[PATCH] i386: Redo semaphore and rwlock assembly helpers

- Move them to a pure assembly file. Previously they were in
a C file that only consisted of inline assembly. Doing it in pure
assembler is much nicer.
- Add a frame.i include with FRAME/ENDFRAME macros to easily
add frame pointers to assembly functions
- Add dwarf2 annotation to them so that the new dwarf2 unwinder
doesn't get stuck on them
- Random cleanups

Includes feedback from Jan Beulich and a UML build fix from Andrew
Morton.

Cc: jbeulich@novell.com
Cc: jdike@addtoit.com
Signed-off-by: Andi Kleen <ak@suse.de>

diff --git a/arch/i386/kernel/Makefile b/arch/i386/kernel/Makefile
index 5427a842e841d90ee09e77628cce1abb3d402ea8..dab497472debbc3e9138801895f7d455ff534a08 100644 (file)
--- a/arch/i386/kernel/Makefile
+++ b/arch/i386/kernel/Makefile
@@ -4,7 +4,7 @@
 
 extra-y := head.o init_task.o vmlinux.lds
 
-obj-y  := process.o semaphore.o signal.o entry.o traps.o irq.o \
+obj-y  := process.o signal.o entry.o traps.o irq.o \
                ptrace.o time.o ioport.o ldt.o setup.o i8259.o sys_i386.o \
                pci-dma.o i386_ksyms.o i387.o bootflag.o \
                quirks.o i8237.o topology.o alternative.o i8253.o tsc.o

diff --git a/arch/i386/kernel/semaphore.c b/arch/i386/kernel/semaphore.c
deleted file mode 100644 (file)
index 98352c3..0000000
--- a/arch/i386/kernel/semaphore.c
+++ /dev/null
@@ -1,134 +0,0 @@
-/*
- * i386 semaphore implementation.
- *
- * (C) Copyright 1999 Linus Torvalds
- *
- * Portions Copyright 1999 Red Hat, Inc.
- *
- *     This program is free software; you can redistribute it and/or
- *     modify it under the terms of the GNU General Public License
- *     as published by the Free Software Foundation; either version
- *     2 of the License, or (at your option) any later version.
- *
- * rw semaphores implemented November 1999 by Benjamin LaHaise <bcrl@kvack.org>
- */
-#include <asm/semaphore.h>
-
-/*
- * The semaphore operations have a special calling sequence that
- * allow us to do a simpler in-line version of them. These routines
- * need to convert that sequence back into the C sequence when
- * there is contention on the semaphore.
- *
- * %eax contains the semaphore pointer on entry. Save the C-clobbered
- * registers (%eax, %edx and %ecx) except %eax whish is either a return
- * value or just clobbered..
- */
-asm(
-".section .sched.text\n"
-".align 4\n"
-".globl __down_failed\n"
-"__down_failed:\n\t"
-#if defined(CONFIG_FRAME_POINTER)
-       "pushl %ebp\n\t"
-       "movl  %esp,%ebp\n\t"
-#endif
-       "pushl %edx\n\t"
-       "pushl %ecx\n\t"
-       "call __down\n\t"
-       "popl %ecx\n\t"
-       "popl %edx\n\t"
-#if defined(CONFIG_FRAME_POINTER)
-       "movl %ebp,%esp\n\t"
-       "popl %ebp\n\t"
-#endif
-       "ret"
-);
-
-asm(
-".section .sched.text\n"
-".align 4\n"
-".globl __down_failed_interruptible\n"
-"__down_failed_interruptible:\n\t"
-#if defined(CONFIG_FRAME_POINTER)
-       "pushl %ebp\n\t"
-       "movl  %esp,%ebp\n\t"
-#endif
-       "pushl %edx\n\t"
-       "pushl %ecx\n\t"
-       "call __down_interruptible\n\t"
-       "popl %ecx\n\t"
-       "popl %edx\n\t"
-#if defined(CONFIG_FRAME_POINTER)
-       "movl %ebp,%esp\n\t"
-       "popl %ebp\n\t"
-#endif
-       "ret"
-);
-
-asm(
-".section .sched.text\n"
-".align 4\n"
-".globl __down_failed_trylock\n"
-"__down_failed_trylock:\n\t"
-#if defined(CONFIG_FRAME_POINTER)
-       "pushl %ebp\n\t"
-       "movl  %esp,%ebp\n\t"
-#endif
-       "pushl %edx\n\t"
-       "pushl %ecx\n\t"
-       "call __down_trylock\n\t"
-       "popl %ecx\n\t"
-       "popl %edx\n\t"
-#if defined(CONFIG_FRAME_POINTER)
-       "movl %ebp,%esp\n\t"
-       "popl %ebp\n\t"
-#endif
-       "ret"
-);
-
-asm(
-".section .sched.text\n"
-".align 4\n"
-".globl __up_wakeup\n"
-"__up_wakeup:\n\t"
-       "pushl %edx\n\t"
-       "pushl %ecx\n\t"
-       "call __up\n\t"
-       "popl %ecx\n\t"
-       "popl %edx\n\t"
-       "ret"
-);
-
-/*
- * rw spinlock fallbacks
- */
-#if defined(CONFIG_SMP)
-asm(
-".section .sched.text\n"
-".align        4\n"
-".globl        __write_lock_failed\n"
-"__write_lock_failed:\n\t"
-       LOCK_PREFIX "addl       $" RW_LOCK_BIAS_STR ",(%eax)\n"
-"1:    rep; nop\n\t"
-       "cmpl   $" RW_LOCK_BIAS_STR ",(%eax)\n\t"
-       "jne    1b\n\t"
-       LOCK_PREFIX "subl       $" RW_LOCK_BIAS_STR ",(%eax)\n\t"
-       "jnz    __write_lock_failed\n\t"
-       "ret"
-);
-
-asm(
-".section .sched.text\n"
-".align        4\n"
-".globl        __read_lock_failed\n"
-"__read_lock_failed:\n\t"
-       LOCK_PREFIX "incl       (%eax)\n"
-"1:    rep; nop\n\t"
-       "cmpl   $1,(%eax)\n\t"
-       "js     1b\n\t"
-       LOCK_PREFIX "decl       (%eax)\n\t"
-       "js     __read_lock_failed\n\t"
-       "ret"
-);
-#endif

diff --git a/arch/i386/lib/Makefile b/arch/i386/lib/Makefile
index 914933e9ec3d29847e8a1b59b08902c87146e3cf..d86a548b8d543af5958961ccce281b83b3e15d6c 100644 (file)
--- a/arch/i386/lib/Makefile
+++ b/arch/i386/lib/Makefile
@@ -4,6 +4,6 @@
 
 
 lib-y = checksum.o delay.o usercopy.o getuser.o putuser.o memcpy.o strstr.o \
-       bitops.o
+       bitops.o semaphore.o
 
 lib-$(CONFIG_X86_USE_3DNOW) += mmx.o

diff --git a/arch/i386/lib/semaphore.S b/arch/i386/lib/semaphore.S
new file mode 100644 (file)
index 0000000..e16ff16
--- /dev/null
+++ b/arch/i386/lib/semaphore.S
@@ -0,0 +1,154 @@
+/*
+ * i386 semaphore implementation.
+ *
+ * (C) Copyright 1999 Linus Torvalds
+ *
+ * Portions Copyright 1999 Red Hat, Inc.
+ *
+ *     This program is free software; you can redistribute it and/or
+ *     modify it under the terms of the GNU General Public License
+ *     as published by the Free Software Foundation; either version
+ *     2 of the License, or (at your option) any later version.
+ *
+ * rw semaphores implemented November 1999 by Benjamin LaHaise <bcrl@kvack.org>
+ */
+
+#include <linux/config.h>
+#include <linux/linkage.h>
+#include <asm/rwlock.h>
+#include <asm/alternative-asm.i>
+#include <asm/frame.i>
+#include <asm/dwarf2.h>
+
+/*
+ * The semaphore operations have a special calling sequence that
+ * allow us to do a simpler in-line version of them. These routines
+ * need to convert that sequence back into the C sequence when
+ * there is contention on the semaphore.
+ *
+ * %eax contains the semaphore pointer on entry. Save the C-clobbered
+ * registers (%eax, %edx and %ecx) except %eax whish is either a return
+ * value or just clobbered..
+ */
+       .section .sched.text
+ENTRY(__down_failed)
+       CFI_STARTPROC
+       FRAME
+       pushl %edx
+       CFI_ADJUST_CFA_OFFSET 4
+       CFI_REL_OFFSET edx,0
+       pushl %ecx
+       CFI_ADJUST_CFA_OFFSET 4
+       CFI_REL_OFFSET ecx,0
+       call __down
+       popl %ecx
+       CFI_ADJUST_CFA_OFFSET -4
+       CFI_RESTORE ecx
+       popl %edx
+       CFI_ADJUST_CFA_OFFSET -4
+       CFI_RESTORE edx
+       ENDFRAME
+       ret
+       CFI_ENDPROC
+       END(__down_failed)
+
+ENTRY(__down_failed_interruptible)
+       CFI_STARTPROC
+       FRAME
+       pushl %edx
+       CFI_ADJUST_CFA_OFFSET 4
+       CFI_REL_OFFSET edx,0
+       pushl %ecx
+       CFI_ADJUST_CFA_OFFSET 4
+       CFI_REL_OFFSET ecx,0
+       call __down_interruptible
+       popl %ecx
+       CFI_ADJUST_CFA_OFFSET -4
+       CFI_RESTORE ecx
+       popl %edx
+       CFI_ADJUST_CFA_OFFSET -4
+       CFI_RESTORE edx
+       ENDFRAME
+       ret
+       CFI_ENDPROC
+       END(__down_failed_interruptible)
+
+ENTRY(__down_failed_trylock)
+       CFI_STARTPROC
+       FRAME
+       pushl %edx
+       CFI_ADJUST_CFA_OFFSET 4
+       CFI_REL_OFFSET edx,0
+       pushl %ecx
+       CFI_ADJUST_CFA_OFFSET 4
+       CFI_REL_OFFSET ecx,0
+       call __down_trylock
+       popl %ecx
+       CFI_ADJUST_CFA_OFFSET -4
+       CFI_RESTORE ecx
+       popl %edx
+       CFI_ADJUST_CFA_OFFSET -4
+       CFI_RESTORE edx
+       ENDFRAME
+       ret
+       CFI_ENDPROC
+       END(__down_failed_trylock)
+
+ENTRY(__up_wakeup)
+       CFI_STARTPROC
+       FRAME
+       pushl %edx
+       CFI_ADJUST_CFA_OFFSET 4
+       CFI_REL_OFFSET edx,0
+       pushl %ecx
+       CFI_ADJUST_CFA_OFFSET 4
+       CFI_REL_OFFSET ecx,0
+       call __up
+       popl %ecx
+       CFI_ADJUST_CFA_OFFSET -4
+       CFI_RESTORE ecx
+       popl %edx
+       CFI_ADJUST_CFA_OFFSET -4
+       CFI_RESTORE edx
+       ENDFRAME
+       ret
+       CFI_ENDPROC
+       END(__up_wakeup)
+
+/*
+ * rw spinlock fallbacks
+ */
+#ifdef CONFIG_SMP
+ENTRY(__write_lock_failed)
+       CFI_STARTPROC simple
+       FRAME
+2:     LOCK_PREFIX
+       addl    $ RW_LOCK_BIAS,(%eax)
+1:     rep; nop
+       cmpl    $ RW_LOCK_BIAS,(%eax)
+       jne     1b
+       LOCK_PREFIX
+       subl    $ RW_LOCK_BIAS,(%eax)
+       jnz     2b
+       ENDFRAME
+       ret
+       CFI_ENDPROC
+       END(__write_lock_failed)
+
+ENTRY(__read_lock_failed)
+       CFI_STARTPROC
+       FRAME
+2:     LOCK_PREFIX
+       incl    (%eax)
+1:     rep; nop
+       cmpl    $1,(%eax)
+       js      1b
+       LOCK_PREFIX
+       decl    (%eax)
+       js      2b
+       ENDFRAME
+       ret
+       CFI_ENDPROC
+       END(__read_lock_failed)
+
+#endif

diff --git a/arch/um/sys-i386/Makefile b/arch/um/sys-i386/Makefile
index 374d61a194392a11d91565bc6e5902d27bc3affc..6289779ca67c937df4c7dfe1819441d363aff2c6 100644 (file)
--- a/arch/um/sys-i386/Makefile
+++ b/arch/um/sys-i386/Makefile
@@ -4,7 +4,7 @@ obj-y = bugs.o checksum.o delay.o fault.o ksyms.o ldt.o ptrace.o \
 
 obj-$(CONFIG_MODE_SKAS) += stub.o stub_segv.o
 
-subarch-obj-y = lib/bitops.o kernel/semaphore.o
+subarch-obj-y = lib/bitops.o lib/semaphore.o
 subarch-obj-$(CONFIG_HIGHMEM) += mm/highmem.o
 subarch-obj-$(CONFIG_MODULES) += kernel/module.o
 

diff --git a/include/asm-i386/frame.i b/include/asm-i386/frame.i
new file mode 100644 (file)
index 0000000..4d68ddc
--- /dev/null
+++ b/include/asm-i386/frame.i
@@ -0,0 +1,24 @@
+#include <linux/config.h>
+#include <asm/dwarf2.h>
+
+/* The annotation hides the frame from the unwinder and makes it look
+   like a ordinary ebp save/restore. This avoids some special cases for
+   frame pointer later */
+#ifdef CONFIG_FRAME_POINTER
+       .macro FRAME
+       pushl %ebp
+       CFI_ADJUST_CFA_OFFSET 4
+       CFI_REL_OFFSET ebp,0
+       movl %esp,%ebp
+       .endm
+       .macro ENDFRAME
+       popl %ebp
+       CFI_ADJUST_CFA_OFFSET -4
+       CFI_RESTORE ebp
+       .endm
+#else
+       .macro FRAME
+       .endm
+       .macro ENDFRAME
+       .endm
+#endif

diff --git a/include/asm-um/alternative-asm.i b/include/asm-um/alternative-asm.i
new file mode 100644 (file)
index 0000000..cae9fac
--- /dev/null
+++ b/include/asm-um/alternative-asm.i
@@ -0,0 +1,6 @@
+#ifndef __UM_ALTERNATIVE_ASM_I
+#define __UM_ALTERNATIVE_ASM_I
+
+#include "asm/arch/alternative-asm.i"
+
+#endif

diff --git a/include/asm-um/frame.i b/include/asm-um/frame.i
new file mode 100644 (file)
index 0000000..09d5dca
--- /dev/null
+++ b/include/asm-um/frame.i
@@ -0,0 +1,6 @@
+#ifndef __UM_FRAME_I
+#define __UM_FRAME_I
+
+#include "asm/arch/frame.i"
+
+#endif