[PATCH] Wrong page protection flags on FreeBSD/PPC

[Krzysztof Parzyszek]

Hi Hal,
Do you work on Linux?  I'm guessing you don't see any problems related 
to this.
What do you think about this patch?

-Krzysztof


On 2/18/2013 12:17 PM, Roman Divacky wrote:
> This is also a problem on Mac OS, or quite possibly everywhere except Linux.
> There was a bug about this, you can search the bugzilla. I suggested pretty
> much the same patch.
>
> On Mon, Feb 18, 2013 at 09:02:52AM -0600, Krzysztof Parzyszek wrote:
>> The LLVM unit tests (Support) fail on FreeBSD/PPC with a segmentation
>> fault.  The problem is in this part:
>>     if (PFlags & MF_EXEC)
>>       Memory::InvalidateInstructionCache(Result.Address, Result.Size);
>>
>> In order to use the instructions in the Invalidate... function, the
>> memory needs to be readable.
>>
>> The proposed fix is to always add PROT_READ to PROT_EXEC on FreeBSD.
>>
>> -Krzysztof
>>
>> --
>> Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
>> hosted by The Linux Foundation
>
>> >From a78e54805687ad090bf8d9ec017e70a383d8320f Mon Sep 17 00:00:00 2001
>> From: Krzysztof Parzyszek <kparzysz at codeaurora.org>
>> Date: Fri, 15 Feb 2013 09:01:15 -0600
>> Subject: [PATCH] On PowerPC, the cache-flush instructions dcbf and icbi are
>>   treated as loads. On FreeBSD, add PROT_READ page protection
>>   flag before flushing cache.
>>
>> ---
>>   lib/Support/Unix/Memory.inc |    4 ++++
>>   1 files changed, 4 insertions(+), 0 deletions(-)
>>
>> diff --git a/lib/Support/Unix/Memory.inc b/lib/Support/Unix/Memory.inc
>> index 40d6b3f..a66e3c7 100644
>> --- a/lib/Support/Unix/Memory.inc
>> +++ b/lib/Support/Unix/Memory.inc
>> @@ -51,7 +51,11 @@ int getPosixProtectionFlags(unsigned Flags) {
>>   	 llvm::sys::Memory::MF_EXEC:
>>       return PROT_READ | PROT_WRITE | PROT_EXEC;
>>     case llvm::sys::Memory::MF_EXEC:
>> +#if defined(__FreeBSD__)
>> +    return PROT_READ | PROT_EXEC;
>> +#else
>>       return PROT_EXEC;
>> +#endif
>>     default:
>>       llvm_unreachable("Illegal memory protection flag specified!");
>>     }
>> --
>> 1.7.6.4
>>
>
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>


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