michaelh/zephyr
1
0
Fork 0
Code Releases Activity

x86: fix arch_user_mode_enter locking

Browse source 
This function iterates over the thread's memory domain
and updates page tables based on it. We need to be holding
z_mem_domain_lock while this happens.

Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
This commit is contained in:
Andrew Boie 2020-10-06 16:04:40 -07:00 • committed by Andrew Boie
commit f6c64e92ce
2 changed files with 8 additions and 1 deletions
Download patch file Download diff file Expand all files Collapse all files

4
arch/x86/core/userspace.c
View file

@ -110,8 +110,11 @@ void *z_x86_userspace_prepare_thread(struct k_thread *thread)
FUNC_NORETURN void arch_user_mode_enter(k_thread_entry_t user_entry,
void *p1, void *p2, void *p3)
{
k_spinlock_key_t key;
z_x86_thread_pt_init(_current);
key = k_spin_lock(&z_mem_domain_lock);
/* Apply memory domain configuration, if assigned. Threads that
* started in user mode already had this done via z_setup_new_thread()
*/
@ -119,6 +122,7 @@ FUNC_NORETURN void arch_user_mode_enter(k_thread_entry_t user_entry,
z_x86_apply_mem_domain(_current,
_current->mem_domain_info.mem_domain);
}
k_spin_unlock(&z_mem_domain_lock, key);
#ifndef CONFIG_X86_KPTI
/* We're synchronously dropping into user mode from a thread that

5
arch/x86/include/x86_mmu.h
View file

@ -119,7 +119,10 @@ extern uint8_t z_shared_kernel_page_start;
/* Set up per-thread page tables just prior to entering user mode */
void z_x86_thread_pt_init(struct k_thread *thread);
/* Apply a memory domain policy to a set of thread page tables */
/* Apply a memory domain policy to a set of thread page tables.
*
* Must be called with z_mem_domain_lock held.
*/
void z_x86_apply_mem_domain(struct k_thread *thread,
struct k_mem_domain *mem_domain);
#endif /* CONFIG_USERSPACE */