Unverified Commit 643437b9 authored Dec 13, 2020 by Damien Le Moal Committed by Palmer Dabbelt Jan 07, 2021

riscv: Enable interrupts during syscalls with M-Mode



When running is M-Mode (no MMU config), MPIE does not get set. This
results in all syscalls being executed with interrupts disabled as
handle_exception never sets SR_IE as it always sees SR_PIE being
cleared. Fix this by always force enabling interrupts in
handle_syscall when CONFIG_RISCV_M_MODE is enabled.

Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Palmer Dabbelt <palmerdabbelt@google.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>

parent 1f1496a9

arch/riscv/kernel/entry.S

+9 −0

Original line number	Diff line number	Diff line
		@@ -155,6 +155,15 @@ skip_context_tracking:
		tail do_trap_unknown

		handle_syscall:
		#ifdef CONFIG_RISCV_M_MODE
		/*
		* When running is M-Mode (no MMU config), MPIE does not get set.
		* As a result, we need to force enable interrupts here because
		* handle_exception did not do set SR_IE as it always sees SR_PIE
		* being cleared.
		*/
		csrs CSR_STATUS, SR_IE
		#endif
		#if defined(CONFIG_TRACE_IRQFLAGS) \|\| defined(CONFIG_CONTEXT_TRACKING)
		/* Recover a0 - a7 for system calls */
		REG_L a0, PT_A0(sp)