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Date: Tue, 19 Jul 2011 13:00:19 +0100
From: "Jan Beulich" <JBeulich@...ell.com>
To: <mingo@...e.hu>, <tglx@...utronix.de>, <hpa@...or.com>
Cc: <linux-kernel@...r.kernel.org>
Subject: [PATCH 2/3, resend] x86: unify rwsem assembly implementation
Rather than having two functionally identical implementations for
32- and 64-bit configurations, use the previously extended assembly
abstractions to fold the rwsem two implementations into a shared one.
Signed-off-by: Jan Beulich <jbeulich@...ell.com>
---
arch/um/sys-i386/Makefile | 2
arch/um/sys-x86_64/Makefile | 2
arch/x86/lib/Makefile | 3
arch/x86/lib/rwsem.S | 136 ++++++++++++++++++++++++++++++++++++++++++++
arch/x86/lib/rwsem_64.S | 93 ------------------------------
arch/x86/lib/semaphore_32.S | 80 -------------------------
6 files changed, 139 insertions(+), 177 deletions(-)
--- 3.0-rc7-x86-rw.orig/arch/um/sys-i386/Makefile
+++ 3.0-rc7-x86-rw/arch/um/sys-i386/Makefile
@@ -8,7 +8,7 @@ obj-y = bug.o bugs.o checksum.o delay.o
obj-$(CONFIG_BINFMT_ELF) += elfcore.o
-subarch-obj-y = lib/semaphore_32.o lib/string_32.o
+subarch-obj-y = lib/rwsem.o lib/string_32.o
subarch-obj-$(CONFIG_HIGHMEM) += mm/highmem_32.o
subarch-obj-$(CONFIG_MODULES) += kernel/module.o
--- 3.0-rc7-x86-rw.orig/arch/um/sys-x86_64/Makefile
+++ 3.0-rc7-x86-rw/arch/um/sys-x86_64/Makefile
@@ -9,7 +9,7 @@ obj-y = bug.o bugs.o delay.o fault.o ldt
sysrq.o ksyms.o tls.o
subarch-obj-y = lib/csum-partial_64.o lib/memcpy_64.o lib/thunk_64.o \
- lib/rwsem_64.o
+ lib/rwsem.o
subarch-obj-$(CONFIG_MODULES) += kernel/module.o
ldt-y = ../sys-i386/ldt.o
--- 3.0-rc7-x86-rw.orig/arch/x86/lib/Makefile
+++ 3.0-rc7-x86-rw/arch/x86/lib/Makefile
@@ -21,6 +21,7 @@ lib-y += thunk_$(BITS).o
lib-y += usercopy_$(BITS).o getuser.o putuser.o
lib-y += memcpy_$(BITS).o
lib-$(CONFIG_SMP) += rwlock.o
+lib-$(CONFIG_RWSEM_XCHGADD_ALGORITHM) += rwsem.o
lib-$(CONFIG_INSTRUCTION_DECODER) += insn.o inat.o
obj-y += msr.o msr-reg.o msr-reg-export.o
@@ -30,7 +31,6 @@ ifeq ($(CONFIG_X86_32),y)
lib-y += atomic64_cx8_32.o
lib-y += checksum_32.o
lib-y += strstr_32.o
- lib-$(CONFIG_RWSEM_XCHGADD_ALGORITHM) += semaphore_32.o
lib-y += string_32.o
lib-y += cmpxchg.o
ifneq ($(CONFIG_X86_CMPXCHG64),y)
@@ -43,6 +43,5 @@ else
lib-y += thunk_64.o clear_page_64.o copy_page_64.o
lib-y += memmove_64.o memset_64.o
lib-y += copy_user_64.o copy_user_nocache_64.o
- lib-$(CONFIG_RWSEM_XCHGADD_ALGORITHM) += rwsem_64.o
lib-y += cmpxchg16b_emu.o
endif
--- /dev/null
+++ 3.0-rc7-x86-rw/arch/x86/lib/rwsem.S
@@ -0,0 +1,136 @@
+/*
+ * x86 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@...ck.org>
+ */
+
+#include <linux/linkage.h>
+#include <asm/alternative-asm.h>
+#include <asm/dwarf2.h>
+
+#define __ASM_HALF_REG(reg) __ASM_SEL(reg, e##reg)
+#define __ASM_HALF_SIZE(inst) __ASM_SEL(inst##w, inst##l)
+
+#ifdef CONFIG_X86_32
+
+/*
+ * 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..
+ */
+
+#define save_common_regs \
+ pushl_cfi %ecx; CFI_REL_OFFSET ecx, 0
+
+#define restore_common_regs \
+ popl_cfi %ecx; CFI_RESTORE ecx
+
+ /* Avoid uglifying the argument copying x86-64 needs to do. */
+ .macro movq src, dst
+ .endm
+
+#else
+
+/*
+ * x86-64 rwsem wrappers
+ *
+ * This interfaces the inline asm code to the slow-path
+ * C routines. We need to save the call-clobbered regs
+ * that the asm does not mark as clobbered, and move the
+ * argument from %rax to %rdi.
+ *
+ * NOTE! We don't need to save %rax, because the functions
+ * will always return the semaphore pointer in %rax (which
+ * is also the input argument to these helpers)
+ *
+ * The following can clobber %rdx because the asm clobbers it:
+ * call_rwsem_down_write_failed
+ * call_rwsem_wake
+ * but %rdi, %rsi, %rcx, %r8-r11 always need saving.
+ */
+
+#define save_common_regs \
+ pushq_cfi %rdi; CFI_REL_OFFSET rdi, 0; \
+ pushq_cfi %rsi; CFI_REL_OFFSET rsi, 0; \
+ pushq_cfi %rcx; CFI_REL_OFFSET rcx, 0; \
+ pushq_cfi %r8; CFI_REL_OFFSET r8, 0; \
+ pushq_cfi %r9; CFI_REL_OFFSET r9, 0; \
+ pushq_cfi %r10; CFI_REL_OFFSET r10, 0; \
+ pushq_cfi %r11; CFI_REL_OFFSET r11, 0
+
+#define restore_common_regs \
+ popq_cfi %r11; CFI_RESTORE r11; \
+ popq_cfi %r10; CFI_RESTORE r10; \
+ popq_cfi %r9; CFI_RESTORE r9; \
+ popq_cfi %r8; CFI_RESTORE r8; \
+ popq_cfi %rcx; CFI_RESTORE rcx; \
+ popq_cfi %rsi; CFI_RESTORE rsi; \
+ popq_cfi %rdi; CFI_RESTORE rdi
+
+#endif
+
+/* Fix up special calling conventions */
+ENTRY(call_rwsem_down_read_failed)
+ CFI_STARTPROC
+ save_common_regs
+ __ASM_SIZE(push,_cfi) %__ASM_REG(dx)
+ CFI_REL_OFFSET __ASM_REG(dx), 0
+ movq %rax,%rdi
+ call rwsem_down_read_failed
+ __ASM_SIZE(pop,_cfi) %__ASM_REG(dx)
+ CFI_RESTORE __ASM_REG(dx)
+ restore_common_regs
+ ret
+ CFI_ENDPROC
+ENDPROC(call_rwsem_down_read_failed)
+
+ENTRY(call_rwsem_down_write_failed)
+ CFI_STARTPROC
+ save_common_regs
+ movq %rax,%rdi
+ call rwsem_down_write_failed
+ restore_common_regs
+ ret
+ CFI_ENDPROC
+ENDPROC(call_rwsem_down_write_failed)
+
+ENTRY(call_rwsem_wake)
+ CFI_STARTPROC
+ /* do nothing if still outstanding active readers */
+ __ASM_HALF_SIZE(dec) %__ASM_HALF_REG(dx)
+ jnz 1f
+ save_common_regs
+ movq %rax,%rdi
+ call rwsem_wake
+ restore_common_regs
+1: ret
+ CFI_ENDPROC
+ENDPROC(call_rwsem_wake)
+
+ENTRY(call_rwsem_downgrade_wake)
+ CFI_STARTPROC
+ save_common_regs
+ __ASM_SIZE(push,_cfi) %__ASM_REG(dx)
+ CFI_REL_OFFSET __ASM_REG(dx), 0
+ movq %rax,%rdi
+ call rwsem_downgrade_wake
+ __ASM_SIZE(pop,_cfi) %__ASM_REG(dx)
+ CFI_RESTORE __ASM_REG(dx)
+ restore_common_regs
+ ret
+ CFI_ENDPROC
+ENDPROC(call_rwsem_downgrade_wake)
--- 3.0-rc7-x86-rw.orig/arch/x86/lib/rwsem_64.S
+++ /dev/null
@@ -1,93 +0,0 @@
-/*
- * x86-64 rwsem wrappers
- *
- * This interfaces the inline asm code to the slow-path
- * C routines. We need to save the call-clobbered regs
- * that the asm does not mark as clobbered, and move the
- * argument from %rax to %rdi.
- *
- * NOTE! We don't need to save %rax, because the functions
- * will always return the semaphore pointer in %rax (which
- * is also the input argument to these helpers)
- *
- * The following can clobber %rdx because the asm clobbers it:
- * call_rwsem_down_write_failed
- * call_rwsem_wake
- * but %rdi, %rsi, %rcx, %r8-r11 always need saving.
- */
-
-#include <linux/linkage.h>
-#include <asm/rwlock.h>
-#include <asm/alternative-asm.h>
-#include <asm/frame.h>
-#include <asm/dwarf2.h>
-
-#define save_common_regs \
- pushq_cfi %rdi; CFI_REL_OFFSET rdi, 0; \
- pushq_cfi %rsi; CFI_REL_OFFSET rsi, 0; \
- pushq_cfi %rcx; CFI_REL_OFFSET rcx, 0; \
- pushq_cfi %r8; CFI_REL_OFFSET r8, 0; \
- pushq_cfi %r9; CFI_REL_OFFSET r9, 0; \
- pushq_cfi %r10; CFI_REL_OFFSET r10, 0; \
- pushq_cfi %r11; CFI_REL_OFFSET r11, 0
-
-#define restore_common_regs \
- popq_cfi %r11; CFI_RESTORE r11; \
- popq_cfi %r10; CFI_RESTORE r10; \
- popq_cfi %r9; CFI_RESTORE r9; \
- popq_cfi %r8; CFI_RESTORE r8; \
- popq_cfi %rcx; CFI_RESTORE rcx; \
- popq_cfi %rsi; CFI_RESTORE rsi; \
- popq_cfi %rdi; CFI_RESTORE rdi
-
-/* Fix up special calling conventions */
-ENTRY(call_rwsem_down_read_failed)
- CFI_STARTPROC
- save_common_regs
- pushq_cfi %rdx
- CFI_REL_OFFSET rdx, 0
- movq %rax,%rdi
- call rwsem_down_read_failed
- popq_cfi %rdx
- CFI_RESTORE rdx
- restore_common_regs
- ret
- CFI_ENDPROC
-ENDPROC(call_rwsem_down_read_failed)
-
-ENTRY(call_rwsem_down_write_failed)
- CFI_STARTPROC
- save_common_regs
- movq %rax,%rdi
- call rwsem_down_write_failed
- restore_common_regs
- ret
- CFI_ENDPROC
-ENDPROC(call_rwsem_down_write_failed)
-
-ENTRY(call_rwsem_wake)
- CFI_STARTPROC
- decl %edx /* do nothing if still outstanding active readers */
- jnz 1f
- save_common_regs
- movq %rax,%rdi
- call rwsem_wake
- restore_common_regs
-1: ret
- CFI_ENDPROC
-ENDPROC(call_rwsem_wake)
-
-/* Fix up special calling conventions */
-ENTRY(call_rwsem_downgrade_wake)
- CFI_STARTPROC
- save_common_regs
- pushq_cfi %rdx
- CFI_REL_OFFSET rdx, 0
- movq %rax,%rdi
- call rwsem_downgrade_wake
- popq_cfi %rdx
- CFI_RESTORE rdx
- restore_common_regs
- ret
- CFI_ENDPROC
-ENDPROC(call_rwsem_downgrade_wake)
--- 3.0-rc7-x86-rw.orig/arch/x86/lib/semaphore_32.S
+++ /dev/null
@@ -1,80 +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@...ck.org>
- */
-
-#include <linux/linkage.h>
-#include <asm/frame.h>
-#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, "ax"
-
-/* Fix up special calling conventions */
-ENTRY(call_rwsem_down_read_failed)
- CFI_STARTPROC
- pushl_cfi %ecx
- CFI_REL_OFFSET ecx,0
- pushl_cfi %edx
- CFI_REL_OFFSET edx,0
- call rwsem_down_read_failed
- popl_cfi %edx
- popl_cfi %ecx
- ret
- CFI_ENDPROC
- ENDPROC(call_rwsem_down_read_failed)
-
-ENTRY(call_rwsem_down_write_failed)
- CFI_STARTPROC
- pushl_cfi %ecx
- CFI_REL_OFFSET ecx,0
- calll rwsem_down_write_failed
- popl_cfi %ecx
- ret
- CFI_ENDPROC
- ENDPROC(call_rwsem_down_write_failed)
-
-ENTRY(call_rwsem_wake)
- CFI_STARTPROC
- decw %dx /* do nothing if still outstanding active readers */
- jnz 1f
- pushl_cfi %ecx
- CFI_REL_OFFSET ecx,0
- call rwsem_wake
- popl_cfi %ecx
-1: ret
- CFI_ENDPROC
- ENDPROC(call_rwsem_wake)
-
-/* Fix up special calling conventions */
-ENTRY(call_rwsem_downgrade_wake)
- CFI_STARTPROC
- pushl_cfi %ecx
- CFI_REL_OFFSET ecx,0
- pushl_cfi %edx
- CFI_REL_OFFSET edx,0
- call rwsem_downgrade_wake
- popl_cfi %edx
- popl_cfi %ecx
- ret
- CFI_ENDPROC
- ENDPROC(call_rwsem_downgrade_wake)
--
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