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GNU C Library master sources branch roland/arm-avoid-pc created. glibc-2.17-354-g2779c87
- From: roland at sourceware dot org
- To: glibc-cvs at sourceware dot org
- Date: 6 Mar 2013 20:31:03 -0000
- Subject: GNU C Library master sources branch roland/arm-avoid-pc created. glibc-2.17-354-g2779c87
This is an automated email from the git hooks/post-receive script. It was
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the project "GNU C Library master sources".
The branch, roland/arm-avoid-pc has been created
at 2779c8799ffdc819e38e611362ef982572849b22 (commit)
- Log -----------------------------------------------------------------
http://sources.redhat.com/git/gitweb.cgi?p=glibc.git;a=commitdiff;h=2779c8799ffdc819e38e611362ef982572849b22
commit 2779c8799ffdc819e38e611362ef982572849b22
Author: Roland McGrath <roland@hack.frob.com>
Date: Wed Mar 6 12:30:21 2013 -0800
ARM_BX_ALIGN_LOG2
diff --git a/ports/ChangeLog.arm b/ports/ChangeLog.arm
index 5200c31..e03d0ac 100644
--- a/ports/ChangeLog.arm
+++ b/ports/ChangeLog.arm
@@ -1,5 +1,9 @@
2013-03-06 Roland McGrath <roland@hack.frob.com>
+ * sysdeps/arm/arm-features.h (ARM_BX_ALIGN_LOG2): New macro.
+ * sysdeps/arm/memcpy.S: Respect ARM_BX_ALIGN_LOG2.
+ * sysdeps/arm/memmove.S: Likewise.
+
* sysdeps/arm/arm-features.h: Add comment about ARM_ALWAYS_BX.
* sysdeps/arm/memcpy.S: Include <arm-features.h>.
[ARM_ALWAYS_BX]: Avoid pc as destination.
diff --git a/ports/sysdeps/arm/arm-features.h b/ports/sysdeps/arm/arm-features.h
index 139a403..921a1c7 100644
--- a/ports/sysdeps/arm/arm-features.h
+++ b/ports/sysdeps/arm/arm-features.h
@@ -40,4 +40,12 @@
that instructions using pc as a destination register must never be used,
so a "bx" (or "blx") instruction is always required. */
+/* The log2 of the minimum alignment required for an address that
+ is the target of a computed branch (i.e. a "bx" instruction).
+ A more-specific arm-features.h file may define this to set a more
+ stringent requirement. */
+#ifndef ARM_BX_ALIGN_LOG2
+# define ARM_BX_ALIGN_LOG2 2
+#endif
+
#endif /* arm-features.h */
diff --git a/ports/sysdeps/arm/memcpy.S b/ports/sysdeps/arm/memcpy.S
index 5df7cd2..556de0c 100644
--- a/ports/sysdeps/arm/memcpy.S
+++ b/ports/sysdeps/arm/memcpy.S
@@ -90,9 +90,9 @@ ENTRY(memcpy)
CALGN( adr r4, 6f )
CALGN( subs r2, r2, r3 ) @ C gets set
#ifndef ARM_ALWAYS_BX
- CALGN( add pc, r4, ip )
+ CALGN( add pc, r4, ip, lsl #(ARM_BX_ALIGN_LOG2 - 2))
#else
- CALGN( add r4, r4, ip )
+ CALGN( add r4, r4, ip, lsl #(ARM_BX_ALIGN_LOG2 - 2))
CALGN( bx r4 )
#endif
@@ -114,38 +114,55 @@ ENTRY(memcpy)
5: ands ip, r2, #28
rsb ip, ip, #32
#ifndef ARM_ALWAYS_BX
- addne pc, pc, ip @ C is always clear here
+ /* C is always clear here. */
+ addne pc, pc, ip, lsl #(ARM_BX_ALIGN_LOG2 - 2)
b 7f
#else
beq 7f
push {r10}
cfi_adjust_cfa_offset (4)
- add r10, pc, ip
+ add r10, pc, ip, lsl #(ARM_BX_ALIGN_LOG2 - 2)
bx r10
#endif
+ .p2align ARM_BX_ALIGN_LOG2
6: nop
+ .p2align ARM_BX_ALIGN_LOG2
ldr r3, [r1], #4
+ .p2align ARM_BX_ALIGN_LOG2
ldr r4, [r1], #4
+ .p2align ARM_BX_ALIGN_LOG2
ldr r5, [r1], #4
+ .p2align ARM_BX_ALIGN_LOG2
ldr r6, [r1], #4
+ .p2align ARM_BX_ALIGN_LOG2
ldr r7, [r1], #4
+ .p2align ARM_BX_ALIGN_LOG2
ldr r8, [r1], #4
+ .p2align ARM_BX_ALIGN_LOG2
ldr lr, [r1], #4
#ifndef ARM_ALWAYS_BX
- add pc, pc, ip
+ add pc, pc, ip, lsl #(ARM_BX_ALIGN_LOG2 - 2)
nop
#else
- add r10, pc, ip
+ add r10, pc, ip, lsl #(ARM_BX_ALIGN_LOG2 - 2)
bx r10
#endif
+ .p2align ARM_BX_ALIGN_LOG2
nop
+ .p2align ARM_BX_ALIGN_LOG2
str r3, [r0], #4
+ .p2align ARM_BX_ALIGN_LOG2
str r4, [r0], #4
+ .p2align ARM_BX_ALIGN_LOG2
str r5, [r0], #4
+ .p2align ARM_BX_ALIGN_LOG2
str r6, [r0], #4
+ .p2align ARM_BX_ALIGN_LOG2
str r7, [r0], #4
+ .p2align ARM_BX_ALIGN_LOG2
str r8, [r0], #4
+ .p2align ARM_BX_ALIGN_LOG2
str lr, [r0], #4
#ifdef ARM_ALWAYS_BX
diff --git a/ports/sysdeps/arm/memmove.S b/ports/sysdeps/arm/memmove.S
index e84050d..769d649 100644
--- a/ports/sysdeps/arm/memmove.S
+++ b/ports/sysdeps/arm/memmove.S
@@ -106,9 +106,9 @@ ENTRY(memmove)
CALGN( adr r4, 6f )
CALGN( subs r2, r2, ip ) @ C is set here
#ifndef ARM_ALWAYS_BX
- CALGN( add pc, r4, ip )
+ CALGN( add pc, r4, ip, lsl #(ARM_BX_ALIGN_LOG2 - 2))
#else
- CALGN( add r4, r4, ip )
+ CALGN( add r4, r4, ip, lsl #(ARM_BX_ALIGN_LOG2 - 2))
CALGN( bx r4 )
#endif
@@ -130,38 +130,55 @@ ENTRY(memmove)
5: ands ip, r2, #28
rsb ip, ip, #32
#ifndef ARM_ALWAYS_BX
- addne pc, pc, ip @ C is always clear here
+ /* C is always clear here. */
+ addne pc, pc, ip, lsl #(ARM_BX_ALIGN_LOG2 - 2)
b 7f
#else
beq 7f
push {r10}
cfi_adjust_cfa_offset (4)
- add r10, pc, ip
+ add r10, pc, ip, lsl #(ARM_BX_ALIGN_LOG2 - 2)
bx r10
#endif
+ .p2align ARM_BX_ALIGN_LOG2
6: nop
+ .p2align ARM_BX_ALIGN_LOG2
ldr r3, [r1, #-4]!
+ .p2align ARM_BX_ALIGN_LOG2
ldr r4, [r1, #-4]!
+ .p2align ARM_BX_ALIGN_LOG2
ldr r5, [r1, #-4]!
+ .p2align ARM_BX_ALIGN_LOG2
ldr r6, [r1, #-4]!
+ .p2align ARM_BX_ALIGN_LOG2
ldr r7, [r1, #-4]!
+ .p2align ARM_BX_ALIGN_LOG2
ldr r8, [r1, #-4]!
+ .p2align ARM_BX_ALIGN_LOG2
ldr lr, [r1, #-4]!
#ifndef ARM_ALWAYS_BX
- add pc, pc, ip
+ add pc, pc, ip, lsl #(ARM_BX_ALIGN_LOG2 - 2)
nop
#else
- add r10, pc, ip
+ add r10, pc, ip, lsl #(ARM_BX_ALIGN_LOG2 - 2)
bx r10
#endif
+ .p2align ARM_BX_ALIGN_LOG2
nop
+ .p2align ARM_BX_ALIGN_LOG2
str r3, [r0, #-4]!
+ .p2align ARM_BX_ALIGN_LOG2
str r4, [r0, #-4]!
+ .p2align ARM_BX_ALIGN_LOG2
str r5, [r0, #-4]!
+ .p2align ARM_BX_ALIGN_LOG2
str r6, [r0, #-4]!
+ .p2align ARM_BX_ALIGN_LOG2
str r7, [r0, #-4]!
+ .p2align ARM_BX_ALIGN_LOG2
str r8, [r0, #-4]!
+ .p2align ARM_BX_ALIGN_LOG2
str lr, [r0, #-4]!
#ifdef ARM_ALWAYS_BX
http://sources.redhat.com/git/gitweb.cgi?p=glibc.git;a=commitdiff;h=667c7e71a87076f74e740436c992fb51b56a2f9c
commit 667c7e71a87076f74e740436c992fb51b56a2f9c
Author: Roland McGrath <roland@hack.frob.com>
Date: Wed Mar 6 12:29:59 2013 -0800
ARM: Support avoiding pc as destination register.
diff --git a/ports/ChangeLog.arm b/ports/ChangeLog.arm
index 4d16601..5200c31 100644
--- a/ports/ChangeLog.arm
+++ b/ports/ChangeLog.arm
@@ -1,3 +1,10 @@
+2013-03-06 Roland McGrath <roland@hack.frob.com>
+
+ * sysdeps/arm/arm-features.h: Add comment about ARM_ALWAYS_BX.
+ * sysdeps/arm/memcpy.S: Include <arm-features.h>.
+ [ARM_ALWAYS_BX]: Avoid pc as destination.
+ * sysdeps/arm/memmove.S: Likewise.
+
2013-03-06 Richard Henderson <rth@redhat.com>
* sysdeps/arm/add_n.S: New file.
diff --git a/ports/sysdeps/arm/arm-features.h b/ports/sysdeps/arm/arm-features.h
index 31801cf..139a403 100644
--- a/ports/sysdeps/arm/arm-features.h
+++ b/ports/sysdeps/arm/arm-features.h
@@ -36,4 +36,8 @@
at runtime (or that we never care about its state) and so need not
be checked for. */
+/* A more-specific arm-features.h file may define ARM_ALWAYS_BX to indicate
+ that instructions using pc as a destination register must never be used,
+ so a "bx" (or "blx") instruction is always required. */
+
#endif /* arm-features.h */
diff --git a/ports/sysdeps/arm/memcpy.S b/ports/sysdeps/arm/memcpy.S
index 98981ef..5df7cd2 100644
--- a/ports/sysdeps/arm/memcpy.S
+++ b/ports/sysdeps/arm/memcpy.S
@@ -20,6 +20,7 @@
/* Thumb requires excessive IT insns here. */
#define NO_THUMB
#include <sysdep.h>
+#include <arm-features.h>
/*
* Data preload for architectures that support it (ARM V5TE and above)
@@ -88,7 +89,12 @@ ENTRY(memcpy)
CALGN( bcs 2f )
CALGN( adr r4, 6f )
CALGN( subs r2, r2, r3 ) @ C gets set
+#ifndef ARM_ALWAYS_BX
CALGN( add pc, r4, ip )
+#else
+ CALGN( add r4, r4, ip )
+ CALGN( bx r4 )
+#endif
PLD( pld [r1, #0] )
2: PLD( subs r2, r2, #96 )
@@ -107,8 +113,16 @@ ENTRY(memcpy)
5: ands ip, r2, #28
rsb ip, ip, #32
+#ifndef ARM_ALWAYS_BX
addne pc, pc, ip @ C is always clear here
b 7f
+#else
+ beq 7f
+ push {r10}
+ cfi_adjust_cfa_offset (4)
+ add r10, pc, ip
+ bx r10
+#endif
6: nop
ldr r3, [r1], #4
ldr r4, [r1], #4
@@ -118,8 +132,13 @@ ENTRY(memcpy)
ldr r8, [r1], #4
ldr lr, [r1], #4
+#ifndef ARM_ALWAYS_BX
add pc, pc, ip
nop
+#else
+ add r10, pc, ip
+ bx r10
+#endif
nop
str r3, [r0], #4
str r4, [r0], #4
@@ -129,6 +148,11 @@ ENTRY(memcpy)
str r8, [r0], #4
str lr, [r0], #4
+#ifdef ARM_ALWAYS_BX
+ pop {r10}
+ cfi_adjust_cfa_offset (-4)
+#endif
+
CALGN( bcs 2b )
7: pop {r5 - r8}
@@ -146,7 +170,8 @@ ENTRY(memcpy)
strcsb r4, [r0], #1
strcsb ip, [r0]
-#if defined (__ARM_ARCH_4T__) && defined(__THUMB_INTERWORK__)
+#if ((defined (__ARM_ARCH_4T__) && defined(__THUMB_INTERWORK__)) \
+ || defined (ARM_ALWAYS_BX))
pop {r0, r4, lr}
cfi_adjust_cfa_offset (-12)
cfi_restore (r4)
@@ -178,7 +203,7 @@ ENTRY(memcpy)
bgt 18f
- .macro forward_copy_shift pull push
+ .macro forward_copy_shift PULL PUSH
subs r2, r2, #28
blt 14f
@@ -249,17 +274,17 @@ ENTRY(memcpy)
CALGN( cmp r2, #0 )
CALGN( bge 11b )
-16: sub r1, r1, #(\push / 8)
+16: sub r1, r1, #(\PUSH / 8)
b 8b
.endm
- forward_copy_shift pull=8 push=24
+ forward_copy_shift PULL=8 PUSH=24
-17: forward_copy_shift pull=16 push=16
+17: forward_copy_shift PULL=16 PUSH=16
-18: forward_copy_shift pull=24 push=8
+18: forward_copy_shift PULL=24 PUSH=8
END(memcpy)
libc_hidden_builtin_def (memcpy)
diff --git a/ports/sysdeps/arm/memmove.S b/ports/sysdeps/arm/memmove.S
index d9fa0e3..e84050d 100644
--- a/ports/sysdeps/arm/memmove.S
+++ b/ports/sysdeps/arm/memmove.S
@@ -20,6 +20,7 @@
/* Thumb requires excessive IT insns here. */
#define NO_THUMB
#include <sysdep.h>
+#include <arm-features.h>
/*
* Data preload for architectures that support it (ARM V5TE and above)
@@ -104,7 +105,12 @@ ENTRY(memmove)
CALGN( bcs 2f )
CALGN( adr r4, 6f )
CALGN( subs r2, r2, ip ) @ C is set here
+#ifndef ARM_ALWAYS_BX
CALGN( add pc, r4, ip )
+#else
+ CALGN( add r4, r4, ip )
+ CALGN( bx r4 )
+#endif
PLD( pld [r1, #-4] )
2: PLD( subs r2, r2, #96 )
@@ -123,8 +129,16 @@ ENTRY(memmove)
5: ands ip, r2, #28
rsb ip, ip, #32
+#ifndef ARM_ALWAYS_BX
addne pc, pc, ip @ C is always clear here
b 7f
+#else
+ beq 7f
+ push {r10}
+ cfi_adjust_cfa_offset (4)
+ add r10, pc, ip
+ bx r10
+#endif
6: nop
ldr r3, [r1, #-4]!
ldr r4, [r1, #-4]!
@@ -134,8 +148,13 @@ ENTRY(memmove)
ldr r8, [r1, #-4]!
ldr lr, [r1, #-4]!
+#ifndef ARM_ALWAYS_BX
add pc, pc, ip
nop
+#else
+ add r10, pc, ip
+ bx r10
+#endif
nop
str r3, [r0, #-4]!
str r4, [r0, #-4]!
@@ -145,6 +164,11 @@ ENTRY(memmove)
str r8, [r0, #-4]!
str lr, [r0, #-4]!
+#ifdef ARM_ALWAYS_BX
+ pop {r10}
+ cfi_adjust_cfa_offset (-4)
+#endif
+
CALGN( bcs 2b )
7: pop {r5 - r8}
@@ -162,7 +186,8 @@ ENTRY(memmove)
strcsb r4, [r0, #-1]!
strcsb ip, [r0, #-1]
-#if defined (__ARM_ARCH_4T__) && defined (__THUMB_INTERWORK__)
+#if ((defined (__ARM_ARCH_4T__) && defined (__THUMB_INTERWORK__)) \
+ || defined (ARM_ALWAYS_BX))
pop {r0, r4, lr}
cfi_adjust_cfa_offset (-12)
cfi_restore (r4)
@@ -193,7 +218,7 @@ ENTRY(memmove)
blt 18f
- .macro backward_copy_shift push pull
+ .macro backward_copy_shift PUSH PULL
subs r2, r2, #28
blt 14f
@@ -264,17 +289,17 @@ ENTRY(memmove)
CALGN( cmp r2, #0 )
CALGN( bge 11b )
-16: add r1, r1, #(\pull / 8)
+16: add r1, r1, #(\PULL / 8)
b 8b
.endm
- backward_copy_shift push=8 pull=24
+ backward_copy_shift PUSH=8 PULL=24
-17: backward_copy_shift push=16 pull=16
+17: backward_copy_shift PUSH=16 PULL=16
-18: backward_copy_shift push=24 pull=8
+18: backward_copy_shift PUSH=24 PULL=8
END(memmove)
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