RISC-V: Add kernel image sections to the resource tree

This patch (previously part of my kexec/kdump series) populates
/proc/iomem with the various sections of the kernel image. We need
this for kexec-tools to be able to prepare the crashkernel image
for kdump to work. Since resource tree initialization is not
related to memory initialization I added the code to kernel/setup.c
and removed the original code (derived from the arm64 tree) from
mm/init.c.

Signed-off-by: Nick Kossifidis <mick@ics.forth.gr>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>

diff --git a/arch/riscv/kernel/setup.c b/arch/riscv/kernel/setup.c
index c424cc6..515b5a6 100644 (file)
--- a/arch/riscv/kernel/setup.c
+++ b/arch/riscv/kernel/setup.c
@@ -4,6 +4,8 @@
  *  Chen Liqin <liqin.chen@sunplusct.com>
  *  Lennox Wu <lennox.wu@sunplusct.com>
  * Copyright (C) 2012 Regents of the University of California
+ * Copyright (C) 2020 FORTH-ICS/CARV
+ *  Nick Kossifidis <mick@ics.forth.gr>
  */
 
 #include <linux/init.h>
@@ -51,6 +53,163 @@ atomic_t hart_lottery __section(".sdata");
 unsigned long boot_cpu_hartid;
 static DEFINE_PER_CPU(struct cpu, cpu_devices);
 
+/*
+ * Place kernel memory regions on the resource tree so that
+ * kexec-tools can retrieve them from /proc/iomem. While there
+ * also add "System RAM" regions for compatibility with other
+ * archs, and the rest of the known regions for completeness.
+ */
+static struct resource code_res = { .name = "Kernel code", };
+static struct resource data_res = { .name = "Kernel data", };
+static struct resource rodata_res = { .name = "Kernel rodata", };
+static struct resource bss_res = { .name = "Kernel bss", };
+
+static int __init add_resource(struct resource *parent,
+                               struct resource *res)
+{
+       int ret = 0;
+
+       ret = insert_resource(parent, res);
+       if (ret < 0) {
+               pr_err("Failed to add a %s resource at %llx\n",
+                       res->name, (unsigned long long) res->start);
+               return ret;
+       }
+
+       return 1;
+}
+
+static int __init add_kernel_resources(struct resource *res)
+{
+       int ret = 0;
+
+       /*
+        * The memory region of the kernel image is continuous and
+        * was reserved on setup_bootmem, find it here and register
+        * it as a resource, then register the various segments of
+        * the image as child nodes
+        */
+       if (!(res->start <= code_res.start && res->end >= data_res.end))
+               return 0;
+
+       res->name = "Kernel image";
+       res->flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
+
+       /*
+        * We removed a part of this region on setup_bootmem so
+        * we need to expand the resource for the bss to fit in.
+        */
+       res->end = bss_res.end;
+
+       ret = add_resource(&iomem_resource, res);
+       if (ret < 0)
+               return ret;
+
+       ret = add_resource(res, &code_res);
+       if (ret < 0)
+               return ret;
+
+       ret = add_resource(res, &rodata_res);
+       if (ret < 0)
+               return ret;
+
+       ret = add_resource(res, &data_res);
+       if (ret < 0)
+               return ret;
+
+       ret = add_resource(res, &bss_res);
+
+       return ret;
+}
+
+static void __init init_resources(void)
+{
+       struct memblock_region *region = NULL;
+       struct resource *res = NULL;
+       int ret = 0;
+
+       code_res.start = __pa_symbol(_text);
+       code_res.end = __pa_symbol(_etext) - 1;
+       code_res.flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
+
+       rodata_res.start = __pa_symbol(__start_rodata);
+       rodata_res.end = __pa_symbol(__end_rodata) - 1;
+       rodata_res.flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
+
+       data_res.start = __pa_symbol(_data);
+       data_res.end = __pa_symbol(_edata) - 1;
+       data_res.flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
+
+       bss_res.start = __pa_symbol(__bss_start);
+       bss_res.end = __pa_symbol(__bss_stop) - 1;
+       bss_res.flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
+
+       /*
+        * Start by adding the reserved regions, if they overlap
+        * with /memory regions, insert_resource later on will take
+        * care of it.
+        */
+       for_each_reserved_mem_region(region) {
+               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 = "Reserved";
+               res->flags = IORESOURCE_MEM | IORESOURCE_BUSY;
+               res->start = __pfn_to_phys(memblock_region_reserved_base_pfn(region));
+               res->end = __pfn_to_phys(memblock_region_reserved_end_pfn(region)) - 1;
+
+               ret = add_kernel_resources(res);
+               if (ret < 0)
+                       goto error;
+               else if (ret)
+                       continue;
+
+               /*
+                * Ignore any other reserved regions within
+                * system memory.
+                */
+               if (memblock_is_memory(res->start))
+                       continue;
+
+               ret = add_resource(&iomem_resource, res);
+               if (ret < 0)
+                       goto error;
+       }
+
+       /* Add /memory regions to the resource tree */
+       for_each_mem_region(region) {
+               res = memblock_alloc(sizeof(struct resource), SMP_CACHE_BYTES);
+               if (!res)
+                       panic("%s: Failed to allocate %zu bytes\n", __func__,
+                             sizeof(struct resource));
+
+               if (unlikely(memblock_is_nomap(region))) {
+                       res->name = "Reserved";
+                       res->flags = IORESOURCE_MEM | IORESOURCE_BUSY;
+               } 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;
+
+               ret = add_resource(&iomem_resource, res);
+               if (ret < 0)
+                       goto error;
+       }
+
+       return;
+
+ error:
+       memblock_free((phys_addr_t) res, sizeof(struct resource));
+       /* Better an empty resource tree than an inconsistent one */
+       release_child_resources(&iomem_resource);
+}
+
+
 static void __init parse_dtb(void)
 {
        /* Early scan of device tree from init memory */
@@ -80,6 +239,7 @@ void __init setup_arch(char **cmdline_p)
        efi_init();
        setup_bootmem();
        paging_init();
+       init_resources();
 #if IS_ENABLED(CONFIG_BUILTIN_DTB)
        unflatten_and_copy_device_tree();
 #else

diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
index ea933b7..e3c1fc4 100644 (file)
--- a/arch/riscv/mm/init.c
+++ b/arch/riscv/mm/init.c
@@ -625,39 +625,12 @@ void mark_rodata_ro(void)
 }
 #endif
 
-static void __init resource_init(void)
-{
-       struct memblock_region *region;
-
-       for_each_mem_region(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();
        sparse_init();
        setup_zero_page();
        zone_sizes_init();
-       resource_init();
 }
 
 #ifdef CONFIG_SPARSEMEM_VMEMMAP