ACK: [SRU Groovy] riscv: Fixup bootup failure with HARDENED_USERCOPY

[Kamal Mostafa]

LGTM

Acked-by: Kamal Mostafa <kamal at canonical.com>

 -Kamal

On Thu, Nov 19, 2020 at 06:10:28PM -0300, Thadeu Lima de Souza Cascardo wrote:
> From: Guo Ren <guoren at linux.alibaba.com>
> 
> BugLink: https://bugs.launchpad.net/bugs/1904912
> 
> 6184358da000 ("riscv: Fixup static_obj() fail") attempted to elide a lockdep
> failure by rearranging our kernel image to place all initdata within [_stext,
> _end], thus triggering lockdep to treat these as static objects.  These objects
> are released and eventually reallocated, causing check_kernel_text_object() to
> trigger a BUG().
> 
> This backs out the change to make [_stext, _end] all-encompassing, instead just
> moving initdata.  This results in initdata being outside of [__init_begin,
> __init_end], which means initdata can't be freed.
> 
> Link: https://lore.kernel.org/linux-riscv/1593266228-61125-1-git-send-email-guoren@kernel.org/T/#t
> Signed-off-by: Guo Ren <guoren at linux.alibaba.com>
> Reported-by: Aurelien Jarno <aurelien at aurel32.net>
> Tested-by: Aurelien Jarno <aurelien at aurel32.net>
> [Palmer: Clean up commit text]
> Signed-off-by: Palmer Dabbelt <palmerdabbelt at google.com>
> (cherry picked from commit 84814460eef9af0fb56a4698341c9cb7996a6312)
> Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo at canonical.com>
> ---
>  arch/riscv/kernel/vmlinux.lds.S | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/riscv/kernel/vmlinux.lds.S b/arch/riscv/kernel/vmlinux.lds.S
> index f3586e31ed1e..34d00d9e6eac 100644
> --- a/arch/riscv/kernel/vmlinux.lds.S
> +++ b/arch/riscv/kernel/vmlinux.lds.S
> @@ -22,13 +22,11 @@ SECTIONS
>  	/* Beginning of code and text segment */
>  	. = LOAD_OFFSET;
>  	_start = .;
> -	_stext = .;
>  	HEAD_TEXT_SECTION
>  	. = ALIGN(PAGE_SIZE);
>  
>  	__init_begin = .;
>  	INIT_TEXT_SECTION(PAGE_SIZE)
> -	INIT_DATA_SECTION(16)
>  	. = ALIGN(8);
>  	__soc_early_init_table : {
>  		__soc_early_init_table_start = .;
> @@ -55,6 +53,7 @@ SECTIONS
>  	. = ALIGN(SECTION_ALIGN);
>  	.text : {
>  		_text = .;
> +		_stext = .;
>  		TEXT_TEXT
>  		SCHED_TEXT
>  		CPUIDLE_TEXT
> @@ -67,6 +66,8 @@ SECTIONS
>  		_etext = .;
>  	}
>  
> +	INIT_DATA_SECTION(16)
> +
>  	/* Start of data section */
>  	_sdata = .;
>  	RO_DATA(SECTION_ALIGN)
> -- 
> 2.27.0
> 
> 
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