Hello, I've got several questions. 1. Is there a simple way to relate a virtual address in the initial threads address space to the corresponding frame cap in the BootInfo? 2. In 8.2.2 of the manual it is stated in that "seL4 provides no way to obtain the physical address of a page from its capability". Isn't that exactly what the GetAddress method of a Page object does(10.4.14)? Cheers, Steve
1. Is there a simple way to relate a virtual address in the initial threads address space to the corresponding frame cap in the BootInfo?
Will leave this one to our kernel experts..
2. In 8.2.2 of the manual it is stated in that "seL4 provides no way to obtain the physical address of a page from its capability". Isn't that exactly what the GetAddress method of a Page object does(10.4.14)?
Nice ;-) This is a classic documentation problem where it’s hard to find (or be aware of) such statements when you make the change in the code. This used to be true, but is not any more. We’ll remove the sentence from the manual. Cheers, Gerwin
Hi Steve, 1. Not sure what you count as simple, but assuming the initial thread knows it's own address space layout then it can easily work out which frame number this corresponds to in bootinfo. Typically this would be something like seL4_CPtr frame = bootinfo->userImageFrames.stat + ((uintptr_t)vaddr - (uintptr_t)&__executable_start) / 4096); You can see a slightly more complicated version of this in the capdl-loader (https://github.com/seL4/capdl/blob/master/capdl-loader-app/src/main.c#L324) 2. Looks like when GetAddress was added nobody noticed to update that in the manual. Thanks for spotting, will fix. Adrian On Tue 13-Sep-2016 7:26 PM, sixpackgurkenwasser@use.startmail.commailto:sixpackgurkenwasser@use.startmail.com wrote: Hello, I've got several questions. 1. Is there a simple way to relate a virtual address in the initial threads address space to the corresponding frame cap in the BootInfo? 2. In 8.2.2 of the manual it is stated in that "seL4 provides no way to obtain the physical address of a page from its capability". Isn't that exactly what the GetAddress method of a Page object does(10.4.14)? Cheers, Steve _______________________________________________ Devel mailing list Devel@sel4.systemsmailto:Devel@sel4.systems https://sel4.systems/lists/listinfo/devel
participants (3)
-
Adrian.Danis＠data61.csiro.au -
Gerwin.Klein＠data61.csiro.au -
sixpackgurkenwasser＠use.startmail.com