davids5 commented on a change in pull request #3517:
URL: https://github.com/apache/incubator-nuttx/pull/3517#discussion_r612489165
##########
File path: arch/arm/src/common/arm_usestack.c
##########
@@ -127,37 +117,17 @@ int up_use_stack(struct tcb_s *tcb, void *stack, size_t
stack_size)
/* Save the new stack allocation */
tcb->stack_alloc_ptr = stack;
-
- /* Align stack top */
-
- tcb->adj_stack_ptr =
- (FAR void *)STACK_ALIGN_DOWN((uintptr_t)stack + stack_size);
-
- /* Offset by tls_size */
-
- stack = (FAR void *)((uintptr_t)stack + tls_size);
-
- /* Is there enough room for at least TLS ? */
-
- if ((uintptr_t)stack > (uintptr_t)tcb->adj_stack_ptr)
- {
- return -ENOMEM;
- }
-
- tcb->adj_stack_size = (uintptr_t)tcb->adj_stack_ptr - (uintptr_t)stack;
-
- /* Initialize the TLS data structure */
-
- memset(tcb->stack_alloc_ptr, 0, tls_size);
+ tcb->adj_stack_ptr = tcb->stack_alloc_ptr;
+ tcb->adj_stack_size =
+ STACK_ALIGN_DOWN((uintptr_t)stack + stack_size) - (uintptr_t)stack;
Review comment:
In the old code the task/thread SP was set to the adj_stack_ptr. That
value by inspection was properly aligned.
This change splits that alignment across the pointer and the size. Making
all this very pron to errors.
##########
File path: arch/arm/src/armv6-m/arm_initialstate.c
##########
@@ -74,7 +74,8 @@ void up_initial_state(struct tcb_s *tcb)
/* Save the initial stack pointer */
- xcp->regs[REG_SP] = (uint32_t)tcb->adj_stack_ptr;
+ xcp->regs[REG_SP] = (uint32_t)tcb->adj_stack_ptr +
Review comment:
@xiaoxiang781216 - the old code's naming make sense and matched the
semantic. `xcp->regs[REG_SP] = (uint32_t)tcb->adj_stack_ptr`
In the new code you have changed the semantics and I feel very strongly that
the naming has change.
tcb->adj_stack_ptr is NOW the stack base. Please call it that.
`stackbase_ptr`
Then a the stack penetration test will start at the `stackbase_ptr` upward
for the guard value.
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