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uml: redo the calculation of NR_syscalls

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Redo the calculation of NR_syscalls since that disappeared from i386 and
use a similar mechanism on x86_64.

We now figure out the size of the system call table in arch code and stick
that in syscall_table_size.  arch/um/kernel/skas/syscall.c defines
NR_syscalls in terms of that since its the only thing that needs to know
how many system calls there are.

The old mechananism that was used on x86_64 is gone.

arch/um/include/sysdep-i386/syscalls.h got some formatting since I was
looking at it.

Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Cc: WANG Cong <xiyou.wangcong@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Jeff Dike 2008-02-04 22:31:29 -08:00 committed by Linus Torvalds
parent 966f1d8f34
commit f87ea91d98
6 changed files with 25 additions and 19 deletions
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5
arch/um/include/sysdep-i386/syscalls.h
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@ -1,5 +1,5 @@
/*
* Copyright (C) 2000 Jeff Dike (jdike@karaya.com)
* Copyright (C) 2000 - 2008 Jeff Dike (jdike@{addtoit,linux.intel}.com)
* Licensed under the GPL
*/
@ -18,7 +18,8 @@ extern syscall_handler_t old_mmap_i386;
extern syscall_handler_t *sys_call_table[];
#define EXECUTE_SYSCALL(syscall, regs) \
((long (*)(struct syscall_args)) (*sys_call_table[syscall]))(SYSCALL_ARGS(&regs->regs))
((long (*)(struct syscall_args)) \
(*sys_call_table[syscall]))(SYSCALL_ARGS(&regs->regs))
extern long sys_mmap2(unsigned long addr, unsigned long len,
unsigned long prot, unsigned long flags,

9
arch/um/include/sysdep-x86_64/kernel-offsets.h
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@ -17,16 +17,7 @@
#define OFFSET(sym, str, mem) \
DEFINE(sym, offsetof(struct str, mem));
#define __NO_STUBS 1
#undef __SYSCALL
#undef _ASM_X86_64_UNISTD_H_
#define __SYSCALL(nr, sym) [nr] = 1,
static char syscalls[] = {
#include <asm/arch/unistd.h>
};
void foo(void)
{
#include <common-offsets.h>
DEFINE(UM_NR_syscall_max, sizeof(syscalls) - 1);
}

2
arch/um/include/sysdep-x86_64/syscalls.h
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@ -30,6 +30,4 @@ extern long old_mmap(unsigned long addr, unsigned long len,
extern syscall_handler_t sys_modify_ldt;
extern syscall_handler_t sys_arch_prctl;
#define NR_syscalls (UM_NR_syscall_max + 1)
#endif

3
arch/um/kernel/skas/syscall.c
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@ -9,6 +9,9 @@
#include "sysdep/ptrace.h"
#include "sysdep/syscalls.h"
extern int syscall_table_size;
#define NR_syscalls (syscall_table_size / sizeof(void *))
void handle_syscall(struct uml_pt_regs *r)
{
struct pt_regs *regs = container_of(r, struct pt_regs, regs);

5
arch/um/sys-i386/sys_call_table.S
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@ -9,4 +9,9 @@
#define old_mmap old_mmap_i386
.section .rodata,"a"
#include "../../x86/kernel/syscall_table_32.S"
ENTRY(syscall_table_size)
.long .-sys_call_table

20
arch/um/sys-x86_64/syscall_table.c
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@ -52,11 +52,19 @@ typedef void (*sys_call_ptr_t)(void);
extern void sys_ni_syscall(void);
sys_call_ptr_t sys_call_table[UM_NR_syscall_max+1] __cacheline_aligned = {
/*
* Smells like a like a compiler bug -- it doesn't work when the &
* below is removed.
*/
[0 ... UM_NR_syscall_max] = &sys_ni_syscall,
/*
* We used to have a trick here which made sure that holes in the
* x86_64 table were filled in with sys_ni_syscall, but a comment in
* unistd_64.h says that holes aren't allowed, so the trick was
* removed.
* The trick looked like this
* [0 ... UM_NR_syscall_max] = &sys_ni_syscall
* before including unistd_64.h - the later initializations overwrote
* the sys_ni_syscall filler.
*/
sys_call_ptr_t sys_call_table[] __cacheline_aligned = {
#include <asm-x86/unistd_64.h>
};
int syscall_table_size = sizeof(sys_call_table);