From: Vincent Chen <vincent.chen@xxxxxxxxxx>
[ Upstream commit 8bb0daef64e5a92db63ad1d3bbf9e280a7b3612a ]
For the kernel space, all ebreak instructions are determined at compile
time because the kernel space debugging module is currently unsupported.
Hence, it should be treated as a bug if an ebreak instruction which does
not belong to BUG_TRAP_TYPE_WARN or BUG_TRAP_TYPE_BUG is executed in
kernel space. For the userspace, debugging module or user problem may
intentionally insert an ebreak instruction to trigger a SIGTRAP signal.
To approach the above two situations, the do_trap_break() will direct
the BUG_TRAP_TYPE_NONE ebreak exception issued in kernel space to die()
and will send a SIGTRAP to the trapped process only when the ebreak is
in userspace.
Signed-off-by: Vincent Chen <vincent.chen@xxxxxxxxxx>
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
[paul.walmsley@xxxxxxxxxx: fixed checkpatch issue]
Signed-off-by: Paul Walmsley <paul.walmsley@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
arch/riscv/kernel/traps.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/arch/riscv/kernel/traps.c b/arch/riscv/kernel/traps.c
index 82f42a55451eb..93742df9067fb 100644
--- a/arch/riscv/kernel/traps.c
+++ b/arch/riscv/kernel/traps.c
@@ -130,8 +130,6 @@ asmlinkage void do_trap_break(struct pt_regs *regs)
type = report_bug(regs->sepc, regs);
switch (type) {
#ifdef CONFIG_GENERIC_BUG
- case BUG_TRAP_TYPE_NONE:
- break;
case BUG_TRAP_TYPE_WARN:
regs->sepc += get_break_insn_length(regs->sepc);
return;
@@ -140,8 +138,10 @@ asmlinkage void do_trap_break(struct pt_regs *regs)
default:
die(regs, "Kernel BUG");
}
+ } else {
+ force_sig_fault(SIGTRAP, TRAP_BRKPT,
+ (void __user *)(regs->sepc));
}
- force_sig_fault(SIGTRAP, TRAP_BRKPT, (void __user *)(regs->sepc));
}
#ifdef CONFIG_GENERIC_BUG
--
2.20.1
