src/rtos/rtos_standard_stackings.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2
   3 /***************************************************************************
   4  *   Copyright (C) 2011 by Broadcom Corporation                            *
   5  *   Evan Hunter - ehunter@broadcom.com                                    *
   6  ***************************************************************************/
   7
   8 #ifdef HAVE_CONFIG_H
   9 #include "config.h"
  10 #endif
  11
  12 #include "rtos.h"
  13 #include "target/armv7m.h"
  14 #include "rtos_standard_stackings.h"
  15
  16 static const struct stack_register_offset rtos_standard_cortex_m3_stack_offsets[ARMV7M_NUM_CORE_REGS] = {
  17         { ARMV7M_R0,   0x20, 32 },              /* r0   */
  18         { ARMV7M_R1,   0x24, 32 },              /* r1   */
  19         { ARMV7M_R2,   0x28, 32 },              /* r2   */
  20         { ARMV7M_R3,   0x2c, 32 },              /* r3   */
  21         { ARMV7M_R4,   0x00, 32 },              /* r4   */
  22         { ARMV7M_R5,   0x04, 32 },              /* r5   */
  23         { ARMV7M_R6,   0x08, 32 },              /* r6   */
  24         { ARMV7M_R7,   0x0c, 32 },              /* r7   */
  25         { ARMV7M_R8,   0x10, 32 },              /* r8   */
  26         { ARMV7M_R9,   0x14, 32 },              /* r9   */
  27         { ARMV7M_R10,  0x18, 32 },              /* r10  */
  28         { ARMV7M_R11,  0x1c, 32 },              /* r11  */
  29         { ARMV7M_R12,  0x30, 32 },              /* r12  */
  30         { ARMV7M_R13,  -2,   32 },              /* sp   */
  31         { ARMV7M_R14,  0x34, 32 },              /* lr   */
  32         { ARMV7M_PC,   0x38, 32 },              /* pc   */
  33         { ARMV7M_XPSR, 0x3c, 32 },              /* xPSR */
  34 };
  35
  36 static const struct stack_register_offset rtos_standard_cortex_m4f_stack_offsets[] = {
  37         { ARMV7M_R0,   0x24, 32 },              /* r0   */
  38         { ARMV7M_R1,   0x28, 32 },              /* r1   */
  39         { ARMV7M_R2,   0x2c, 32 },              /* r2   */
  40         { ARMV7M_R3,   0x30, 32 },              /* r3   */
  41         { ARMV7M_R4,   0x00, 32 },              /* r4   */
  42         { ARMV7M_R5,   0x04, 32 },              /* r5   */
  43         { ARMV7M_R6,   0x08, 32 },              /* r6   */
  44         { ARMV7M_R7,   0x0c, 32 },              /* r7   */
  45         { ARMV7M_R8,   0x10, 32 },              /* r8   */
  46         { ARMV7M_R9,   0x14, 32 },              /* r9   */
  47         { ARMV7M_R10,  0x18, 32 },              /* r10  */
  48         { ARMV7M_R11,  0x1c, 32 },              /* r11  */
  49         { ARMV7M_R12,  0x34, 32 },              /* r12  */
  50         { ARMV7M_R13,  -2,   32 },              /* sp   */
  51         { ARMV7M_R14,  0x38, 32 },              /* lr   */
  52         { ARMV7M_PC,   0x3c, 32 },              /* pc   */
  53         { ARMV7M_XPSR, 0x40, 32 },              /* xPSR */
  54 };
  55
  56 static const struct stack_register_offset rtos_standard_cortex_m4f_fpu_stack_offsets[] = {
  57         { ARMV7M_R0,   0x64, 32 },              /* r0   */
  58         { ARMV7M_R1,   0x68, 32 },              /* r1   */
  59         { ARMV7M_R2,   0x6c, 32 },              /* r2   */
  60         { ARMV7M_R3,   0x70, 32 },              /* r3   */
  61         { ARMV7M_R4,   0x00, 32 },              /* r4   */
  62         { ARMV7M_R5,   0x04, 32 },              /* r5   */
  63         { ARMV7M_R6,   0x08, 32 },              /* r6   */
  64         { ARMV7M_R7,   0x0c, 32 },              /* r7   */
  65         { ARMV7M_R8,   0x10, 32 },              /* r8   */
  66         { ARMV7M_R9,   0x14, 32 },              /* r9   */
  67         { ARMV7M_R10,  0x18, 32 },              /* r10  */
  68         { ARMV7M_R11,  0x1c, 32 },              /* r11  */
  69         { ARMV7M_R12,  0x74, 32 },              /* r12  */
  70         { ARMV7M_R13,  -2,   32 },              /* sp   */
  71         { ARMV7M_R14,  0x78, 32 },              /* lr   */
  72         { ARMV7M_PC,   0x7c, 32 },              /* pc   */
  73         { ARMV7M_XPSR, 0x80, 32 },              /* xPSR */
  74 };
  75
  76
  77 static const struct stack_register_offset rtos_standard_cortex_r4_stack_offsets[] = {
  78         { 0,  0x08, 32 },               /* r0  (a1)   */
  79         { 1,  0x0c, 32 },               /* r1  (a2)  */
  80         { 2,  0x10, 32 },               /* r2  (a3)  */
  81         { 3,  0x14, 32 },               /* r3  (a4)  */
  82         { 4,  0x18, 32 },               /* r4  (v1)  */
  83         { 5,  0x1c, 32 },               /* r5  (v2)  */
  84         { 6,  0x20, 32 },               /* r6  (v3)  */
  85         { 7,  0x24, 32 },               /* r7  (v4)  */
  86         { 8,  0x28, 32 },               /* r8  (a1)  */
  87         { 10, 0x2c, 32 },               /* r9  (sb)  */
  88         { 11, 0x30, 32 },               /* r10 (sl) */
  89         { 12, 0x34, 32 },               /* r11 (fp) */
  90         { 13, 0x38, 32 },               /* r12 (ip) */
  91         { 14, -2,   32 },               /* sp   */
  92         { 15, 0x3c, 32 },               /* lr   */
  93         { 16, 0x40, 32 },               /* pc   */
  94         { 17, -1,   96 },               /* FPA1 */
  95         { 18, -1,   96 },               /* FPA2 */
  96         { 19, -1,   96 },               /* FPA3 */
  97         { 20, -1,   96 },               /* FPA4 */
  98         { 21, -1,   96 },               /* FPA5 */
  99         { 22, -1,   96 },               /* FPA6 */
 100         { 23, -1,   96 },               /* FPA7 */
 101         { 24, -1,   96 },               /* FPA8 */
 102         { 25, -1,   32 },               /* FPS  */
 103         { 26, 0x04, 32 },               /* CSPR */
 104 };
 105
 106 static target_addr_t rtos_generic_stack_align(struct target *target,
 107         const uint8_t *stack_data, const struct rtos_register_stacking *stacking,
 108         target_addr_t stack_ptr, int align)
 109 {
 110         target_addr_t new_stack_ptr;
 111         target_addr_t aligned_stack_ptr;
 112         new_stack_ptr = stack_ptr - stacking->stack_growth_direction *
 113                 stacking->stack_registers_size;
 114         aligned_stack_ptr = new_stack_ptr & ~((target_addr_t)align - 1);
 115         if (aligned_stack_ptr != new_stack_ptr &&
 116                 stacking->stack_growth_direction == -1) {
 117                 /* If we have a downward growing stack, the simple alignment code
 118                  * above results in a wrong result (since it rounds down to nearest
 119                  * alignment).  We want to round up so add an extra align.
 120                  */
 121                 aligned_stack_ptr += (target_addr_t)align;
 122         }
 123         return aligned_stack_ptr;
 124 }
 125
 126 target_addr_t rtos_generic_stack_align8(struct target *target,
 127         const uint8_t *stack_data, const struct rtos_register_stacking *stacking,
 128         target_addr_t stack_ptr)
 129 {
 130         return rtos_generic_stack_align(target, stack_data,
 131                         stacking, stack_ptr, 8);
 132 }
 133
 134 /* The Cortex-M3 will indicate that an alignment adjustment
 135  * has been done on the stack by setting bit 9 of the stacked xPSR
 136  * register.  In this case, we can just add an extra 4 bytes to get
 137  * to the program stack.  Note that some places in the ARM documentation
 138  * make this a little unclear but the padding takes place before the
 139  * normal exception stacking - so xPSR is always available at a fixed
 140  * location.
 141  *
 142  * Relevant documentation:
 143  *    Cortex-M series processors -> Cortex-M3 -> Revision: xxx ->
 144  *        Cortex-M3 Devices Generic User Guide -> The Cortex-M3 Processor ->
 145  *        Exception Model -> Exception entry and return -> Exception entry
 146  *    Cortex-M series processors -> Cortex-M3 -> Revision: xxx ->
 147  *        Cortex-M3 Devices Generic User Guide -> Cortex-M3 Peripherals ->
 148  *        System control block -> Configuration and Control Register (STKALIGN)
 149  *
 150  * This is just a helper function for use in the calculate_process_stack
 151  * function for a given architecture/rtos.
 152  */
 153 target_addr_t rtos_cortex_m_stack_align(struct target *target,
 154         const uint8_t *stack_data, const struct rtos_register_stacking *stacking,
 155         target_addr_t stack_ptr, size_t xpsr_offset)
 156 {
 157         const uint32_t ALIGN_NEEDED = (1 << 9);
 158         uint32_t xpsr;
 159         target_addr_t new_stack_ptr;
 160
 161         new_stack_ptr = stack_ptr - stacking->stack_growth_direction *
 162                 stacking->stack_registers_size;
 163         xpsr = (target->endianness == TARGET_LITTLE_ENDIAN) ?
 164                         le_to_h_u32(&stack_data[xpsr_offset]) :
 165                         be_to_h_u32(&stack_data[xpsr_offset]);
 166         if ((xpsr & ALIGN_NEEDED) != 0) {
 167                 LOG_DEBUG("XPSR(0x%08" PRIx32 ") indicated stack alignment was necessary\r\n",
 168                         xpsr);
 169                 new_stack_ptr -= (stacking->stack_growth_direction * 4);
 170         }
 171         return new_stack_ptr;
 172 }
 173
 174 static target_addr_t rtos_standard_cortex_m3_stack_align(struct target *target,
 175         const uint8_t *stack_data, const struct rtos_register_stacking *stacking,
 176         target_addr_t stack_ptr)
 177 {
 178         const int XPSR_OFFSET = 0x3c;
 179         return rtos_cortex_m_stack_align(target, stack_data, stacking,
 180                 stack_ptr, XPSR_OFFSET);
 181 }
 182
 183 static target_addr_t rtos_standard_cortex_m4f_stack_align(struct target *target,
 184         const uint8_t *stack_data, const struct rtos_register_stacking *stacking,
 185         target_addr_t stack_ptr)
 186 {
 187         const int XPSR_OFFSET = 0x40;
 188         return rtos_cortex_m_stack_align(target, stack_data, stacking,
 189                 stack_ptr, XPSR_OFFSET);
 190 }
 191
 192 static target_addr_t rtos_standard_cortex_m4f_fpu_stack_align(struct target *target,
 193         const uint8_t *stack_data, const struct rtos_register_stacking *stacking,
 194         target_addr_t stack_ptr)
 195 {
 196         const int XPSR_OFFSET = 0x80;
 197         return rtos_cortex_m_stack_align(target, stack_data, stacking,
 198                 stack_ptr, XPSR_OFFSET);
 199 }
 200
 201
 202 const struct rtos_register_stacking rtos_standard_cortex_m3_stacking = {
 203         .stack_registers_size = 0x40,
 204         .stack_growth_direction = -1,
 205         .num_output_registers = ARMV7M_NUM_CORE_REGS,
 206         .calculate_process_stack = rtos_standard_cortex_m3_stack_align,
 207         .register_offsets = rtos_standard_cortex_m3_stack_offsets
 208 };
 209
 210 const struct rtos_register_stacking rtos_standard_cortex_m4f_stacking = {
 211         .stack_registers_size = 0x44,
 212         .stack_growth_direction = -1,
 213         .num_output_registers = ARMV7M_NUM_CORE_REGS,
 214         .calculate_process_stack = rtos_standard_cortex_m4f_stack_align,
 215         .register_offsets = rtos_standard_cortex_m4f_stack_offsets
 216 };
 217
 218 const struct rtos_register_stacking rtos_standard_cortex_m4f_fpu_stacking = {
 219         .stack_registers_size = 0xcc,
 220         .stack_growth_direction = -1,
 221         .num_output_registers = ARMV7M_NUM_CORE_REGS,
 222         .calculate_process_stack = rtos_standard_cortex_m4f_fpu_stack_align,
 223         .register_offsets = rtos_standard_cortex_m4f_fpu_stack_offsets
 224 };
 225
 226 const struct rtos_register_stacking rtos_standard_cortex_r4_stacking = {
 227         .stack_registers_size = 0x48,
 228         .stack_growth_direction = -1,
 229         .num_output_registers = 26,
 230         .calculate_process_stack = rtos_generic_stack_align8,
 231         .register_offsets = rtos_standard_cortex_r4_stack_offsets
 232 };