[PATCH] backends: add checks for _GLOBAL_OFFSET_TABLE_ and __global_pointer$ on riscv
Andreas Schwab
schwab@suse.de
Tue May 15 11:47:00 GMT 2018
Signed-off-by: Andreas Schwab <schwab@suse.de>
---
backends/ChangeLog | 5 +++++
backends/riscv_init.c | 1 +
backends/riscv_symbol.c | 32 ++++++++++++++++++++++++++++++++
3 files changed, 38 insertions(+)
diff --git a/backends/ChangeLog b/backends/ChangeLog
index 63bb7e444e..0dde0ff3f5 100644
--- a/backends/ChangeLog
+++ b/backends/ChangeLog
@@ -1,3 +1,8 @@
+2018-05-15 Andreas Schwab <schwab@suse.de>
+
+ * riscv_init.c (riscv_init): Hook check_special_symbol.
+ * riscv_symbol.c (riscv_check_special_symbol): New function.
+
2018-04-19 Andreas Schwab <schwab@suse.de>
* Makefile.am (modules): Add riscv.
diff --git a/backends/riscv_init.c b/backends/riscv_init.c
index 0203eac8b8..4234cded2b 100644
--- a/backends/riscv_init.c
+++ b/backends/riscv_init.c
@@ -52,6 +52,7 @@ riscv_init (Elf *elf __attribute__ ((unused)),
riscv_init_reloc (eh);
HOOK (eh, register_info);
HOOK (eh, reloc_simple_type);
+ HOOK (eh, check_special_symbol);
HOOK (eh, machine_flag_check);
return MODVERSION;
diff --git a/backends/riscv_symbol.c b/backends/riscv_symbol.c
index 628e0572ae..dce8e3586b 100644
--- a/backends/riscv_symbol.c
+++ b/backends/riscv_symbol.c
@@ -60,3 +60,35 @@ riscv_machine_flag_check (GElf_Word flags)
return ((flags &~ (EF_RISCV_RVC
| EF_RISCV_FLOAT_ABI)) == 0);
}
+
+/* Check whether given symbol's st_value and st_size are OK despite failing
+ normal checks. */
+bool
+riscv_check_special_symbol (Elf *elf, GElf_Ehdr *ehdr, const GElf_Sym *sym,
+ const char *name, const GElf_Shdr *destshdr)
+{
+ if (name == NULL)
+ return false;
+
+ const char *sname = elf_strptr (elf, ehdr->e_shstrndx, destshdr->sh_name);
+ if (sname == NULL)
+ return false;
+
+ /* _GLOBAL_OFFSET_TABLE_ points to the start of the .got section, but it
+ is preceded by the .got.plt section in the output .got section. */
+ if (strcmp (name, "_GLOBAL_OFFSET_TABLE_") == 0)
+ return (strcmp (sname, ".got") == 0
+ && sym->st_value >= destshdr->sh_addr
+ && sym->st_value < destshdr->sh_addr + destshdr->sh_size);
+
+ /* __global_pointer$ points to the .sdata section with an offset of
+ 0x800. It might however fall in the .got section, in which case we
+ cannot check the offset. The size always should be zero. */
+ if (strcmp (name, "__global_pointer$") == 0)
+ return (((strcmp (sname, ".sdata") == 0
+ && sym->st_value == destshdr->sh_addr + 0x800)
+ || strcmp (sname, ".got") == 0)
+ && sym->st_size == 0);
+
+ return false;
+}
--
2.17.0
--
Andreas Schwab, SUSE Labs, schwab@suse.de
GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE 1748 E4D4 88E3 0EEA B9D7
"And now for something completely different."
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