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linux/arch/m68k/kernel/sys_m68k.c
Al Viro d878d6dace m68k: switch to generic sys_execve()/kernel_execve() 
The tricky part here is that task_pt_regs() on m68k works *only* for
process inside do_signal().  However, we need something much simpler -
pt_regs of a process inside do_signal() may be at different offsets
from the stack bottom, depending on the way we'd entered the kernel,
but for a task inside sys_execve() it *is* at constant offset.
Moreover, for a kernel thread about to become a userland process the
same location is also fine - setting sp to that will leave the kernel
stack pointer at the very bottom of the kernel stack when we finally
switch to userland.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-10-01 00:44:44 -04:00

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/*
* linux/arch/m68k/kernel/sys_m68k.c
*
* This file contains various random system calls that
* have a non-standard calling sequence on the Linux/m68k
* platform.
*/
#include <linux/capability.h>
#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/ipc.h>
#include <asm/setup.h>
#include <asm/uaccess.h>
#include <asm/cachectl.h>
#include <asm/traps.h>
#include <asm/page.h>
#include <asm/unistd.h>
#include <asm/cacheflush.h>
#ifdef CONFIG_MMU
#include <asm/tlb.h>
asmlinkage int do_page_fault(struct pt_regs *regs, unsigned long address,
unsigned long error_code);
asmlinkage long sys_mmap2(unsigned long addr, unsigned long len,
unsigned long prot, unsigned long flags,
unsigned long fd, unsigned long pgoff)
{
/*
* This is wrong for sun3 - there PAGE_SIZE is 8Kb,
* so we need to shift the argument down by 1; m68k mmap64(3)
* (in libc) expects the last argument of mmap2 in 4Kb units.
*/
return sys_mmap_pgoff(addr, len, prot, flags, fd, pgoff);
}
/* Convert virtual (user) address VADDR to physical address PADDR */
#define virt_to_phys_040(vaddr) \
({ \
unsigned long _mmusr, _paddr; \
\
__asm__ __volatile__ (".chip 68040\n\t" \
"ptestr (%1)\n\t" \
"movec %%mmusr,%0\n\t" \
".chip 68k" \
: "=r" (_mmusr) \
: "a" (vaddr)); \
_paddr = (_mmusr & MMU_R_040) ? (_mmusr & PAGE_MASK) : 0; \
_paddr; \
})
static inline int
cache_flush_040 (unsigned long addr, int scope, int cache, unsigned long len)
{
unsigned long paddr, i;
switch (scope)
{
case FLUSH_SCOPE_ALL:
switch (cache)
{
case FLUSH_CACHE_DATA:
/* This nop is needed for some broken versions of the 68040. */
__asm__ __volatile__ ("nop\n\t"
".chip 68040\n\t"
"cpusha %dc\n\t"
".chip 68k");
break;
case FLUSH_CACHE_INSN:
__asm__ __volatile__ ("nop\n\t"
".chip 68040\n\t"
"cpusha %ic\n\t"
".chip 68k");
break;
default:
case FLUSH_CACHE_BOTH:
__asm__ __volatile__ ("nop\n\t"
".chip 68040\n\t"
"cpusha %bc\n\t"
".chip 68k");
break;
}
break;
case FLUSH_SCOPE_LINE:
/* Find the physical address of the first mapped page in the
address range. */
if ((paddr = virt_to_phys_040(addr))) {
paddr += addr & ~(PAGE_MASK | 15);
len = (len + (addr & 15) + 15) >> 4;
} else {
unsigned long tmp = PAGE_SIZE - (addr & ~PAGE_MASK);
if (len <= tmp)
return 0;
addr += tmp;
len -= tmp;
tmp = PAGE_SIZE;
for (;;)
{
if ((paddr = virt_to_phys_040(addr)))
break;
if (len <= tmp)
return 0;
addr += tmp;
len -= tmp;
}
len = (len + 15) >> 4;
}
i = (PAGE_SIZE - (paddr & ~PAGE_MASK)) >> 4;
while (len--)
{
switch (cache)
{
case FLUSH_CACHE_DATA:
__asm__ __volatile__ ("nop\n\t"
".chip 68040\n\t"
"cpushl %%dc,(%0)\n\t"
".chip 68k"
: : "a" (paddr));
break;
case FLUSH_CACHE_INSN:
__asm__ __volatile__ ("nop\n\t"
".chip 68040\n\t"
"cpushl %%ic,(%0)\n\t"
".chip 68k"
: : "a" (paddr));
break;
default:
case FLUSH_CACHE_BOTH:
__asm__ __volatile__ ("nop\n\t"
".chip 68040\n\t"
"cpushl %%bc,(%0)\n\t"
".chip 68k"
: : "a" (paddr));
break;
}
if (!--i && len)
{
/*
* No need to page align here since it is done by
* virt_to_phys_040().
*/
addr += PAGE_SIZE;
i = PAGE_SIZE / 16;
/* Recompute physical address when crossing a page
boundary. */
for (;;)
{
if ((paddr = virt_to_phys_040(addr)))
break;
if (len <= i)
return 0;
len -= i;
addr += PAGE_SIZE;
}
}
else
paddr += 16;
}
break;
default:
case FLUSH_SCOPE_PAGE:
len += (addr & ~PAGE_MASK) + (PAGE_SIZE - 1);
for (len >>= PAGE_SHIFT; len--; addr += PAGE_SIZE)
{
if (!(paddr = virt_to_phys_040(addr)))
continue;
switch (cache)
{
case FLUSH_CACHE_DATA:
__asm__ __volatile__ ("nop\n\t"
".chip 68040\n\t"
"cpushp %%dc,(%0)\n\t"
".chip 68k"
: : "a" (paddr));
break;
case FLUSH_CACHE_INSN:
__asm__ __volatile__ ("nop\n\t"
".chip 68040\n\t"
"cpushp %%ic,(%0)\n\t"
".chip 68k"
: : "a" (paddr));
break;
default:
case FLUSH_CACHE_BOTH:
__asm__ __volatile__ ("nop\n\t"
".chip 68040\n\t"
"cpushp %%bc,(%0)\n\t"
".chip 68k"
: : "a" (paddr));
break;
}
}
break;
}
return 0;
}
#define virt_to_phys_060(vaddr) \
({ \
unsigned long paddr; \
__asm__ __volatile__ (".chip 68060\n\t" \
"plpar (%0)\n\t" \
".chip 68k" \
: "=a" (paddr) \
: "0" (vaddr)); \
(paddr); /* XXX */ \
})
static inline int
cache_flush_060 (unsigned long addr, int scope, int cache, unsigned long len)
{
unsigned long paddr, i;
/*
* 68060 manual says:
* cpush %dc : flush DC, remains valid (with our %cacr setup)
* cpush %ic : invalidate IC
* cpush %bc : flush DC + invalidate IC
*/
switch (scope)
{
case FLUSH_SCOPE_ALL:
switch (cache)
{
case FLUSH_CACHE_DATA:
__asm__ __volatile__ (".chip 68060\n\t"
"cpusha %dc\n\t"
".chip 68k");
break;
case FLUSH_CACHE_INSN:
__asm__ __volatile__ (".chip 68060\n\t"
"cpusha %ic\n\t"
".chip 68k");
break;
default:
case FLUSH_CACHE_BOTH:
__asm__ __volatile__ (".chip 68060\n\t"
"cpusha %bc\n\t"
".chip 68k");
break;
}
break;
case FLUSH_SCOPE_LINE:
/* Find the physical address of the first mapped page in the
address range. */
len += addr & 15;
addr &= -16;
if (!(paddr = virt_to_phys_060(addr))) {
unsigned long tmp = PAGE_SIZE - (addr & ~PAGE_MASK);
if (len <= tmp)
return 0;
addr += tmp;
len -= tmp;
tmp = PAGE_SIZE;
for (;;)
{
if ((paddr = virt_to_phys_060(addr)))
break;
if (len <= tmp)
return 0;
addr += tmp;
len -= tmp;
}
}
len = (len + 15) >> 4;
i = (PAGE_SIZE - (paddr & ~PAGE_MASK)) >> 4;
while (len--)
{
switch (cache)
{
case FLUSH_CACHE_DATA:
__asm__ __volatile__ (".chip 68060\n\t"
"cpushl %%dc,(%0)\n\t"
".chip 68k"
: : "a" (paddr));
break;
case FLUSH_CACHE_INSN:
__asm__ __volatile__ (".chip 68060\n\t"
"cpushl %%ic,(%0)\n\t"
".chip 68k"
: : "a" (paddr));
break;
default:
case FLUSH_CACHE_BOTH:
__asm__ __volatile__ (".chip 68060\n\t"
"cpushl %%bc,(%0)\n\t"
".chip 68k"
: : "a" (paddr));
break;
}
if (!--i && len)
{
/*
* We just want to jump to the first cache line
* in the next page.
*/
addr += PAGE_SIZE;
addr &= PAGE_MASK;
i = PAGE_SIZE / 16;
/* Recompute physical address when crossing a page
boundary. */
for (;;)
{
if ((paddr = virt_to_phys_060(addr)))
break;
if (len <= i)
return 0;
len -= i;
addr += PAGE_SIZE;
}
}
else
paddr += 16;
}
break;
default:
case FLUSH_SCOPE_PAGE:
len += (addr & ~PAGE_MASK) + (PAGE_SIZE - 1);
addr &= PAGE_MASK; /* Workaround for bug in some
revisions of the 68060 */
for (len >>= PAGE_SHIFT; len--; addr += PAGE_SIZE)
{
if (!(paddr = virt_to_phys_060(addr)))
continue;
switch (cache)
{
case FLUSH_CACHE_DATA:
__asm__ __volatile__ (".chip 68060\n\t"
"cpushp %%dc,(%0)\n\t"
".chip 68k"
: : "a" (paddr));
break;
case FLUSH_CACHE_INSN:
__asm__ __volatile__ (".chip 68060\n\t"
"cpushp %%ic,(%0)\n\t"
".chip 68k"
: : "a" (paddr));
break;
default:
case FLUSH_CACHE_BOTH:
__asm__ __volatile__ (".chip 68060\n\t"
"cpushp %%bc,(%0)\n\t"
".chip 68k"
: : "a" (paddr));
break;
}
}
break;
}
return 0;
}
/* sys_cacheflush -- flush (part of) the processor cache. */
asmlinkage int
sys_cacheflush (unsigned long addr, int scope, int cache, unsigned long len)
{
struct vm_area_struct *vma;
int ret = -EINVAL;
if (scope < FLUSH_SCOPE_LINE || scope > FLUSH_SCOPE_ALL ||
cache & ~FLUSH_CACHE_BOTH)
goto out;
if (scope == FLUSH_SCOPE_ALL) {
/* Only the superuser may explicitly flush the whole cache. */
ret = -EPERM;
if (!capable(CAP_SYS_ADMIN))
goto out;
} else {
/*
* Verify that the specified address region actually belongs
* to this process.
*/
vma = find_vma (current->mm, addr);
ret = -EINVAL;
/* Check for overflow. */
if (addr + len < addr)
goto out;
if (vma == NULL || addr < vma->vm_start || addr + len > vma->vm_end)
goto out;
}
if (CPU_IS_020_OR_030) {
if (scope == FLUSH_SCOPE_LINE && len < 256) {
unsigned long cacr;
__asm__ ("movec %%cacr, %0" : "=r" (cacr));
if (cache & FLUSH_CACHE_INSN)
cacr |= 4;
if (cache & FLUSH_CACHE_DATA)
cacr |= 0x400;
len >>= 2;
while (len--) {
__asm__ __volatile__ ("movec %1, %%caar\n\t"
"movec %0, %%cacr"
: /* no outputs */
: "r" (cacr), "r" (addr));
addr += 4;
}
} else {
/* Flush the whole cache, even if page granularity requested. */
unsigned long cacr;
__asm__ ("movec %%cacr, %0" : "=r" (cacr));
if (cache & FLUSH_CACHE_INSN)
cacr |= 8;
if (cache & FLUSH_CACHE_DATA)
cacr |= 0x800;
__asm__ __volatile__ ("movec %0, %%cacr" : : "r" (cacr));
}
ret = 0;
goto out;
} else {
/*
* 040 or 060: don't blindly trust 'scope', someone could
* try to flush a few megs of memory.
*/
if (len>=3*PAGE_SIZE && scope<FLUSH_SCOPE_PAGE)
scope=FLUSH_SCOPE_PAGE;
if (len>=10*PAGE_SIZE && scope<FLUSH_SCOPE_ALL)
scope=FLUSH_SCOPE_ALL;
if (CPU_IS_040) {
ret = cache_flush_040 (addr, scope, cache, len);
} else if (CPU_IS_060) {
ret = cache_flush_060 (addr, scope, cache, len);
}
}
out:
return ret;
}
/* This syscall gets its arguments in A0 (mem), D2 (oldval) and
D1 (newval). */
asmlinkage int
sys_atomic_cmpxchg_32(unsigned long newval, int oldval, int d3, int d4, int d5,
unsigned long __user * mem)
{
/* This was borrowed from ARM's implementation. */
for (;;) {
struct mm_struct *mm = current->mm;
pgd_t *pgd;
pmd_t *pmd;
pte_t *pte;
spinlock_t *ptl;
unsigned long mem_value;
down_read(&mm->mmap_sem);
pgd = pgd_offset(mm, (unsigned long)mem);
if (!pgd_present(*pgd))
goto bad_access;
pmd = pmd_offset(pgd, (unsigned long)mem);
if (!pmd_present(*pmd))
goto bad_access;
pte = pte_offset_map_lock(mm, pmd, (unsigned long)mem, &ptl);
if (!pte_present(*pte) || !pte_dirty(*pte)
|| !pte_write(*pte)) {
pte_unmap_unlock(pte, ptl);
goto bad_access;
}
/*
* No need to check for EFAULT; we know that the page is
* present and writable.
*/
__get_user(mem_value, mem);
if (mem_value == oldval)
__put_user(newval, mem);
pte_unmap_unlock(pte, ptl);
up_read(&mm->mmap_sem);
return mem_value;
bad_access:
up_read(&mm->mmap_sem);
/* This is not necessarily a bad access, we can get here if
a memory we're trying to write to should be copied-on-write.
Make the kernel do the necessary page stuff, then re-iterate.
Simulate a write access fault to do that. */
{
/* The first argument of the function corresponds to
D1, which is the first field of struct pt_regs. */
struct pt_regs *fp = (struct pt_regs *)&newval;
/* '3' is an RMW flag. */
if (do_page_fault(fp, (unsigned long)mem, 3))
/* If the do_page_fault() failed, we don't
have anything meaningful to return.
There should be a SIGSEGV pending for
the process. */
return 0xdeadbeef;
}
}
}
#else
/* sys_cacheflush -- flush (part of) the processor cache. */
asmlinkage int
sys_cacheflush (unsigned long addr, int scope, int cache, unsigned long len)
{
flush_cache_all();
return 0;
}
/* This syscall gets its arguments in A0 (mem), D2 (oldval) and
D1 (newval). */
asmlinkage int
sys_atomic_cmpxchg_32(unsigned long newval, int oldval, int d3, int d4, int d5,
unsigned long __user * mem)
{
struct mm_struct *mm = current->mm;
unsigned long mem_value;
down_read(&mm->mmap_sem);
mem_value = *mem;
if (mem_value == oldval)
*mem = newval;
up_read(&mm->mmap_sem);
return mem_value;
}
#endif /* CONFIG_MMU */
asmlinkage int sys_getpagesize(void)
{
return PAGE_SIZE;
}
asmlinkage unsigned long sys_get_thread_area(void)
{
return current_thread_info()->tp_value;
}
asmlinkage int sys_set_thread_area(unsigned long tp)
{
current_thread_info()->tp_value = tp;
return 0;
}
asmlinkage int sys_atomic_barrier(void)
{
/* no code needed for uniprocs */
return 0;
}
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