October 2015 - Darwin-kernel

RE: Virtual memory map - some insight please !
by Manu . 29 Oct '15

29 Oct '15

_______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists… This email sent to site_archiver(a)lists.apple.com

1 0

Re: Process virtual address space
by Prokash Sinha 29 Oct '15

29 Oct '15

Thanks Shantonu, That’s a great insight ! -Prokash On Oct 28, 2015, at 8:34 PM, Shantonu Sen <ssen(a)apple.com> wrote: > Yes, it's shared unless you set the -no_shared_cr3 boot arg > > 32-bit Mach-O doesn't change that. The kernel maintains page tables for processes regardless of whether they are 32-bit or 64-bit, but 32-bit processes only use 0-4GB of the address space. > > Shantonu > >> On Oct 28, 2015, at 6:40 PM, Prokash Sinha <prokash(a)garlic.com> wrote: >> >> Folks, >> >> I just saw in osx internal book ( by Levin), that in 64bit indeed the kernel space is shared mapped, like Windows and Linux. >> >> So that was the confusion. >> >> Correct me if I’m wrong, please. >> >> What would happen if the process is 32 Mach-O ? Would there be some thunk layer, that would make it as if the process virtual address space is shared. >> >> Thanks, >> Prokash >> _______________________________________________ >> Do not post admin requests to the list. They will be ignored. >> Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) >> Help/Unsubscribe/Update your Subscription: >> https://lists.apple.com/mailman/options/darwin-kernel/ssen%40apple.com >> >> This email sent to ssen(a)apple.com > _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists… This email sent to site_archiver(a)lists.apple.com

1 0

Re: Virtual memory map - some insight please !
by James Wise 29 Oct '15

29 Oct '15

_______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists… This email sent to site_archiver(a)lists.apple.com

1 0

Re: Virtual memory map - some insight please !
by Rustam Muginov 29 Oct '15

29 Oct '15

_______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists… This email sent to site_archiver(a)lists.apple.com

1 0

Re: Process virtual address space
by Manu . 29 Oct '15

29 Oct '15

_______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists… This email sent to site_archiver(a)lists.apple.com

1 0

Process virtual address space
by Prokash Sinha 29 Oct '15

29 Oct '15

Folks, I just saw in osx internal book ( by Levin), that in 64bit indeed the kernel space is shared mapped, like Windows and Linux. So that was the confusion. Correct me if I’m wrong, please. What would happen if the process is 32 Mach-O ? Would there be some thunk layer, that would make it as if the process virtual address space is shared. Thanks, Prokash _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists… This email sent to site_archiver(a)lists.apple.com

1 0

Virtual memory map - some insight please !
by Prokash Sinha 29 Oct '15

29 Oct '15

Folks, As I read from different books on osx internals, it seems like kernel has its own virtual memory space. At least in 32-bit, when address space was limited to 32bit, and 2GB(on Windows), 1GB in linux kernel space. So … For example, in window, if we can guarantee that a kernel module is a top level module, we can access user memory from kernel module ( with address 0x80000000 or greater ). Though there are some basic address verification but there is hardly any need to have kernel side map using Memory descriptor list for user mode data, then mapped into system virtual space. So in essence, if the same process is executing is kernel mode context, user space address can be accessed. This is mainly because of kernel shared memory space. In OSX, I heard for not sure if this mechanism(shared kernel address space) is there or not ? Scenario, I’ve a kext that has an LAPIC range interrupt handler. When the handler gets invoked, the register context of the process from which the interrupt is coming is saved (definitely in kernel allocated address range). Now when the interrupt handler executes, being kernel mode code, it must be in kernel virtual address space. Meaning that the translation of the instructions being executed must be going thru the kernel virtual address space !!!. If so, then addresses I’ve got using shared page from kernel virtual space should cause fault when accessing, if I don’t use copyinstr or its cousins. Since the addresses are the process data section, and parameters to some function call at user-space, by using printf() I get all the details of the arguments. Whereas copyinstr does not give me those, actually the call fails. So my question is that when I’m in the kext code, how does it manage to pull of the data that was pushed thru arguments to user-mode call. Thanks in advance. -Prokash _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists… This email sent to site_archiver(a)lists.apple.com

1 0

Downloading list archives
by Tom Seddon 14 Oct '15

14 Oct '15

Thanks, -- --Tom Seddon _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists… This email sent to site_archiver(a)lists.apple.com Is it possible to download the archives of this list in some standard format suitable for offline use, such as an mbox file? I'm aware the archives are available via the web site, but there doesn't appear to be any search functionality, limiting its usefulness somewhat! (Since the list appears to be run by Mailman, I tried using the standard 'wget http://example.com/mailman/private/LIST.mbox/LIST.mbox?username=XXX&passwor…', but the result was an HTML page telling me the private archive file was not found.)

1 0

Re: 10.11
by Nicoló Blasi 01 Oct '15

01 Oct '15

Apple took around 1 month to release the 10.10.5 sources. Looks like they're speeding up lately! > On 01 Oct 2015, at 9:00 PM, darwin-kernel-request(a)lists.apple.com wrote: > > Send Darwin-kernel mailing list submissions to > darwin-kernel(a)lists.apple.com > > To subscribe or unsubscribe via the World Wide Web, visit > https://lists.apple.com/mailman/listinfo/darwin-kernel > or, via email, send a message with subject or body 'help' to > darwin-kernel-request(a)lists.apple.com > > You can reach the person managing the list at > darwin-kernel-owner(a)lists.apple.com > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of Darwin-kernel digest..." > > > Today's Topics: > > 1. 10.11 (Andreas Fink) > 2. Re: 10.11 (Berni McCoy) > 3. Re: 10.11 (Andreas Fink) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Thu, 01 Oct 2015 14:18:21 +0200 > From: Andreas Fink <afink(a)list.fink.org> > To: darwin-kernel(a)lists.apple.com > Subject: 10.11 > Message-ID: <DF5F272F-90BD-43A8-85AC-92A6222B3FE3(a)list.fink.org> > Content-Type: text/plain; charset="utf-8" > > is there any expected, speculative, wild guess date when the kernel sources of 10.11 will be available on opensource.apple.com <http://opensource.apple.com/>? > We need them to rebuild our kext so our customers can upgrade to El Capitan > >

1 0

Re: 10.11
by Berni McCoy 01 Oct '15

01 Oct '15

_______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists… This email sent to site_archiver(a)lists.apple.com

1 0