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authorRich Felker <dalias@aerifal.cx>2015-09-12 03:10:44 +0000
committerRich Felker <dalias@aerifal.cx>2015-09-12 03:10:44 +0000
commit6d03c4ee586576bf199cf8d6dc86ba4cd54e4186 (patch)
tree2bd7197c16633f897d1e13a162ed2321efede9c4 /src
parent234c58467c3709bafdd3ffa6ac73655e1dfd9ddb (diff)
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provide arch-generic fdpic self-relocation code for crt1 to use
this file is intended to be included by crt_arch.h on fdpic-based targets and needs to be called from the entry point asm.
Diffstat (limited to 'src')
-rw-r--r--src/internal/fdpic_crt.h28
1 files changed, 28 insertions, 0 deletions
diff --git a/src/internal/fdpic_crt.h b/src/internal/fdpic_crt.h
new file mode 100644
index 00000000..7eb50c6b
--- /dev/null
+++ b/src/internal/fdpic_crt.h
@@ -0,0 +1,28 @@
+#include <stdint.h>
+
+__attribute__((__visibility__("hidden")))
+void *__fdpic_fixup(void *map, uintptr_t *a, uintptr_t *z)
+{
+ /* If map is a null pointer, the program was loaded by a
+ * non-FDPIC-aware ELF loader, and fixups are not needed,
+ * but the value for the GOT pointer is. */
+ if (!map) return (void *)z[-1];
+
+ struct {
+ unsigned short version, nsegs;
+ struct fdpic_loadseg {
+ uintptr_t addr, p_vaddr, p_memsz;
+ } segs[];
+ } *lm = map;
+ int nsegs = lm->nsegs, rseg = 0, vseg = 0;
+ for (;;) {
+ while (*a-lm->segs[rseg].p_vaddr >= lm->segs[rseg].p_memsz)
+ if (++rseg == nsegs) rseg = 0;
+ uintptr_t *r = (uintptr_t *)
+ (*a + lm->segs[rseg].addr - lm->segs[rseg].p_vaddr);
+ if (++a == z) return r;
+ while (*r-lm->segs[vseg].p_vaddr >= lm->segs[vseg].p_memsz)
+ if (++vseg == nsegs) vseg = 0;
+ *r += lm->segs[vseg].addr - lm->segs[vseg].p_vaddr;
+ }
+}