Re: [PATCH v4 5/6] sparc32: move early memory setup to setup_arch

[Andreas Larsson]

On 2026-09-27 23:43, Magnus Lindholm wrote:
> +static void __init setup_memory(void)
> +{
> +	unsigned long ram_base = memblock_start_of_DRAM();
> +	unsigned long real_base = __get_phys(PAGE_OFFSET);
> +	unsigned long size;
> +
> +	memblock_set_bottom_up(true);
> +	memblock_allow_resize();
> +
> +	phys_base = ram_base;
> +	if (real_base && real_base != phys_base) {
> +		prom_printf("phys_base: RAM starts 0x%x but kernel is at 0x%x\n",
> +			    (unsigned int)phys_base, (unsigned int)real_base);
> +		phys_base = real_base;
> +		memblock_remove(0, phys_base);
> +		prom_printf("phys_base: adopted 0x%x, RAM below it dropped\n",
> +			    (unsigned int)phys_base);

This undos the v3 changes of https://lore.kernel.org/sparclinux/cover.1790548064.git.linmag7@xxxxxxxxx/T/#t ...

>  	}
> -	sp_banks[j].base_addr = 0;
> -	sp_banks[j].num_bytes = 0;
> +
> +	if (cmdline_memory_size)
> +		memblock_enforce_memory_limit(cmdline_memory_size);
> +
> +	min_low_pfn = PFN_DOWN(memblock_start_of_DRAM());
> +	pfn_base = PHYS_PFN(phys_base);
> +	max_pfn = PFN_DOWN(memblock_end_of_DRAM());
> +	max_low_pfn = max_pfn;
> +
> +	if (max_low_pfn > pfn_base + PHYS_PFN(SRMMU_MAXMEM))
> +		max_low_pfn = calc_max_low_pfn();
> +
> +	find_ramdisk(memblock_end_of_DRAM());
> +
> +	/* Reserve the kernel text/data/bss. */
> +	size = __pa(PAGE_ALIGN((unsigned long)&_end)) - phys_base;
> +	memblock_reserve(phys_base, size);
> +	memblock_add(phys_base, size);
> +
> +	/* Only allow low memory to be allocated by memblock. */
> +	memblock_set_current_limit(PFN_PHYS(max_low_pfn));
>  }
>  
>  /* Called from head_32.S - before we have setup anything
> @@ -306,9 +350,6 @@ void __init sparc32_start_kernel(struct linux_romvec *rp)
>  
>  void __init setup_arch(char **cmdline_p)
>  {
> -	int i;
> -	unsigned long highest_paddr;
> -
>  	sparc_ttable = &trapbase[0];
>  
>  	/* Initialize PROM console and command line. */
> @@ -343,36 +384,7 @@ void __init setup_arch(char **cmdline_p)
>  
>  	idprom_init();
>  	load_mmu();
> -
> -	phys_base = 0xffffffffUL;
> -	highest_paddr = 0UL;
> -	for (i = 0; sp_banks[i].num_bytes != 0; i++) {
> -		unsigned long top;
> -
> -		if (sp_banks[i].base_addr < phys_base)
> -			phys_base = sp_banks[i].base_addr;
> -		top = sp_banks[i].base_addr +
> -			sp_banks[i].num_bytes;
> -		if (highest_paddr < top)
> -			highest_paddr = top;
> -	}
> -
> -	/* phys_base must describe what PAGE_OFFSET maps to, not where RAM starts. */
> -	{
> -		unsigned long real_base = __get_phys(PAGE_OFFSET);
> -
> -		if (real_base && real_base != phys_base) {
> -			prom_printf("phys_base: RAM starts 0x%x but kernel is at 0x%x\n",
> -				    (unsigned int)phys_base,
> -				    (unsigned int)real_base);
> -			phys_base = real_base;
> -			trim_sp_banks_below(phys_base);
> -			prom_printf("phys_base: adopted 0x%x, RAM below it dropped\n",
> -				    (unsigned int)phys_base);
> -		}
> -	}

...and does not apply on top of that. 

Please rework the series on top of the for-next branch of 
git://git.kernel.org/pub/scm/linux/kernel/git/alarsson/linux-sparc.git

Thanks,
Andreas