Align not only VDSO entries as on timens VDSO, but also addresses of
local functions. Otherwise, ld will put them after everything else
into *(.text*). That will result in common VDSO size bigger than
timens VDSO size (sic!).
Unfortunately, filtering by STB_WEAK doesn't work for ia32 VDSO:
by some reason gcc transforms weak symbols into local symbols in .so,
i.e.:
27: 00000000 219 FUNC WEAK DEFAULT 12 clock_gettime
29: 00000000 95 FUNC WEAK DEFAULT 14 gettimeofday
32: 00000000 40 FUNC WEAK DEFAULT 16 time
become:
20: 000006e0 219 FUNC LOCAL DEFAULT 12 clock_gettime
31: 000007c0 95 FUNC LOCAL DEFAULT 12 gettimeofday
33: 00000820 40 FUNC LOCAL DEFAULT 12 time
that results in the same align for two functions in .entries file:
. = ABSOLUTE(0x6e0);
*(.text.__vdso_clock_gettime*)
. = ABSOLUTE(0x6e0);
*(.text.clock_gettime*)
As result, ld becomes a very sad animal and refuses to cooperate:
ld:arch/x86/entry/vdso/vdso32/vdso32.lds:339 cannot move location counter backwards (from 0000000000000762 to 00000000000006e0)
Align local functions on VDSO to timens VDSO and filter weak functions
from .lds script.
Signed-off-by: Dmitry Safonov <dima@xxxxxxxxxx>
---
arch/x86/entry/vdso/vdso2c.h | 15 +++++++++++++--
1 file changed, 13 insertions(+), 2 deletions(-)
diff --git a/arch/x86/entry/vdso/vdso2c.h b/arch/x86/entry/vdso/vdso2c.h
index 50566dd94451..7096710140fe 100644
--- a/arch/x86/entry/vdso/vdso2c.h
+++ b/arch/x86/entry/vdso/vdso2c.h
@@ -15,7 +15,7 @@ static void BITSFUNC(go)(void *raw_addr, size_t raw_len,
unsigned long mapping_size;
ELF(Ehdr) *hdr = (ELF(Ehdr) *)raw_addr;
unsigned int i, syms_nr;
- unsigned long j;
+ unsigned long j, last_entry_addr;
ELF(Shdr) *symtab_hdr = NULL, *strtab_hdr, *secstrings_hdr,
*alt_sec = NULL;
ELF(Dyn) *dyn = 0, *dyn_end = 0;
@@ -121,7 +121,7 @@ static void BITSFUNC(go)(void *raw_addr, size_t raw_len,
if (!out_entries_lds)
continue;
- if (ELF_FUNC(ST_BIND, sym->st_info) != STB_GLOBAL)
+ if (ELF_FUNC(ST_BIND, sym->st_info) == STB_WEAK)
continue;
if (ELF_FUNC(ST_TYPE, sym->st_info) != STT_FUNC)
@@ -134,8 +134,19 @@ static void BITSFUNC(go)(void *raw_addr, size_t raw_len,
qsort(entries, next_entry - entries, sizeof(*entries), entry_addr_cmp);
+ last_entry_addr = -1UL;
while (next_entry != entries && out_entries_lds) {
next_entry--;
+
+ /*
+ * Unfortunately, WEAK symbols from objects are resoved
+ * into LOCAL symbols on ia32. Filter them here, as
+ * linker wouldn't like aligning the same symbol twice.
+ */
+ if (last_entry_addr == next_entry->addr)
+ continue;
+ last_entry_addr = next_entry->addr;
+
fprintf(out_entries_lds, "\t\t. = ABSOLUTE(%#lx);\n\t\t*(.text.%s*)\n",
next_entry->addr, next_entry->name);
}
--
2.20.1
