git: 05504819e39d - stable/13 - riscv: Assert that SUM is not set in SSTATUS for exceptions.

From: John Baldwin <jhb_at_FreeBSD.org>
Date: Tue, 23 Nov 2021 23:48:55 UTC
The branch stable/13 has been updated by jhb:

URL: https://cgit.FreeBSD.org/src/commit/?id=05504819e39d12cbb0772f69e06ceb49a10fd580

commit 05504819e39d12cbb0772f69e06ceb49a10fd580
Author:     John Baldwin <jhb@FreeBSD.org>
AuthorDate: 2021-04-21 20:57:20 +0000
Commit:     John Baldwin <jhb@FreeBSD.org>
CommitDate: 2021-11-23 23:47:57 +0000

    riscv: Assert that SUM is not set in SSTATUS for exceptions.
    
    Reviewed by:    mhorne
    Sponsored by:   DARPA
    Differential Revision:  https://reviews.freebsd.org/D29764
    
    (cherry picked from commit 6a3a6fe34bf36b6e745b3e9ad1a991de057729c7)
---
 sys/riscv/riscv/trap.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/sys/riscv/riscv/trap.c b/sys/riscv/riscv/trap.c
index abf527b2ef13..d378bfe1383d 100644
--- a/sys/riscv/riscv/trap.c
+++ b/sys/riscv/riscv/trap.c
@@ -280,6 +280,9 @@ do_trap_supervisor(struct trapframe *frame)
 	KASSERT((csr_read(sstatus) & (SSTATUS_SPP | SSTATUS_SIE)) ==
 	    SSTATUS_SPP, ("Came from S mode with interrupts enabled"));
 
+	KASSERT((csr_read(sstatus) & (SSTATUS_SUM)) == 0,
+	    ("Came from S mode with SUM enabled"));
+
 	exception = frame->tf_scause & SCAUSE_CODE;
 	if ((frame->tf_scause & SCAUSE_INTR) != 0) {
 		/* Interrupt */
@@ -348,6 +351,9 @@ do_trap_user(struct trapframe *frame)
 	KASSERT((csr_read(sstatus) & (SSTATUS_SPP | SSTATUS_SIE)) == 0,
 	    ("Came from U mode with interrupts enabled"));
 
+	KASSERT((csr_read(sstatus) & (SSTATUS_SUM)) == 0,
+	    ("Came from U mode with SUM enabled"));
+
 	exception = frame->tf_scause & SCAUSE_CODE;
 	if ((frame->tf_scause & SCAUSE_INTR) != 0) {
 		/* Interrupt */