Unverified Commit e1ceb096 authored by Palmer Dabbelt's avatar Palmer Dabbelt
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Merge patch "RISC-V: Fix unannoted hardirqs-on in return to userspace slow-path" 

I'm merging this in as a single patch to make it easier to handle the
backports.

* b4-shazam-merge:
  RISC-V: Fix unannoted hardirqs-on in return to userspace slow-path

Link: https://lore.kernel.org/r/20221111223108.1976562-1-abrestic@rivosinc.com


Signed-off-by: default avatarPalmer Dabbelt <palmer@rivosinc.com>
parents 4bd1d80e b0f4c74e

arch/riscv/kernel/entry.S

+5 −13
Original line number Diff line number Diff line
@@ -264,12 +264,11 @@ SYM_CODE_START_NOALIGN(ret_from_exception) 
	bnez s0, resume_kernel

SYM_CODE_END(ret_from_exception)



resume_userspace:

	/* Interrupts must be disabled here so flags are checked atomically */

	REG_L s0, TASK_TI_FLAGS(tp) /* current_thread_info->flags */

	andi s1, s0, _TIF_WORK_MASK

	bnez s1, work_pending



	bnez s1, resume_userspace_slow

resume_userspace:

#ifdef CONFIG_CONTEXT_TRACKING_USER

	call user_enter_callable

#endif
@@ -369,19 +368,12 @@ resume_kernel: 
	j restore_all

#endif



work_pending:

resume_userspace_slow:

	/* Enter slow path for supplementary processing */

	la ra, ret_from_exception

	andi s1, s0, _TIF_NEED_RESCHED

	bnez s1, work_resched

work_notifysig:

	/* Handle pending signals and notify-resume requests */

	csrs CSR_STATUS, SR_IE /* Enable interrupts for do_notify_resume() */

	move a0, sp /* pt_regs */

	move a1, s0 /* current_thread_info->flags */

	tail do_notify_resume

work_resched:

	tail schedule

	call do_work_pending

	j resume_userspace



/* Slow paths for ptrace. */

handle_syscall_trace_enter:

arch/riscv/kernel/signal.c

+21 −13
Original line number Diff line number Diff line
@@ -313,19 +313,27 @@ static void do_signal(struct pt_regs *regs) 
}



/*

 * notification of userspace execution resumption

 * - triggered by the _TIF_WORK_MASK flags

 * Handle any pending work on the resume-to-userspace path, as indicated by

 * _TIF_WORK_MASK. Entered from assembly with IRQs off.

 */

asmlinkage __visible void do_notify_resume(struct pt_regs *regs,

asmlinkage __visible void do_work_pending(struct pt_regs *regs,

					  unsigned long thread_info_flags)

{

	do {

		if (thread_info_flags & _TIF_NEED_RESCHED) {

			schedule();

		} else {

			local_irq_enable();

			if (thread_info_flags & _TIF_UPROBE)

				uprobe_notify_resume(regs);



			/* Handle pending signal delivery */

	if (thread_info_flags & (_TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL))

			if (thread_info_flags & (_TIF_SIGPENDING |

						 _TIF_NOTIFY_SIGNAL))

				do_signal(regs);



			if (thread_info_flags & _TIF_NOTIFY_RESUME)

				resume_user_mode_work(regs);

		}

		local_irq_disable();

		thread_info_flags = read_thread_flags();

	} while (thread_info_flags & _TIF_WORK_MASK);

}