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Subject: Re: [PATCH v2] init: consolidate trap_init()
To:     Jisheng Zhang <Jisheng.Zhang@synaptics.com>,
        Vineet Gupta <vgupta@synopsys.com>,
        Russell King <linux@armlinux.org.uk>,
        Yoshinori Sato <ysato@users.sourceforge.jp>,
        Brian Cain <bcain@codeaurora.org>,
        Nick Hu <nickhu@andestech.com>,
        Greentime Hu <green.hu@gmail.com>,
        Vincent Chen <deanbo422@gmail.com>,
        Ley Foon Tan <ley.foon.tan@intel.com>,
        Jonas Bonn <jonas@southpole.se>,
        Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>,
        Stafford Horne <shorne@gmail.com>,
        "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>,
        Michael Ellerman <mpe@ellerman.id.au>,
        Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        Paul Mackerras <paulus@samba.org>,
        Paul Walmsley <paul.walmsley@sifive.com>,
        Palmer Dabbelt <palmer@dabbelt.com>,
        Albert Ou <aou@eecs.berkeley.edu>,
        Jeff Dike <jdike@addtoit.com>,
        Richard Weinberger <richard@nod.at>,
        Anton Ivanov <anton.ivanov@cambridgegreys.com>,
        Richard Henderson <rth@twiddle.net>,
        Ivan Kokshaysky <ink@jurassic.park.msu.ru>,
        Matt Turner <mattst88@gmail.com>,
        Michal Simek <monstr@monstr.eu>,
        "David S. Miller" <davem@davemloft.net>,
        Christophe Leroy <christophe.leroy@csgroup.eu>
Cc:     linux-snps-arc@lists.infradead.org, linux-kernel@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org,
        uclinux-h8-devel@lists.sourceforge.jp,
        linux-hexagon@vger.kernel.org, openrisc@lists.librecores.org,
        linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
        linux-riscv@lists.infradead.org, linux-um@lists.infradead.org,
        Anup Patel <anup@brainfault.org>, linux-alpha@vger.kernel.org,
        sparclinux@vger.kernel.org
References: <20210414165808.458a3d11@xhacker.debian>
 <20210414180037.14602dab@xhacker.debian>
From:   Helge Deller <deller@gmx.de>
Message-ID: <8638c5bc-71cd-9407-e597-77bf9bec17ee@gmx.de>
Date:   Sun, 22 Aug 2021 21:48:36 +0200
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On 4/14/21 12:00 PM, Jisheng Zhang wrote:
> 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.
>
> The alpha, microblaze and sparc32 have real trap_init() implementation
> but the __init marker is missing, so add it to these three platforms.
>
> Signed-off-by: Jisheng Zhang <Jisheng.Zhang@synaptics.com>
> ---
> Since v1:
>   - add __init marker to trap_init() for alpha, microblaze and sparc32
>   - adjust the generic weak NOP trap_init() location to make it sits wit=
h
>     other NOP implementations together
>
>   arch/alpha/kernel/traps.c      |  2 +-
>   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/microblaze/kernel/traps.c |  2 +-
>   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/sparc/kernel/traps_32.c   |  2 +-
>   arch/um/kernel/trap.c          |  4 ----
>   init/main.c                    |  2 ++
>   15 files changed, 5 insertions(+), 63 deletions(-)


For parisc:

Acked-by: Helge Deller <deller@gmx.de> # parisc

Thanks!
Helge

>
> diff --git a/arch/alpha/kernel/traps.c b/arch/alpha/kernel/traps.c
> index 921d4b6e4d95..96b203199c6c 100644
> --- a/arch/alpha/kernel/traps.c
> +++ b/arch/alpha/kernel/traps.c
> @@ -973,7 +973,7 @@ do_entUnaUser(void __user * va, unsigned long opcode=
,
>   	return;
>   }
>
> -void
> +void __init
>   trap_init(void)
>   {
>   	/* Tell PAL-code what global pointer we want in the kernel.  */
> diff --git a/arch/arc/kernel/traps.c b/arch/arc/kernel/traps.c
> index 57235e5c0cea..6b83e3f2b41c 100644
> --- a/arch/arc/kernel/traps.c
> +++ b/arch/arc/kernel/traps.c
> @@ -20,11 +20,6 @@
>   #include <asm/unaligned.h>
>   #include <asm/kprobes.h>
>
> -void __init trap_init(void)
> -{
> -	return;
> -}
> -
>   void die(const char *str, struct pt_regs *regs, unsigned long address)
>   {
>   	show_kernel_fault_diag(str, regs, address);
> diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c
> index 17d5a785df28..9baccef20392 100644
> --- a/arch/arm/kernel/traps.c
> +++ b/arch/arm/kernel/traps.c
> @@ -780,11 +780,6 @@ void abort(void)
>   	panic("Oops failed to kill thread");
>   }
>
> -void __init trap_init(void)
> -{
> -	return;
> -}
> -
>   #ifdef CONFIG_KUSER_HELPERS
>   static void __init kuser_init(void *vectors)
>   {
> diff --git a/arch/h8300/kernel/traps.c b/arch/h8300/kernel/traps.c
> index 5d8b969cd8f3..c3a3ebf77fbb 100644
> --- a/arch/h8300/kernel/traps.c
> +++ b/arch/h8300/kernel/traps.c
> @@ -30,19 +30,6 @@
>
>   static DEFINE_SPINLOCK(die_lock);
>
> -/*
> - * this must be called very early as the kernel might
> - * use some instruction that are emulated on the 060
> - */
> -
> -void __init base_trap_init(void)
> -{
> -}
> -
> -void __init trap_init(void)
> -{
> -}
> -
>   asmlinkage void set_esp0(unsigned long ssp)
>   {
>   	current->thread.esp0 =3D ssp;
> diff --git a/arch/hexagon/kernel/traps.c b/arch/hexagon/kernel/traps.c
> index 904134b37232..edfc35dafeb1 100644
> --- a/arch/hexagon/kernel/traps.c
> +++ b/arch/hexagon/kernel/traps.c
> @@ -28,10 +28,6 @@
>   #define TRAP_SYSCALL	1
>   #define TRAP_DEBUG	0xdb
>
> -void __init trap_init(void)
> -{
> -}
> -
>   #ifdef CONFIG_GENERIC_BUG
>   /* Maybe should resemble arch/sh/kernel/traps.c ?? */
>   int is_valid_bugaddr(unsigned long addr)
> diff --git a/arch/microblaze/kernel/traps.c b/arch/microblaze/kernel/tra=
ps.c
> index 94b6fe93147d..7c15704fe56e 100644
> --- a/arch/microblaze/kernel/traps.c
> +++ b/arch/microblaze/kernel/traps.c
> @@ -18,7 +18,7 @@
>   #include <asm/exceptions.h>
>   #include <asm/unwind.h>
>
> -void trap_init(void)
> +void __init trap_init(void)
>   {
>   	__enable_hw_exceptions();
>   }
> diff --git a/arch/nds32/kernel/traps.c b/arch/nds32/kernel/traps.c
> index ee0d9ae192a5..f06421c645af 100644
> --- a/arch/nds32/kernel/traps.c
> +++ b/arch/nds32/kernel/traps.c
> @@ -183,11 +183,6 @@ void __pgd_error(const char *file, int line, unsign=
ed long val)
>   }
>
>   extern char *exception_vector, *exception_vector_end;
> -void __init trap_init(void)
> -{
> -	return;
> -}
> -
>   void __init early_trap_init(void)
>   {
>   	unsigned long ivb =3D 0;
> diff --git a/arch/nios2/kernel/traps.c b/arch/nios2/kernel/traps.c
> index b172da4eb1a9..596986a74a26 100644
> --- a/arch/nios2/kernel/traps.c
> +++ b/arch/nios2/kernel/traps.c
> @@ -105,11 +105,6 @@ void show_stack(struct task_struct *task, unsigned =
long *stack,
>   	printk("%s\n", loglvl);
>   }
>
> -void __init trap_init(void)
> -{
> -	/* Nothing to do here */
> -}
> -
>   /* Breakpoint handler */
>   asmlinkage void breakpoint_c(struct pt_regs *fp)
>   {
> diff --git a/arch/openrisc/kernel/traps.c b/arch/openrisc/kernel/traps.c
> index 4d61333c2623..aa1e709405ac 100644
> --- a/arch/openrisc/kernel/traps.c
> +++ b/arch/openrisc/kernel/traps.c
> @@ -231,11 +231,6 @@ void unhandled_exception(struct pt_regs *regs, int =
ea, int vector)
>   	die("Oops", regs, 9);
>   }
>
> -void __init trap_init(void)
> -{
> -	/* Nothing needs to be done */
> -}
> -
>   asmlinkage void do_trap(struct pt_regs *regs, unsigned long address)
>   {
>   	force_sig_fault(SIGTRAP, TRAP_BRKPT, (void __user *)regs->pc);
> diff --git a/arch/parisc/kernel/traps.c b/arch/parisc/kernel/traps.c
> index 8d8441d4562a..747c328fb886 100644
> --- a/arch/parisc/kernel/traps.c
> +++ b/arch/parisc/kernel/traps.c
> @@ -859,7 +859,3 @@ void  __init early_trap_init(void)
>
>   	initialize_ivt(&fault_vector_20);
>   }
> -
> -void __init trap_init(void)
> -{
> -}
> diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c
> index a44a30b0688c..e952bee89684 100644
> --- a/arch/powerpc/kernel/traps.c
> +++ b/arch/powerpc/kernel/traps.c
> @@ -2207,11 +2207,6 @@ DEFINE_INTERRUPT_HANDLER(kernel_bad_stack)
>   	die("Bad kernel stack pointer", regs, SIGABRT);
>   }
>
> -void __init trap_init(void)
> -{
> -}
> -
> -
>   #ifdef CONFIG_PPC_EMULATED_STATS
>
>   #define WARN_EMULATED_SETUP(type)	.type =3D { .name =3D #type }
> diff --git a/arch/riscv/kernel/traps.c b/arch/riscv/kernel/traps.c
> index 0879b5df11b9..b3f3d84de779 100644
> --- a/arch/riscv/kernel/traps.c
> +++ b/arch/riscv/kernel/traps.c
> @@ -194,8 +194,3 @@ int is_valid_bugaddr(unsigned long pc)
>   		return ((insn & __COMPRESSED_INSN_MASK) =3D=3D __BUG_INSN_16);
>   }
>   #endif /* CONFIG_GENERIC_BUG */
> -
> -/* stvec & scratch is already set from head.S */
> -void trap_init(void)
> -{
> -}
> diff --git a/arch/sparc/kernel/traps_32.c b/arch/sparc/kernel/traps_32.c
> index 247a0d9683b2..c4df20ec01e2 100644
> --- a/arch/sparc/kernel/traps_32.c
> +++ b/arch/sparc/kernel/traps_32.c
> @@ -365,7 +365,7 @@ EXPORT_SYMBOL(do_BUG);
>    * up here so that timer interrupts work during initialization.
>    */
>
> -void trap_init(void)
> +void __init trap_init(void)
>   {
>   	extern void thread_info_offsets_are_bolixed_pete(void);
>
> diff --git a/arch/um/kernel/trap.c b/arch/um/kernel/trap.c
> index ad12f78bda7e..3198c4767387 100644
> --- a/arch/um/kernel/trap.c
> +++ b/arch/um/kernel/trap.c
> @@ -311,7 +311,3 @@ void winch(int sig, struct siginfo *unused_si, struc=
t uml_pt_regs *regs)
>   {
>   	do_IRQ(WINCH_IRQ, regs);
>   }
> -
> -void trap_init(void)
> -{
> -}
> diff --git a/init/main.c b/init/main.c
> index 53b278845b88..8d14674c4e00 100644
> --- a/init/main.c
> +++ b/init/main.c
> @@ -779,6 +779,8 @@ void __init __weak poking_init(void) { }
>
>   void __init __weak pgtable_cache_init(void) { }
>
> +void __init __weak trap_init(void) { }
> +
>   bool initcall_debug;
>   core_param(initcall_debug, initcall_debug, bool, 0644);
>
>