feat(esp8266): Add panic function when crash

components/esp8266/source/panic.c

@@ -0,0 +1,133 @@
+// Copyright 2018 Espressif Systems (Shanghai) PTE LTD
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include <string.h>
+
+#include "c_types.h"
+
+#include "esp8266/ets_sys.h"
+#include "esp8266/eagle_soc.h"
+#include "esp8266/uart_register.h"
+
+/*
+ * Todo: panic output UART ID, we may add it to 'kconfig' to select target UART.
+ */
+#define PANIC_UART 0
+
+/*
+ * @brief output a character
+ * 
+ * @param c a character
+ * 
+ * @return none
+ */
+static IRAM_ATTR void panit_putc(char c)
+{
+    while (1) {
+        uint32_t fifo_cnt = READ_PERI_REG(UART_STATUS(PANIC_UART)) & (UART_TXFIFO_CNT << UART_TXFIFO_CNT_S);
+
+        if ((fifo_cnt >> UART_TXFIFO_CNT_S & UART_TXFIFO_CNT) < 126)
+            break;
+    }
+
+    WRITE_PERI_REG(UART_FIFO(PANIC_UART) , c);
+}
+
+/*
+ * @brief output a left-aligned string
+ * 
+ * @param s string pointer
+ * @param left_aligned left-aligned bytes
+ * 
+ * @return none
+ */
+static IRAM_ATTR void panic_puts(const char *s, int left_aligned)
+{
+    int bytes = left_aligned - strlen(s);
+
+    while (bytes-- > 0)
+        panit_putc(' ');
+
+    while (*s)
+        panit_putc(*s++);
+}
+
+/*
+ * @brief output a hex value string of 32-bites data
+ * 
+ * @param hex 32-bites data
+ * 
+ * @return none
+ */
+static IRAM_ATTR void panic_puthex(int hex)
+{
+    char buf[8];
+    int bytes = 0;
+
+    while (bytes < 8) {
+        char c = (uint32_t)hex % 16;
+
+        if (c < 10)
+            c = c + '0';
+        else
+            c = c - 10 + 'a';
+
+        buf[bytes++] = c;
+        hex >>= 4;
+    }
+
+    while (bytes)
+        panit_putc(buf[--bytes]);
+}
+
+/*
+ * @brief output xtensa register value map when crash
+ * 
+ * @param frame xtensa register value map pointer
+ * 
+ * @return none
+ */
+void IRAM_ATTR panicHandler(void *frame)
+{
+    int *regs = (int *)frame;
+    int x, y;
+    const char *sdesc[] = {
+        "PC",   "PS",   "A0",   "A1",
+        "A2",   "A3",   "A4",   "A5",
+        "A6",   "A7",   "A8",   "A9",
+        "A10",  "A11",  "A12",  "A13",
+        "A14",  "A15",  "SAR",  "EXCCAUSE"
+    };
+
+    /* NMI can interrupt exception. */
+    ETS_INTR_LOCK();
+
+    for (x = 0; x < 20; x += 4) {
+        for (y = 0; y < 4; y++) {
+            panic_puts(sdesc[x + y], 8);
+            panic_puts(": 0x", 0);
+            panic_puthex(regs[x + y + 1]);
+            panic_puts("  ", 0);
+        }
+        panit_putc('\n');
+    }
+
+    /*
+     * Todo: add more option to select here to 'Kconfig':
+     *     1. blocking
+     *     2. restart
+     *     3. GBD break
+     */
+    while (1);
+}

components/esp8266/source/xtensa_vectors.S

@@ -122,6 +122,9 @@ STRUCT_END(HighPriFrame)
 #define PRI_N_STACK_SIZE     512    /* default to 1 kB stack for each level-N handling */
 #define PRI_N_STACK_SIZE2    256    /* default to 1 kB stack for each level-N handling */
 
+#define PANIC_STK_FRMSZ      0x60
+
+    .global panicHandler
 
     //  Allocate save area and stack:
     //  (must use .bss, not .comm, because the subsequent .set does not work otherwise)
@@ -669,6 +672,8 @@ Double exceptions are not a normal occurrence. They indicate a bug of some kind.
     .align      4
     .literal_position
 _DoubleExceptionVector:
+    wsr     a0, EXCSAVE_1
+    j       _xt_ext_panic
 
     #if XCHAL_HAVE_DEBUG
     break   1, 4                            /* unhandled double exception */
@@ -692,9 +697,9 @@ Kernel Exception (including Level 1 Interrupt from kernel mode).
     .align      4
     .literal_position
 _KernelExceptionVector:
-
     wsr     a0, EXCSAVE_1                   /* preserve a0 */
-    call0   _xt_kernel_exc                  /* kernel exception handler */
+    j       _xt_ext_panic
+
     /* never returns here - call0 is used as a jump (see note at top) */
 
     .end        literal_prefix
@@ -768,7 +773,11 @@ _xt_user_exc:
     #endif
     beqi    a0, EXCCAUSE_SYSCALL, _xt_to_syscall_exc
     beqi    a0, EXCCAUSE_LOAD_STORE_ERROR, LoadStoreErrorHandler
+    beqi    a0, EXCCAUSE_LEVEL1INTERRUPT, _xt_user_entry1
 
+    j   _xt_ext_panic
+
+_xt_user_entry1:
     /* Allocate interrupt stack frame and save minimal context. */
     mov     a0, sp                          /* sp == a1 */
     addi    sp, sp, -XT_STK_FRMSZ           /* allocate interrupt stack frame */
@@ -1395,3 +1404,41 @@ nmi_rfi:
     rfi     XCHAL_NMILEVEL
 #endif
 #endif  /* NMI */
+
+    .global     _xt_ext_panic
+    .type       _xt_ext_panic, @function
+    .align      4
+    .literal_position
+_xt_ext_panic:
+    /* Allocate exception frame and save minimal context. */
+    mov     a0, sp
+    addi    sp, sp, -XT_STK_FRMSZ
+    s32i    a0, sp, XT_STK_A1
+
+    rsr     a0, PS                          /* save interruptee's PS */
+    s32i    a0, sp, XT_STK_PS
+    rsr     a0, EPC_1                       /* save interruptee's PC */
+    s32i    a0, sp, XT_STK_PC
+
+    s32i    a12, sp, XT_STK_A12             /* _xt_context_save requires A12- */
+    s32i    a13, sp, XT_STK_A13             /* A13 to have already been saved */
+    s32i    a14, sp, XT_STK_A14             
+    s32i    a15, sp, XT_STK_A15             
+    call0   _xt_context_save
+
+    /* Save exc cause and vaddr into exception frame */
+    rsr     a0, EXCCAUSE
+    s32i    a0, sp, XT_STK_EXCCAUSE
+
+    /* _xt_context_save seems to save the current a0, but we need the interuptees a0. Fix this. */
+    rsr     a0, EXCSAVE_1                   /* save interruptee's a0 */
+
+    s32i    a0, sp, XT_STK_A0
+
+    /* Set up PS for C, disable all interrupts except NMI and debug, and clear EXCM. */
+    movi    a0, PS_INTLEVEL(5) | PS_UM | PS_WOE
+    wsr     a0, PS
+
+    //Call panic handler
+    mov     a2, sp
+    call0   panicHandler

components/freertos/include/freertos/xtensa_context.h

@@ -77,6 +77,7 @@ space to help manage the spilling of the register windows.
 #define XT_STK_A14              0x44    /* Call0 callee-save */
 #define XT_STK_A15              0x48    /* Call0 callee-save */
 #define XT_STK_SAR              0x4C
+#define XT_STK_EXCCAUSE         0x50
 
 #if XCHAL_HAVE_LOOPS
 #define XT_STK_LBEG             0x50