Merge branch 'bugfix/riscv_stack_alignment_v4.3' into 'release/v4.3'

core: fix cases where riscv SP were not 16 byte aligned (v4.3)

See merge request espressif/esp-idf!13653

components/freertos/port/riscv/portasm.S

@@ -88,12 +88,13 @@ isr_skip_decrement:
     lw t2, 0x0(t0)
     beq t2, zero, no_switch
 
-    /* preserve return address and schedule next task */
-    addi sp,sp,-4
+    /* preserve return address and schedule next task
+       stack pointer for riscv should always be 16 byte aligned */
+    addi sp,sp,-16
     sw  ra, 0(sp)
     call vTaskSwitchContext
     lw  ra, 0(sp)
-    addi sp, sp, 4
+    addi sp, sp, 16
 
     /* Clears the switch pending flag */
     la t0, xPortSwitchFlag

components/newlib/test/test_newlib.c

@@ -37,7 +37,7 @@ TEST_CASE("test sprintf function", "[newlib]")
     char *res = NULL;
     asprintf(&res, "%d %011i %lu %p %x %c %.4f\n", 42, 2147483647, 2147483648UL, (void *) 0x40010000, 0x40020000, 'Q', 1.0f / 137.0f);
     TEST_ASSERT_NOT_NULL(res);
-    TEST_ASSERT_EQUAL_STRING(res, "42 02147483647 2147483648 0x40010000 40020000 Q 0.0073\n");
+    TEST_ASSERT_EQUAL_STRING("42 02147483647 2147483648 0x40010000 40020000 Q 0.0073\n", res);
     free(res);
 }
 

components/newlib/test/test_shared_stack_printf.c

@@ -15,7 +15,16 @@ static StackType_t *shared_stack_sp = NULL;
 void external_stack_function(void)
 {
     printf("Executing this printf from external stack! sp=%p\n", get_sp());
+
     shared_stack_sp = (StackType_t *)get_sp();
+
+    char *res = NULL;
+    /* Test return value from asprintf, this could potentially help catch a misaligned
+       stack pointer error */
+    asprintf(&res, "%d %011i %lu %p %x %c %.4f\n", 42, 2147483647, 2147483648UL, (void *) 0x40010000, 0x40020000, 'Q', 1.0f / 137.0f);
+    TEST_ASSERT_NOT_NULL(res);
+    TEST_ASSERT_EQUAL_STRING("42 02147483647 2147483648 0x40010000 40020000 Q 0.0073\n", res);
+    free(res);
 }
 
 void another_external_stack_function(void)

components/riscv/expression_with_stack_riscv.c

@@ -38,8 +38,7 @@ static StackType_t *esp_switch_stack_setup(StackType_t *stack, size_t stack_size
 
     //Align stack to a 16byte boundary, as required by CPU specific:
     top_of_stack =  (StackType_t *)(((UBaseType_t)(top_of_stack - 16) & ~0xf));
-    RvExcFrame *adjusted_top_of_stack = (RvExcFrame *) top_of_stack;
-    adjusted_top_of_stack--;
+    StackType_t *adjusted_top_of_stack = top_of_stack - RV_STK_FRMSZ;
 
 #if CONFIG_FREERTOS_WATCHPOINT_END_OF_STACK
     vPortSetStackWatchpoint(stack);

components/riscv/expression_with_stack_riscv_asm.S

@@ -24,8 +24,9 @@ esp_shared_stack_invoke_function:
     /* Set shared stack as new stack pointer */
     mv sp, a1
 
-    /* store the ra and previous stack pointer in a safe place */
-    addi sp,sp,-4
+    /* store the ra and previous stack pointer in a safe place
+       stack pointer for riscv should always be 16 byte aligned */
+    addi sp,sp,-16
     sw  t0, 0(sp)
     sw  t1, 4(sp)
 
@@ -35,7 +36,7 @@ esp_shared_stack_invoke_function:
     /* gets the ra and stack pointer saved previously */
     lw  t0, 0(sp)
     lw  t1, 4(sp)
-    addi sp, sp, 4
+    addi sp, sp, 16
 
     /* restore both ra and real stack pointer of current task */
     mv ra, t1