Support for building and running external apps (#112)

Libraries/elf_loader/src/arch/esp_elf_xtensa.c

@@ -0,0 +1,112 @@
+/*
+ * SPDX-FileCopyrightText: 2023 Espressif Systems (Shanghai) CO LTD
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <assert.h>
+#include <sys/errno.h>
+#include "esp_elf.h"
+#include "esp_log.h"
+#include "private/elf_platform.h"
+
+/** @brief Xtensa relocations defined by the ABIs */
+
+#define R_XTENSA_NONE           0
+#define R_XTENSA_32             1
+#define R_XTENSA_RTLD           2
+#define R_XTENSA_GLOB_DAT       3
+#define R_XTENSA_JMP_SLOT       4
+#define R_XTENSA_RELATIVE       5
+#define R_XTENSA_PLT            6
+#define R_XTENSA_OP0            8
+#define R_XTENSA_OP1            9
+#define R_XTENSA_OP2            10
+#define R_XTENSA_ASM_EXPAND     11
+#define R_XTENSA_ASM_SIMPLIFY   12
+#define R_XTENSA_GNU_VTINHERIT  15
+#define R_XTENSA_GNU_VTENTRY    16
+#define R_XTENSA_DIFF8          17
+#define R_XTENSA_DIFF16         18
+#define R_XTENSA_DIFF32         19
+#define R_XTENSA_SLOT0_OP       20
+#define R_XTENSA_SLOT1_OP       21
+#define R_XTENSA_SLOT2_OP       22
+#define R_XTENSA_SLOT3_OP       23
+#define R_XTENSA_SLOT4_OP       24
+#define R_XTENSA_SLOT5_OP       25
+#define R_XTENSA_SLOT6_OP       26
+#define R_XTENSA_SLOT7_OP       27
+#define R_XTENSA_SLOT8_OP       28
+#define R_XTENSA_SLOT9_OP       29
+#define R_XTENSA_SLOT10_OP      30
+#define R_XTENSA_SLOT11_OP      31
+#define R_XTENSA_SLOT12_OP      32
+#define R_XTENSA_SLOT13_OP      33
+#define R_XTENSA_SLOT14_OP      34
+#define R_XTENSA_SLOT0_ALT      35
+#define R_XTENSA_SLOT1_ALT      36
+#define R_XTENSA_SLOT2_ALT      37
+#define R_XTENSA_SLOT3_ALT      38
+#define R_XTENSA_SLOT4_ALT      39
+#define R_XTENSA_SLOT5_ALT      40
+#define R_XTENSA_SLOT6_ALT      41
+#define R_XTENSA_SLOT7_ALT      42
+#define R_XTENSA_SLOT8_ALT      43
+#define R_XTENSA_SLOT9_ALT      44
+#define R_XTENSA_SLOT10_ALT     45
+#define R_XTENSA_SLOT11_ALT     46
+#define R_XTENSA_SLOT12_ALT     47
+#define R_XTENSA_SLOT13_ALT     48
+#define R_XTENSA_SLOT14_ALT     49
+
+static const char *TAG = "elf_arch";
+
+/**
+ * @brief Relocates target architecture symbol of ELF
+ *
+ * @param elf  - ELF object pointer
+ * @param rela - Relocated symbol data
+ * @param sym  - ELF symbol table
+ * @param addr - Jumping target address
+ * 
+ * @return ESP_OK if sucess or other if failed.
+ */
+int esp_elf_arch_relocate(esp_elf_t *elf, const elf32_rela_t *rela,
+                          const elf32_sym_t *sym, uint32_t addr)
+{
+    uint32_t val;
+    uint32_t *where;
+
+    assert(elf && rela);
+
+    where = (uint32_t *)esp_elf_map_sym(elf, rela->offset);
+
+    ESP_LOGD(TAG, "where=%p addr=%x offset=%x\n", where, (int)addr, (int)rela->offset);
+
+    switch (ELF_R_TYPE(rela->info)) {
+    case R_XTENSA_RELATIVE:
+        val = esp_elf_map_sym(elf, *where);
+#ifdef CONFIG_ELF_LOADER_CACHE_OFFSET
+        *where = elf_remap_text(elf, val);
+#else
+        *where  = val;
+#endif
+        break;
+    case R_XTENSA_RTLD:
+        break;
+    case R_XTENSA_GLOB_DAT:
+    case R_XTENSA_JMP_SLOT:
+#ifdef CONFIG_ELF_LOADER_CACHE_OFFSET
+        *where = elf_remap_text(elf, addr);
+#else
+        *where = addr;
+#endif
+        break;
+    default:
+        ESP_LOGE(TAG, "info=%d is not supported", ELF_R_TYPE(rela->info));
+        return -EINVAL;
+    }
+
+    return 0;
+}