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riscv: entry: Add noinstr to prevent instrumentation inserted

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Without noinstr the compiler is free to insert instrumentation (think
all the k*SAN, KCov, GCov, ftrace etc..) which can call code we're not
yet ready to run this early in the entry path, for instance it could
rely on RCU which isn't on yet, or expect lockdep state. (by peterz)

Link: https://lore.kernel.org/linux-riscv/YxcQ6NoPf3AH0EXe@hirez.programming.kicks-ass.net/
Reviewed-by: Björn Töpel <bjorn@rivosinc.com>
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Tested-by: Jisheng Zhang <jszhang@kernel.org>
Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Signed-off-by: Guo Ren <guoren@kernel.org>
Link: https://lore.kernel.org/r/20230222033021.983168-4-guoren@kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
This commit is contained in:
Guo Ren 2023-02-21 22:30:17 -05:00 committed by Palmer Dabbelt
parent 8574bf8d0d
commit d0db02c628
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1 changed files with 2 additions and 2 deletions
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4
arch/riscv/kernel/traps.c
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@ -119,9 +119,9 @@ static void do_trap_error(struct pt_regs *regs, int signo, int code,
}
#if defined(CONFIG_XIP_KERNEL) && defined(CONFIG_RISCV_ALTERNATIVE)
#define __trap_section __section(".xip.traps")
#define __trap_section __noinstr_section(".xip.traps")
#else
#define __trap_section
#define __trap_section noinstr
#endif
#define DO_ERROR_INFO(name, signo, code, str) \
asmlinkage __visible __trap_section void name(struct pt_regs *regs) \