add some ARM EABI-specific exception handling infrastructure

patch by Timo Teräs

diff --git a/arch/arm/src/find_exidx.c b/arch/arm/src/find_exidx.c
new file mode 100644 (file)
index 0000000..77c4472
--- /dev/null
+++ b/arch/arm/src/find_exidx.c
@@ -0,0 +1,42 @@
+#define _GNU_SOURCE
+#include <link.h>
+#include <stdint.h>
+
+struct find_exidx_data {
+       uintptr_t pc, exidx_start;
+       int exidx_len;
+};
+
+static int find_exidx(struct dl_phdr_info *info, size_t size, void *ptr)
+{
+       struct find_exidx_data *data = ptr;
+       const ElfW(Phdr) *phdr = info->dlpi_phdr;
+       uintptr_t addr, exidx_start = 0;
+       int i, match = 0, exidx_len = 0;
+
+       for (i = info->dlpi_phnum; i > 0; i--, phdr++) {
+               addr = info->dlpi_addr + phdr->p_vaddr;
+               switch (phdr->p_type) {
+               case PT_LOAD:
+                       match |= data->pc >= addr && data->pc < addr + phdr->p_memsz;
+                       break;
+               case PT_ARM_EXIDX:
+                       exidx_start = addr;
+                       exidx_len = phdr->p_memsz;
+                       break;
+               }
+       }
+       data->exidx_start = exidx_start;
+       data->exidx_len = exidx_len;
+       return match;
+}
+
+uintptr_t __gnu_Unwind_Find_exidx(uintptr_t pc, int *pcount)
+{
+       struct find_exidx_data data;
+       data.pc = pc;
+       if (dl_iterate_phdr(find_exidx, &data) <= 0)
+               return 0;
+       *pcount = data.exidx_len / 8;
+       return data.exidx_start;
+}