linux-kernel - Re: [PATCH v4] sh: Restructure setup code to reserve memory regions earlier

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Message-ID: <636943c1-6e32-4dd1-abdd-5a110e9aa07c@quicinc.com>
Date: Wed, 17 Jul 2024 19:22:42 -0700
From: Oreoluwa Babatunde <quic_obabatun@...cinc.com>
To: John Paul Adrian Glaubitz <glaubitz@...sik.fu-berlin.de>,
        <ysato@...rs.sourceforge.jp>, <dalias@...c.org>
CC: <linux-sh@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <robh+dt@...nel.org>, <kernel@...cinc.com>
Subject: Re: [PATCH v4] sh: Restructure setup code to reserve memory regions
 earlier


On 7/16/2024 3:42 AM, John Paul Adrian Glaubitz wrote:
> Hi Oreoluwa,
>
> On Mon, 2024-07-15 at 17:12 -0700, Oreoluwa Babatunde wrote:
>> On 7/13/2024 12:58 AM, John Paul Adrian Glaubitz wrote:
>>
>> Hi Adrian,
>>
>>>> diff --git a/arch/sh/include/asm/setup.h b/arch/sh/include/asm/setup.h
>>>> index 84bb23a771f3..f8b814fb1c7f 100644
>>>> --- a/arch/sh/include/asm/setup.h
>>>> +++ b/arch/sh/include/asm/setup.h
>>>> @@ -19,7 +19,6 @@
>>>>  #define COMMAND_LINE ((char *) (PARAM+0x100))
>>>>  
>>>>  void sh_mv_setup(void);
>>>> -void check_for_initrd(void);
>>>>  void per_cpu_trap_init(void);
>>>>  void sh_fdt_init(phys_addr_t dt_phys);
>>>>  
>>>> diff --git a/arch/sh/kernel/setup.c b/arch/sh/kernel/setup.c
>>>> index 620e5cf8ae1e..8477491f4ffd 100644
>>>> --- a/arch/sh/kernel/setup.c
>>>> +++ b/arch/sh/kernel/setup.c
>>>> @@ -35,6 +35,7 @@
>>>>  #include <asm/io.h>
>>>>  #include <asm/page.h>
>>>>  #include <asm/elf.h>
>>>> +#include <asm/kexec.h>
>>>>  #include <asm/sections.h>
>>>>  #include <asm/irq.h>
>>>>  #include <asm/setup.h>
>>>> @@ -114,7 +115,7 @@ static int __init early_parse_mem(char *p)
>>>>  }
>>>>  early_param("mem", early_parse_mem);
>>>>  
>>>> -void __init check_for_initrd(void)
>>>> +static void __init check_for_initrd(void)
>>>>  {
>>>>  #ifdef CONFIG_BLK_DEV_INITRD
>>>>  	unsigned long start, end;
>>>> @@ -172,6 +173,42 @@ void __init check_for_initrd(void)
>>>>  #endif
>>>>  }
>>> Making check_for_initrd() static seems like an unrelated change to me or am
>>> I missing something? If yes, it should go into a separate patch.
>> ack.
>>>> +static void __init early_reserve_mem(void)
>>>> +{
>>>> +	unsigned long start_pfn;
>>>> +	u32 zero_base = (u32)__MEMORY_START + (u32)PHYSICAL_OFFSET;
>>>> +	u32 start = zero_base + (u32)CONFIG_ZERO_PAGE_OFFSET;
>>>> +
>>>> +	/*
>>>> +	 * Partially used pages are not usable - thus
>>>> +	 * we are rounding upwards:
>>>> +	 */
>>>> +	start_pfn = PFN_UP(__pa(_end));
>>>> +
>>>> +	/*
>>>> +	 * Reserve the kernel text and Reserve the bootmem bitmap. We do
>>>> +	 * this in two steps (first step was init_bootmem()), because
>>>> +	 * this catches the (definitely buggy) case of us accidentally
>>>> +	 * initializing the bootmem allocator with an invalid RAM area.
>>>> +	 */
>>>> +	memblock_reserve(start, (PFN_PHYS(start_pfn) + PAGE_SIZE - 1) - start);
>>>> +
>>>> +	/*
>>>> +	 * Reserve physical pages below CONFIG_ZERO_PAGE_OFFSET.
>>>> +	 */
>>>> +	if (CONFIG_ZERO_PAGE_OFFSET != 0)
>>>> +		memblock_reserve(zero_base, CONFIG_ZERO_PAGE_OFFSET);
>>>> +
>>>> +	/*
>>>> +	 * Handle additional early reservations
>>>> +	 */
>>>> +	check_for_initrd();
>>>> +	reserve_crashkernel();
>>>> +
>>>> +	if (sh_mv.mv_mem_reserve)
>>>> +		sh_mv.mv_mem_reserve();
>>>> +}
>>>> +
>>>>  #ifndef CONFIG_GENERIC_CALIBRATE_DELAY
>>>>  void calibrate_delay(void)
>>>>  {
>>> I'm not really happy with moving early_reserve_mem() from mm/init.c to
>>> kernel/setup.c. Can't we just leave it where it is while still keeping
>>> the changes to paging_init()?
>> ack.
>>>> @@ -319,9 +356,14 @@ void __init setup_arch(char **cmdline_p)
>>>>  
>>>>  	sh_mv_setup();
>>>>  
>>>> +	sh_mv.mv_mem_init();
>>>> +
>>>>  	/* Let earlyprintk output early console messages */
>>>>  	sh_early_platform_driver_probe("earlyprintk", 1, 1);
>>>>  
>>>> +	/* set aside reserved memory regions */
>>>> +	early_reserve_mem();
>>>> +
>>>>  #ifdef CONFIG_OF_EARLY_FLATTREE
>>>>  #ifdef CONFIG_USE_BUILTIN_DTB
>>>>  	unflatten_and_copy_device_tree();
>> I'll make adjustments based on your comments and
>> resend another version.
> Okay, I will wait with my pull request to Linus a few more days then.
>
> Thanks so much for being super patient with me. It took me way too long
> to test and review your patch, but I hope in the end we'll get the best
> possible version merged.
>
> Adrian
Hi Adrian,

Thanks for your feedback and for working with me on this.
I have uploaded a new version here:
https://lore.kernel.org/all/20240718021822.1545976-1-quic_obabatun@quicinc.com/

Please let me know if this properly addresses your comments.

Regards,
Oreoluwa