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[-next,V14,3/7] riscv: entry: Add noinstr to prevent instrumentation inserted

Message ID 20230112095848.1464404-4-guoren@kernel.org (mailing list archive)
State Superseded
Delegated to: Palmer Dabbelt
Headers show
Series riscv: Add GENERIC_ENTRY support | expand

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conchuod/build_warn_rv64 success Errors and warnings before: 2054 this patch: 2054
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conchuod/maintainers_pattern success MAINTAINERS pattern errors before the patch: 13 and now 13
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conchuod/alphanumeric_selects success Out of order selects before the patch: 57 and now 57
conchuod/build_rv32_defconfig success Build OK
conchuod/dtb_warn_rv64 success Errors and warnings before: 4 this patch: 4
conchuod/header_inline success No static functions without inline keyword in header files
conchuod/checkpatch success total: 0 errors, 0 warnings, 0 checks, 11 lines checked
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conchuod/build_rv64_nommu_k210_defconfig success Build OK
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Commit Message

Guo Ren Jan. 12, 2023, 9:58 a.m. UTC 
From: Guo Ren <guoren@linux.alibaba.com>

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>
---
 arch/riscv/kernel/traps.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
diff mbox series

Patch

diff --git a/arch/riscv/kernel/traps.c b/arch/riscv/kernel/traps.c
index 549bde5c970a..96ec76c54ff2 100644
--- a/arch/riscv/kernel/traps.c
+++ b/arch/riscv/kernel/traps.c
@@ -95,9 +95,9 @@  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)	\