Implement an assert() callable from assembly code
The patch implements a macro ASM_ASSERT() which can
be invoked from assembly code. When assertion happens,
file name and line number of the check is written
to the crash console.
Fixes ARM-software/tf-issues#95
Change-Id: I6f905a068e1c0fa4f746d723f18df60daaa00a86
diff --git a/common/aarch64/assert.S b/common/aarch64/assert.S
new file mode 100644
index 0000000..a62c8f5
--- /dev/null
+++ b/common/aarch64/assert.S
@@ -0,0 +1,141 @@
+/*
+ * Copyright (c) 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 <arch.h>
+#include <asm_macros.S>
+
+ .globl asm_print_str
+ .globl asm_print_hex
+ .globl asm_assert
+ .globl do_panic
+
+/* Since the max decimal input number is 65536 */
+#define MAX_DEC_DIVISOR 10000
+/* The offset to add to get ascii for numerals '0 - 9' */
+#define ASCII_OFFSET_NUM 0x30
+
+#if ASM_ASSERTION
+.section .rodata.assert_str, "aS"
+assert_msg1:
+ .asciz "ASSERT: File "
+assert_msg2:
+ .asciz " Line "
+
+ /*
+ * This macro is intended to be used to print the
+ * line number in decimal. Used by asm_assert macro.
+ * The max number expected is 65536.
+ * In: x4 = the decimal to print.
+ * Clobber: x30, x0, x1, x2, x5, x6
+ */
+ .macro asm_print_line_dec
+ mov x6, #10 /* Divide by 10 after every loop iteration */
+ mov x5, #MAX_DEC_DIVISOR
+1:
+ udiv x0, x4, x5 /* Get the quotient */
+ msub x4, x0, x5, x4 /* Find the remainder */
+ add x0, x0, #ASCII_OFFSET_NUM /* Convert to ascii */
+ bl plat_crash_console_putc
+ udiv x5, x5, x6 /* Reduce divisor */
+ cbnz x5, 1b
+ .endm
+
+
+/* ---------------------------------------------------------------------------
+ * Assertion support in assembly.
+ * The below function helps to support assertions in assembly where we do not
+ * have a C runtime stack. Arguments to the function are :
+ * x0 - File name
+ * x1 - Line no
+ * Clobber list : x30, x0, x1, x2, x3, x4, x5, x6.
+ * ---------------------------------------------------------------------------
+ */
+func asm_assert
+ mov x5, x0
+ mov x6, x1
+ /* Ensure the console is initialized */
+ bl plat_crash_console_init
+ /* Check if the console is initialized */
+ cbz x0, _assert_loop
+ /* The console is initialized */
+ adr x4, assert_msg1
+ bl asm_print_str
+ mov x4, x5
+ bl asm_print_str
+ adr x4, assert_msg2
+ bl asm_print_str
+ /* Check if line number higher than max permitted */
+ tst x6, #~0xffff
+ b.ne _assert_loop
+ mov x4, x6
+ asm_print_line_dec
+_assert_loop:
+ b _assert_loop
+#endif
+
+/*
+ * This function prints a string from address in x4.
+ * In: x4 = pointer to string.
+ * Clobber: x30, x0, x1, x2, x3
+ */
+func asm_print_str
+ mov x3, x30
+1:
+ ldrb w0, [x4], #0x1
+ cbz x0, 2f
+ bl plat_crash_console_putc
+ b 1b
+2:
+ ret x3
+
+/*
+ * This function prints a hexadecimal number in x4.
+ * In: x4 = the hexadecimal to print.
+ * Clobber: x30, x0, x5, x1, x2, x3
+ */
+func asm_print_hex
+ mov x3, x30
+ mov x5, #64 /* No of bits to convert to ascii */
+1:
+ sub x5, x5, #4
+ lsrv x0, x4, x5
+ and x0, x0, #0xf
+ cmp x0, #0xA
+ b.lo 2f
+ /* Add by 0x27 in addition to ASCII_OFFSET_NUM
+ * to get ascii for characters 'a - f'.
+ */
+ add x0, x0, #0x27
+2:
+ add x0, x0, #ASCII_OFFSET_NUM
+ bl plat_crash_console_putc
+ cbnz x5, 1b
+ ret x3
+