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[PATCH v2 01/14] arm: Introduce and use LDST_PCREL
- 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 09:35:07 -0800
- Subject: [PATCH v2 01/14] arm: Introduce and use LDST_PCREL
- References: <1362159320-5934-1-git-send-email-rth@twiddle.net>
Macro-ising the few instances where we need to distinguish between
arm and thumb pc-relative memory operations.
---
* sysdeps/arm/sysdep.h (LDST_PCREL): New macro.
* sysdeps/unix/arm/sysdep.S (__syscall_error): Use LDST_PCREL.
Fix up gottpoff load of errno for thumb2.
* sysdeps/unix/sysv/linux/arm/nptl/sysdep-cancel.h
(SINGLE_THREAD_P): Use LDST_PCREL.
(PSEUDO_PROLOGUE): Remove.
(PSEUDO): Don't use it.
* sysdeps/unix/sysv/linux/arm/sysdep.h (SYSCALL_ERROR_HANDLER):
Use LDST_PCREL.
---
ports/sysdeps/arm/sysdep.h | 17 +++++++++++++++++
ports/sysdeps/unix/arm/sysdep.S | 22 ++++++++++++----------
.../unix/sysv/linux/arm/nptl/sysdep-cancel.h | 10 ++--------
ports/sysdeps/unix/sysv/linux/arm/sysdep.h | 10 ++++------
4 files changed, 35 insertions(+), 24 deletions(-)
diff --git a/ports/sysdeps/arm/sysdep.h b/ports/sysdeps/arm/sysdep.h
index 4af7429..29a78f0 100644
--- a/ports/sysdeps/arm/sysdep.h
+++ b/ports/sysdeps/arm/sysdep.h
@@ -117,6 +117,23 @@
the caller. */
.eabi_attribute 24, 1
+/* Load or store to/from a pc-relative EXPR into/from R, using T. */
+# ifdef __thumb2__
+# define LDST_PCREL(OP, R, T, EXPR) \
+ ldr T, 98f; \
+ .subsection 2; \
+98: .word EXPR - 99f - PC_OFS; \
+ .previous; \
+99: add T, T, pc; \
+ OP R, [T]
+# else
+# define LDST_PCREL(OP, R, T, EXPR) \
+ ldr T, 98f; \
+ .subsection 2; \
+98: .word EXPR - 99f - PC_OFS; \
+ .previous; \
+99: OP R, [pc, T]
+# endif
#endif /* __ASSEMBLER__ */
/* This number is the offset from the pc at the current location. */
diff --git a/ports/sysdeps/unix/arm/sysdep.S b/ports/sysdeps/unix/arm/sysdep.S
index 40e4d80..d44ee48 100644
--- a/ports/sysdeps/unix/arm/sysdep.S
+++ b/ports/sysdeps/unix/arm/sysdep.S
@@ -45,20 +45,22 @@ __syscall_error:
mov lr, pc
sub pc, r0, #31
- ldr r2, 1f
-2: ldr r2, [pc, r2]
- str r1, [r0, r2]
- mvn r0, #0
- RETINSTR (, ip)
+ ldr r2, 1f
+#ifdef __thumb__
+2: add r2, r2, pc
+ ldr r2, [r2]
+#else
+2: ldr r2, [pc, r2]
+#endif
+ str r1, [r0, r2]
+ mvn r0, #0
+ DO_RET(ip)
1: .word errno(gottpoff) + (. - 2b - PC_OFS)
#elif RTLD_PRIVATE_ERRNO
- ldr r1, 1f
-0: str r0, [pc, r1]
- mvn r0, $0
+ LDST_PCREL(str, r0, r1, C_SYMBOL_NAME(rtld_errno))
+ mvn r0, #0
DO_RET(r14)
-
-1: .word C_SYMBOL_NAME(rtld_errno) - 0b - PC_OFS
#else
#error "Unsupported non-TLS case"
#endif
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 df85d51..8889369 100644
--- a/ports/sysdeps/unix/sysv/linux/arm/nptl/sysdep-cancel.h
+++ b/ports/sysdeps/unix/sysv/linux/arm/nptl/sysdep-cancel.h
@@ -31,7 +31,6 @@
# undef PSEUDO
# define PSEUDO(name, syscall_name, args) \
.text; \
- PSEUDO_PROLOGUE; \
ENTRY (__##syscall_name##_nocancel); \
CFI_SECTIONS; \
DO_CALL (syscall_name, args); \
@@ -203,12 +202,8 @@ extern int __local_multiple_threads attribute_hidden;
# define SINGLE_THREAD_P __builtin_expect (__local_multiple_threads == 0, 1)
# else
# define SINGLE_THREAD_P \
- ldr ip, 1b; \
- 2: \
- ldr ip, [pc, ip]; \
- teq ip, #0;
-# define PSEUDO_PROLOGUE \
- 1: .word __local_multiple_threads - 2f - PC_OFS;
+ LDST_PCREL(ldr, ip, ip, __local_multiple_threads); \
+ teq ip, #0
# endif
# else
/* There is no __local_multiple_threads for librt, so use the TCB. */
@@ -217,7 +212,6 @@ extern int __local_multiple_threads attribute_hidden;
__builtin_expect (THREAD_GETMEM (THREAD_SELF, \
header.multiple_threads) == 0, 1)
# else
-# define PSEUDO_PROLOGUE
# define SINGLE_THREAD_P \
stmfd sp!, {r0, lr}; \
cfi_adjust_cfa_offset (8); \
diff --git a/ports/sysdeps/unix/sysv/linux/arm/sysdep.h b/ports/sysdeps/unix/sysv/linux/arm/sysdep.h
index f40cb95..89208a9 100644
--- a/ports/sysdeps/unix/sysv/linux/arm/sysdep.h
+++ b/ports/sysdeps/unix/sysv/linux/arm/sysdep.h
@@ -110,12 +110,10 @@
# if RTLD_PRIVATE_ERRNO
# define SYSCALL_ERROR_HANDLER \
__local_syscall_error: \
- ldr r1, 1f; \
- rsb r0, r0, #0; \
-0: str r0, [pc, r1]; \
- mvn r0, #0; \
- DO_RET(lr); \
-1: .word C_SYMBOL_NAME(rtld_errno) - 0b - PC_OFS;
+ rsb r0, r0, #0; \
+ LDST_PCREL(str, r0, r1, C_SYMBOL_NAME(rtld_errno)); \
+ mvn r0, #0; \
+ DO_RET(lr)
# else
# if defined(__ARM_ARCH_4T__) && defined(__THUMB_INTERWORK__)
# define POP_PC \
--
1.8.1.2