[klibc 37/43] x86_64 support for klibc

[klibc 37/43] x86_64 support for klibc

[H. Peter Anvin]

The parts of klibc specific to the x86_64 architecture.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>

---
commit f889dd04bef1aed36ba18161c727af47338e167a
tree c25f184d2e3337b52dfe3abd191ec639d4d9543d
parent f30fa3db62972125afa68d3b53d03cdb843d3bbd
author H. Peter Anvin <hpa@zytor.com> Sun, 25 Jun 2006 16:58:53 -0700
committer H. Peter Anvin <hpa@zytor.com> Sun, 25 Jun 2006 16:58:53 -0700

 usr/include/arch/x86_64/klibc/archconfig.h |   15 +++
 usr/include/arch/x86_64/klibc/archsetjmp.h |   21 +++++
 usr/include/arch/x86_64/klibc/archsignal.h |   18 ++++
 usr/include/arch/x86_64/klibc/archstat.h   |   28 ++++++
 usr/include/arch/x86_64/klibc/archsys.h    |  109 ++++++++++++++++++++++++
 usr/include/arch/x86_64/sys/io.h           |  127 ++++++++++++++++++++++++++++
 usr/klibc/arch/x86_64/MCONFIG              |   35 ++++++++
 usr/klibc/arch/x86_64/Makefile.inc         |   18 ++++
 usr/klibc/arch/x86_64/crt0.S               |   22 +++++
 usr/klibc/arch/x86_64/setjmp.S             |   54 ++++++++++++
 usr/klibc/arch/x86_64/sigreturn.S          |   15 +++
 usr/klibc/arch/x86_64/syscall.S            |   28 ++++++
 usr/klibc/arch/x86_64/sysstub.ph           |   23 +++++
 usr/klibc/arch/x86_64/vfork.S              |   26 ++++++
 14 files changed, 539 insertions(+), 0 deletions(-)

diff --git a/usr/include/arch/x86_64/klibc/archconfig.h b/usr/include/arch/x86_64/klibc/archconfig.h
new file mode 100644
index 0000000..b8a2a6d
--- /dev/null
+++ b/usr/include/arch/x86_64/klibc/archconfig.h
@@ -0,0 +1,15 @@
+/*
+ * include/arch/x86_64/klibc/archconfig.h
+ *
+ * See include/klibc/sysconfig.h for the options that can be set in
+ * this file.
+ *
+ */
+
+#ifndef _KLIBC_ARCHCONFIG_H
+#define _KLIBC_ARCHCONFIG_H
+
+/* x86-64 doesn't provide a default sigreturn. */
+#define _KLIBC_NEEDS_SA_RESTORER 1
+
+#endif				/* _KLIBC_ARCHCONFIG_H */
diff --git a/usr/include/arch/x86_64/klibc/archsetjmp.h b/usr/include/arch/x86_64/klibc/archsetjmp.h
new file mode 100644
index 0000000..454fc60
--- /dev/null
+++ b/usr/include/arch/x86_64/klibc/archsetjmp.h
@@ -0,0 +1,21 @@
+/*
+ * arch/x86_64/include/klibc/archsetjmp.h
+ */
+
+#ifndef _KLIBC_ARCHSETJMP_H
+#define _KLIBC_ARCHSETJMP_H
+
+struct __jmp_buf {
+	unsigned long __rbx;
+	unsigned long __rsp;
+	unsigned long __rbp;
+	unsigned long __r12;
+	unsigned long __r13;
+	unsigned long __r14;
+	unsigned long __r15;
+	unsigned long __rip;
+};
+
+typedef struct __jmp_buf jmp_buf[1];
+
+#endif				/* _SETJMP_H */
diff --git a/usr/include/arch/x86_64/klibc/archsignal.h b/usr/include/arch/x86_64/klibc/archsignal.h
new file mode 100644
index 0000000..6c8ec77
--- /dev/null
+++ b/usr/include/arch/x86_64/klibc/archsignal.h
@@ -0,0 +1,18 @@
+/*
+ * arch/x86_64/include/klibc/archsignal.h
+ *
+ * Architecture-specific signal definitions
+ *
+ */
+
+#ifndef _KLIBC_ARCHSIGNAL_H
+#define _KLIBC_ARCHSIGNAL_H
+
+#include <asm/signal.h>
+/* The x86-64 headers defines NSIG 32, but it's actually 64 */
+#undef  _NSIG
+#undef  NSIG
+#define _NSIG 64
+#define NSIG  _NSIG
+
+#endif
diff --git a/usr/include/arch/x86_64/klibc/archstat.h b/usr/include/arch/x86_64/klibc/archstat.h
new file mode 100644
index 0000000..de168ac
--- /dev/null
+++ b/usr/include/arch/x86_64/klibc/archstat.h
@@ -0,0 +1,28 @@
+#ifndef _KLIBC_ARCHSTAT_H
+#define _KLIBC_ARCHSTAT_H
+
+#include <klibc/stathelp.h>
+
+#define _STATBUF_ST_NSEC
+
+struct stat {
+	__stdev64	(st_dev);
+	unsigned long	st_ino;
+	unsigned long	st_nlink;
+
+	unsigned int	st_mode;
+	unsigned int	st_uid;
+	unsigned int	st_gid;
+	unsigned int	__pad0;
+	__stdev64	(st_rdev);
+	long		st_size;
+	long		st_blksize;
+	long		st_blocks;	/* Number 512-byte blocks allocated. */
+
+	struct timespec st_atim;
+	struct timespec st_mtim;
+	struct timespec st_ctim;
+  	long		__unused[3];
+};
+
+#endif
diff --git a/usr/include/arch/x86_64/klibc/archsys.h b/usr/include/arch/x86_64/klibc/archsys.h
new file mode 100644
index 0000000..45c71a7
--- /dev/null
+++ b/usr/include/arch/x86_64/klibc/archsys.h
@@ -0,0 +1,109 @@
+/*
+ * arch/x86_64/include/klibc/archsys.h
+ *
+ * Architecture-specific syscall definitions
+ */
+
+#ifndef _KLIBC_ARCHSYS_H
+#define _KLIBC_ARCHSYS_H
+
+/* The x86-64 syscall headers are needlessly inefficient */
+
+#undef _syscall0
+#undef _syscall1
+#undef _syscall2
+#undef _syscall3
+#undef _syscall4
+#undef _syscall5
+#undef _syscall6
+
+#define _syscall0(type,name) \
+type name (void) \
+{ \
+long __res; \
+__asm__ volatile (__syscall \
+        : "=a" (__res) \
+        : "0" (__NR_##name) \
+        : __syscall_clobber); \
+__syscall_return(type,__res); \
+}
+
+#define _syscall1(type,name,type1,arg1) \
+type name (type1 arg1) \
+{ \
+long __res; \
+__asm__ volatile (__syscall \
+        : "=a" (__res) \
+        : "0" (__NR_##name),"D" (arg1) \
+        : __syscall_clobber); \
+__syscall_return(type,__res); \
+}
+
+#define _syscall2(type,name,type1,arg1,type2,arg2) \
+type name (type1 arg1,type2 arg2) \
+{ \
+long __res; \
+__asm__ volatile (__syscall \
+        : "=a" (__res) \
+        : "0" (__NR_##name),"D" (arg1),"S" (arg2) \
+        : __syscall_clobber); \
+__syscall_return(type,__res); \
+}
+
+#define _syscall3(type,name,type1,arg1,type2,arg2,type3,arg3) \
+type name (type1 arg1,type2 arg2,type3 arg3) \
+{ \
+long __res; \
+__asm__ volatile (__syscall \
+        : "=a" (__res) \
+        : "0" (__NR_##name),"D" (arg1),"S" (arg2), \
+          "d" (arg3) \
+        : __syscall_clobber); \
+__syscall_return(type,__res); \
+}
+
+#define _syscall4(type,name,type1,arg1,type2,arg2,type3,arg3,type4,arg4) \
+type name (type1 arg1,type2 arg2,type3 arg3,type4 arg4) \
+{ \
+long __res; \
+register type4 __r10 asm("%r10") = arg4; \
+__asm__ volatile (__syscall \
+        : "=a" (__res) \
+        : "0" (__NR_##name),"D" (arg1),"S" (arg2), \
+          "d" (arg3),"r" (__r10) \
+        : __syscall_clobber); \
+__syscall_return(type,__res); \
+}
+
+#define _syscall5(type,name,type1,arg1,type2,arg2,type3,arg3,type4,arg4, \
+          type5,arg5) \
+type name (type1 arg1,type2 arg2,type3 arg3,type4 arg4,type5 arg5) \
+{ \
+long __res; \
+register type4 __r10 asm("%r10") = arg4; \
+register type5 __r8  asm("%r8")  = arg5; \
+__asm__ volatile (__syscall \
+        : "=a" (__res) \
+        : "0" (__NR_##name),"D" (arg1),"S" (arg2), \
+          "d" (arg3),"r" (__r10),"r" (__r8) \
+        : __syscall_clobber); \
+__syscall_return(type,__res); \
+}
+
+#define _syscall6(type,name,type1,arg1,type2,arg2,type3,arg3,type4,arg4, \
+          type5,arg5,type6,arg6) \
+type name (type1 arg1,type2 arg2,type3 arg3,type4 arg4,type5 arg5,type6 arg6) \
+{ \
+long __res; \
+register type4 __r10 asm("%r10") = arg4; \
+register type5 __r8  asm("%r8")  = arg5; \
+register type6 __r9  asm("%r9")  = arg6; \
+__asm__ volatile (__syscall \
+        : "=a" (__res) \
+        : "0" (__NR_##name),"D" (arg1),"S" (arg2), \
+          "d" (arg3),"r" (__r10),"r" (__r8), "r" (__r9) \
+        : __syscall_clobber); \
+__syscall_return(type,__res); \
+}
+
+#endif				/* _KLIBC_ARCHSYS_H */
diff --git a/usr/include/arch/x86_64/sys/io.h b/usr/include/arch/x86_64/sys/io.h
new file mode 100644
index 0000000..2a0ca48
--- /dev/null
+++ b/usr/include/arch/x86_64/sys/io.h
@@ -0,0 +1,127 @@
+/* ----------------------------------------------------------------------- *
+ *
+ *   Copyright 2004 H. Peter Anvin - All Rights Reserved
+ *
+ *   Permission is hereby granted, free of charge, to any person
+ *   obtaining a copy of this software and associated documentation
+ *   files (the "Software"), to deal in the Software without
+ *   restriction, including without limitation the rights to use,
+ *   copy, modify, merge, publish, distribute, sublicense, and/or
+ *   sell copies of the Software, and to permit persons to whom
+ *   the Software is furnished to do so, subject to the following
+ *   conditions:
+ *
+ *   The above copyright notice and this permission notice shall
+ *   be included in all copies or substantial portions of the Software.
+ *
+ *   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ *   EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+ *   OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ *   NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+ *   HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+ *   WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ *   FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ *   OTHER DEALINGS IN THE SOFTWARE.
+ *
+ * ----------------------------------------------------------------------- */
+
+/*
+ * sys/io.h for the i386 architecture
+ *
+ * Basic I/O macros
+ */
+
+#ifndef _SYS_IO_H
+#define _SYS_IO_H 1
+
+/* I/O-related system calls */
+
+int iopl(int);
+int ioperm(unsigned long, unsigned long, int);
+
+/* Basic I/O macros */
+
+static __inline__ void outb(unsigned char __v, unsigned short __p)
+{
+	asm volatile ("outb %0,%1" : : "a" (__v), "dN"(__p));
+}
+
+static __inline__ void outw(unsigned short __v, unsigned short __p)
+{
+	asm volatile ("outw %0,%1" : : "a" (__v), "dN"(__p));
+}
+
+static __inline__ void outl(unsigned int __v, unsigned short __p)
+{
+	asm volatile ("outl %0,%1" : : "a" (__v), "dN"(__p));
+}
+
+static __inline__ unsigned char inb(unsigned short __p)
+{
+	unsigned char __v;
+	asm volatile ("inb %1,%0" : "=a" (__v) : "dN"(__p));
+	return v;
+}
+
+static __inline__ unsigned short inw(unsigned short __p)
+{
+	unsigned short __v;
+	asm volatile ("inw %1,%0" : "=a" (__v) : "dN"(__p));
+	return v;
+}
+
+static __inline__ unsigned int inl(unsigned short __p)
+{
+	unsigned int __v;
+	asm volatile ("inl %1,%0" : "=a" (__v) : "dN"(__p));
+	return v;
+}
+
+/* String I/O macros */
+
+static __inline__ void
+outsb(unsigned short __p, const void *__d, unsigned long __n)
+{
+	asm volatile ("cld; rep; outsb"
+		      : "+S" (__d), "+c"(__n)
+		      : "d"(__p));
+}
+
+static __inline__ void
+outsw(unsigned short __p, const void *__d, unsigned long __n)
+{
+	asm volatile ("cld; rep; outsw"
+		      : "+S" (__d), "+c"(__n)
+		      : "d"(__p));
+}
+
+static __inline__ void
+outsl(unsigned short __p, const void *__d, unsigned long __n)
+{
+	asm volatile ("cld; rep; outsl"
+		      : "+S" (__d), "+c"(__n)
+		      : "d"(__p));
+}
+
+static __inline__ void insb(unsigned short __p, void *__d, unsigned long __n)
+{
+	asm volatile ("cld; rep; insb"
+		      : "+D" (__d), "+c"(__n)
+		      : "d"(__p));
+}
+
+static __inline__ void insw(unsigned short __p, void *__d, unsigned long __n)
+{
+	asm volatile ("cld; rep; insw"
+		      : "+D" (__d), "+c"(__n)
+		      : "d"(__p));
+}
+
+static __inline__ void insl(unsigned short __p, void *__d, unsigned long __n)
+{
+	asm volatile ("cld; rep; insl"
+		      : "+D" (__d), "+c"(__n)
+		      : "d"(__p));
+}
+
+#endif				/* _SYS_IO_H */
diff --git a/usr/klibc/arch/x86_64/MCONFIG b/usr/klibc/arch/x86_64/MCONFIG
new file mode 100644
index 0000000..edcd638
--- /dev/null
+++ b/usr/klibc/arch/x86_64/MCONFIG
@@ -0,0 +1,35 @@
+# -*- makefile -*-
+#
+# arch/x86-64/MCONFIG
+#
+# Special rules for this architecture.  Note that this is actually
+# included from the main Makefile, and that pathnames should be
+# accordingly.
+#
+# Blatantly copied and modified from i386 version by Mats Petersson, AMD.
+#
+
+#
+# NOTE: -fno-asynchronous-unwind-tables produce significantly smaller
+# binaries (20% smaller), but makes the code completely useless for
+# debugging using gdb.
+#
+KLIBCARCHREQFLAGS = -m64
+ifeq ($(DEBUG),y)
+KLIBCOPTFLAGS     = -Os -fomit-frame-pointer \
+		-falign-functions=1 -falign-jumps=1 -falign-loops=1
+else
+KLIBCOPTFLAGS     = -Os -fno-asynchronous-unwind-tables -fomit-frame-pointer \
+		-falign-functions=1 -falign-jumps=1 -falign-loops=1
+endif
+KLIBCBITSIZE      = 64
+KLIBCLDFLAGS      = -m elf_x86_64
+
+# Extra linkflags when building the shared version of the library
+# This address needs to be reachable using normal inter-module
+# calls, and work on the memory models for this architecture
+# 2 MB - normal binaries start at 4 MB
+KLIBCSHAREDFLAGS     = -Ttext 0x00200200
+
+# Additional asm- directories needed during installation
+ASMARCH = asm-i386
diff --git a/usr/klibc/arch/x86_64/Makefile.inc b/usr/klibc/arch/x86_64/Makefile.inc
new file mode 100644
index 0000000..4bfe56a
--- /dev/null
+++ b/usr/klibc/arch/x86_64/Makefile.inc
@@ -0,0 +1,18 @@
+# -*- makefile -*-
+#
+# arch/x86_64/Makefile.inc
+#
+# Special rules for this architecture.  Note that this is actually
+# included from the main Makefile, and that pathnames should be
+# accordingly.
+#
+
+KLIBCARCHOBJS = \
+	arch/$(KLIBCARCH)/setjmp.o \
+	arch/$(KLIBCARCH)/syscall.o \
+	arch/$(KLIBCARCH)/sigreturn.o \
+	arch/$(KLIBCARCH)/vfork.o
+
+KLIBCARCHSOOBJS = $(patsubst %.o,%.lo,$(KLIBCARCHOBJS))
+
+archclean:
diff --git a/usr/klibc/arch/x86_64/crt0.S b/usr/klibc/arch/x86_64/crt0.S
new file mode 100644
index 0000000..6a5f335
--- /dev/null
+++ b/usr/klibc/arch/x86_64/crt0.S
@@ -0,0 +1,22 @@
+#
+# arch/x86_64/crt0.S
+#
+# Does arch-specific initialization and invokes __libc_init
+# with the appropriate arguments.
+#
+# See __static_init.c or __shared_init.c for the expected
+# arguments.
+#
+
+	.text
+	.align 4
+	.type _start,@function
+	.globl _start
+_start:
+	movq %rsp,%rdi			# Offset of the ELF data structure
+	movq %rdx,%rsi			# The atexit() pointer (if any)
+	call __libc_init
+	# We should never get here...
+	hlt
+
+	.size _start,.-_start
diff --git a/usr/klibc/arch/x86_64/setjmp.S b/usr/klibc/arch/x86_64/setjmp.S
new file mode 100644
index 0000000..45f547b
--- /dev/null
+++ b/usr/klibc/arch/x86_64/setjmp.S
@@ -0,0 +1,54 @@
+#
+# arch/x86_64/setjmp.S
+#
+# setjmp/longjmp for the x86-64 architecture
+#
+
+#
+# The jmp_buf is assumed to contain the following, in order:
+#	%rbx
+#	%rsp (post-return)
+#	%rbp
+#	%r12
+#	%r13
+#	%r14
+#	%r15
+#	<return address>
+#
+
+	.text
+	.align 4
+	.globl setjmp
+	.type setjmp, @function
+setjmp:
+	pop  %rsi			# Return address, and adjust the stack
+	xorl %eax,%eax			# Return value
+	movq %rbx,(%rdi)
+	movq %rsp,8(%rdi)		# Post-return %rsp!
+	push %rsi			# Make the call/return stack happy
+	movq %rbp,16(%rdi)
+	movq %r12,24(%rdi)
+	movq %r13,32(%rdi)
+	movq %r14,40(%rdi)
+	movq %r15,48(%rdi)
+	movq %rsi,56(%rdi)		# Return address
+	ret
+
+	.size setjmp,.-setjmp
+
+	.text
+	.align 4
+	.globl longjmp
+	.type longjmp, @function
+longjmp:
+	movl %esi,%eax			# Return value (int)
+	movq (%rdi),%rbx
+	movq 8(%rdi),%rsp
+	movq 16(%rdi),%rbp
+	movq 24(%rdi),%r12
+	movq 32(%rdi),%r13
+	movq 40(%rdi),%r14
+	movq 48(%rdi),%r15
+	jmp *56(%rdi)
+
+	.size longjmp,.-longjmp
diff --git a/usr/klibc/arch/x86_64/sigreturn.S b/usr/klibc/arch/x86_64/sigreturn.S
new file mode 100644
index 0000000..46a5a0b
--- /dev/null
+++ b/usr/klibc/arch/x86_64/sigreturn.S
@@ -0,0 +1,15 @@
+/*
+ * arch/x86_64/sigreturn.S
+ */
+
+#include <asm/unistd.h>
+
+	.text
+	.align	4
+	.globl	__sigreturn
+	.type	__sigreturn,@function
+__sigreturn:
+	movl	$__NR_rt_sigreturn,%eax
+	syscall
+
+	.size	__sigreturn,.-__sigreturn
diff --git a/usr/klibc/arch/x86_64/syscall.S b/usr/klibc/arch/x86_64/syscall.S
new file mode 100644
index 0000000..1797797
--- /dev/null
+++ b/usr/klibc/arch/x86_64/syscall.S
@@ -0,0 +1,28 @@
+/*
+ * arch/x86-64/syscall.S
+ *
+ * Common tail-handling code for system calls.
+ *
+ * The arguments are in the standard argument registers; the system
+ * call number in %eax.
+ */
+	.text
+	.align	4
+	.globl	__syscall_common
+	.type	__syscall_common,@function
+__syscall_common:
+	movq	%rcx,%r10		# The kernel uses %r10 istf %rcx
+	syscall
+
+	cmpq	$-4095,%rax
+	jnb	1f
+	ret
+
+	# Error return, must set errno
+1:
+	negl	%eax
+	movl	%eax,errno(%rip)	# errno is type int, so 32 bits
+	orq	$-1,%rax		# orq $-1 smaller than movq $-1
+	ret
+
+	.size	__syscall_common,.-__syscall_common
diff --git a/usr/klibc/arch/x86_64/sysstub.ph b/usr/klibc/arch/x86_64/sysstub.ph
new file mode 100644
index 0000000..e2d797b
--- /dev/null
+++ b/usr/klibc/arch/x86_64/sysstub.ph
@@ -0,0 +1,23 @@
+# -*- perl -*-
+#
+# arch/x86_64/sysstub.ph
+#
+# Script to generate system call stubs
+#
+
+sub make_sysstub($$$$$@) {
+    my($outputdir, $fname, $type, $sname, $stype, @args) = @_;
+
+    open(OUT, '>', "${outputdir}/${fname}.S");
+    print OUT "#include <asm/unistd.h>\n";
+    print OUT "\n";
+    print OUT "\t.type ${fname},\@function\n";
+    print OUT "\t.globl ${fname}\n";
+    print OUT "${fname}:\n";
+    print OUT "\tmovl \$__NR_${sname},%eax\n"; # Zero-extends to 64 bits
+    print OUT "\tjmp __syscall_common\n";
+    print OUT "\t.size ${fname},.-${fname}\n";
+    close(OUT);
+}
+
+1;
diff --git a/usr/klibc/arch/x86_64/vfork.S b/usr/klibc/arch/x86_64/vfork.S
new file mode 100644
index 0000000..e1c8090
--- /dev/null
+++ b/usr/klibc/arch/x86_64/vfork.S
@@ -0,0 +1,26 @@
+#
+# usr/klibc/arch/x86_64/vfork.S
+#
+# vfork is nasty - there must be nothing at all on the stack above
+# the stack frame of the enclosing function.
+#
+
+#include <asm/unistd.h>
+
+	.text
+	.align	4
+	.globl	vfork
+	.type	vfork, @function
+vfork:
+	pop	%rdx			/* Return address */
+	movl	$__NR_vfork, %eax
+	syscall
+	push	%rdx
+	cmpq	$-4095, %rax
+	jae	1f
+	ret
+1:
+	negl	%eax
+	movl	%eax, errno(%rip)
+	orq	$-1, %rax
+	ret

Re: [klibc 37/43] x86_64 support for klibc

[Andi Kleen]

"H. Peter Anvin" <hpa@zytor.com> writes:
> +
> +#include <asm/signal.h>
> +/* The x86-64 headers defines NSIG 32, but it's actually 64 */
> +#undef  _NSIG
> +#undef  NSIG
> +#define _NSIG 64
> +#define NSIG  _NSIG

If it's really wrong it should be fixed, not workarounded.

> +
> +/* The x86-64 syscall headers are needlessly inefficient */
> +
> +#undef _syscall0
> +#undef _syscall1
> +#undef _syscall2
> +#undef _syscall3
> +#undef _syscall4
> +#undef _syscall5
> +#undef _syscall6

What do you mean with that?

-Andi

Re: [klibc 37/43] x86_64 support for klibc

[H. Peter Anvin]

Andi Kleen wrote:
> "H. Peter Anvin" <hpa@zytor.com> writes:
>> +
>> +#include <asm/signal.h>
>> +/* The x86-64 headers defines NSIG 32, but it's actually 64 */
>> +#undef  _NSIG
>> +#undef  NSIG
>> +#define _NSIG 64
>> +#define NSIG  _NSIG
> 
> If it's really wrong it should be fixed, not workarounded.
> 

It is wrong... include/asm-x86_64/signal.h has cribbed a bit too much 
from i386:

ifdef __KERNEL__
/* Most things should be clean enough to redefine this at will, if care
    is taken to make libc match.  */

#define _NSIG           64
#define _NSIG_BPW       64
#define _NSIG_WORDS     (_NSIG / _NSIG_BPW)

typedef unsigned long old_sigset_t;             /* at least 32 bits */

typedef struct {
         unsigned long sig[_NSIG_WORDS];
} sigset_t;


struct pt_regs;
asmlinkage int do_signal(struct pt_regs *regs, sigset_t *oldset);


#else
/* Here we must cater to libcs that poke about in kernel headers.  */

#define NSIG            32
typedef unsigned long sigset_t;

#endif /* __KERNEL__ */
#endif


I can't remove the workaround just yet, since I have active users of the 
out-of-tree version.  However, I will send you a patch for 
include/asm-x86_64/signal.h.

>> +
>> +/* The x86-64 syscall headers are needlessly inefficient */
>> +
>> +#undef _syscall0
>> +#undef _syscall1
>> +#undef _syscall2
>> +#undef _syscall3
>> +#undef _syscall4
>> +#undef _syscall5
>> +#undef _syscall6
> 
> What do you mean with that?
> 

At one point klibc was using the _syscall() macros, and I observed that 
the x86-64 ones generated extra instructions because of the "movq"s that 
were hard-coded in the patterns (using register variables, one can make 
gcc do any moves that may or may not be necessary.)

However, klibc no longer uses these except on ia64, so I removed 
<klibc/archsys.h> for all other architectures from the tree last night.

	-hpa

Re: [klibc 37/43] x86_64 support for klibc

[Andi Kleen]

On Tuesday 27 June 2006 17:01, H. Peter Anvin wrote:
> Andi Kleen wrote:
> > "H. Peter Anvin" <hpa@zytor.com> writes:
> >> +
> >> +#include <asm/signal.h>
> >> +/* The x86-64 headers defines NSIG 32, but it's actually 64 */
> >> +#undef  _NSIG
> >> +#undef  NSIG
> >> +#define _NSIG 64
> >> +#define NSIG  _NSIG
> > 
> > If it's really wrong it should be fixed, not workarounded.
> > 
> 
> It is wrong... include/asm-x86_64/signal.h has cribbed a bit too much 
> from i386:
> 
> ifdef __KERNEL__
> /* Most things should be clean enough to redefine this at will, if care
>     is taken to make libc match.  */
> 
> #define _NSIG           64
> #define _NSIG_BPW       64
> #define _NSIG_WORDS     (_NSIG / _NSIG_BPW)
> 
> typedef unsigned long old_sigset_t;             /* at least 32 bits */
> 
> typedef struct {
>          unsigned long sig[_NSIG_WORDS];
> } sigset_t;
> 
> 
> struct pt_regs;
> asmlinkage int do_signal(struct pt_regs *regs, sigset_t *oldset);
> 
> 
> #else
> /* Here we must cater to libcs that poke about in kernel headers.  */
> 
> #define NSIG            32
> typedef unsigned long sigset_t;
> 
> #endif /* __KERNEL__ */
> #endif
> 
> 
> I can't remove the workaround just yet, since I have active users of the 
> out-of-tree version.  However, I will send you a patch for 
> include/asm-x86_64/signal.h.

Please do.

> >> +
> >> +/* The x86-64 syscall headers are needlessly inefficient */
> >> +
> >> +#undef _syscall0
> >> +#undef _syscall1
> >> +#undef _syscall2
> >> +#undef _syscall3
> >> +#undef _syscall4
> >> +#undef _syscall5
> >> +#undef _syscall6
> > 
> > What do you mean with that?
> > 
> 
> At one point klibc was using the _syscall() macros, and I observed that 
> the x86-64 ones generated extra instructions because of the "movq"s that 
> were hard-coded in the patterns (using register variables, one can make 
> gcc do any moves that may or may not be necessary.)

No you can't. We tried that first, but it generated incorrect code
on older gcc versions. gcc doesn't behave gratefully when an inline
statement takes nearly all register classes (x86-64 has less register
classes than real registers so it's a bit non obvious). I added the 
moves to hide some registers at the advice of gcc hackers.

Maybe you got lucky with newer gcc versions, but I would recommend
to use the standard versions to be backwards compatible.

-Andi