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kernel: overhaul stack specification

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The core kernel computes the initial stack pointer
for a thread, properly aligning it and subtracting out
any random offsets or thread-local storage areas.
arch_new_thread() no longer needs to make any calculations,
an initial stack frame may be placed at the bounds of
the new 'stack_ptr' parameter passed in. This parameter
replaces 'stack_size'.

thread->stack_info is now set before arch_new_thread()
is invoked, z_new_thread_init() has been removed.
The values populated may need to be adjusted on arches
which carve-out MPU guard space from the actual stack
buffer.

thread->stack_info now has a new member 'delta' which
indicates any offset applied for TLS or random offset.
It's used so the calculations don't need to be repeated
if the thread later drops to user mode.

CONFIG_INIT_STACKS logic is now performed inside
z_setup_new_thread(), before arch_new_thread() is called.

thread->stack_info is now defined as the canonical
user-accessible area within the stack object, including
random offsets and TLS. It will never include any
carved-out memory for MPU guards and must be updated at
runtime if guards are removed.

Available stack space is now optimized. Some arches may
need to significantly round up the buffer size to account
for page-level granularity or MPU power-of-two requirements.
This space is now accounted for and used by virtue of
the Z_THREAD_STACK_SIZE_ADJUST() call in z_setup_new_thread.

Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
This commit is contained in:
Andrew Boie 2020-04-23 13:55:56 -07:00 • committed by Anas Nashif
commit b0c155f3ca
27 changed files with 570 additions and 764 deletions
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15
arch/x86/core/intel64/thread.c
View file

@ -11,13 +11,17 @@
extern void x86_sse_init(struct k_thread *); /* in locore.S */
struct x86_initial_frame {
/* zeroed return address for ABI */
uint64_t rip;
};
void arch_new_thread(struct k_thread *thread, k_thread_stack_t *stack,
size_t stack_size, k_thread_entry_t entry,
char *stack_ptr, k_thread_entry_t entry,
void *p1, void *p2, void *p3)
{
void *switch_entry;
z_new_thread_init(thread, Z_THREAD_STACK_BUFFER(stack), stack_size);
struct x86_initial_frame *iframe;
#if CONFIG_X86_STACK_PROTECTION
struct z_x86_thread_stack_header *header =
@ -35,8 +39,9 @@ void arch_new_thread(struct k_thread *thread, k_thread_stack_t *stack,
#else
switch_entry = z_thread_entry;
#endif
thread->callee_saved.rsp = (long) Z_THREAD_STACK_BUFFER(stack);
thread->callee_saved.rsp += (stack_size - 8); /* fake RIP for ABI */
iframe = Z_STACK_PTR_TO_FRAME(struct x86_initial_frame, stack_ptr);
iframe->rip = 0;
thread->callee_saved.rsp = (long) iframe;
thread->callee_saved.rip = (long) switch_entry;
thread->callee_saved.rflags = EFLAGS_INITIAL;