[PATCH] RISC-V: Add kernel image sections to the resource tree
Nick Kossifidis
mick at ics.forth.gr
Mon Oct 12 10:24:10 EDT 2020
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 at ics.forth.gr>
---
arch/riscv/kernel/setup.c | 160 ++++++++++++++++++++++++++++++++++++++
arch/riscv/mm/init.c | 27 -------
2 files changed, 160 insertions(+), 27 deletions(-)
diff --git a/arch/riscv/kernel/setup.c b/arch/riscv/kernel/setup.c
index 2c6dd3293..450f0142f 100644
--- a/arch/riscv/kernel/setup.c
+++ b/arch/riscv/kernel/setup.c
@@ -4,6 +4,8 @@
* Chen Liqin <liqin.chen at sunplusct.com>
* Lennox Wu <lennox.wu at sunplusct.com>
* Copyright (C) 2012 Regents of the University of California
+ * Copyright (C) 2020 FORTH-ICS/CARV
+ * Nick Kossifidis <mick at ics.forth.gr>
*/
#include <linux/init.h>
@@ -48,6 +50,163 @@ 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_memblock(reserved, 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_memblock(memory, 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);
+}
+
+
void __init parse_dtb(void)
{
if (early_init_dt_scan(dtb_early_va))
@@ -73,6 +232,7 @@ void __init setup_arch(char **cmdline_p)
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 f750e012d..05d6cf0c2 100644
--- a/arch/riscv/mm/init.c
+++ b/arch/riscv/mm/init.c
@@ -541,39 +541,12 @@ void mark_rodata_ro(void)
}
#endif
-static 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();
sparse_init();
setup_zero_page();
zone_sizes_init();
- resource_init();
}
#ifdef CONFIG_SPARSEMEM_VMEMMAP
--
2.26.2
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