From ae5fe7e6bca2874c5f1ef077204bb63124fb3db3 Mon Sep 17 00:00:00 2001
From: Chris Johns <chrisj@rtems.org>
Date: Sun, 26 Oct 2014 18:09:41 -0700
Subject: cpukit: Add libdl with the Runtime Loader (RTL) code.

This is a merge of the RTL project.
---
 cpukit/libdl/rtl-mdreloc-arm.c | 323 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 323 insertions(+)
 create mode 100644 cpukit/libdl/rtl-mdreloc-arm.c

(limited to 'cpukit/libdl/rtl-mdreloc-arm.c')

diff --git a/cpukit/libdl/rtl-mdreloc-arm.c b/cpukit/libdl/rtl-mdreloc-arm.c
new file mode 100644
index 0000000000..692c8297a8
--- /dev/null
+++ b/cpukit/libdl/rtl-mdreloc-arm.c
@@ -0,0 +1,323 @@
+/*
+ * Taken from NetBSD and stripped of the relocations not needed on RTEMS.
+ */
+
+/*  $NetBSD: mdreloc.c,v 1.33 2010/01/14 12:12:07 skrll Exp $  */
+
+#include <sys/cdefs.h>
+
+#include <errno.h>
+#include <stdio.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+
+#include <rtems/rtl/rtl.h>
+#include "rtl-elf.h"
+#include "rtl-error.h"
+#include "rtl-trace.h"
+
+/*
+ * It is possible for the compiler to emit relocations for unaligned data.
+ * We handle this situation with these inlines.
+ */
+#define	RELOC_ALIGNED_P(x) \
+	(((uintptr_t)(x) & (sizeof(void *) - 1)) == 0)
+
+static inline Elf_Addr
+load_ptr(void *where)
+{
+	Elf_Addr res;
+
+	memcpy(&res, where, sizeof(res));
+
+	return (res);
+}
+
+static inline void
+store_ptr(void *where, Elf_Addr val)
+{
+
+	memcpy(where, &val, sizeof(val));
+}
+
+/*
+ * The address of Thumb function symbols is it's real address plus one.
+ * This is done by compiler, thus do not consider symtype here.
+ */
+static inline int
+isThumb(Elf_Word symvalue)
+{
+  if ((symvalue & 0x1) == 0x1)
+    return true;
+  else return false;
+}
+
+bool
+rtems_rtl_elf_rel_resolve_sym (Elf_Word type)
+{
+  return true;
+}
+
+bool
+rtems_rtl_elf_relocate_rela (const rtems_rtl_obj_t*      obj,
+                             const Elf_Rela*             rela,
+                             const rtems_rtl_obj_sect_t* sect,
+                             const char*                 symname,
+                             const Elf_Byte              syminfo,
+                             const Elf_Word              symvalue)
+{
+  rtems_rtl_set_error (EINVAL, "rela type record not supported");
+  return false;
+}
+
+bool
+rtems_rtl_elf_relocate_rel (const rtems_rtl_obj_t*      obj,
+                            const Elf_Rel*              rel,
+                            const rtems_rtl_obj_sect_t* sect,
+                            const char*                 symname,
+                            const Elf_Byte              syminfo,
+                            const Elf_Word              symvalue)
+{
+  Elf_Addr *where;
+  Elf_Addr tmp;
+  Elf_Word insn, addend;
+  Elf_Word sign, i1, i2;
+  uint16_t lower_insn, upper_insn;
+
+  where = (Elf_Addr *)(sect->base + rel->r_offset);
+
+  switch (ELF_R_TYPE(rel->r_info)) {
+		case R_TYPE(NONE):
+			break;
+
+    case R_TYPE(CALL):    /* BL/BLX */
+    case R_TYPE(JUMP24):  /* B/BL<cond> */
+      insn = *where;
+
+      if (insn & 0x00800000)
+        addend = insn | 0xff000000;
+      else addend = insn & 0x00ffffff;
+
+      if (isThumb(symvalue)) {
+        if ((insn & 0xfe000000) == 0xfa000000);         /* Already blx */
+        else {
+          if ((insn & 0xff000000) == 0xeb000000) {      /* BL <label> */
+            *where = (insn & 0x00ffffff) | 0xfa000000;  /* BL-->BLX */
+          } else {
+            printf("JUMP24 is not suppored from arm to thumb\n");
+            return false;
+          }
+        }
+      }
+
+      tmp = symvalue + (addend << 2) - (Elf_Addr)where;
+      tmp = (Elf_Sword)tmp >> 2;
+
+      if (((Elf_Sword)tmp > 0x7fffff) || ((Elf_Sword)tmp < -0x800000)) {
+        printf("CALL/JUMP24 Overflow\n");
+        return false;
+      }
+
+      *where = (*where & 0xff000000) | (tmp & 0xffffff);
+
+      if (rtems_rtl_trace (RTEMS_RTL_TRACE_RELOC))
+        printf ("rtl: JUMP24/PC24/CALL %p @ %p in %s\n",
+                (void *)*where, where, rtems_rtl_obj_oname (obj));
+
+      break;
+
+    case R_TYPE(V4BX):
+      /* Miscellaneous, ignore */
+      if (rtems_rtl_trace (RTEMS_RTL_TRACE_RELOC)) {
+        printf ("rtl: V4BX %p @ %p in %s\n",
+                (void *)*where, where, rtems_rtl_obj_oname (obj));
+      }
+      break;
+
+    case R_TYPE(MOVT_ABS):
+    case R_TYPE(MOVW_ABS_NC):
+      insn = *where;
+
+      addend = ((insn >> 4) & 0xf000) | (insn & 0x0fff);
+      if (addend & 0x8000)
+        addend |= 0xffff0000;
+
+      tmp = symvalue + addend;
+
+      if (ELF_R_TYPE(rel->r_info) == R_TYPE(MOVW_ABS_NC))
+        tmp &= 0xffff;
+      else {
+        tmp = (Elf_Sword)tmp >> 16;
+        if (((Elf_Sword)tmp > 0x7fff) || ((Elf_Sword)tmp < -0x8000)) {
+          printf("MOVT_ABS Overflow\n");
+          return false;
+        }
+      }
+
+      *where = (insn & 0xfff0f000) | ((tmp & 0xf000) << 4) | (tmp & 0xfff);
+
+      if (rtems_rtl_trace (RTEMS_RTL_TRACE_RELOC))
+        printf ("rtl: MOVT_ABS/MOVW_ABS_NC %p @ %p in %s\n",
+                (void *)*where, where, rtems_rtl_obj_oname (obj));
+      break;
+
+
+    case R_TYPE(REL32):     /* word32 (S + A) | T - P */
+    case R_TYPE(ABS32):     /* word32 (S + A) | T */
+    case R_TYPE(GLOB_DAT):  /* word32 (S + A) | T */
+      if (__predict_true(RELOC_ALIGNED_P(where))) {
+        tmp = *where + symvalue;
+        if (isThumb(symvalue))
+          tmp |= 1;
+        if (ELF_R_TYPE(rel->r_info) == R_TYPE(REL32))
+          tmp -= (Elf_Addr)where;
+        *where = tmp;
+      } else {
+        tmp = load_ptr(where) + symvalue;
+        if (isThumb(symvalue))
+          tmp |= 1;
+        if (ELF_R_TYPE(rel->r_info) == R_TYPE(REL32))
+          tmp -= (Elf_Addr)where;
+        store_ptr(where, tmp);
+      }
+
+      if (rtems_rtl_trace (RTEMS_RTL_TRACE_RELOC))
+        printf ("rtl: REL32/ABS32/GLOB_DAT %p @ %p in %s",
+                (void *)tmp, where, rtems_rtl_obj_oname (obj));
+      break;
+
+    case R_TYPE(THM_MOVT_ABS):
+    case R_TYPE(THM_MOVW_ABS_NC):
+      upper_insn = *(uint16_t *)where;
+      lower_insn = *((uint16_t *)where + 1);
+
+      addend = ((upper_insn & 0x000f) << 12) | ((upper_insn & 0x0400) << 1) |
+               ((lower_insn & 0x7000) >> 4) | (lower_insn & 0x00ff);
+      addend = (addend ^ 0x8000) - 0x8000;
+
+      tmp = addend + symvalue;
+      if (ELF32_R_TYPE(rel->r_info) == R_ARM_THM_MOVT_ABS)
+        tmp >>= 16;
+
+      *(uint16_t *)where = (uint16_t)((upper_insn & 0xfbf0) |
+                                     ((tmp & 0xf000) >> 12) |
+                                     ((tmp & 0x0800) >> 1));
+      *((uint16_t *)where + 1) = (uint16_t)((lower_insn & 0x8f00) |
+                                           ((tmp & 0x0700) << 4) |
+                                           (tmp & 0x00ff));
+
+      if (rtems_rtl_trace (RTEMS_RTL_TRACE_RELOC)) {
+        printf ("rtl: THM_MOVT_ABS/THM_MOVW_ABS_NC %p @ %p in %s\n",
+                (void *)*where, where, rtems_rtl_obj_oname (obj));
+      }
+
+      break;
+
+    case R_TYPE(THM_JUMP24):
+      /* same to THM_CALL; insn b.w */
+    case R_TYPE(THM_CALL):
+      upper_insn = *(uint16_t *)where;
+      lower_insn = *((uint16_t *)where + 1);
+      sign = (upper_insn & (1 << 10)) >> 10;
+      i1 = ((lower_insn >> 13) & 1) ^ sign ? 0 : 1;
+      i2 = ((lower_insn >> 11) & 1) ^ sign ? 0 : 1;
+      tmp = (i1 << 23) | (i2 << 22) | ((upper_insn & 0x3ff) << 12) | ((lower_insn & 0x7ff) << 1);
+      addend = (tmp | ((sign ? 0 : 1) << 24)) - (1 << 24);
+
+      if (isThumb(symvalue)) ;/*Thumb to Thumb call, nothing to care */
+      else {
+        if (ELF_R_TYPE(rel->r_info) == R_TYPE(THM_JUMP24)) {
+          tmp = (tmp + 2) & ~3; /* aligned to 4 bytes only for JUMP24 */
+          printf("THM_JUMP24 to arm not supported\n");
+          return false;
+        }
+        else {
+          /* THM_CALL bl-->blx */
+          lower_insn &=~(1<<12);
+        }
+      }
+
+      tmp = symvalue + addend;
+      tmp = tmp - (Elf_Addr)where;
+
+      if (((Elf_Sword)tmp > 0x7fffff) || ((Elf_Sword)tmp < -0x800000)) {
+        printf("THM_CALL/JUMP24 overflow\n");
+        return false;
+      }
+
+      sign = (tmp >> 24) & 1;
+      *(uint16_t *)where = (uint16_t)((upper_insn & 0xf800) | (sign << 10) |
+                                     ((tmp >> 12) & 0x3ff));
+
+      *((uint16_t *)where + 1) = (uint16_t)((lower_insn & 0xd000)|
+                                           ((sign ^ (~(tmp >> 23) & 1)) << 13) |
+                                           ((sign ^ (~(tmp >> 22) & 1)) << 11) |
+                                           ((tmp >> 1) & 0x7ff));
+
+      if (rtems_rtl_trace (RTEMS_RTL_TRACE_RELOC)){
+        printf ("rtl: THM_CALL/JUMP24 %p @ %p in %s\n",
+                (void *)*where, where, rtems_rtl_obj_oname (obj));
+      }
+
+      break;
+
+    case R_TYPE(THM_JUMP19):
+
+      if (!isThumb(symvalue)) {
+        printf("THM_JUMP19 to arm not supported\n");
+        return false;
+      }
+
+      upper_insn = *(uint16_t *)where;
+      lower_insn = *((uint16_t *)where + 1);
+      sign = (upper_insn >> 10) & 0x1;
+
+      if ((((upper_insn & 0x3f) >> 7) & 0x7) == 0x7) {
+        printf("THM_JUMP19 failed\n");
+        return false; /*if cond <3:1> == '111', see Related codings in armv7a manual */
+      }
+
+      i1 = (lower_insn >> 13) & 0x1;
+      i2 = (lower_insn >> 11) & 0x1;
+
+      tmp = ((i2 << 19) | (i1 << 18) | ((upper_insn & 0x3f) << 12) | ((lower_insn & 0x7ff) << 1));
+      addend = (tmp | ((sign ? 0 : 1) << 20)) - (1 << 20);
+      tmp = symvalue + addend;
+
+      tmp = tmp - (Elf_Addr)where;
+
+      if (((Elf_Sword)tmp > 0x7ffffe) || ((Elf_Sword)tmp < -0x800000)) {
+        rtems_rtl_set_error (EINVAL, "%s: Overflow %ld "
+                             "THM_JUMP19 relocations",
+                             sect->name, (uint32_t) ELF_R_TYPE(rel->r_info));
+        return false;
+      }
+
+      sign = (tmp >> 20) & 0x1;
+      i2 = (tmp >> 19) & 0x1;
+      i1 = (tmp >> 18) & 0x1;
+
+      *(uint16_t*)where = (upper_insn & 0xfbc0) | (sign << 10) | ((tmp >> 12) & 0x3f);
+      *((uint16_t*)where + 1) = (lower_insn & 0xd000) | (i1 << 13) |
+                                (i2 << 11) | ((tmp >> 1) & 0x7ff);
+
+      if (rtems_rtl_trace (RTEMS_RTL_TRACE_RELOC))
+        printf ("rtl: THM_JUMP19 %p @ %p in %s\n",
+                (void *)*where, where, rtems_rtl_obj_oname (obj));
+      break;
+
+		default:
+      printf ("rtl: reloc unknown: sym = %lu, type = %lu, offset = %p, "
+              "contents = %p\n",
+              ELF_R_SYM(rel->r_info), (uint32_t) ELF_R_TYPE(rel->r_info),
+              (void *)rel->r_offset, (void *)*where);
+      rtems_rtl_set_error (EINVAL,
+                           "%s: Unsupported relocation type %ld "
+                           "in non-PLT relocations",
+                           sect->name, (uint32_t) ELF_R_TYPE(rel->r_info));
+			return false;
+  }
+
+	return true;
+}
+
-- 
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