riscv: initialize privileged stack during thread init (bb313355) · Commits · Wenxi XU / zephyr

This adds the bits to initialize the privileged stack when a thread is transitioning to user mode. This prevents information leaking if the stack is reused, and also aids in calculating stack space usage during system calls. Signed-off-by:

Daniel Leung <daniel.leung@intel.com>

arch/riscv/core/thread.c

+6 −0

Original line number	Diff line number	Diff line
		@@ -144,6 +144,12 @@ FUNC_NORETURN void arch_user_mode_enter(k_thread_entry_t user_entry,
		K_KERNEL_STACK_RESERVED +
		CONFIG_PRIVILEGED_STACK_SIZE);

		#ifdef CONFIG_INIT_STACKS
		/* Initialize the privileged stack */
		(void)memset((void *)_current->arch.priv_stack_start, 0xaa,
		Z_STACK_PTR_ALIGN(K_KERNEL_STACK_RESERVED + CONFIG_PRIVILEGED_STACK_SIZE));
		#endif /* CONFIG_INIT_STACKS */

		top_of_user_stack = Z_STACK_PTR_ALIGN(
		_current->stack_info.start +
		_current->stack_info.size -

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