linux-kernel - Re: [PATCH 1/2] riscv: Register System RAM as iomem resources

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Date:   Thu, 09 Jul 2020 11:27:18 -0700 (PDT)
From:   Palmer Dabbelt <palmer@...belt.com>
To:     zong.li@...ive.com
CC:     Paul Walmsley <paul.walmsley@...ive.com>,
        linux-riscv@...ts.infradead.org, linux-kernel@...r.kernel.org,
        zong.li@...ive.com
Subject:     Re: [PATCH 1/2] riscv: Register System RAM as iomem resources

On Tue, 16 Jun 2020 00:45:46 PDT (-0700), zong.li@...ive.com wrote:
> Add System RAM to /proc/iomem, various tools expect it such as kdump.
> It is also needed for page_is_ram API which checks the specified address
> whether registered as System RAM in iomem_resource list.
>
> Signed-off-by: Zong Li <zong.li@...ive.com>
> ---
>  arch/riscv/mm/init.c | 22 ++++++++++++++++++++++
>  1 file changed, 22 insertions(+)
>
> diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
> index f4adb3684f3d..bbe816e03b2f 100644
> --- a/arch/riscv/mm/init.c
> +++ b/arch/riscv/mm/init.c
> @@ -517,6 +517,27 @@ void mark_rodata_ro(void)
>  }
>  #endif
>
> +void __init resource_init(void)
> +{
> +	struct memblock_region *region;
> +
> +	for_each_memblock(memory, region) {
> +		struct resource *res;
> +
> +		res = memblock_alloc(sizeof(struct resource), SMP_CACHE_BYTES);
> +		if (!res)
> +			panic("%s: Failed to allocate %zu bytes\n", __func__,
> +			      sizeof(struct resource));
> +
> +		res->name = "System RAM";
> +		res->start = __pfn_to_phys(memblock_region_memory_base_pfn(region));
> +		res->end = __pfn_to_phys(memblock_region_memory_end_pfn(region)) - 1;
> +		res->flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;

Looks like everyone else is checking MEMBLOCK_NOMAP before registering memory
regions.  I've added that and put this on for-next.  Thanks!

commit 11dc632bf515874c84887727614e8044452f1f28
gpg: Signature made Thu 09 Jul 2020 11:24:08 AM PDT
gpg:                using RSA key 2B3C3747446843B24A943A7A2E1319F35FBB1889
gpg:                issuer "palmer@...belt.com"
gpg: Good signature from "Palmer Dabbelt <palmer@...belt.com>" [ultimate]
gpg:                 aka "Palmer Dabbelt <palmerdabbelt@...gle.com>" [ultimate]
Author: Zong Li <zong.li@...ive.com>
Date:   Tue Jun 16 15:45:46 2020 +0800

    riscv: Register System RAM as iomem resources
    
    Add System RAM to /proc/iomem, various tools expect it such as kdump.
    It is also needed for page_is_ram API which checks the specified address
    whether registered as System RAM in iomem_resource list.
    
    Signed-off-by: Zong Li <zong.li@...ive.com>
    [Palmer: check MEMBLOCK_NOMAP]
    Signed-off-by: Palmer Dabbelt <palmerdabbelt@...gle.com>

diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
index f4adb3684f3d..8b78fd23713e 100644
--- a/arch/riscv/mm/init.c
+++ b/arch/riscv/mm/init.c
@@ -517,6 +517,32 @@ void mark_rodata_ro(void)
 }
 #endif
 
+void __init resource_init(void)
+{
+	struct memblock_region *region;
+
+	for_each_memblock(memory, region) {
+		struct resource *res;
+
+		res = memblock_alloc(sizeof(struct resource), SMP_CACHE_BYTES);
+		if (!res)
+			panic("%s: Failed to allocate %zu bytes\n", __func__,
+			      sizeof(struct resource));
+
+		if (memblock_is_nomap(region) {
+			res->name = "reserved";
+			res->flags = IORESOURCE_MEM;
+		} else {
+			res->name = "System RAM";
+			res->flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
+		}
+		res->start = __pfn_to_phys(memblock_region_memory_base_pfn(region));
+		res->end = __pfn_to_phys(memblock_region_memory_end_pfn(region)) - 1;
+
+		request_resource(&iomem_resource, res);
+	}
+}
+
 void __init paging_init(void)
 {
 	setup_vm_final();
@@ -524,6 +550,7 @@ void __init paging_init(void)
 	sparse_init();
 	setup_zero_page();
 	zone_sizes_init();
+	resource_init();
 }
 
 #ifdef CONFIG_SPARSEMEM_VMEMMAP


> +
> +		request_resource(&iomem_resource, res);
> +	}
> +}
> +
>  void __init paging_init(void)
>  {
>  	setup_vm_final();
> @@ -524,6 +545,7 @@ void __init paging_init(void)
>  	sparse_init();
>  	setup_zero_page();
>  	zone_sizes_init();
> +	resource_init();
>  }
>
>  #ifdef CONFIG_SPARSEMEM_VMEMMAP