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Date: Sat, 04 Sep 2004 14:19:15 +0200
From: Filip Navara <xnavara@volny.cz>
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Subject: Re: [Qemu-devel] [PATCH] fix interaction with noexecstack
References: <20040904000017.GA27986@xi.wantstofly.org>
	<41399DC2.2030404@bellard.org>
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To: qemu-devel@nongnu.org

Fabrice Bellard wrote:

> The patch seems OK for me, at least until the instruction cache is 
> dynamically allocated.

I haven't tried the patch, but there isn't any "mprotect" function on 
Windows so I guess it would break MinGW builds. See the code below. It 
should work, but *I HAVEN'T TESTED IT*:

Regards,
Filip

> Lennert Buytenhek wrote:

[snip]

>> --- qemu-20040804.orig/exec.c    2004-07-06 02:00:18.000000000 +0300
>> +++ qemu-20040804.test/exec.c    2004-09-04 02:49:25.414945456 +0300
>> @@ -127,6 +127,9 @@
>>  
>>  static void page_init(void)
>>  {
>> +    unsigned long address;
>> +    unsigned long length;
>
#ifdef _WIN32
   DWORD old_protect;
#endif

>> +
>>      /* NOTE: we can always suppose that qemu_host_page_size >=
>>         TARGET_PAGE_SIZE */
>>  #ifdef _WIN32
>> @@ -134,6 +137,17 @@
>>  #else
>>      qemu_real_host_page_size = getpagesize();
>>  #endif
>> +
>> +    address = (unsigned long)code_gen_buffer;
>> +    address &= ~(qemu_real_host_page_size - 1);
>> +
>> +    length = (unsigned long)code_gen_buffer + sizeof(code_gen_buffer);
>> +    length -= address;
>> +    length += qemu_real_host_page_size - 1;
>> +    length &= ~(qemu_real_host_page_size - 1);
>> +
>
#ifdef _WIN32
*   *VirtualProtect(address, length, PAGE_EXECUTE_READWRITE, &old_protect);
#else

>> +    mprotect(address, length, PROT_READ | PROT_WRITE | PROT_EXEC);
>
#endif

>> +
>>      if (qemu_host_page_size == 0)
>>          qemu_host_page_size = qemu_real_host_page_size;
>>      if (qemu_host_page_size < TARGET_PAGE_SIZE)
>