This is the mail archive of the
libc-ports@sources.redhat.com
mailing list for the libc-ports project.
[PATCH v2 02/14] arm: Introduce and use NEGOFF series of macros
- From: Richard Henderson <rth at twiddle dot net>
- To: libc-ports at sourceware dot org
- Cc: joseph at codesourcery dot com
- Date: Fri, 1 Mar 2013 09:35:08 -0800
- Subject: [PATCH v2 02/14] arm: Introduce and use NEGOFF series of macros
- References: <1362159320-5934-1-git-send-email-rth@twiddle.net>
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 ++++++-----
ports/sysdeps/unix/sysv/linux/arm/nptl/sysdep-cancel.h | 3 ++-
ports/sysdeps/unix/sysv/linux/arm/nptl/vfork.S | 14 ++++++++------
5 files changed, 35 insertions(+), 14 deletions(-)
diff --git a/ports/sysdeps/arm/sysdep.h b/ports/sysdeps/arm/sysdep.h
index 29a78f0..9230131 100644
--- a/ports/sysdeps/arm/sysdep.h
+++ b/ports/sysdeps/arm/sysdep.h
@@ -134,6 +134,22 @@
.previous; \
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__ */
/* This number is the offset from the pc at the current location. */
diff --git a/ports/sysdeps/unix/sysv/linux/arm/clone.S b/ports/sysdeps/unix/sysv/linux/arm/clone.S
index 732a3ff..a5f9b4d 100644
--- a/ports/sysdeps/unix/sysv/linux/arm/clone.S
+++ b/ports/sysdeps/unix/sysv/linux/arm/clone.S
@@ -83,8 +83,9 @@ 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 a38d564..ff88510 100644
--- a/ports/sysdeps/unix/sysv/linux/arm/nptl/pt-vfork.S
+++ b/ports/sysdeps/unix/sysv/linux/arm/nptl/pt-vfork.S
@@ -28,14 +28,15 @@
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 8889369..47d4c70 100644
--- a/ports/sysdeps/unix/sysv/linux/arm/nptl/sysdep-cancel.h
+++ b/ports/sysdeps/unix/sysv/linux/arm/nptl/sysdep-cancel.h
@@ -217,7 +217,8 @@ extern int __local_multiple_threads attribute_hidden;
cfi_adjust_cfa_offset (8); \
cfi_rel_offset (lr, 4); \
bl __aeabi_read_tp; \
- ldr ip, [r0, #MULTIPLE_THREADS_OFFSET]; \
+ 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); \
diff --git a/ports/sysdeps/unix/sysv/linux/arm/nptl/vfork.S b/ports/sysdeps/unix/sysv/linux/arm/nptl/vfork.S
index 3fce2d1..c4be1e2 100644
--- a/ports/sysdeps/unix/sysv/linux/arm/nptl/vfork.S
+++ b/ports/sysdeps/unix/sysv/linux/arm/nptl/vfork.S
@@ -28,15 +28,17 @@
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