linux/arch/powerpc/kernel/syscalls.c
Balbir Singh 9c355917fc powerpc/tracing: Allow tracing of mmap syscalls
Currently sys_mmap() and sys_mmap2() (32-bit only), are not visible to the
syscall tracing machinery. This means users are not able to see the execution of
mmap() syscalls using the syscall tracer.

Fix that by using SYSCALL_DEFINE6 for sys_mmap() and sys_mmap2() so that the
meta-data associated with these syscalls is visible to the syscall tracer.

A side-effect of this change is that the return type has changed from unsigned
long to long. However this should have no effect, the only code in the kernel
which uses the result of these syscalls is in the syscall return path, which is
written in asm and treats the result as unsigned regardless.

Example output:
  cat-3399  [001] ....   196.542410: sys_mmap(addr: 7fff922a0000, len: 20000, prot: 3, flags: 812, fd: 3, offset: 1b0000)
  cat-3399  [001] ....   196.542443: sys_mmap -> 0x7fff922a0000
  cat-3399  [001] ....   196.542668: sys_munmap(addr: 7fff922c0000, len: 6d2c)
  cat-3399  [001] ....   196.542677: sys_munmap -> 0x0

Signed-off-by: Balbir Singh <bsingharora@gmail.com>
[mpe: Massage change log, add detail on return type change]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-04-12 22:32:43 +10:00

142 lines
3.8 KiB
C

/*
* Implementation of various system calls for Linux/PowerPC
*
* Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
*
* Derived from "arch/i386/kernel/sys_i386.c"
* Adapted from the i386 version by Gary Thomas
* Modified by Cort Dougan (cort@cs.nmt.edu)
* and Paul Mackerras (paulus@cs.anu.edu.au).
*
* This file contains various random system calls that
* have a non-standard calling sequence on the Linux/PPC
* platform.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
*/
#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/syscalls.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/mman.h>
#include <linux/sys.h>
#include <linux/ipc.h>
#include <linux/utsname.h>
#include <linux/file.h>
#include <linux/personality.h>
#include <linux/uaccess.h>
#include <asm/syscalls.h>
#include <asm/time.h>
#include <asm/unistd.h>
#include <asm/asm-prototypes.h>
static inline long do_mmap2(unsigned long addr, size_t len,
unsigned long prot, unsigned long flags,
unsigned long fd, unsigned long off, int shift)
{
long ret = -EINVAL;
if (!arch_validate_prot(prot))
goto out;
if (shift) {
if (off & ((1 << shift) - 1))
goto out;
off >>= shift;
}
ret = sys_mmap_pgoff(addr, len, prot, flags, fd, off);
out:
return ret;
}
SYSCALL_DEFINE6(mmap2, unsigned long, addr, size_t, len,
unsigned long, prot, unsigned long, flags,
unsigned long, fd, unsigned long, pgoff)
{
return do_mmap2(addr, len, prot, flags, fd, pgoff, PAGE_SHIFT-12);
}
SYSCALL_DEFINE6(mmap, unsigned long, addr, size_t, len,
unsigned long, prot, unsigned long, flags,
unsigned long, fd, off_t, offset)
{
return do_mmap2(addr, len, prot, flags, fd, offset, PAGE_SHIFT);
}
#ifdef CONFIG_PPC32
/*
* Due to some executables calling the wrong select we sometimes
* get wrong args. This determines how the args are being passed
* (a single ptr to them all args passed) then calls
* sys_select() with the appropriate args. -- Cort
*/
int
ppc_select(int n, fd_set __user *inp, fd_set __user *outp, fd_set __user *exp, struct timeval __user *tvp)
{
if ( (unsigned long)n >= 4096 )
{
unsigned long __user *buffer = (unsigned long __user *)n;
if (!access_ok(VERIFY_READ, buffer, 5*sizeof(unsigned long))
|| __get_user(n, buffer)
|| __get_user(inp, ((fd_set __user * __user *)(buffer+1)))
|| __get_user(outp, ((fd_set __user * __user *)(buffer+2)))
|| __get_user(exp, ((fd_set __user * __user *)(buffer+3)))
|| __get_user(tvp, ((struct timeval __user * __user *)(buffer+4))))
return -EFAULT;
}
return sys_select(n, inp, outp, exp, tvp);
}
#endif
#ifdef CONFIG_PPC64
long ppc64_personality(unsigned long personality)
{
long ret;
if (personality(current->personality) == PER_LINUX32
&& personality(personality) == PER_LINUX)
personality = (personality & ~PER_MASK) | PER_LINUX32;
ret = sys_personality(personality);
if (personality(ret) == PER_LINUX32)
ret = (ret & ~PER_MASK) | PER_LINUX;
return ret;
}
#endif
long ppc_fadvise64_64(int fd, int advice, u32 offset_high, u32 offset_low,
u32 len_high, u32 len_low)
{
return sys_fadvise64(fd, (u64)offset_high << 32 | offset_low,
(u64)len_high << 32 | len_low, advice);
}
long sys_switch_endian(void)
{
struct thread_info *ti;
current->thread.regs->msr ^= MSR_LE;
/*
* Set TIF_RESTOREALL so that r3 isn't clobbered on return to
* userspace. That also has the effect of restoring the non-volatile
* GPRs, so we saved them on the way in here.
*/
ti = current_thread_info();
ti->flags |= _TIF_RESTOREALL;
return 0;
}