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[PATCH] i386: Update I386_USE_SYSENTER for early PIC syscall
- From: "H.J. Lu" <hongjiu dot lu at intel dot com>
- To: GNU C Library <libc-alpha at sourceware dot org>
- Date: Wed, 2 Aug 2017 10:36:09 -0700
- Subject: [PATCH] i386: Update I386_USE_SYSENTER for early PIC syscall
- Authentication-results: sourceware.org; auth=none
- Reply-to: "H.J. Lu" <hjl dot tools at gmail dot com>
Define I386_USE_SYSENTER to 0 or 1 so that special versions of syscalls
with "int $0x80" can be provided for static PIE during self relocation.
Also check PIC instead SHARED for PIC version of syscall macros.
Any comments or objections?
H.J.
---
* sysdeps/unix/sysv/linux/i386/sysdep.h (I386_USE_SYSENTER):
Define to I386_USE_SYSENTER to 0 or 1 if not defined.
(ENTER_KERNEL): Check if I386_USE_SYSENTER is 1 and check PIC.
(INTERNAL_SYSCALL_MAIN_INLINE): Likewise.
(INTERNAL_SYSCALL_NCS): Likewise.
(LOADARGS_1): Likewise.
(LOADARGS_5): Likewise.
(RESTOREARGS_1): Likewise.
(RESTOREARGS_5): Likewise.
---
sysdeps/unix/sysv/linux/i386/sysdep.h | 26 ++++++++++++++------------
1 file changed, 14 insertions(+), 12 deletions(-)
diff --git a/sysdeps/unix/sysv/linux/i386/sysdep.h b/sysdeps/unix/sysv/linux/i386/sysdep.h
index 449b23e49b..c455c9b1b4 100644
--- a/sysdeps/unix/sysv/linux/i386/sysdep.h
+++ b/sysdeps/unix/sysv/linux/i386/sysdep.h
@@ -34,11 +34,13 @@
#undef SYS_ify
#define SYS_ify(syscall_name) __NR_##syscall_name
-#if defined USE_DL_SYSINFO \
- && (IS_IN (libc) || IS_IN (libpthread))
-# define I386_USE_SYSENTER 1
-#else
-# undef I386_USE_SYSENTER
+#ifndef I386_USE_SYSENTER
+# if defined USE_DL_SYSINFO \
+ && (IS_IN (libc) || IS_IN (libpthread))
+# define I386_USE_SYSENTER 1
+# else
+# define I386_USE_SYSENTER 0
+# endif
#endif
/* Since GCC 5 and above can properly spill %ebx with PIC when needed,
@@ -110,8 +112,8 @@
/* The original calling convention for system calls on Linux/i386 is
to use int $0x80. */
-#ifdef I386_USE_SYSENTER
-# ifdef SHARED
+#if I386_USE_SYSENTER
+# ifdef PIC
# define ENTER_KERNEL call *%gs:SYSINFO_OFFSET
# else
# define ENTER_KERNEL call *_dl_sysinfo
@@ -357,9 +359,9 @@ struct libc_do_syscall_args
register unsigned int resultvar; \
INTERNAL_SYSCALL_MAIN_##nr (name, err, args); \
(int) resultvar; })
-#ifdef I386_USE_SYSENTER
+#if I386_USE_SYSENTER
# ifdef OPTIMIZE_FOR_GCC_5
-# ifdef SHARED
+# ifdef PIC
# define INTERNAL_SYSCALL_MAIN_INLINE(name, err, nr, args...) \
LOADREGS_##nr(args) \
asm volatile ( \
@@ -395,7 +397,7 @@ struct libc_do_syscall_args
(int) resultvar; })
# endif
# else /* GCC 5 */
-# ifdef SHARED
+# ifdef PIC
# define INTERNAL_SYSCALL_MAIN_INLINE(name, err, nr, args...) \
EXTRAVAR_##nr \
asm volatile ( \
@@ -494,7 +496,7 @@ struct libc_do_syscall_args
#define LOADARGS_0
#ifdef __PIC__
-# if defined I386_USE_SYSENTER && defined SHARED
+# if I386_USE_SYSENTER && defined PIC
# define LOADARGS_1 \
"bpushl .L__X'%k3, %k3\n\t"
# define LOADARGS_5 \
@@ -521,7 +523,7 @@ struct libc_do_syscall_args
#define RESTOREARGS_0
#ifdef __PIC__
-# if defined I386_USE_SYSENTER && defined SHARED
+# if I386_USE_SYSENTER && defined PIC
# define RESTOREARGS_1 \
"bpopl .L__X'%k3, %k3\n\t"
# define RESTOREARGS_5 \
--
2.13.3