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linux/arch/m32r/kernel/sys_m32r.c
David Howells d7627467b7 Make do_execve() take a const filename pointer
Make do_execve() take a const filename pointer so that kernel_execve() compiles
correctly on ARM:

arch/arm/kernel/sys_arm.c:88: warning: passing argument 1 of 'do_execve' discards qualifiers from pointer target type

This also requires the argv and envp arguments to be consted twice, once for
the pointer array and once for the strings the array points to.  This is
because do_execve() passes a pointer to the filename (now const) to
copy_strings_kernel().  A simpler alternative would be to cast the filename
pointer in do_execve() when it's passed to copy_strings_kernel().

do_execve() may not change any of the strings it is passed as part of the argv
or envp lists as they are some of them in .rodata, so marking these strings as
const should be fine.

Further kernel_execve() and sys_execve() need to be changed to match.

This has been test built on x86_64, frv, arm and mips.

Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: Ralf Baechle <ralf@linux-mips.org>
Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-17 18:07:43 -07:00

112 lines
2.5 KiB
C

/*
* linux/arch/m32r/kernel/sys_m32r.c
*
* This file contains various random system calls that
* have a non-standard calling sequence on the Linux/M32R platform.
*
* Taken from i386 version.
*/
#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/fs.h>
#include <linux/smp.h>
#include <linux/sem.h>
#include <linux/msg.h>
#include <linux/shm.h>
#include <linux/stat.h>
#include <linux/syscalls.h>
#include <linux/mman.h>
#include <linux/file.h>
#include <linux/utsname.h>
#include <linux/ipc.h>
#include <asm/uaccess.h>
#include <asm/cachectl.h>
#include <asm/cacheflush.h>
#include <asm/syscall.h>
#include <asm/unistd.h>
/*
* sys_tas() - test-and-set
*/
asmlinkage int sys_tas(int __user *addr)
{
int oldval;
if (!access_ok(VERIFY_WRITE, addr, sizeof (int)))
return -EFAULT;
/* atomic operation:
* oldval = *addr; *addr = 1;
*/
__asm__ __volatile__ (
DCACHE_CLEAR("%0", "r4", "%1")
" .fillinsn\n"
"1:\n"
" lock %0, @%1 -> unlock %2, @%1\n"
"2:\n"
/* NOTE:
* The m32r processor can accept interrupts only
* at the 32-bit instruction boundary.
* So, in the above code, the "unlock" instruction
* can be executed continuously after the "lock"
* instruction execution without any interruptions.
*/
".section .fixup,\"ax\"\n"
" .balign 4\n"
"3: ldi %0, #%3\n"
" seth r14, #high(2b)\n"
" or3 r14, r14, #low(2b)\n"
" jmp r14\n"
".previous\n"
".section __ex_table,\"a\"\n"
" .balign 4\n"
" .long 1b,3b\n"
".previous\n"
: "=&r" (oldval)
: "r" (addr), "r" (1), "i"(-EFAULT)
: "r14", "memory"
#ifdef CONFIG_CHIP_M32700_TS1
, "r4"
#endif /* CONFIG_CHIP_M32700_TS1 */
);
return oldval;
}
asmlinkage int sys_cacheflush(void *addr, int bytes, int cache)
{
/* This should flush more selectively ... */
_flush_cache_all();
return 0;
}
asmlinkage int sys_cachectl(char *addr, int nbytes, int op)
{
/* Not implemented yet. */
return -ENOSYS;
}
/*
* Do a system call from kernel instead of calling sys_execve so we
* end up with proper pt_regs.
*/
int kernel_execve(const char *filename,
const char *const argv[],
const char *const envp[])
{
register long __scno __asm__ ("r7") = __NR_execve;
register long __arg3 __asm__ ("r2") = (long)(envp);
register long __arg2 __asm__ ("r1") = (long)(argv);
register long __res __asm__ ("r0") = (long)(filename);
__asm__ __volatile__ (
"trap #" SYSCALL_VECTOR "|| nop"
: "=r" (__res)
: "r" (__scno), "0" (__res), "r" (__arg2),
"r" (__arg3)
: "memory");
return __res;
}