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linux-next/arch/mips/kernel/syscall.c
David Daney 652b14aa84 MIPS: Enable heap randomization.
Based somewhat on the PPC implementation.

32-bit processes have the heap randomized in an 8MB space, 256MB for
64-bit processes.

Signed-off-by: David Daney <ddaney@caviumnetworks.com>
To: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/1479/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2010-08-05 13:26:06 +01:00

463 lines
10 KiB
C

/*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* Copyright (C) 1995, 1996, 1997, 2000, 2001, 05 by Ralf Baechle
* Copyright (C) 1999, 2000 Silicon Graphics, Inc.
* Copyright (C) 2001 MIPS Technologies, Inc.
*/
#include <linux/capability.h>
#include <linux/errno.h>
#include <linux/linkage.h>
#include <linux/mm.h>
#include <linux/fs.h>
#include <linux/smp.h>
#include <linux/mman.h>
#include <linux/ptrace.h>
#include <linux/sched.h>
#include <linux/string.h>
#include <linux/syscalls.h>
#include <linux/file.h>
#include <linux/utsname.h>
#include <linux/unistd.h>
#include <linux/sem.h>
#include <linux/msg.h>
#include <linux/shm.h>
#include <linux/compiler.h>
#include <linux/module.h>
#include <linux/ipc.h>
#include <linux/uaccess.h>
#include <linux/slab.h>
#include <linux/random.h>
#include <linux/elf.h>
#include <asm/asm.h>
#include <asm/branch.h>
#include <asm/cachectl.h>
#include <asm/cacheflush.h>
#include <asm/asm-offsets.h>
#include <asm/signal.h>
#include <asm/sim.h>
#include <asm/shmparam.h>
#include <asm/sysmips.h>
#include <asm/uaccess.h>
/*
* For historic reasons the pipe(2) syscall on MIPS has an unusual calling
* convention. It returns results in registers $v0 / $v1 which means there
* is no need for it to do verify the validity of a userspace pointer
* argument. Historically that used to be expensive in Linux. These days
* the performance advantage is negligible.
*/
asmlinkage int sysm_pipe(nabi_no_regargs volatile struct pt_regs regs)
{
int fd[2];
int error, res;
error = do_pipe_flags(fd, 0);
if (error) {
res = error;
goto out;
}
regs.regs[3] = fd[1];
res = fd[0];
out:
return res;
}
unsigned long shm_align_mask = PAGE_SIZE - 1; /* Sane caches */
EXPORT_SYMBOL(shm_align_mask);
#define COLOUR_ALIGN(addr,pgoff) \
((((addr) + shm_align_mask) & ~shm_align_mask) + \
(((pgoff) << PAGE_SHIFT) & shm_align_mask))
unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr,
unsigned long len, unsigned long pgoff, unsigned long flags)
{
struct vm_area_struct * vmm;
int do_color_align;
unsigned long task_size;
#ifdef CONFIG_32BIT
task_size = TASK_SIZE;
#else /* Must be CONFIG_64BIT*/
task_size = test_thread_flag(TIF_32BIT_ADDR) ? TASK_SIZE32 : TASK_SIZE;
#endif
if (len > task_size)
return -ENOMEM;
if (flags & MAP_FIXED) {
/* Even MAP_FIXED mappings must reside within task_size. */
if (task_size - len < addr)
return -EINVAL;
/*
* We do not accept a shared mapping if it would violate
* cache aliasing constraints.
*/
if ((flags & MAP_SHARED) &&
((addr - (pgoff << PAGE_SHIFT)) & shm_align_mask))
return -EINVAL;
return addr;
}
do_color_align = 0;
if (filp || (flags & MAP_SHARED))
do_color_align = 1;
if (addr) {
if (do_color_align)
addr = COLOUR_ALIGN(addr, pgoff);
else
addr = PAGE_ALIGN(addr);
vmm = find_vma(current->mm, addr);
if (task_size - len >= addr &&
(!vmm || addr + len <= vmm->vm_start))
return addr;
}
addr = current->mm->mmap_base;
if (do_color_align)
addr = COLOUR_ALIGN(addr, pgoff);
else
addr = PAGE_ALIGN(addr);
for (vmm = find_vma(current->mm, addr); ; vmm = vmm->vm_next) {
/* At this point: (!vmm || addr < vmm->vm_end). */
if (task_size - len < addr)
return -ENOMEM;
if (!vmm || addr + len <= vmm->vm_start)
return addr;
addr = vmm->vm_end;
if (do_color_align)
addr = COLOUR_ALIGN(addr, pgoff);
}
}
void arch_pick_mmap_layout(struct mm_struct *mm)
{
unsigned long random_factor = 0UL;
if (current->flags & PF_RANDOMIZE) {
random_factor = get_random_int();
random_factor = random_factor << PAGE_SHIFT;
if (TASK_IS_32BIT_ADDR)
random_factor &= 0xfffffful;
else
random_factor &= 0xffffffful;
}
mm->mmap_base = TASK_UNMAPPED_BASE + random_factor;
mm->get_unmapped_area = arch_get_unmapped_area;
mm->unmap_area = arch_unmap_area;
}
static inline unsigned long brk_rnd(void)
{
unsigned long rnd = get_random_int();
rnd = rnd << PAGE_SHIFT;
/* 8MB for 32bit, 256MB for 64bit */
if (TASK_IS_32BIT_ADDR)
rnd = rnd & 0x7ffffful;
else
rnd = rnd & 0xffffffful;
return rnd;
}
unsigned long arch_randomize_brk(struct mm_struct *mm)
{
unsigned long base = mm->brk;
unsigned long ret;
ret = PAGE_ALIGN(base + brk_rnd());
if (ret < mm->brk)
return mm->brk;
return ret;
}
SYSCALL_DEFINE6(mips_mmap, unsigned long, addr, unsigned long, len,
unsigned long, prot, unsigned long, flags, unsigned long,
fd, off_t, offset)
{
unsigned long result;
result = -EINVAL;
if (offset & ~PAGE_MASK)
goto out;
result = sys_mmap_pgoff(addr, len, prot, flags, fd, offset >> PAGE_SHIFT);
out:
return result;
}
SYSCALL_DEFINE6(mips_mmap2, unsigned long, addr, unsigned long, len,
unsigned long, prot, unsigned long, flags, unsigned long, fd,
unsigned long, pgoff)
{
if (pgoff & (~PAGE_MASK >> 12))
return -EINVAL;
return sys_mmap_pgoff(addr, len, prot, flags, fd, pgoff >> (PAGE_SHIFT-12));
}
save_static_function(sys_fork);
static int __used noinline
_sys_fork(nabi_no_regargs struct pt_regs regs)
{
return do_fork(SIGCHLD, regs.regs[29], &regs, 0, NULL, NULL);
}
save_static_function(sys_clone);
static int __used noinline
_sys_clone(nabi_no_regargs struct pt_regs regs)
{
unsigned long clone_flags;
unsigned long newsp;
int __user *parent_tidptr, *child_tidptr;
clone_flags = regs.regs[4];
newsp = regs.regs[5];
if (!newsp)
newsp = regs.regs[29];
parent_tidptr = (int __user *) regs.regs[6];
#ifdef CONFIG_32BIT
/* We need to fetch the fifth argument off the stack. */
child_tidptr = NULL;
if (clone_flags & (CLONE_CHILD_SETTID | CLONE_CHILD_CLEARTID)) {
int __user *__user *usp = (int __user *__user *) regs.regs[29];
if (regs.regs[2] == __NR_syscall) {
if (get_user (child_tidptr, &usp[5]))
return -EFAULT;
}
else if (get_user (child_tidptr, &usp[4]))
return -EFAULT;
}
#else
child_tidptr = (int __user *) regs.regs[8];
#endif
return do_fork(clone_flags, newsp, &regs, 0,
parent_tidptr, child_tidptr);
}
/*
* sys_execve() executes a new program.
*/
asmlinkage int sys_execve(nabi_no_regargs struct pt_regs regs)
{
int error;
char * filename;
filename = getname((char __user *) (long)regs.regs[4]);
error = PTR_ERR(filename);
if (IS_ERR(filename))
goto out;
error = do_execve(filename, (char __user *__user *) (long)regs.regs[5],
(char __user *__user *) (long)regs.regs[6], &regs);
putname(filename);
out:
return error;
}
SYSCALL_DEFINE1(set_thread_area, unsigned long, addr)
{
struct thread_info *ti = task_thread_info(current);
ti->tp_value = addr;
if (cpu_has_userlocal)
write_c0_userlocal(addr);
return 0;
}
static inline int mips_atomic_set(struct pt_regs *regs,
unsigned long addr, unsigned long new)
{
unsigned long old, tmp;
unsigned int err;
if (unlikely(addr & 3))
return -EINVAL;
if (unlikely(!access_ok(VERIFY_WRITE, addr, 4)))
return -EINVAL;
if (cpu_has_llsc && R10000_LLSC_WAR) {
__asm__ __volatile__ (
" .set mips3 \n"
" li %[err], 0 \n"
"1: ll %[old], (%[addr]) \n"
" move %[tmp], %[new] \n"
"2: sc %[tmp], (%[addr]) \n"
" beqzl %[tmp], 1b \n"
"3: \n"
" .section .fixup,\"ax\" \n"
"4: li %[err], %[efault] \n"
" j 3b \n"
" .previous \n"
" .section __ex_table,\"a\" \n"
" "STR(PTR)" 1b, 4b \n"
" "STR(PTR)" 2b, 4b \n"
" .previous \n"
" .set mips0 \n"
: [old] "=&r" (old),
[err] "=&r" (err),
[tmp] "=&r" (tmp)
: [addr] "r" (addr),
[new] "r" (new),
[efault] "i" (-EFAULT)
: "memory");
} else if (cpu_has_llsc) {
__asm__ __volatile__ (
" .set mips3 \n"
" li %[err], 0 \n"
"1: ll %[old], (%[addr]) \n"
" move %[tmp], %[new] \n"
"2: sc %[tmp], (%[addr]) \n"
" bnez %[tmp], 4f \n"
"3: \n"
" .subsection 2 \n"
"4: b 1b \n"
" .previous \n"
" \n"
" .section .fixup,\"ax\" \n"
"5: li %[err], %[efault] \n"
" j 3b \n"
" .previous \n"
" .section __ex_table,\"a\" \n"
" "STR(PTR)" 1b, 5b \n"
" "STR(PTR)" 2b, 5b \n"
" .previous \n"
" .set mips0 \n"
: [old] "=&r" (old),
[err] "=&r" (err),
[tmp] "=&r" (tmp)
: [addr] "r" (addr),
[new] "r" (new),
[efault] "i" (-EFAULT)
: "memory");
} else {
do {
preempt_disable();
ll_bit = 1;
ll_task = current;
preempt_enable();
err = __get_user(old, (unsigned int *) addr);
err |= __put_user(new, (unsigned int *) addr);
if (err)
break;
rmb();
} while (!ll_bit);
}
if (unlikely(err))
return err;
regs->regs[2] = old;
regs->regs[7] = 0; /* No error */
/*
* Don't let your children do this ...
*/
__asm__ __volatile__(
" move $29, %0 \n"
" j syscall_exit \n"
: /* no outputs */
: "r" (regs));
/* unreached. Honestly. */
while (1);
}
save_static_function(sys_sysmips);
static int __used noinline
_sys_sysmips(nabi_no_regargs struct pt_regs regs)
{
long cmd, arg1, arg2, arg3;
cmd = regs.regs[4];
arg1 = regs.regs[5];
arg2 = regs.regs[6];
arg3 = regs.regs[7];
switch (cmd) {
case MIPS_ATOMIC_SET:
return mips_atomic_set(&regs, arg1, arg2);
case MIPS_FIXADE:
if (arg1 & ~3)
return -EINVAL;
if (arg1 & 1)
set_thread_flag(TIF_FIXADE);
else
clear_thread_flag(TIF_FIXADE);
if (arg1 & 2)
set_thread_flag(TIF_LOGADE);
else
clear_thread_flag(TIF_FIXADE);
return 0;
case FLUSH_CACHE:
__flush_cache_all();
return 0;
}
return -EINVAL;
}
/*
* No implemented yet ...
*/
SYSCALL_DEFINE3(cachectl, char *, addr, int, nbytes, int, op)
{
return -ENOSYS;
}
/*
* If we ever come here the user sp is bad. Zap the process right away.
* Due to the bad stack signaling wouldn't work.
*/
asmlinkage void bad_stack(void)
{
do_exit(SIGSEGV);
}
/*
* 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, char *const argv[], char *const envp[])
{
register unsigned long __a0 asm("$4") = (unsigned long) filename;
register unsigned long __a1 asm("$5") = (unsigned long) argv;
register unsigned long __a2 asm("$6") = (unsigned long) envp;
register unsigned long __a3 asm("$7");
unsigned long __v0;
__asm__ volatile (" \n"
" .set noreorder \n"
" li $2, %5 # __NR_execve \n"
" syscall \n"
" move %0, $2 \n"
" .set reorder \n"
: "=&r" (__v0), "=r" (__a3)
: "r" (__a0), "r" (__a1), "r" (__a2), "i" (__NR_execve)
: "$2", "$8", "$9", "$10", "$11", "$12", "$13", "$14", "$15", "$24",
"memory");
if (__a3 == 0)
return __v0;
return -__v0;
}