[PATCH] bfd: check for truncation with R_RISCV_32 relocations

[Joseph Faulls <Joseph.Faulls@imgtec.com>]

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Relevant bug report: https://sourceware.org/bugzilla/show_bug.cgi?id=31318

With high addresses, these relocations can be truncated. In these cases,
throw an error instead of silently truncating.

bfd/
        * elfnn-riscv.c (perform_relocation): Check for overflow.

ld/
        * ld/testsuite/ld-riscv-elf/ld-riscv-elf.exp: Updated.
        * ld/testsuite/ld-riscv-elf/data-reloc-rv64-abs32-truncation.d:
          New test case.
---
bfd/elfnn-riscv.c                                            | 3 +++
ld/testsuite/ld-riscv-elf/data-reloc-rv64-abs32-truncation.d | 4 ++++
ld/testsuite/ld-riscv-elf/ld-riscv-elf.exp                   | 1 +
3 files changed, 8 insertions(+)
create mode 100644 ld/testsuite/ld-riscv-elf/data-reloc-rv64-abs32-truncation.d

diff --git a/bfd/elfnn-riscv.c b/bfd/elfnn-riscv.c
index 8b27e3b8d6a..975b40e5f53 100644
--- a/bfd/elfnn-riscv.c
+++ b/bfd/elfnn-riscv.c
@@ -1865,6 +1865,9 @@ perform_relocation (const reloc_howto_type *howto,
       }

     case R_RISCV_32:
+      if (value & ~howto->dst_mask)
+       return bfd_reloc_overflow;
+      break;
     case R_RISCV_64:
     case R_RISCV_ADD8:
     case R_RISCV_ADD16:
diff --git a/ld/testsuite/ld-riscv-elf/data-reloc-rv64-abs32-truncation.d b/ld/testsuite/ld-riscv-elf/data-reloc-rv64-abs32-truncation.d
new file mode 100644
index 00000000000..925d1cdb662
--- /dev/null
+++ b/ld/testsuite/ld-riscv-elf/data-reloc-rv64-abs32-truncation.d
@@ -0,0 +1,4 @@
+#source: data-reloc.s
+#as: -march=rv64i -mabi=lp64 -defsym __abs__=1
+#ld: -m[riscv_choose_lp64_emul] -Ttext 0x8000 --defsym _start=0x0 --defsym abs=0xc00000100 --defsym abs_local=0x200
+#error: .*relocation truncated to fit: R_RISCV_32
diff --git a/ld/testsuite/ld-riscv-elf/ld-riscv-elf.exp b/ld/testsuite/ld-riscv-elf/ld-riscv-elf.exp
index 7e1281d826b..5a4d8728366 100644
--- a/ld/testsuite/ld-riscv-elf/ld-riscv-elf.exp
+++ b/ld/testsuite/ld-riscv-elf/ld-riscv-elf.exp
@@ -175,6 +175,7 @@ if [istarget "riscv*-*-*"] {
     run_dump_test "uleb128"
     run_dump_test "pr31179"
     run_dump_test "pr31179-r"
+    run_dump_test "data-reloc-rv64-abs32-truncation"
     run_ld_link_tests [list \
        [list "Weak reference 32" "-T weakref.ld -m[riscv_choose_ilp32_emul]" "" \
            "-march=rv32i -mabi=ilp32" {weakref32.s} \
--
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