Structure to define a stack in memory. More...

#include <stack_pointer.h>

Data Fields
uintptr_t	top
	The top of the stack, this address is not inclusive.

uintptr_t	bottom
	The bottom of the stack, this address is inclusive.

uintptr_t	guardTop
	The top of the guard page, this address is inclusive.

uintptr_t	guardBottom
	The bottom of the guard page, this address is inclusive.

uintptr_t	lastPageFault
	The last page that caused a page fault, used to prevent infinite loops.

Detailed Description

Structure to define a stack in memory.

A stack is defined as a region of page aligned memory that includes a guard page to catch stack overflows. The region of memory starts unmapped and when a page fault occurs within the stack region a new page is mapped to the faulting address.

The guard page is always the page just below the bottom of the stack, and is never mapped. If a thread tries to access the guard page a page fault will occur, which can be used to detect stack overflows.

The exception to the above is when using stack_pointer_init_buffer() to create a stack from a provided buffer, in this case there is no guard page and the entire region starts mapped.

Note that in x86 the stack grows downwards, so we start at the top and grow towards the bottom and that the "push" operation moves the stack pointer first then writes to the location of the stack pointer, this means we actually set the inital stack pointer to be the address just outside the top of the stack.

Definition at line 38 of file stack_pointer.h.

Field Documentation

◆ bottom

uintptr_t stack_pointer_t::bottom

The bottom of the stack, this address is inclusive.

Definition at line 41 of file stack_pointer.h.

Referenced by cpu_init(), and cpu_stacks_overflow_check().

◆ guardBottom

uintptr_t stack_pointer_t::guardBottom

The bottom of the guard page, this address is inclusive.

Definition at line 43 of file stack_pointer.h.

Referenced by panic().

◆ guardTop

uintptr_t stack_pointer_t::guardTop

The top of the guard page, this address is inclusive.

Definition at line 42 of file stack_pointer.h.

◆ lastPageFault

uintptr_t stack_pointer_t::lastPageFault

The last page that caused a page fault, used to prevent infinite loops.

Definition at line 44 of file stack_pointer.h.

◆ top

uintptr_t stack_pointer_t::top

The top of the stack, this address is not inclusive.

Definition at line 40 of file stack_pointer.h.

Referenced by init_early(), loader_setup_argv(), loader_spawn(), loader_thread_create(), sched_cpu_ctx_init(), syscall_ctx_init(), and trampoline_c_entry().

The documentation for this struct was generated from the following file:

include/kernel/cpu/stack_pointer.h