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[PATCH 11/26] arm: Introduce and use NEGOFF series of macros


There are several places in which we access negative offsets from
the thread-pointer, but thumb2 only supports positive offsets in
memory references.

Avoid duplicating the rather large macros in which these references
are embedded by abstracting out the operation.
---
	* sysdeps/arm/sysdep.h (NEGOFF_ADJ_BASE): New macro.
	(NEGOFF_ADJ_BASE2, NEGOFF_OFF1, NEGOFF_OFF2): New macros.
	* sysdeps/unix/sysv/linux/arm/clone.S (__clone): Use them.
	* sysdeps/unix/sysv/linux/arm/nptl/vfork.S: Likewise.
	* sysdeps/unix/sysv/linux/arm/nptl/pt-vfork.S: Likewise.
	* sysdeps/unix/sysv/linux/arm/nptl/sysdep-cancel.h (SINGLE_THREAD_P):
	Likewise.
---
 ports/sysdeps/arm/sysdep.h                            | 16 ++++++++++++++++
 ports/sysdeps/unix/sysv/linux/arm/clone.S             |  5 +++--
 ports/sysdeps/unix/sysv/linux/arm/nptl/pt-vfork.S     | 11 ++++++-----
 .../sysdeps/unix/sysv/linux/arm/nptl/sysdep-cancel.h  | 19 ++++++++++---------
 ports/sysdeps/unix/sysv/linux/arm/nptl/vfork.S        | 14 ++++++++------
 5 files changed, 43 insertions(+), 22 deletions(-)

diff --git a/ports/sysdeps/arm/sysdep.h b/ports/sysdeps/arm/sysdep.h
index b7ba9b1..2d40823 100644
--- a/ports/sysdeps/arm/sysdep.h
+++ b/ports/sysdeps/arm/sysdep.h
@@ -147,4 +147,20 @@
 99:	OP	R, [pc, T]
 #endif
 
+/* Cope with negative memory offsets, which thumb can't encode.
+   Use NEGOFF_ADJ_BASE to (conditionally) alter the base register,
+   and then NEGOFF_OFF1 to use 0 for thumb and the offset for arm,
+   or NEGOFF_OFF2 to use A-B for thumb and A for arm.  */
+#ifdef __thumb2__
+# define NEGOFF_ADJ_BASE(R, OFF)	add R, R, $OFF
+# define NEGOFF_ADJ_BASE2(D, S, OFF)	add D, S, $OFF
+# define NEGOFF_OFF1(R, OFF)		[R]
+# define NEGOFF_OFF2(R, OFFA, OFFB)	[R, $((OFFA) - (OFFB))]
+#else
+# define NEGOFF_ADJ_BASE(R, OFF)
+# define NEGOFF_ADJ_BASE2(D, S, OFF)	mov D, S
+# define NEGOFF_OFF1(R, OFF)		[R, $OFF]
+# define NEGOFF_OFF2(R, OFFA, OFFB)	[R, $OFFA]
+#endif
+
 #endif	/* __ASSEMBLER__ */
diff --git a/ports/sysdeps/unix/sysv/linux/arm/clone.S b/ports/sysdeps/unix/sysv/linux/arm/clone.S
index 9de37f2..58ee7b4 100644
--- a/ports/sysdeps/unix/sysv/linux/arm/clone.S
+++ b/ports/sysdeps/unix/sysv/linux/arm/clone.S
@@ -81,8 +81,9 @@ PSEUDO_END (__clone)
 	ite	ne
 	movne	r0, #-1
 	swieq	0x0
-	str	r0, [r1, #PID_OFFSET]
-	str	r0, [r1, #TID_OFFSET]
+	NEGOFF_ADJ_BASE(r1, TID_OFFSET)
+	str	r0, NEGOFF_OFF1(r1, TID_OFFSET)
+	str	r0, NEGOFF_OFF2(r1, PID_OFFSET, TID_OFFSET)
 3:
 #endif
 	@ pick the function arg and call address off the stack and execute
diff --git a/ports/sysdeps/unix/sysv/linux/arm/nptl/pt-vfork.S b/ports/sysdeps/unix/sysv/linux/arm/nptl/pt-vfork.S
index 749aaab..bc0a771 100644
--- a/ports/sysdeps/unix/sysv/linux/arm/nptl/pt-vfork.S
+++ b/ports/sysdeps/unix/sysv/linux/arm/nptl/pt-vfork.S
@@ -26,14 +26,15 @@
 	ldr	lr, [sp], #4;		/* Restore LR.  */		\
 	cfi_adjust_cfa_offset (-4);					\
 	cfi_restore (lr);						\
-	mov	r2, r0;			/* Save the TLS addr in r2.  */	\
-	ldr	r3, [r2, #PID_OFFSET];	/* Load the saved PID.  */	\
-	rsb	r0, r3, #0;		/* Negate it.  */		\
-	str	r0, [r2, #PID_OFFSET]	/* Store the temporary PID.  */
+	NEGOFF_ADJ_BASE2(r2, r0, PID_OFFSET); /* Save the TLS addr in r2. */ \
+	ldr	r3, NEGOFF_OFF1(r2, PID_OFFSET); /* Load the saved PID.  */  \
+	rsb	r0, r3, #0;		/* Negate it.  */		     \
+	str	r0, NEGOFF_OFF1(r2, PID_OFFSET); /* Store the temp PID.  */
 
 /* Restore the old PID value in the parent.  */
 #define RESTORE_PID \
 	cmp	r0, #0;			/* If we are the parent... */	\
-	strne	r3, [r2, #PID_OFFSET]	/* ... restore the saved PID.  */
+	it	ne;							\
+	strne	r3, NEGOFF_OFF1(r2, PID_OFFSET); /* restore the saved PID.  */
 
 #include "../vfork.S"
diff --git a/ports/sysdeps/unix/sysv/linux/arm/nptl/sysdep-cancel.h b/ports/sysdeps/unix/sysv/linux/arm/nptl/sysdep-cancel.h
index b6dc3e0..0c9e780 100644
--- a/ports/sysdeps/unix/sysv/linux/arm/nptl/sysdep-cancel.h
+++ b/ports/sysdeps/unix/sysv/linux/arm/nptl/sysdep-cancel.h
@@ -217,15 +217,16 @@ extern int __local_multiple_threads attribute_hidden;
 				   header.multiple_threads) == 0, 1)
 #  else
 #   define SINGLE_THREAD_P						\
-  stmfd	sp!, {r0, lr};							\
-  cfi_adjust_cfa_offset (8);						\
-  cfi_rel_offset (lr, 4);						\
-  bl	__aeabi_read_tp;						\
-  ldr	ip, [r0, #MULTIPLE_THREADS_OFFSET];				\
-  ldmfd	sp!, {r0, lr};							\
-  cfi_adjust_cfa_offset (-8);						\
-  cfi_restore (lr);							\
-  teq	ip, #0
+	stmfd	sp!, {r0, lr};						\
+	cfi_adjust_cfa_offset (8);					\
+	cfi_rel_offset (lr, 4);						\
+	bl	__aeabi_read_tp;					\
+	NEGOFF_ADJ_BASE(r0, MULTIPLE_THREADS_OFFSET);			\
+	ldr	ip, NEGOFF_OFF1(r0, MULTIPLE_THREADS_OFFSET);		\
+	ldmfd	sp!, {r0, lr};						\
+	cfi_adjust_cfa_offset (-8);					\
+	cfi_restore (lr);						\
+	teq	ip, #0
 #   define SINGLE_THREAD_P_PIC(x) SINGLE_THREAD_P
 #  endif
 # endif
diff --git a/ports/sysdeps/unix/sysv/linux/arm/nptl/vfork.S b/ports/sysdeps/unix/sysv/linux/arm/nptl/vfork.S
index 1bbe5c6..3c0ef78 100644
--- a/ports/sysdeps/unix/sysv/linux/arm/nptl/vfork.S
+++ b/ports/sysdeps/unix/sysv/linux/arm/nptl/vfork.S
@@ -26,15 +26,17 @@
 	ldr	lr, [sp], #4;		/* Restore LR.  */		\
 	cfi_adjust_cfa_offset (-4);					\
 	cfi_restore (lr);						\
-	mov	r2, r0;			/* Save the TLS addr in r2.  */	\
-	ldr	r3, [r2, #PID_OFFSET];	/* Load the saved PID.  */	\
-	rsbs	r0, r3, #0;		/* Negate it.  */		\
-	moveq	r0, #0x80000000;	/* Use 0x80000000 if it was 0.  */ \
-	str	r0, [r2, #PID_OFFSET]	/* Store the temporary PID.  */
+	NEGOFF_ADJ_BASE2(r2, r0, PID_OFFSET); /* Save the TLS addr in r2.  */ \
+	ldr	r3, NEGOFF_OFF1(r2, PID_OFFSET); /* Load the saved PID.  */   \
+	rsbs	r0, r3, #0;		/* Negate it.  */		      \
+	it	eq;							      \
+	moveq	r0, #0x80000000;	/* Use 0x80000000 if it was 0.  */    \
+	str	r0, NEGOFF_OFF1(r2, PID_OFFSET); /* Store the temp PID.  */
 
 /* Restore the old PID value in the parent.  */
 #define RESTORE_PID \
 	cmp	r0, #0;		/* If we are the parent... */		\
-	strne	r3, [r2, #PID_OFFSET]	/* ... restore the saved PID.  */
+	it	ne;							\
+	strne	r3, NEGOFF_OFF1(r2, PID_OFFSET); /* restore the saved PID.  */
 
 #include "../vfork.S"
-- 
1.8.1.2


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