smc.h>

typedef struct zx_smc_parameters {
    uint32_t func_id;
    uint64_t arg1;
    uint64_t arg2;
    uint64_t arg3;
    uint64_t arg4;
    uint64_t arg5;
    uint64_t arg6;
    uint16_t client_id;
    uint16_t secure_os_id;
} zx_smc_parameters_t;

typedef struct zx_smc_result {
    uint64_t arg0;
    uint64_t arg1;
    uint64_t arg2;
    uint64_t arg3;
} zx_smc_result_t;

zx_status_t zx_smc_call(zx_handle_t handle,
                        const zx_smc_parameters_t* parameters,
                        zx_smc_result_t* out_smc_result);

DESCRIPTION

smc_call() makes a Secure Monitor Call (SMC) from user space. It supports the ARM SMC Calling Convention using the zx_smc_parameters_t input parameter and zx_smc_result_t output parameter. The input handle must be a resource object with sufficient privileges in order to be executed.

The majority of the parameters are opaque from smc_call perspective because they are dependent upon the func_id. The func_id informs the Secure Monitor the service and function to be invoked. The client_id is an optional field intended for secure software to track and index the calling client OS. The secure_os_id is an optional field intended for use when there are multiple secure operating systems at S-EL1, so that the caller may specify the intended secure OS.

More information is available in the ARM SMC Calling Convention documentation.

RIGHTS

TODO(ZX-2399)

RETURN VALUE

smc_call() returns ZX_OK if handle has sufficient privilege. The return value of the smc call is returned via out_smc_result on success. In the event of failure, a negative error value is returned.

ERRORS

ZX_ERR_BAD_HANDLE handle is not a valid handle.

ZX_ERR_WRONG_TYPE handle is not a resource handle.

ZX_ERR_ACCESS_DENIED handle does not have sufficient privileges.

ZX_ERR_NOT_SUPPORTED smc_call is not supported on this system.

ZX_ERR_INVALID_ARGS parameters or out_smc_result a null pointer