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riscv: Correct the handling of unexpected ebreak in do_trap_break() 

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@sifive.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
[paul.walmsley@sifive.com: fixed checkpatch issue]
Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>
alistair/sunxi64-5.4-dsi
Vincent Chen 2019-09-23 08:45:16 +08:00 committed by Paul Walmsley
parent e0c0fc18f1
commit 8bb0daef64
1 changed files with 3 additions and 3 deletions
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6
arch/riscv/kernel/traps.c
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@ -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