diff options
Diffstat (limited to 'services/spd/tspd/tspd_helpers.S')
| -rw-r--r-- | services/spd/tspd/tspd_helpers.S | 101 |
1 files changed, 101 insertions, 0 deletions
diff --git a/services/spd/tspd/tspd_helpers.S b/services/spd/tspd/tspd_helpers.S new file mode 100644 index 0000000..dd3b07b --- /dev/null +++ b/services/spd/tspd/tspd_helpers.S @@ -0,0 +1,101 @@ +/* + * Copyright (c) 2013-2014, ARM Limited and Contributors. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions are met: + * + * Redistributions of source code must retain the above copyright notice, this + * list of conditions and the following disclaimer. + * + * Redistributions in binary form must reproduce the above copyright notice, + * this list of conditions and the following disclaimer in the documentation + * and/or other materials provided with the distribution. + * + * Neither the name of ARM nor the names of its contributors may be used + * to endorse or promote products derived from this software without specific + * prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" + * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE + * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR + * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF + * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS + * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN + * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE + * POSSIBILITY OF SUCH DAMAGE. + */ + +#include <asm_macros.S> +#include "tspd_private.h" + + .global tspd_enter_sp + /* --------------------------------------------- + * This function is called with SP_EL0 as stack. + * Here we stash our EL3 callee-saved registers + * on to the stack as a part of saving the C + * runtime and enter the secure payload. + * 'x0' contains a pointer to the memory where + * the address of the C runtime context is to be + * saved. + * --------------------------------------------- + */ +func tspd_enter_sp + /* Make space for the registers that we're going to save */ + mov x3, sp + str x3, [x0, #0] + sub sp, sp, #TSPD_C_RT_CTX_SIZE + + /* Save callee-saved registers on to the stack */ + stp x19, x20, [sp, #TSPD_C_RT_CTX_X19] + stp x21, x22, [sp, #TSPD_C_RT_CTX_X21] + stp x23, x24, [sp, #TSPD_C_RT_CTX_X23] + stp x25, x26, [sp, #TSPD_C_RT_CTX_X25] + stp x27, x28, [sp, #TSPD_C_RT_CTX_X27] + stp x29, x30, [sp, #TSPD_C_RT_CTX_X29] + + /* --------------------------------------------- + * Everything is setup now. el3_exit() will + * use the secure context to restore to the + * general purpose and EL3 system registers to + * ERET into the secure payload. + * --------------------------------------------- + */ + b el3_exit + + /* --------------------------------------------- + * This function is called 'x0' pointing to a C + * runtime context saved in tspd_enter_sp(). It + * restores the saved registers and jumps to + * that runtime with 'x0' as the new sp. This + * destroys the C runtime context that had been + * built on the stack below the saved context by + * the caller. Later the second parameter 'x1' + * is passed as return value to the caller + * --------------------------------------------- + */ + .global tspd_exit_sp +func tspd_exit_sp + /* Restore the previous stack */ + mov sp, x0 + + /* Restore callee-saved registers on to the stack */ + ldp x19, x20, [x0, #(TSPD_C_RT_CTX_X19 - TSPD_C_RT_CTX_SIZE)] + ldp x21, x22, [x0, #(TSPD_C_RT_CTX_X21 - TSPD_C_RT_CTX_SIZE)] + ldp x23, x24, [x0, #(TSPD_C_RT_CTX_X23 - TSPD_C_RT_CTX_SIZE)] + ldp x25, x26, [x0, #(TSPD_C_RT_CTX_X25 - TSPD_C_RT_CTX_SIZE)] + ldp x27, x28, [x0, #(TSPD_C_RT_CTX_X27 - TSPD_C_RT_CTX_SIZE)] + ldp x29, x30, [x0, #(TSPD_C_RT_CTX_X29 - TSPD_C_RT_CTX_SIZE)] + + /* --------------------------------------------- + * This should take us back to the instruction + * after the call to the last tspd_enter_sp(). + * Place the second parameter to x0 so that the + * caller will see it as a return value from the + * original entry call + * --------------------------------------------- + */ + mov x0, x1 + ret |