On Wed, 14 Apr 2021 11:10:42 +0200
Christophe Leroy [off-list ref] wrote:

Le 14/04/2021 à 10:58, Jisheng Zhang a écrit :

quoted

Many architectures implement the trap_init() as NOP, since there is
no such default for trap_init(), this empty stub is duplicated among
these architectures. Provide a generic but weak NOP implementation
to drop the empty stubs of trap_init() in these architectures.  

You define the weak function in the __init section.

Most but not all architectures had it in __init section.

And the remaining ones may not be defined in __init section. For instance look at the one in alpha
architecture.

Have you checked that it is not a problem ? It would be good to say something about it in the commit
description.

For those non-nop platforms, I can only test x86/arm64/, but both has
__init mark. I'm not sure whether this is a problem for alpha etc. Maybe
I can check which section the trap_init() sits. Or to avoid any possible
regression, I can add __init mark to those remaining ones without it in
preparation patches.

quoted

Signed-off-by: Jisheng Zhang <redacted>
---
  arch/arc/kernel/traps.c      |  5 -----
  arch/arm/kernel/traps.c      |  5 -----
  arch/h8300/kernel/traps.c    | 13 -------------
  arch/hexagon/kernel/traps.c  |  4 ----
  arch/nds32/kernel/traps.c    |  5 -----
  arch/nios2/kernel/traps.c    |  5 -----
  arch/openrisc/kernel/traps.c |  5 -----
  arch/parisc/kernel/traps.c   |  4 ----
  arch/powerpc/kernel/traps.c  |  5 -----
  arch/riscv/kernel/traps.c    |  5 -----
  arch/um/kernel/trap.c        |  4 ----
  init/main.c                  |  2 ++
  12 files changed, 2 insertions(+), 60 deletions(-)

diff --git a/init/main.c b/init/main.c
index 53b278845b88..4bdbe2928530 100644
--- a/init/main.c
+++ b/init/main.c

@@ -790,6 +790,8 @@ static inline void initcall_debug_enable(void)
  }
  #endif

+void __init __weak trap_init(void) { }
+  

I think in a C file we don't try to save space as much as in a header file.

This is to follow most weak NOP implementations in init/main.c to make
the style unified in the same file. I'm not sure which is better.

I would prefer something like:


void __init __weak trap_init(void)
{
}

quoted

  /* Report memory auto-initialization states for this boot. */
  static void __init report_meminit(void)
  {
 

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