[PATCH v7 08/11] arch/arm64: adopt prepare_exit_to_usermode() model from x86
From: Chris Metcalf <hidden>
Date: 2015-09-28 15:18:21
Also in:
lkml
Subsystem:
arm64 port (aarch64 architecture), the rest · Maintainers:
Catalin Marinas, Will Deacon, Linus Torvalds
This change is a prerequisite change for TASK_ISOLATION but also
stands on its own for readability and maintainability. The existing
arm64 do_notify_resume() is called in a loop from assembly on
the slow path; this change moves the loop into C code as well.
For the x86 version see commit c5c46f59e4e7 ("x86/entry: Add new,
comprehensible entry and exit handlers written in C").
Signed-off-by: Chris Metcalf <redacted>
---
arch/arm64/kernel/entry.S | 6 +++---
arch/arm64/kernel/signal.c | 32 ++++++++++++++++++++++----------
2 files changed, 25 insertions(+), 13 deletions(-)
diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
index 4306c937b1ff..6fcbf8ea307b 100644
--- a/arch/arm64/kernel/entry.S
+++ b/arch/arm64/kernel/entry.S@@ -628,9 +628,8 @@ work_pending: mov x0, sp // 'regs' tst x2, #PSR_MODE_MASK // user mode regs? b.ne no_work_pending // returning to kernel - enable_irq // enable interrupts for do_notify_resume() - bl do_notify_resume - b ret_to_user + bl prepare_exit_to_usermode + b no_user_work_pending work_resched: bl schedule
@@ -642,6 +641,7 @@ ret_to_user: ldr x1, [tsk, #TI_FLAGS] and x2, x1, #_TIF_WORK_MASK cbnz x2, work_pending +no_user_work_pending: enable_step_tsk x1, x2 no_work_pending: kernel_exit 0
diff --git a/arch/arm64/kernel/signal.c b/arch/arm64/kernel/signal.c
index e18c48cb6db1..fde59c1139a9 100644
--- a/arch/arm64/kernel/signal.c
+++ b/arch/arm64/kernel/signal.c@@ -399,18 +399,30 @@ static void do_signal(struct pt_regs *regs) restore_saved_sigmask(); } -asmlinkage void do_notify_resume(struct pt_regs *regs, - unsigned int thread_flags) +asmlinkage void prepare_exit_to_usermode(struct pt_regs *regs, + unsigned int thread_flags) { - if (thread_flags & _TIF_SIGPENDING) - do_signal(regs); + do { + local_irq_enable(); - if (thread_flags & _TIF_NOTIFY_RESUME) { - clear_thread_flag(TIF_NOTIFY_RESUME); - tracehook_notify_resume(regs); - } + if (thread_flags & _TIF_NEED_RESCHED) + schedule(); + + if (thread_flags & _TIF_SIGPENDING) + do_signal(regs); + + if (thread_flags & _TIF_NOTIFY_RESUME) { + clear_thread_flag(TIF_NOTIFY_RESUME); + tracehook_notify_resume(regs); + } + + if (thread_flags & _TIF_FOREIGN_FPSTATE) + fpsimd_restore_current_state(); + + local_irq_disable(); - if (thread_flags & _TIF_FOREIGN_FPSTATE) - fpsimd_restore_current_state(); + thread_flags = READ_ONCE(current_thread_info()->flags) & + _TIF_WORK_MASK; + } while (thread_flags); }
--
2.1.2