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authorFlorian Weimer <fweimer@redhat.com>2016-12-02 16:52:57 +0100
committerFlorian Weimer <fweimer@redhat.com>2016-12-02 16:52:57 +0100
commit67aae64512cb42332f76a83e84ac2bc608ad4ad2 (patch)
treef53b04d34129d9f7b60ce44dfb7c0ac06329ed12
parent8068094f6e2b3d29acbed8d738deaaf5cae5e320 (diff)
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aarch64: Use explicit offsets in _dl_tlsdesc_dynamic
Commit 389d1f1b232b3d6b9d73ee2c50e543ace6675621 (“Partial ILP32
support for aarch64”) broke dynamic TLS support because a load
offset changed:

 0000000000000030 <_dl_tlsdesc_dynamic>:
   30:  a9bc7bfd        stp     x29, x30, [sp,#-64]!
   34:  910003fd        mov     x29, sp
   38:  a9020be1        stp     x1, x2, [sp,#32]
   3c:  a90313e3        stp     x3, x4, [sp,#48]
   40:  d53bd044        mrs     x4, tpidr_el0
   44:  c8dffc1f        ldar    xzr, [x0]
   48:  f9400401        ldr     x1, [x0,#8]
   4c:  f9400080        ldr     x0, [x4]
   50:  f9400823        ldr     x3, [x1,#16]
   54:  f9400002        ldr     x2, [x0]
   58:  eb02007f        cmp     x3, x2
   5c:  540001a8        b.hi    90 <_dl_tlsdesc_dynamic+0x60>
   60:  f9400022        ldr     x2, [x1]
   64:  8b021000        add     x0, x0, x2, lsl #4
   68:  f9400000        ldr     x0, [x0]
   6c:  b100041f        cmn     x0, #0x1
   70:  54000100        b.eq    90 <_dl_tlsdesc_dynamic+0x60>
-  74:  f9400421        ldr     x1, [x1,#8]
+  74:  f9400821        ldr     x1, [x1,#16]
   78:  8b010000        add     x0, x0, x1
…

This commit introduces explicit struct offsets, generated
from the C headers, fixing the regression.
-rw-r--r--ChangeLog7
-rw-r--r--sysdeps/aarch64/dl-tlsdesc.S18
-rw-r--r--sysdeps/aarch64/tlsdesc.sym3
3 files changed, 19 insertions, 9 deletions
diff --git a/ChangeLog b/ChangeLog
index 1be316c072..f75137bbea 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2016-12-02  Florian Weimer  <fweimer@redhat.com>
+
+	* sysdeps/aarch64/tlsdesc.sym (TCBHEAD_DTV, DTV_COUNTER)
+	(TLS_DTV_UNALLOCATED): Add.
+	* sysdeps/aarch64/dl-tlsdesc.S (_dl_tlsdesc_dynamic): Use explicit
+	offsets.
+
 2016-12-02  Stefan Liebler  <stli@linux.vnet.ibm.com>
 
 	* sysdeps/s390/fpu/libm-test-ulps: Regenerated.
diff --git a/sysdeps/aarch64/dl-tlsdesc.S b/sysdeps/aarch64/dl-tlsdesc.S
index 42fa943859..9e557dd134 100644
--- a/sysdeps/aarch64/dl-tlsdesc.S
+++ b/sysdeps/aarch64/dl-tlsdesc.S
@@ -154,7 +154,7 @@ _dl_tlsdesc_undefweak:
 	   _dl_tlsdesc_dynamic (struct tlsdesc *tdp)
 	   {
 	     struct tlsdesc_dynamic_arg *td = tdp->arg;
-	     dtv_t *dtv = *(dtv_t **)((char *)__thread_pointer + DTV_OFFSET);
+	     dtv_t *dtv = *(dtv_t **)((char *)__thread_pointer + TCBHEAD_DTV);
 	     if (__builtin_expect (td->gen_count <= dtv[0].counter
 		&& (dtv[td->tlsinfo.ti_module].pointer.val
 		    != TLS_DTV_UNALLOCATED),
@@ -193,18 +193,18 @@ _dl_tlsdesc_dynamic:
 	   td->entry in _dl_tlsdesc_resolve_rela_fixup ensuring that the load
 	   from [x0,#PTR_SIZE] here happens after the initialization of td->arg.  */
 	ldar	PTR_REG (zr), [x0]
-	ldr	PTR_REG (1), [x0,#PTR_SIZE]
-	ldr	PTR_REG (0), [x4]
-	ldr	PTR_REG (3), [x1,#(PTR_SIZE * 2)]
-	ldr	PTR_REG (2), [x0]
+	ldr	PTR_REG (1), [x0,#TLSDESC_ARG]
+	ldr	PTR_REG (0), [x4,#TCBHEAD_DTV]
+	ldr	PTR_REG (3), [x1,#TLSDESC_GEN_COUNT]
+	ldr	PTR_REG (2), [x0,#DTV_COUNTER]
 	cmp	PTR_REG (3), PTR_REG (2)
 	b.hi	2f
-	ldr	PTR_REG (2), [x1]
+	ldr	PTR_REG (2), [x1,#TLSDESC_MODID]
 	add	PTR_REG (0), PTR_REG (0), PTR_REG (2), lsl #(PTR_LOG_SIZE + 1)
-	ldr	PTR_REG (0), [x0]
-	cmn	x0, #0x1
+	ldr	PTR_REG (0), [x0] /* Load val member of DTV entry.  */
+	cmp	x0, #TLS_DTV_UNALLOCATED
 	b.eq	2f
-	ldr	PTR_REG (1), [x1,#(PTR_SIZE * 2)]
+	ldr	PTR_REG (1), [x1,#TLSDESC_MODOFF]
 	add	PTR_REG (0), PTR_REG (0), PTR_REG (1)
 	sub	PTR_REG (0), PTR_REG (0), PTR_REG (4)
 1:
diff --git a/sysdeps/aarch64/tlsdesc.sym b/sysdeps/aarch64/tlsdesc.sym
index 63766af612..a06a719779 100644
--- a/sysdeps/aarch64/tlsdesc.sym
+++ b/sysdeps/aarch64/tlsdesc.sym
@@ -13,3 +13,6 @@ TLSDESC_ARG			offsetof(struct tlsdesc, arg)
 TLSDESC_GEN_COUNT	offsetof(struct tlsdesc_dynamic_arg, gen_count)
 TLSDESC_MODID		offsetof(struct tlsdesc_dynamic_arg, tlsinfo.ti_module)
 TLSDESC_MODOFF		offsetof(struct tlsdesc_dynamic_arg, tlsinfo.ti_offset)
+TCBHEAD_DTV		offsetof(tcbhead_t, dtv)
+DTV_COUNTER		offsetof(dtv_t, counter)
+TLS_DTV_UNALLOCATED	TLS_DTV_UNALLOCATED