linux-kernel - Re: [PATCH 1/2] riscv, crash: don't export some symbols when CONFIG

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Message-ID: <694baf13-65d0-4877-b6c7-56e3006f83be@infradead.org>
Date:   Mon, 4 Dec 2023 11:14:03 -0800
From:   Randy Dunlap <rdunlap@...radead.org>
To:     Baoquan He <bhe@...hat.com>
Cc:     Stephen Rothwell <sfr@...b.auug.org.au>, akpm@...ux-foundation.org,
        ignat@...udflare.com, linux-next@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-riscv@...ts.infradead.org,
        kexec@...ts.infradead.org, eric_devolder@...oo.com
Subject: Re: [PATCH 1/2] riscv, crash: don't export some symbols when
 CONFIG_MMU=n



On 12/3/23 18:19, Baoquan He wrote:
> When dropping select of KEXEC and dependency on ARCH_SUPPORTS_KEXEC
> from CRASH_DUMP, compiling error is reported when below config items are
> set:
> -----------------------
> CONFIG_CRASH_CORE=y
> CONFIG_KEXEC_CORE=y
> CONFIG_CRASH_DUMP=y
> ......
> -----------------------
> 

[]

> 
> Currently, riscv's ARCH_SUPPORTS_KEXEC has dependency on MMU. Before
> dropping ARCH_SUPPORTS_KEXEC, disabling CONFIG_MMU will unset
> CONFIG_CRASH_DUMP, CONFIG_KEXEC_CORE, CONFIG_CRASH_CORE. Hence
> crash_core related codes won't be compiled.
> 
> ---------------------
> arch/riscv/Kconfig:
> config ARCH_SUPPORTS_KEXEC
>         def_bool MMU
> ---------------------
> 
> After dropping ARCH_SUPPORTS_KEXEC, CONFIG_CRASH_DUMP, CONFIG_KEXEC_CORE,
> CONFIG_CRASH_CORE can be set independently of CONFIG_MMU. However, there
> are several macro definitions, such as VA_BITS, VMEMMAP_START, VMEMMAP_END,
> MODULES_VADDR, MODULES_END are only available when CONFIG_MMU=y. Then
> compiling errors are triggered.
> 
> Here, add CONFIG_MMU ifdeffery in arch_crash_save_vmcoreinfo() to export
> those symbols when CONFIG_MMU is enabled.
> 
> Signed-off-by: Baoquan He <bhe@...hat.com>
> ---
>  arch/riscv/kernel/crash_core.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/riscv/kernel/crash_core.c b/arch/riscv/kernel/crash_core.c
> index 55f1d7856b54..8706736fd4e2 100644
> --- a/arch/riscv/kernel/crash_core.c
> +++ b/arch/riscv/kernel/crash_core.c
> @@ -5,17 +5,19 @@
>  
>  void arch_crash_save_vmcoreinfo(void)
>  {
> -	VMCOREINFO_NUMBER(VA_BITS);
>  	VMCOREINFO_NUMBER(phys_ram_base);
>  
>  	vmcoreinfo_append_str("NUMBER(PAGE_OFFSET)=0x%lx\n", PAGE_OFFSET);
>  	vmcoreinfo_append_str("NUMBER(VMALLOC_START)=0x%lx\n", VMALLOC_START);
>  	vmcoreinfo_append_str("NUMBER(VMALLOC_END)=0x%lx\n", VMALLOC_END);
> +#ifdef CONFIG_MMU
> +	VMCOREINFO_NUMBER(VA_BITS);
>  	vmcoreinfo_append_str("NUMBER(VMEMMAP_START)=0x%lx\n", VMEMMAP_START);
>  	vmcoreinfo_append_str("NUMBER(VMEMMAP_END)=0x%lx\n", VMEMMAP_END);
>  #ifdef CONFIG_64BIT
>  	vmcoreinfo_append_str("NUMBER(MODULES_VADDR)=0x%lx\n", MODULES_VADDR);
>  	vmcoreinfo_append_str("NUMBER(MODULES_END)=0x%lx\n", MODULES_END);
> +#endif
>  #endif
>  	vmcoreinfo_append_str("NUMBER(KERNEL_LINK_ADDR)=0x%lx\n", KERNEL_LINK_ADDR);
>  	vmcoreinfo_append_str("NUMBER(va_kernel_pa_offset)=0x%lx\n",

Both riscv 32-bit and 64-bit complain:

../arch/riscv/kernel/crash_core.c: In function 'arch_crash_save_vmcoreinfo':
../arch/riscv/kernel/crash_core.c:11:58: warning: format '%lx' expects argument of type 'long unsigned int', but argument 2 has type 'int' [-Wformat=]
   11 |         vmcoreinfo_append_str("NUMBER(VMALLOC_START)=0x%lx\n", VMALLOC_START);
      |                                                        ~~^
      |                                                          |
      |                                                          long unsigned int
      |                                                        %x


Otherwise this builds without failure.

Tested-by: Randy Dunlap <rdunlap@...radead.org> # build-tested

Thanks.

-- 
~Randy