[LibOS/Glibc] Remove Glibc modification which disabled vDSO

vDSO is supported by Graphene now, so this commit removes the
modification of Glibc which disabled vDSO in Graphene. Currently,
compile-time option GLIBC_DISABLE_VDSO is introduced to be able
to revert to the old behaviour (disabled by default).

LibOS/Makefile

@@ -3,6 +3,7 @@ export SYS
 
 export DEBUG
 
+# GLIBC_DISABLE_VDSO = true
 GLIBC_SRC = glibc-2.19
 GLIBC_CHECKSUM = 18ad6db70724699d264add80b1f813630d0141cf3a3558b4e1a7c15f6beac796
 SHIM_DIR = shim
@@ -74,6 +75,11 @@ GLIBC_PATCHES = \
 	glibc-no-pie.patch \
 	glibc-liblibos.patch
 
+ifeq ($(GLIBC_DISABLE_VDSO),true)
+GLIBC_PATCHES += \
+	glibc-2.19-remove-vdso.patch
+endif
+
 ifneq ($(filter %.gold,$(shell readlink -f /usr/bin/ld)),)
 GLIBC_PATCHES += glibc-ld.gold.patch
 endif

LibOS/glibc-2.19-remove-vdso.patch

@@ -0,0 +1,196 @@
+unchanged:
+--- a/sysdeps/unix/sysv/linux/x86_64/clock_gettime.c
++++ b/sysdeps/unix/sysv/linux/x86_64/clock_gettime.c
+@@ -1,5 +1,6 @@
+ #include "bits/libc-vdso.h"
+ 
++#if 0 /* in Graphene, disallow VDSO calls */
+ #ifdef SHARED
+ # define SYSCALL_GETTIME(id, tp) \
+   ({ long int (*f) (clockid_t, struct timespec *) = __vdso_clock_gettime; \
+@@ -16,5 +17,6 @@
+   PTR_DEMANGLE (f);							  \
+   f (id, tp); })
+ #endif
++#endif
+ 
+ #include "../clock_gettime.c"
+unchanged:
+--- a/sysdeps/unix/sysv/linux/x86_64/gettimeofday.c
++++ b/sysdeps/unix/sysv/linux/x86_64/gettimeofday.c
+@@ -17,6 +17,7 @@
+ 
+ #include <sys/time.h>
+ 
++#if 0 /* In graphene, do not use vsyscall or VDSO call */
+ #ifdef SHARED
+ 
+ # include <dl-vdso.h>
+@@ -42,7 +43,8 @@ asm (".type __gettimeofday, %gnu_indirect_function");
+ asm (".globl __GI___gettimeofday\n"
+      "__GI___gettimeofday = __gettimeofday");
+ 
+-#else
++#endif
++#endif
+ 
+ # include <sysdep.h>
+ # include <errno.h>
+@@ -54,6 +56,5 @@ __gettimeofday (struct timeval *tv, struct timezone *tz)
+ }
+ libc_hidden_def (__gettimeofday)
+ 
+-#endif
+ weak_alias (__gettimeofday, gettimeofday)
+ libc_hidden_weak (gettimeofday)
+unchanged:
+--- a/nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_timedwait.S	2019-08-13 16:07:35.878486727 -0700
++++ b/nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_timedwait.S	2019-08-13 16:07:56.166508488 -0700
+@@ -485,15 +485,8 @@ __pthread_cond_timedwait:
+ 	/* Only clocks 0 and 1 are allowed so far.  Both are handled in the
+ 	   kernel.  */
+ 	leaq	32(%rsp), %rsi
+-#  ifdef SHARED
+-	mov	__vdso_clock_gettime@GOTPCREL(%rip), %RAX_LP
+-	mov	(%rax), %RAX_LP
+-	PTR_DEMANGLE (%RAX_LP)
+-	call	*%rax
+-#  else
+ 	movl	$__NR_clock_gettime, %eax
+ 	SYSCALLDB
+-#  endif
+ 
+ 	/* Compute relative timeout.  */
+ 	movq	(%r13), %rcx
+unchanged:
+--- a/sysdeps/unix/sysv/linux/x86_64/sched_getcpu.S	2019-08-13 16:02:43.550205689 -0700
++++ b/sysdeps/unix/sysv/linux/x86_64/sched_getcpu.S	2019-08-13 16:03:29.282244893 -0700
+@@ -30,6 +30,7 @@ ENTRY (sched_getcpu)
+ 	sub	$0x8, %rsp
+ 	cfi_adjust_cfa_offset(8)
+ 
++#if 0 /* for Graphene, never do VDSO calls */
+ 	movq	%rsp, %rdi
+ 	xorl	%esi, %esi
+ 	movl	$VGETCPU_CACHE_OFFSET, %edx
+@@ -39,16 +40,19 @@ ENTRY (sched_getcpu)
+ 	movq	__vdso_getcpu(%rip), %rax
+ 	PTR_DEMANGLE (%rax)
+ 	callq	*%rax
+-#else
+-# ifdef __NR_getcpu
++#endif
++#endif
++
++#ifdef __NR_getcpu
+ 	movl	$__NR_getcpu, %eax
+ 	SYSCALLDB
+-#  ifndef __ASSUME_GETCPU_SYSCALL
++#endif
++
++#if 0 /* for Graphene, never do vsyscall */
++# ifndef __ASSUME_GETCPU_SYSCALL
+ 	cmpq	$-ENOSYS, %rax
+ 	jne	1f
+-#  endif
+-# endif
+-# ifndef __ASSUME_GETCPU_SYSCALL
++
+ 	movq	$VSYSCALL_ADDR_vgetcpu, %rax
+ 	callq	*%rax
+ 1:
+unchanged:
+--- glibc-2.19-orig/sysdeps/unix/sysv/linux/x86_64/time.c	2014-02-07 01:04:38.000000000 -0800
++++ glibc-2.19-modify/sysdeps/unix/sysv/linux/x86_64/time.c	1969-12-31 16:00:00.000000000 -0800
+@@ -1,60 +0,0 @@
+-/* Copyright (C) 2001-2014 Free Software Foundation, Inc.
+-   This file is part of the GNU C Library.
+-
+-   The GNU C Library is free software; you can redistribute it and/or
+-   modify it under the terms of the GNU Lesser General Public
+-   License as published by the Free Software Foundation; either
+-   version 2.1 of the License, or (at your option) any later version.
+-
+-   The GNU C Library is distributed in the hope that it will be useful,
+-   but WITHOUT ANY WARRANTY; without even the implied warranty of
+-   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+-   Lesser General Public License for more details.
+-
+-   You should have received a copy of the GNU Lesser General Public
+-   License along with the GNU C Library; if not, see
+-   <http://www.gnu.org/licenses/>.  */
+-
+-#ifdef SHARED
+-/* Redefine time so that the compiler won't complain about the type
+-   mismatch with the IFUNC selector in strong_alias, below.  */
+-#undef time
+-#define time __redirect_time
+-#include <time.h>
+-
+-#include <dl-vdso.h>
+-
+-#define VSYSCALL_ADDR_vtime	0xffffffffff600400
+-
+-/* Avoid DWARF definition DIE on ifunc symbol so that GDB can handle
+-   ifunc symbol properly.  */
+-extern __typeof (__redirect_time) __libc_time;
+-void *time_ifunc (void) __asm__ ("__libc_time");
+-
+-void *
+-time_ifunc (void)
+-{
+-  PREPARE_VERSION (linux26, "LINUX_2.6", 61765110);
+-
+-  /* If the vDSO is not available we fall back on the old vsyscall.  */
+-  return _dl_vdso_vsym ("__vdso_time", &linux26) ?: (void *) VSYSCALL_ADDR_vtime;
+-}
+-__asm (".type __libc_time, %gnu_indirect_function");
+-
+-#undef time
+-strong_alias (__libc_time, time)
+-libc_hidden_ver (__libc_time, time)
+-
+-#else
+-
+-# include <time.h>
+-# include <sysdep.h>
+-
+-time_t
+-time (time_t *t)
+-{
+-  INTERNAL_SYSCALL_DECL (err);
+-  return INTERNAL_SYSCALL (time, err, 1, t);
+-}
+-
+-#endif
+only in patch2:
+unchanged:
+--- a/sysdeps/unix/sysv/linux/x86_64/sysdep.h
++++ b/sysdeps/unix/sysv/linux/x86_64/sysdep.h
+@@ -252,6 +252,7 @@
+ # undef INTERNAL_SYSCALL_ERRNO
+ # define INTERNAL_SYSCALL_ERRNO(val, err)	(-(val))
+ 
++# if 0 /* for Graphene, never do vsyscall */
+ # ifdef SHARED
+ #  define INLINE_VSYSCALL(name, nr, args...) \
+   ({									      \
+@@ -300,12 +301,13 @@
+     v_ret;								      \
+   })
+ 
+-# else
+-#  define INLINE_VSYSCALL(name, nr, args...) \
+-  INLINE_SYSCALL (name, nr, ##args)
+-#  define INTERNAL_VSYSCALL(name, err, nr, args...) \
+-  INTERNAL_SYSCALL (name, err, nr, ##args)
+ # endif
++# endif
++
++#  define INLINE_VSYSCALL(name, nr_args...) \
++  INLINE_SYSCALL (name, ##nr_args)
++#  define INTERNAL_VSYSCALL(name, err, nr_args...) \
++  INTERNAL_SYSCALL (name, err, ##nr_args)
+ 
+ # define LOAD_ARGS_0()
+ # define LOAD_REGS_0

LibOS/glibc-2.19.patch

@@ -595,23 +595,14 @@ index 0dc2340..8aff242 100644
  	subq	$cond_nwaiters, %rdi
  
  55:	LOCK
-@@ -485,15 +485,8 @@ __pthread_cond_timedwait:
- 	/* Only clocks 0 and 1 are allowed so far.  Both are handled in the
- 	   kernel.  */
- 	leaq	32(%rsp), %rsi
--#  ifdef SHARED
--	mov	__vdso_clock_gettime@GOTPCREL(%rip), %RAX_LP
--	mov	(%rax), %RAX_LP
--	PTR_DEMANGLE (%RAX_LP)
--	call	*%rax
--#  else
+@@ -493,6 +488,6 @@
+ #  else
  	movl	$__NR_clock_gettime, %eax
 -	syscall
--#  endif
 +	SYSCALLDB
+ #  endif
  
  	/* Compute relative timeout.  */
- 	movq	(%r13), %rcx
 @@ -560,7 +553,7 @@ __pthread_cond_timedwait:
  # endif
  	addq	$cond_futex, %rdi
@@ -929,24 +920,6 @@ index 49f0384..6b1a975 100644
  	/* Without working sigaltstack we cannot perform the test.  */
  	testl	%eax, %eax
  	jne	.Lok2
-diff --git a/sysdeps/unix/sysv/linux/x86_64/clock_gettime.c b/sysdeps/unix/sysv/linux/x86_64/clock_gettime.c
-index f712110..f6bad14 100644
---- a/sysdeps/unix/sysv/linux/x86_64/clock_gettime.c
-+++ b/sysdeps/unix/sysv/linux/x86_64/clock_gettime.c
-@@ -1,5 +1,6 @@
- #include "bits/libc-vdso.h"
- 
-+#if 0 /* in Graphene, disallow VDSO calls */
- #ifdef SHARED
- # define SYSCALL_GETTIME(id, tp) \
-   ({ long int (*f) (clockid_t, struct timespec *) = __vdso_clock_gettime; \
-@@ -16,5 +17,6 @@
-   PTR_DEMANGLE (f);							  \
-   f (id, tp); })
- #endif
-+#endif
- 
- #include "../clock_gettime.c"
 diff --git a/sysdeps/unix/sysv/linux/x86_64/clone.S b/sysdeps/unix/sysv/linux/x86_64/clone.S
 index 0508730..e1b35ec 100644
 --- a/sysdeps/unix/sysv/linux/x86_64/clone.S
@@ -983,74 +956,19 @@ index 140db03..6967f10 100644
  	cmpq	$-4095, %rax		/* Check %rax for error.  */
  	jae	SYSCALL_ERROR_LABEL	/* Jump to error handler if error.  */
  
-diff --git a/sysdeps/unix/sysv/linux/x86_64/gettimeofday.c b/sysdeps/unix/sysv/linux/x86_64/gettimeofday.c
-index 440ca7f..571125d 100644
---- a/sysdeps/unix/sysv/linux/x86_64/gettimeofday.c
-+++ b/sysdeps/unix/sysv/linux/x86_64/gettimeofday.c
-@@ -17,6 +17,7 @@
- 
- #include <sys/time.h>
- 
-+#if 0 /* In graphene, do not use vsyscall or VDSO call */
- #ifdef SHARED
- 
- # include <dl-vdso.h>
-@@ -42,7 +43,8 @@ asm (".type __gettimeofday, %gnu_indirect_function");
- asm (".globl __GI___gettimeofday\n"
-      "__GI___gettimeofday = __gettimeofday");
- 
--#else
-+#endif
-+#endif
- 
- # include <sysdep.h>
- # include <errno.h>
-@@ -54,6 +56,5 @@ __gettimeofday (struct timeval *tv, struct timezone *tz)
- }
- libc_hidden_def (__gettimeofday)
- 
--#endif
- weak_alias (__gettimeofday, gettimeofday)
- libc_hidden_weak (gettimeofday)
 diff --git a/sysdeps/unix/sysv/linux/x86_64/sched_getcpu.S b/sysdeps/unix/sysv/linux/x86_64/sched_getcpu.S
 index 0fd47f2..7a82975 100644
 --- a/sysdeps/unix/sysv/linux/x86_64/sched_getcpu.S
 +++ b/sysdeps/unix/sysv/linux/x86_64/sched_getcpu.S
-@@ -30,6 +30,7 @@ ENTRY (sched_getcpu)
- 	sub	$0x8, %rsp
- 	cfi_adjust_cfa_offset(8)
- 
-+#if 0 /* for Graphene, never do VDSO calls */
- 	movq	%rsp, %rdi
- 	xorl	%esi, %esi
- 	movl	$VGETCPU_CACHE_OFFSET, %edx
-@@ -39,16 +40,19 @@ ENTRY (sched_getcpu)
- 	movq	__vdso_getcpu(%rip), %rax
- 	PTR_DEMANGLE (%rax)
- 	callq	*%rax
--#else
--# ifdef __NR_getcpu
-+#endif
-+#endif
-+
-+#ifdef __NR_getcpu
+@@ -44,7 +45,7 @@
+ #else
+ # ifdef __NR_getcpu
  	movl	$__NR_getcpu, %eax
 -	syscall
--#  ifndef __ASSUME_GETCPU_SYSCALL
 +	SYSCALLDB
-+#endif
-+
-+#if 0 /* for Graphene, never do vsyscall */
-+# ifndef __ASSUME_GETCPU_SYSCALL
- 	cmpq	$-ENOSYS, %rax
- 	jne	1f
--#  endif
--# endif
--# ifndef __ASSUME_GETCPU_SYSCALL
-+
- 	movq	$VSYSCALL_ADDR_vgetcpu, %rax
- 	callq	*%rax
- 1:
+ #  ifndef __ASSUME_GETCPU_SYSCALL
+        cmpq    $-ENOSYS, %rax
+        jne     1f
 diff --git a/sysdeps/unix/sysv/linux/x86_64/setcontext.S b/sysdeps/unix/sysv/linux/x86_64/setcontext.S
 index b726fa0..bb3ae34 100644
 --- a/sysdeps/unix/sysv/linux/x86_64/setcontext.S
@@ -1196,99 +1114,6 @@ index 4a9a9d9..dc452ed 100644
      : "=a" (resultvar)							      \
      : "0" (name) ASM_ARGS_##nr : "memory", "cc", "r11", "cx");		      \
      (long int) resultvar; })
-@@ -252,6 +270,7 @@
- # undef INTERNAL_SYSCALL_ERRNO
- # define INTERNAL_SYSCALL_ERRNO(val, err)	(-(val))
- 
-+# if 0 /* for Graphene, never do vsyscall */
- # ifdef SHARED
- #  define INLINE_VSYSCALL(name, nr, args...) \
-   ({									      \
-@@ -300,12 +319,13 @@
-     v_ret;								      \
-   })
- 
--# else
--#  define INLINE_VSYSCALL(name, nr, args...) \
--  INLINE_SYSCALL (name, nr, ##args)
--#  define INTERNAL_VSYSCALL(name, err, nr, args...) \
--  INTERNAL_SYSCALL (name, err, nr, ##args)
- # endif
-+# endif
-+
-+#  define INLINE_VSYSCALL(name, nr_args...) \
-+  INLINE_SYSCALL (name, ##nr_args)
-+#  define INTERNAL_VSYSCALL(name, err, nr_args...) \
-+  INTERNAL_SYSCALL (name, err, ##nr_args)
- 
- # define LOAD_ARGS_0()
- # define LOAD_REGS_0
-diff --git a/sysdeps/unix/sysv/linux/x86_64/time.c b/sysdeps/unix/sysv/linux/x86_64/time.c
-deleted file mode 100644
-index 79f1fab..0000000
---- a/sysdeps/unix/sysv/linux/x86_64/time.c
-+++ /dev/null
-@@ -1,60 +0,0 @@
--/* Copyright (C) 2001-2014 Free Software Foundation, Inc.
--   This file is part of the GNU C Library.
--
--   The GNU C Library is free software; you can redistribute it and/or
--   modify it under the terms of the GNU Lesser General Public
--   License as published by the Free Software Foundation; either
--   version 2.1 of the License, or (at your option) any later version.
--
--   The GNU C Library is distributed in the hope that it will be useful,
--   but WITHOUT ANY WARRANTY; without even the implied warranty of
--   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
--   Lesser General Public License for more details.
--
--   You should have received a copy of the GNU Lesser General Public
--   License along with the GNU C Library; if not, see
--   <http://www.gnu.org/licenses/>.  */
--
--#ifdef SHARED
--/* Redefine time so that the compiler won't complain about the type
--   mismatch with the IFUNC selector in strong_alias, below.  */
--#undef time
--#define time __redirect_time
--#include <time.h>
--
--#include <dl-vdso.h>
--
--#define VSYSCALL_ADDR_vtime	0xffffffffff600400
--
--/* Avoid DWARF definition DIE on ifunc symbol so that GDB can handle
--   ifunc symbol properly.  */
--extern __typeof (__redirect_time) __libc_time;
--void *time_ifunc (void) __asm__ ("__libc_time");
--
--void *
--time_ifunc (void)
--{
--  PREPARE_VERSION (linux26, "LINUX_2.6", 61765110);
--
--  /* If the vDSO is not available we fall back on the old vsyscall.  */
--  return _dl_vdso_vsym ("__vdso_time", &linux26) ?: (void *) VSYSCALL_ADDR_vtime;
--}
--__asm (".type __libc_time, %gnu_indirect_function");
--
--#undef time
--strong_alias (__libc_time, time)
--libc_hidden_ver (__libc_time, time)
--
--#else
--
--# include <time.h>
--# include <sysdep.h>
--
--time_t
--time (time_t *t)
--{
--  INTERNAL_SYSCALL_DECL (err);
--  return INTERNAL_SYSCALL (time, err, 1, t);
--}
--
--#endif
 diff --git a/sysdeps/unix/sysv/linux/x86_64/vfork.S b/sysdeps/unix/sysv/linux/x86_64/vfork.S
 index d3b450a..75a63e1 100644
 --- a/sysdeps/unix/sysv/linux/x86_64/vfork.S