[PATCH v4 03/21] riscv: Enable interrupts during syscalls with M-Mode
Damien Le Moal
damien.lemoal at wdc.com
Tue Dec 1 22:24:42 EST 2020
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 at wdc.com>
---
arch/riscv/kernel/entry.S | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/arch/riscv/kernel/entry.S b/arch/riscv/kernel/entry.S
index 524d918f3601..080eb8d78589 100644
--- a/arch/riscv/kernel/entry.S
+++ b/arch/riscv/kernel/entry.S
@@ -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)
--
2.28.0
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