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Message-Id: <1373481699-17888-1-git-send-email-timo.teras@iki.fi>
Date: Wed, 10 Jul 2013 21:41:39 +0300
From: Timo Teräs <timo.teras@....fi>
To: musl@...ts.openwall.com
Cc: Timo Teräs <timo.teras@....fi>
Subject: [PATCH v2] Unwind support for ARM EABI
ARM EABI does not use the .eh_frame and .eh_frame_hdr for unwinding.
Instead the ABI specifies it's own way to unwind using .ARM.exidx and
.ARM.extab.
libgcc uses __gnu_Unwind_Find_exidx (libc must implement this) when
unwinding using exidx. This function is implemented here.
---
arch/arm/src/find_exidx.c | 46 ++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 46 insertions(+)
create mode 100644 arch/arm/src/find_exidx.c
diff --git a/arch/arm/src/find_exidx.c b/arch/arm/src/find_exidx.c
new file mode 100644
index 0000000..8ba9f30
--- /dev/null
+++ b/arch/arm/src/find_exidx.c
@@ -0,0 +1,46 @@
+#define _GNU_SOURCE
+#include <link.h>
+#include <stdint.h>
+
+typedef uintptr_t _Unwind_Ptr;
+
+struct find_exidx_data {
+ _Unwind_Ptr 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;
+ _Unwind_Ptr 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;
+ }
+ }
+ if (match) {
+ data->exidx_start = exidx_start;
+ data->exidx_len = exidx_len;
+ }
+ return match;
+}
+
+_Unwind_Ptr __gnu_Unwind_Find_exidx(_Unwind_Ptr 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;
+}
--
1.8.3.2
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