function stack frames in the kernel
Hello, I am wondering how the compiler divines which stack to use for function calls and placement of locals and arguments when a function call is made inside the kernel since the kernel has multiple call stacks. Are function calls handled manually inside kernel code or is there something special inside the compiler for handling this? Thanks, Carter ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: function stack frames in the kernel
On Sun, Nov 11, 2018 at 6:04 PM Carter Cheng wrote: > I am wondering how the compiler divines which stack to use for function calls > and placement of locals and arguments when a function call is made inside the > kernel since the kernel has multiple call stacks. Are function calls handled > manually inside kernel code or is there something special inside the compiler > for handling this? I think this link can answer your question... https://stackoverflow.com/questions/12911841/kernel-stack-and-user-space-stack -- Augusto Mecking Caringi ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: function stack frames in the kernel
Thanks for the reply but the link doesn't quite answer the question. I am wondering how the pointer is handled so that there is one per thread by the compiler. I perhaps was under the perhaps mistaken impression that the stack pointer frame pointer management inside the compiler makes certain assumptions in user space- but i am unsure how this applies to kernel space. On Mon, Nov 12, 2018 at 1:55 AM Augusto Mecking Caringi < augustocari...@gmail.com> wrote: > On Sun, Nov 11, 2018 at 6:04 PM Carter Cheng > wrote: > > I am wondering how the compiler divines which stack to use for function > calls and placement of locals and arguments when a function call is made > inside the kernel since the kernel has multiple call stacks. Are function > calls handled manually inside kernel code or is there something special > inside the compiler for handling this? > > I think this link can answer your question... > > > https://stackoverflow.com/questions/12911841/kernel-stack-and-user-space-stack > > -- > Augusto Mecking Caringi > ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: function stack frames in the kernel
On Mon, 12 Nov 2018 02:00:02 +0800, Carter Cheng said: > Thanks for the reply but the link doesn't quite answer the question. I am > wondering how the pointer is handled so that there is one per thread by the > compiler. I perhaps was under the perhaps mistaken impression that the > stack pointer frame pointer management inside the compiler makes certain > assumptions in user space- but i am unsure how this applies to kernel space. For regular function calls, a kernel stack works exactly the same as a function stack in userspace (remember, it's the same compiler, and other tools like the linker and gdb need to be able to understand function calls). Where things are different are what happens if an interrupt or a call to schedule() or enter/exit the kernel (or a few other similar situations I can't remember at 2AM) causes a different thread to start running - for those cases, there's architecture-dependent shim code (usually involving at least a bit of assembler) to do the register swapping needed. pgpn3gz1qohHY.pgp Description: PGP signature ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
