Remove init stack #611
Open
Remove init stack #611
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Commit 676e741 introduced the side effect of breaking the stack unwinder because init_stack no longer exists after the first context switch in schedule_init(). This commit fixes that by completely removing init_stack: - BSP is not impacted because it never uses init_stack and uses bsp_stack instead - AP now uses context_switch_stack as its initial stack because this stack was originally designed to be used only when switching between tasks In both cases, IRQs requiring a stack can safely occur during context switching because these stacks are accessible after switching to the first task's page table. Let the stack unwinder inspect context_switch_stack instead of init_stack. This stack will always exist as long as its PerCpu is in use. Fixes: 676e741 ("task/schedule: Free init stack during first context switch") Signed-off-by: Peter Fang <[email protected]>
Record the initial stack in PerCpu's current_stack field. This allows the stack unwinder to properly dump the stack when executing in the initial stack. Also, explicitly mark the bottom stack frame in the initial stack using RBP = 0 so that the stack unwinder knows when to stop. Signed-off-by: Peter Fang <[email protected]>
The x86-64 ABI requires 16b-aligned stack frames. Detect misaligned
stack frames in the stack unwinder and mark them with a pound sign ('#')
when printing a stack.
Signed-off-by: Peter Fang <[email protected]>
peterfang
force-pushed
the
remove-init-stack
branch
from
87b7b96 to
79c31c3
Compare
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Commit 676e741 introduced the side effect of breaking the stack unwinder because
init_stackno longer exists after the first context switch inschedule_init(). This commit fixes that by completely removinginit_stack:init_stackand usesbsp_stackinsteadcontext_switch_stackas its initial stack because this stack was originally designed to be used only when switching between tasksAlso, improve the stack unwinder by allowing it to dump the stack while running in the initial stack and detecting stack misalignment.