diff options
Diffstat (limited to 'sysdeps/unix')
-rw-r--r-- | sysdeps/unix/sysv/linux/s390/s390-32/clone.S | 16 | ||||
-rw-r--r-- | sysdeps/unix/sysv/linux/s390/s390-32/sysdep.S | 139 | ||||
-rw-r--r-- | sysdeps/unix/sysv/linux/s390/s390-32/sysdep.h | 84 | ||||
-rw-r--r-- | sysdeps/unix/sysv/linux/s390/s390-64/clone.S | 26 | ||||
-rw-r--r-- | sysdeps/unix/sysv/linux/s390/s390-64/mmap.S | 2 | ||||
-rw-r--r-- | sysdeps/unix/sysv/linux/s390/s390-64/socket.S | 2 | ||||
-rw-r--r-- | sysdeps/unix/sysv/linux/s390/s390-64/syscall.S | 2 | ||||
-rw-r--r-- | sysdeps/unix/sysv/linux/s390/s390-64/sysdep.S | 113 | ||||
-rw-r--r-- | sysdeps/unix/sysv/linux/s390/s390-64/sysdep.h | 65 |
9 files changed, 290 insertions, 159 deletions
diff --git a/sysdeps/unix/sysv/linux/s390/s390-32/clone.S b/sysdeps/unix/sysv/linux/s390/s390-32/clone.S index c93570e..23fb464 100644 --- a/sysdeps/unix/sysv/linux/s390/s390-32/clone.S +++ b/sysdeps/unix/sysv/linux/s390/s390-32/clone.S @@ -24,20 +24,24 @@ #define _ERRNO_H 1 #include <bits/errno.h> -/*int __clone(int (*fn)(void *arg), void *child_stack, int flags, void *arg);*/ -/* sys_clone(void *child_stack, unsigned long flags) */ +/* int __clone(int (*fn)(void *arg), void *child_stack, int flags, void *arg, + void *tls, pid_t *parent_tid, pid_t *child_tid); */ +/* sys_clone (void *child_stack, unsigned long flags, + pid_t *parent_tid, pid_t *child_tid, void *tls); */ .text ENTRY(__clone) /* Sanity check arguments & move registers */ + lr %r0,%r5 /* move *arg out of the way */ ltr %r1,%r2 /* no NULL function pointers */ lhi %r2,-EINVAL jz SYSCALL_ERROR_LABEL ltr %r3,%r3 /* no NULL stack pointers */ jz SYSCALL_ERROR_LABEL - /* move child_stack and flags, then call SVC */ + /* set up registers, then call SVC */ lr %r2,%r3 lr %r3,%r4 + lm %r4,%r5,96(%r15) svc SYS_ify(clone) ltr %r2,%r2 /* check return code */ jm SYSCALL_ERROR_LABEL @@ -45,10 +49,10 @@ ENTRY(__clone) br %r14 thread_start: - /* fn is in gpr 1, arg in gpr 5 */ - lr %r2,%r5 /* set first parameter to void *arg */ - sr %r11,%r11 /* terminate the stack frame */ + /* fn is in gpr 1, arg in gpr 0 */ + lr %r2,%r0 /* set first parameter to void *arg */ ahi %r15,-96 /* make room on the stack for the save area */ + xc 0(4,%r15),0(%r15) basr %r14,%r1 /* jump to fn */ #ifdef PIC basr %r12,0 diff --git a/sysdeps/unix/sysv/linux/s390/s390-32/sysdep.S b/sysdeps/unix/sysv/linux/s390/s390-32/sysdep.S index 98b0072..94d772f 100644 --- a/sysdeps/unix/sysv/linux/s390/s390-32/sysdep.S +++ b/sysdeps/unix/sysv/linux/s390/s390-32/sysdep.S @@ -1,4 +1,4 @@ -/* Copyright (C) 2000, 2001, 2002 Free Software Foundation, Inc. +/* Copyright (C) 2000, 2001, 2002, 2003 Free Software Foundation, Inc. Contributed by Martin Schwidefsky (schwidefsky@de.ibm.com). This file is part of the GNU C Library. @@ -31,59 +31,94 @@ .text ENTRY(__syscall_error) #ifndef PIC -#ifndef _LIBC_REENTRANT - lcr %r2,%r2 - basr %r1,0 -.L0: l %r1,.L1-.L0(%r1) - st %r2,0(0,%r1) - lhi %r2,-1 - br %r14 -.L1: .long errno -#else - stm %r11,%r15,44(%r15) - lr %r0,%r15 - ahi %r15,-96 - st %r0,0(%r15) - lcr %r11,%r2 - basr %r13,0 -.L0: l %r1,.L1-.L0(%r13) - basr %r14,%r1 - st %r11,0(%r2) - lhi %r2,-1 - l %r15,0(%r15) - lm %r11,%r15,44(%r15) - br %r14 -.L1: .long __errno_location +# if USE___THREAD +# ifndef NOT_IN_libc +# define SYSCALL_ERROR_ERRNO __libc_errno +# else +# define SYSCALL_ERROR_ERRNO errno +# endif + basr %r1,0 +0: l %r1,1f-0b(%r1) + ear %r3,%a0 + lcr %r2,%r2 + st %r2,0(%r1,%r3) + lhi %r2,-1 + br %r14 +1: .long SYSCALL_ERROR_ERRNO@ntpoff +# elif !defined _LIBC_REENTRANT + basr %r1,0 +0: l %r1,1f-0b(%r1) + lcr %r2,%r2 + st %r2,0(%r1) + lhi %r2,-1 + br %r14 +1: .long errno +# else + stm %r13,%r15,52(%r15) + lr %r0,%r15 + ahi %r15,-96 + lcr %r13,%r2 + st %r0,0(%r15) + basr %r1,0 +0: l %r1,1f-0b(%r1) + basr %r14,%r1 + st %r13,0(%r2) + lm %r13,%r15,148(%r15) + lhi %r2,-1 + br %r14 +1: .long __errno_location #endif #else -#ifndef _LIBC_REENTRANT - basr %r1,0 -.L0: al %r1,.L1-.L0(%r1) - l %r1,errno@GOT12(%r1) - lcr %r2,%r2 - st %r2,0(0,%r1) - lhi %r2,-1 - br %r14 -.L1: .long _GLOBAL_OFFSET_TABLE_-0b -#else - stm %r11,%r15,44(%r15) - lr %r0,%r15 - ahi %r15,-96 - st %r0,0(%r15) - lcr %r11,%r2 - basr %r13,0 -.L0: l %r12,.L1-.L0(%r13) - ar %r12,%r13 - l %r14,.L2-.L0(%r13) - bas %r14,0(%r14,%r13) - st %r11,0(0,%r2) - lhi %r2,-1 - l %r15,0(%r15) - lm %r11,%r15,44(%r15) - br %r14 -.L1: .long _GLOBAL_OFFSET_TABLE_ - .L0 -.L2: .long __errno_location@PLT - .L0 -#endif +# if RTLD_PRIVATE_ERRNO + basr %r1,0 +0: al %r1,1f-0b(%r1) + lcr %r2,%r2 + st %r2,0(%r1) + lhi %r2,-1 + br %r14 +1: .long errno - 0b +# elif USE___THREAD +# ifndef NOT_IN_libc +# define SYSCALL_ERROR_ERRNO __libc_errno +# else +# define SYSCALL_ERROR_ERRNO errno +# endif + basr %r1,0 +0: al %r1,1f-0b(%r1) + ear %r3,%a0 + l %r1,SYSCALL_ERROR_ERRNO@gotntpoff(%r1) + lcr %r2,%r2 + st %r2,0(%r1,%r3) + lhi %r2,-1 + br %r14 +1: .long _GLOBAL_OFFSET_TABLE_-0b +# elif !defined _LIBC_REENTRANT + basr %r1,0 +0: al %r1,1f-0b(%r1) + l %r1,errno@GOT(%r1) + lcr %r2,%r2 + st %r2,0(0,%r1) + lhi %r2,-1 + br %r14 +1: .long _GLOBAL_OFFSET_TABLE_-0b +# else + stm %r11,%r15,44(%r15) + lr %r0,%r15 + ahi %r15,-96 + lcr %r11,%r2 + st %r0,0(%r15) + basr %r13,0 +0: l %r12,1f-0b(%r13) + l %r1,2f-0b(%r13) + la %r12,0(%r12,%r13) + bas %r14,0(%r1,%r13) + st %r11,0(%r2) + lm %r11,%r15,140(%r15) + lhi %r2,-1 + br %r14 +1: .long _GLOBAL_OFFSET_TABLE_-0b +2: .long __errno_location@PLT-0b +# endif #endif END (__syscall_error) diff --git a/sysdeps/unix/sysv/linux/s390/s390-32/sysdep.h b/sysdeps/unix/sysv/linux/s390/s390-32/sysdep.h index e89e6a1..f7bfb8d 100644 --- a/sysdeps/unix/sysv/linux/s390/s390-32/sysdep.h +++ b/sysdeps/unix/sysv/linux/s390/s390-32/sysdep.h @@ -45,8 +45,6 @@ number. Linus said he will make sure the no syscall returns a value in -1 .. -4095 as a valid result so we can savely test with -4095. */ -#define SYSCALL_ERROR_LABEL 0f - #undef PSEUDO #define PSEUDO(name, syscall_name, args) \ .text; \ @@ -54,42 +52,70 @@ DO_CALL (syscall_name, args); \ lhi %r4,-4095 ; \ clr %r2,%r4 ; \ - jnl SYSCALL_ERROR_LABEL ; \ - L(pseudo_end): + jnl SYSCALL_ERROR_LABEL #undef PSEUDO_END #define PSEUDO_END(name) \ SYSCALL_ERROR_HANDLER; \ END (name) -#ifndef _LIBC_REENTRANT #ifndef PIC -#define SYSCALL_ERROR_HANDLER \ -0: lcr %r2,%r2 ; \ - basr %r1,0 ; \ -1: l %r1,2f-1b(%r1) \ - st %r2,0(%r1) \ - lhi %r2,-1 \ - br %r14 \ -2: .long errno +# define SYSCALL_ERROR_LABEL 0f +# define SYSCALL_ERROR_HANDLER \ +0: basr %r1,0; \ +1: l %r1,2f-1b(%r1); \ + br %r1; \ +2: .long syscall_error #else -#define SYSCALL_ERROR_HANDLER \ -0: basr %r1,0 ; \ -1: al %r1,2f-1b(%r1) ; \ - l %r1,errno@GOT12(%r1) ; \ - lcr %r2,%r2 ; \ - st %r2,0(%r1) ; \ - lhi %r2,-1 ; \ - br %r14 ; \ -2: .long _GLOBAL_OFFSET_TABLE_-1b +# if RTLD_PRIVATE_ERRNO +# define SYSCALL_ERROR_LABEL 0f +# define SYSCALL_ERROR_HANDLER \ +0: basr %r1,0; \ +1: al %r1,2f-1b(%r1); \ + lcr %r2,%r2; \ + st %r2,0(%r1); \ + lhi %r2,-1; \ + br %r14; \ +2: .long errno-1b +# elif defined _LIBC_REENTRANT +# if USE___THREAD +# ifndef NOT_IN_libc +# define SYSCALL_ERROR_ERRNO __libc_errno +# else +# define SYSCALL_ERROR_ERRNO errno +# endif +# define SYSCALL_ERROR_LABEL 0f +# define SYSCALL_ERROR_HANDLER \ +0: lcr %r0,%r2; \ + basr %r1,0; \ +1: al %r1,2f-1b(%r1); \ + l %r1,SYSCALL_ERROR_ERRNO@gotntpoff(%r1) \ + ear %r2,%a0 \ + st %r0,0(%r1,%r2); \ + lhi %r2,-1; \ + br %r14; \ +2: .long _GLOBAL_OFFSET_TABLE_-1b +# else +# define SYSCALL_ERROR_LABEL 0f +# define SYSCALL_ERROR_HANDLER \ +0: basr %r1,0; \ +1: al %r1,2f-1b(%r1); \ + br %r1; \ +2: .long syscall_error@plt-1b +# endif +# else +# define SYSCALL_ERROR_LABEL 0f +# define SYSCALL_ERROR_HANDLER \ +0: basr %r1,0; \ +1: al %r1,2f-1b(%r1); \ + l %r1,errno@GOT(%r1); \ + lcr %r2,%r2; \ + st %r2,0(%r1); \ + lhi %r2,-1; \ + br %r14; \ +2: .long _GLOBAL_OFFSET_TABLE_-1b +# endif /* _LIBC_REENTRANT */ #endif /* PIC */ -#else -#define SYSCALL_ERROR_HANDLER \ -0: basr %r1,0 ; \ -1: al %r1,2f-1b(%r1) ; \ - br %r1 ; \ -2: .long __syscall_error@PLT-1b -#endif /* _LIBC_REENTRANT */ /* Linux takes system call arguments in registers: diff --git a/sysdeps/unix/sysv/linux/s390/s390-64/clone.S b/sysdeps/unix/sysv/linux/s390/s390-64/clone.S index 992cb2f..1174118 100644 --- a/sysdeps/unix/sysv/linux/s390/s390-64/clone.S +++ b/sysdeps/unix/sysv/linux/s390/s390-64/clone.S @@ -25,32 +25,40 @@ #define _ERRNO_H 1 #include <bits/errno.h> +/* int __clone(int (*fn)(void *arg), void *child_stack, int flags, void *arg, + void *tls, pid_t *parent_tid, pid_t *child_tid); */ +/* sys_clone (void *child_stack, unsigned long flags, + pid_t *parent_tid, pid_t *child_tid, void *tls); */ + .text ENTRY(__clone) /* Sanity check arguments & move registers */ + lgr %r0,%r5 /* move *arg out of the way */ ltgr %r1,%r2 /* no NULL function pointers */ lghi %r2,-EINVAL - jz SYSCALL_ERROR_LABEL + jgz SYSCALL_ERROR_LABEL ltgr %r3,%r3 /* no NULL stack pointers */ - jz SYSCALL_ERROR_LABEL - /* move child_stack and flags, then call SVC */ + jgz SYSCALL_ERROR_LABEL + /* set up registers, then call SVC */ lgr %r2,%r3 lgr %r3,%r4 + lmg %r4,%r5,160(%r15) svc SYS_ify(clone) ltgr %r2,%r2 /* check return code */ - jm SYSCALL_ERROR_LABEL + jgm SYSCALL_ERROR_LABEL jz thread_start br %r14 thread_start: - /* fn is in gpr 1, arg in gpr 5 */ - lgr %r2,%r5 /* set first parameter to void *arg */ - sgr %r11,%r11 /* terminate the stack frame */ + /* fn is in gpr 1, arg in gpr 0 */ + lgr %r2,%r0 /* set first parameter to void *arg */ aghi %r15,-160 /* make room on the stack for the save area */ + xc 0(8,%r15),0(%r15) basr %r14,%r1 /* jump to fn */ #ifdef PIC - larl %r12,_GLOBAL_OFFSET_TABLE_ -#endif jg _exit@PLT /* branch to _exit -> thread termination */ +#else + jg _exit /* branch to _exit -> thread termination */ +#endif PSEUDO_END (__clone) weak_alias (__clone, clone) diff --git a/sysdeps/unix/sysv/linux/s390/s390-64/mmap.S b/sysdeps/unix/sysv/linux/s390/s390-64/mmap.S index 2320590..8c94fd4 100644 --- a/sysdeps/unix/sysv/linux/s390/s390-64/mmap.S +++ b/sysdeps/unix/sysv/linux/s390/s390-64/mmap.S @@ -55,7 +55,7 @@ ENTRY(__mmap) /* Check gpr 2 for error. */ lghi %r0,-4096 clgr %r2,%r0 - jnl SYSCALL_ERROR_LABEL + jgnl SYSCALL_ERROR_LABEL /* Successful; return the syscall's value. */ br %r14 diff --git a/sysdeps/unix/sysv/linux/s390/s390-64/socket.S b/sysdeps/unix/sysv/linux/s390/s390-64/socket.S index c9bd02b..3a2454e 100644 --- a/sysdeps/unix/sysv/linux/s390/s390-64/socket.S +++ b/sysdeps/unix/sysv/linux/s390/s390-64/socket.S @@ -93,7 +93,7 @@ ENTRY(__socket) /* gpr2 is < 0 if there was an error. */ lghi %r0,-125 clgr %r2,%r0 - jnl SYSCALL_ERROR_LABEL + jgnl SYSCALL_ERROR_LABEL /* Successful; return the syscall's value. */ br %r14 diff --git a/sysdeps/unix/sysv/linux/s390/s390-64/syscall.S b/sysdeps/unix/sysv/linux/s390/s390-64/syscall.S index 047c667..718d559 100644 --- a/sysdeps/unix/sysv/linux/s390/s390-64/syscall.S +++ b/sysdeps/unix/sysv/linux/s390/s390-64/syscall.S @@ -45,7 +45,7 @@ ENTRY (syscall) lghi %r0,-4095 clgr %r2,%r0 /* Check R2 for error. */ - jnl SYSCALL_ERROR_LABEL + jgnl SYSCALL_ERROR_LABEL br %r14 /* Return to caller. */ .L1: .word 0x0A00 /* Opcode for SVC 0. */ PSEUDO_END (syscall) diff --git a/sysdeps/unix/sysv/linux/s390/s390-64/sysdep.S b/sysdeps/unix/sysv/linux/s390/s390-64/sysdep.S index a29b0b9..84c747a 100644 --- a/sysdeps/unix/sysv/linux/s390/s390-64/sysdep.S +++ b/sysdeps/unix/sysv/linux/s390/s390-64/sysdep.S @@ -1,4 +1,4 @@ -/* Copyright (C) 2001, 2002 Free Software Foundation, Inc. +/* Copyright (C) 2001, 2002, 2003 Free Software Foundation, Inc. Contributed by Martin Schwidefsky (schwidefsky@de.ibm.com). This file is part of the GNU C Library. @@ -29,47 +29,84 @@ #undef CALL_MCOUNT #define CALL_MCOUNT - .text +.text ENTRY(__syscall_error) #ifndef PIC -#ifndef _LIBC_REENTRANT - lcr %r2,%r2 - larl %r1,errno - st %r2,0(%r1) - lghi %r2,-1 - br %r14 -#else - stmg %r13,%r15,104(%r15) - lgr %r0,%r15 - aghi %r15,-160 - lcr %r13,%r2 - stg %r0,0(%r15) - brasl %r14,__errno_location - st %r13,0(%r2) - lmg %r13,%r15,264(%r15) - lghi %r2,-1 - br %r14 +# if USE___THREAD +# ifndef NOT_IN_libc +# define SYSCALL_ERROR_ERRNO __libc_errno +# else +# define SYSCALL_ERROR_ERRNO errno +# endif + basr %r1,0 +0: lg %r1,1f-0b(%r1) + ear %r3,%a0 + sllg %r3,%r3,32 + ear %r3,%a1 + lcr %r2,%r2 + st %r2,0(%r1,%r3) + lghi %r2,-1 + br %r14 +1: .quad SYSCALL_ERROR_ERRNO@ntpoff +# elif !defined _LIBC_REENTRANT + larl %r1,errno + lcr %r2,%r2 + st %r2,0(%r1) + lghi %r2,-1 + br %r14 +# else + stmg %r13,%r15,104(%r15) + lgr %r0,%r15 + aghi %r15,-160 + lcr %r13,%r2 + stg %r0,0(%r15) + brasl %r14,__errno_location + st %r13,0(%r2) + lmg %r13,%r15,264(%r15) + lghi %r2,-1 + br %r14 #endif #else -#ifndef _LIBC_REENTRANT - larl %r1,_GLOBAL_OFFSET_TABLE_ - lg %r1,errno@GOT(%r1) - lcr %r2,%r2 - st %r2,0(%r1) - lghi %r2,-1 - br %r14 -#else - stmg %r13,%r15,104(%r15) - lgr %r0,%r15 - aghi %r15,-160 - lcr %r13,%r2 - stg %r0,0(%r15) - brasl %r14,__errno_location@PLT - st %r13,0(%r2) - lmg %r13,%r15,264(%r15) - lghi %r2,-1 - br %r14 -#endif +# if RTLD_PRIVATE_ERRNO + larl %r1,errno + lcr %r2,%r2 + st %r2,0(%r1) + lghi %r2,-1 + br %r14 +# elif USE___THREAD +# ifndef NOT_IN_libc +# define SYSCALL_ERROR_ERRNO __libc_errno +# else +# define SYSCALL_ERROR_ERRNO errno +# endif + larl %r1,_GLOBAL_OFFSET_TABLE_ + lg %r1,SYSCALL_ERROR_ERRNO@gotntpoff(%r1) + ear %r3,%a0 + sllg %r3,%r3,32 + ear %r3,%a1 + lcr %r2,%r2 + st %r2,0(%r1,%r3) + lghi %r2,-1 + br %r14 +# elif !defined _LIBC_REENTRANT + larl %r1,_GLOBAL_OFFSET_TABLE_ + lg %r1,errno@GOT(%r1) + lcr %r2,%r2 + st %r2,0(%r1) + lghi %r2,-1 + br %r14 +# else + stmg %r13,%r15,104(%r15) + lgr %r0,%r15 + aghi %r15,-160 + lcr %r13,%r2 + stg %r0,0(%r15) + brasl %r14,__errno_location@PLT + st %r13,0(%r2) + lmg %r13,%r15,264(%r15) + lghi %r2,-1 + br %r14 +# endif #endif END (__syscall_error) diff --git a/sysdeps/unix/sysv/linux/s390/s390-64/sysdep.h b/sysdeps/unix/sysv/linux/s390/s390-64/sysdep.h index dbe77df..976fd26 100644 --- a/sysdeps/unix/sysv/linux/s390/s390-64/sysdep.h +++ b/sysdeps/unix/sysv/linux/s390/s390-64/sysdep.h @@ -46,8 +46,6 @@ number. Linus said he will make sure the no syscall returns a value in -1 .. -4095 as a valid result so we can savely test with -4095. */ -#define SYSCALL_ERROR_LABEL 0f - #undef PSEUDO #define PSEUDO(name, syscall_name, args) \ .text; \ @@ -55,35 +53,58 @@ DO_CALL (syscall_name, args); \ lghi %r4,-4095 ; \ clgr %r2,%r4 ; \ - jnl SYSCALL_ERROR_LABEL ; \ - L(pseudo_end): + jgnl SYSCALL_ERROR_LABEL #undef PSEUDO_END #define PSEUDO_END(name) \ SYSCALL_ERROR_HANDLER; \ END (name) -#ifndef _LIBC_REENTRANT #ifndef PIC -#define SYSCALL_ERROR_HANDLER \ -0: lcr %r2,%r2 ; \ - larl %r1,errno ; \ - st %r2,0(%r1) ; \ - lghi %r2,-1 ; \ - br %r14 +# define SYSCALL_ERROR_LABEL syscall_error +# define SYSCALL_ERROR_HANDLER #else -#define SYSCALL_ERROR_HANDLER \ -0: larl %r1,_GLOBAL_OFFSET_TABLE_ ; \ - lg %r1,errno@GOT(%r1) ; \ - lcr %r2,%r2 ; \ - st %r2,0(%r1) ; \ - lghi %r2,-1 ; \ - br %r14 +# if RTLD_PRIVATE_ERRNO +# define SYSCALL_ERROR_LABEL 0f +# define SYSCALL_ERROR_HANDLER \ +0: larl %r1,errno; \ + lcr %r2,%r2; \ + st %r2,0(%r1); \ + lghi %r2,-1; \ + br %r14 +# elif defined _LIBC_REENTRANT +# if USE___THREAD +# ifndef NOT_IN_libc +# define SYSCALL_ERROR_ERRNO __libc_errno +# else +# define SYSCALL_ERROR_ERRNO errno +# endif +# define SYSCALL_ERROR_LABEL 0f +# define SYSCALL_ERROR_HANDLER \ +0: lcr %r0,%r2; \ + larl %r1,SYSCALL_ERROR_ERRNO@indntpoff; \ + lg %r1,0(%r1); \ + ear %r2,%a0; \ + sllg %r2,%r2,32; \ + ear %r2,%a1; \ + st %r0,0(%r1,%r2); \ + lghi %r2,-1; \ + br %r14 +# else +# define SYSCALL_ERROR_LABEL syscall_error@plt +# define SYSCALL_ERROR_HANDLER +# endif +# else +# define SYSCALL_ERROR_LABEL 0f +# define SYSCALL_ERROR_HANDLER \ +0: larl %r1,_GLOBAL_OFFSET_TABLE_; \ + lg %r1,errno@GOT(%r1); \ + lcr %r2,%r2; \ + st %r2,0(%r1); \ + lghi %r2,-1; \ + br %r14 +# endif /* _LIBC_REENTRANT */ #endif /* PIC */ -#else -#define SYSCALL_ERROR_HANDLER \ -0: jg __syscall_error@PLT -#endif /* _LIBC_REENTRANT */ /* Linux takes system call arguments in registers: |