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| author | Vincent Chen <vincentc@andestech.com> | 2019-03-05 06:23:34 +0300 |
|---|---|---|
| committer | Palmer Dabbelt <palmer@sifive.com> | 2019-05-17 06:42:12 +0300 |
| commit | ee72e0e70cf7c846a4e0b6160f771da8f68571dc (patch) | |
| tree | d08fef2622f07eb5df0825c147348fe149c696f3 | |
| parent | d18ebc274ca78f61094fba39ec9f206d46be5a85 (diff) | |
| download | linux-ee72e0e70cf7c846a4e0b6160f771da8f68571dc.tar.xz | |
riscv: Add the support for c.ebreak check in is_valid_bugaddr()
The macro __BUG_INSN currently is defined as the "ebreak" opcode.
The is_valid_bugaddr() function compares the instruction pointed to by
$sepc with macro __BUG_INSN to check whether the current trap exception
is caused by an "ebreak" instruction. However, this check flow is possibly
erroneous because if C extension is supported, the expected trap
instruction "ebreak" is possibly translated to "c.ebreak" by the assembler.
Therefore, it requires a mechanism to distinguish the length of the
instruction in $spec and compare it to the correct trap instruction.
Signed-off-by: Vincent Chen <vincentc@andestech.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
| -rw-r--r-- | arch/riscv/include/asm/bug.h | 7 | ||||
| -rw-r--r-- | arch/riscv/kernel/traps.c | 20 |
2 files changed, 23 insertions, 4 deletions
diff --git a/arch/riscv/include/asm/bug.h b/arch/riscv/include/asm/bug.h index 4d906d82277b..52a1fbdeab3b 100644 --- a/arch/riscv/include/asm/bug.h +++ b/arch/riscv/include/asm/bug.h @@ -21,7 +21,12 @@ #include <asm/asm.h> #ifdef CONFIG_GENERIC_BUG -#define __BUG_INSN _AC(0x00100073, UL) /* ebreak */ +#define __INSN_LENGTH_MASK _UL(0x3) +#define __INSN_LENGTH_32 _UL(0x3) +#define __COMPRESSED_INSN_MASK _UL(0xffff) + +#define __BUG_INSN_32 _UL(0x00100073) /* ebreak */ +#define __BUG_INSN_16 _UL(0x9002) /* c.ebreak */ #ifndef __ASSEMBLY__ typedef u32 bug_insn_t; diff --git a/arch/riscv/kernel/traps.c b/arch/riscv/kernel/traps.c index cc9405420c70..c34cc5418e21 100644 --- a/arch/riscv/kernel/traps.c +++ b/arch/riscv/kernel/traps.c @@ -118,6 +118,17 @@ DO_ERROR_INFO(do_trap_ecall_s, 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 @@ -129,8 +140,8 @@ asmlinkage void do_trap_break(struct pt_regs *regs) case BUG_TRAP_TYPE_NONE: break; case BUG_TRAP_TYPE_WARN: - regs->sepc += sizeof(bug_insn_t); - return; + regs->sepc += get_break_insn_length(regs->sepc); + break; case BUG_TRAP_TYPE_BUG: die(regs, "Kernel BUG"); } @@ -149,7 +160,10 @@ int is_valid_bugaddr(unsigned long pc) return 0; if (probe_kernel_address((bug_insn_t *)pc, insn)) return 0; - return (insn == __BUG_INSN); + if ((insn & __INSN_LENGTH_MASK) == __INSN_LENGTH_32) + return (insn == __BUG_INSN_32); + else + return ((insn & __COMPRESSED_INSN_MASK) == __BUG_INSN_16); } #endif /* CONFIG_GENERIC_BUG */ |