From: Vincent Chen <vincentc@andestech.com>
To: <palmer@sifive.com>, <aou@eecs.berkeley.edu>,
<ebiederm@xmission.com>, <jimw@sifive.com>, <arnd@arndb.de>,
<linux-riscv@lists.infradead.org>, <linux-kernel@vger.kernel.org>
Cc: <deanbo422@gmail.com>, <vincentc@andestech.com>
Subject: [PATCH 3/3] riscv: Make WARN() related functions able to trigger a trap exception
Date: Thu, 28 Feb 2019 18:31:31 +0800 [thread overview]
Message-ID: <1551349891-22683-4-git-send-email-vincentc@andestech.com> (raw)
In-Reply-To: <1551349891-22683-1-git-send-email-vincentc@andestech.com>
This can help developers to analyze the cause of WARN() because the
control will be transferred to debugging environment if the debugger is
connected.
Signed-off-by: Vincent Chen <vincentc@andestech.com>
---
arch/riscv/include/asm/bug.h | 27 ++++++++++++++++++---------
arch/riscv/kernel/traps.c | 19 ++++++++++++++++---
2 files changed, 34 insertions(+), 12 deletions(-)
diff --git a/arch/riscv/include/asm/bug.h b/arch/riscv/include/asm/bug.h
index 1cab7f4..b2aa88f 100644
--- a/arch/riscv/include/asm/bug.h
+++ b/arch/riscv/include/asm/bug.h
@@ -43,38 +43,47 @@
#define __BUG_ENTRY \
__BUG_ENTRY_ADDR "\n\t" \
__BUG_ENTRY_FILE "\n\t" \
- RISCV_SHORT " %1"
+ RISCV_SHORT " %1 \n\t" \
+ RISCV_SHORT " %2"
#else
#define __BUG_ENTRY \
- __BUG_ENTRY_ADDR
+ __BUG_ENTRY_ADDR "\n\t" \
+ RISCV_SHORT " %2"
#endif
-#define BUG() \
+#define __BUG_FLAGS(flags) \
do { \
__asm__ __volatile__ ( \
"1:\n\t" \
"ebreak\n" \
- ".pushsection __bug_table,\"a\"\n\t" \
+ ".pushsection __bug_table,\"aw\"\n\t" \
"2:\n\t" \
__BUG_ENTRY "\n\t" \
- ".org 2b + %2\n\t" \
+ ".org 2b + %3\n\t" \
".popsection" \
: \
: "i" (__FILE__), "i" (__LINE__), \
- "i" (sizeof(struct bug_entry))); \
- unreachable(); \
+ "i" (flags), \
+ "i" (sizeof(struct bug_entry))); \
} while (0)
+
#endif /* !__ASSEMBLY__ */
#else /* CONFIG_GENERIC_BUG */
#ifndef __ASSEMBLY__
-#define BUG() \
+#define __BUG_FLAGS(flags) \
do { \
__asm__ __volatile__ ("ebreak\n"); \
- unreachable(); \
} while (0)
#endif /* !__ASSEMBLY__ */
#endif /* CONFIG_GENERIC_BUG */
+#define BUG() do { \
+ __BUG_FLAGS(0); \
+ unreachable(); \
+} while (0)
+
+#define __WARN_FLAGS(flags) __BUG_FLAGS(BUGFLAG_WARNING|(flags))
+
#define HAVE_ARCH_BUG
#include <asm-generic/bug.h>
diff --git a/arch/riscv/kernel/traps.c b/arch/riscv/kernel/traps.c
index dee0e5e..023208b 100644
--- a/arch/riscv/kernel/traps.c
+++ b/arch/riscv/kernel/traps.c
@@ -118,6 +118,17 @@ asmlinkage void name(struct pt_regs *regs) \
DO_ERROR_INFO(do_trap_ecall_m,
SIGILL, ILL_ILLTRP, "environment call from M-mode");
+#ifdef CONFIG_GENERIC_BUG
+static inline unsigned long get_break_insn_length(unsigned long pc)
+{
+ bug_insn_t insn;
+
+ if (probe_kernel_address((bug_insn_t *)pc, insn))
+ return 0;
+ return ((insn & __INSN_LENGTH_MASK) == __INSN_LENGTH_32) ? 4UL : 2UL;
+}
+#endif /* CONFIG_GENERIC_BUG */
+
asmlinkage void do_trap_break(struct pt_regs *regs)
{
#ifdef CONFIG_GENERIC_BUG
@@ -129,7 +140,8 @@ asmlinkage void do_trap_break(struct pt_regs *regs)
case BUG_TRAP_TYPE_NONE:
break;
case BUG_TRAP_TYPE_WARN:
- die(regs, "Kernel BUG. Kernel got an unexpected WARN trapped by ebreak");
+ regs->sepc += get_break_insn_length(regs->sepc);
+ break;
case BUG_TRAP_TYPE_BUG:
die(regs, "Kernel BUG");
}
@@ -149,12 +161,13 @@ int is_valid_bugaddr(unsigned long pc)
if (probe_kernel_address((bug_insn_t *)pc, insn))
return 0;
if ((insn & __INSN_LENGTH_MASK) == __INSN_LENGTH_32)
- return insn == __BUG_INSN_32;
+ return (insn == __BUG_INSN_32);
else
- return (insn & __COMPRESSED_INSN_MASK) == __BUG_INSN_16;
+ return ((insn & __COMPRESSED_INSN_MASK) == __BUG_INSN_16);
}
#endif /* CONFIG_GENERIC_BUG */
+
void __init trap_init(void)
{
/*
--
1.7.1
next prev parent reply other threads:[~2019-02-28 10:57 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-28 10:31 [PATCH 0/3] riscv: Fix debug instruction check and support trap-based WARN() Vincent Chen
2019-02-28 10:31 ` [PATCH 1/3] riscv: Add the support for c.ebreak check in is_valid_bugaddr() Vincent Chen
2019-02-28 10:31 ` [PATCH 2/3] riscv: Support BUG() in kernel module Vincent Chen
2019-02-28 10:31 ` Vincent Chen [this message]
2019-03-04 20:35 ` [PATCH 0/3] riscv: Fix debug instruction check and support trap-based WARN() Palmer Dabbelt
2019-03-05 0:21 ` Vincent Chen
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