On 07.05.2012, at 12:37, Peter Maydell wrote:
> On 7 May 2012 10:30, Alexander Graf <ag...@suse.de> wrote:
>> @@ -587,6 +587,7 @@ abi_long target_mmap(abi_ulong start, abi_ulong len, int
>> prot,
>> page_dump(stdout);
>> printf("\n");
>> #endif
>> + tb_invalidate_phys_page_range(start, start + len, 0);
>> mmap_unlock();
>> return start;
>
> The comment at the top of tb_invalidate_phys_page_range() says
> "start and end must refer to the same physical page" -- is it
> out of date or does that not apply to user-mode?
>
> Do you need to also invalidate the range on munmap() and
> mprotect-to-not-executable in order to correctly fault on
> the case of:
> map something
> execute it
> unmap it
> try to execute it again
>
> ? (haven't tested that case but it seems like it might be an issue)
Yeah, the issue does exist:
#include <stdio.h>
#include <sys/mman.h>
#include <string.h>
#include <unistd.h>
#include <stdlib.h>
static int foo(void)
{
return 5;
}
int main(int argc, char **argv)
{
void *p;
int x;
int (*f)(void);
p =
mmap(NULL,0x1000,PROT_EXEC|PROT_READ|PROT_WRITE,MAP_PRIVATE|MAP_ANONYMOUS,0,0);
if (!p) {
printf("Error: mmap returned failure\n");
exit(1);
}
memcpy(p, (void*)foo, 0x10);
f = p;
x = f();
printf("returned %d\n", x);
munmap(p, 0x1000);
x = f();
printf("returned %d\n", x);
}
-----
baur:/> ./test
returned 5
returned 5
