[PATCH v16 04/16] powerpc, kexec_file: factor out memblock-based arch_kexec_walk_mem()

From: AKASHI Takahiro
Date: Thu Nov 15 2018 - 00:52:35 EST


Memblock list is another source for usable system memory layout.
So move powerpc's arch_kexec_walk_mem() to common code so that other
memblock-based architectures, particularly arm64, can also utilise it.
A moved function is now renamed to kexec_walk_memblock() and integrated
into kexec_locate_mem_hole(), which will now be usable for all
architectures with no need for overriding arch_kexec_walk_mem().

With this change, arch_kexec_walk_mem() need no longer be a weak function,
and was now renamed to kexec_walk_resources().

Since powerpc doesn't support kdump in its kexec_file_load(), the current
kexec_walk_memblock() won't work for kdump either in this form, this will
be fixed in the next patch.

Signed-off-by: AKASHI Takahiro <takahiro.akashi@xxxxxxxxxx>
Cc: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
Acked-by: Dave Young <dyoung@xxxxxxxxxx>
Cc: Vivek Goyal <vgoyal@xxxxxxxxxx>
Cc: Baoquan He <bhe@xxxxxxxxxx>
Acked-by: James Morse <james.morse@xxxxxxx>
---
arch/powerpc/kernel/machine_kexec_file_64.c | 54 ------------------
include/linux/kexec.h | 2 -
kernel/kexec_file.c | 61 +++++++++++++++++++--
3 files changed, 57 insertions(+), 60 deletions(-)

diff --git a/arch/powerpc/kernel/machine_kexec_file_64.c b/arch/powerpc/kernel/machine_kexec_file_64.c
index c77e95e9b384..0d20c7ad40fa 100644
--- a/arch/powerpc/kernel/machine_kexec_file_64.c
+++ b/arch/powerpc/kernel/machine_kexec_file_64.c
@@ -24,7 +24,6 @@

#include <linux/slab.h>
#include <linux/kexec.h>
-#include <linux/memblock.h>
#include <linux/of_fdt.h>
#include <linux/libfdt.h>
#include <asm/ima.h>
@@ -46,59 +45,6 @@ int arch_kexec_kernel_image_probe(struct kimage *image, void *buf,
return kexec_image_probe_default(image, buf, buf_len);
}

-/**
- * arch_kexec_walk_mem - call func(data) for each unreserved memory block
- * @kbuf: Context info for the search. Also passed to @func.
- * @func: Function to call for each memory block.
- *
- * This function is used by kexec_add_buffer and kexec_locate_mem_hole
- * to find unreserved memory to load kexec segments into.
- *
- * Return: The memory walk will stop when func returns a non-zero value
- * and that value will be returned. If all free regions are visited without
- * func returning non-zero, then zero will be returned.
- */
-int arch_kexec_walk_mem(struct kexec_buf *kbuf,
- int (*func)(struct resource *, void *))
-{
- int ret = 0;
- u64 i;
- phys_addr_t mstart, mend;
- struct resource res = { };
-
- if (kbuf->top_down) {
- for_each_free_mem_range_reverse(i, NUMA_NO_NODE, 0,
- &mstart, &mend, NULL) {
- /*
- * In memblock, end points to the first byte after the
- * range while in kexec, end points to the last byte
- * in the range.
- */
- res.start = mstart;
- res.end = mend - 1;
- ret = func(&res, kbuf);
- if (ret)
- break;
- }
- } else {
- for_each_free_mem_range(i, NUMA_NO_NODE, 0, &mstart, &mend,
- NULL) {
- /*
- * In memblock, end points to the first byte after the
- * range while in kexec, end points to the last byte
- * in the range.
- */
- res.start = mstart;
- res.end = mend - 1;
- ret = func(&res, kbuf);
- if (ret)
- break;
- }
- }
-
- return ret;
-}
-
/**
* setup_purgatory - initialize the purgatory's global variables
* @image: kexec image.
diff --git a/include/linux/kexec.h b/include/linux/kexec.h
index f378cb786f1b..d58d1f2fab10 100644
--- a/include/linux/kexec.h
+++ b/include/linux/kexec.h
@@ -192,8 +192,6 @@ int __weak arch_kexec_apply_relocations(struct purgatory_info *pi,
const Elf_Shdr *relsec,
const Elf_Shdr *symtab);

-int __weak arch_kexec_walk_mem(struct kexec_buf *kbuf,
- int (*func)(struct resource *, void *));
extern int kexec_add_buffer(struct kexec_buf *kbuf);
int kexec_locate_mem_hole(struct kexec_buf *kbuf);

diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
index 9e6529da12ed..d03195a8cb6e 100644
--- a/kernel/kexec_file.c
+++ b/kernel/kexec_file.c
@@ -16,6 +16,7 @@
#include <linux/file.h>
#include <linux/slab.h>
#include <linux/kexec.h>
+#include <linux/memblock.h>
#include <linux/mutex.h>
#include <linux/list.h>
#include <linux/fs.h>
@@ -499,8 +500,57 @@ static int locate_mem_hole_callback(struct resource *res, void *arg)
return locate_mem_hole_bottom_up(start, end, kbuf);
}

+#ifdef CONFIG_ARCH_DISCARD_MEMBLOCK
+static int kexec_walk_memblock(struct kexec_buf *kbuf,
+ int (*func)(struct resource *, void *))
+{
+ return 0;
+}
+#else
+static int kexec_walk_memblock(struct kexec_buf *kbuf,
+ int (*func)(struct resource *, void *))
+{
+ int ret = 0;
+ u64 i;
+ phys_addr_t mstart, mend;
+ struct resource res = { };
+
+ if (kbuf->top_down) {
+ for_each_free_mem_range_reverse(i, NUMA_NO_NODE, 0,
+ &mstart, &mend, NULL) {
+ /*
+ * In memblock, end points to the first byte after the
+ * range while in kexec, end points to the last byte
+ * in the range.
+ */
+ res.start = mstart;
+ res.end = mend - 1;
+ ret = func(&res, kbuf);
+ if (ret)
+ break;
+ }
+ } else {
+ for_each_free_mem_range(i, NUMA_NO_NODE, 0, &mstart, &mend,
+ NULL) {
+ /*
+ * In memblock, end points to the first byte after the
+ * range while in kexec, end points to the last byte
+ * in the range.
+ */
+ res.start = mstart;
+ res.end = mend - 1;
+ ret = func(&res, kbuf);
+ if (ret)
+ break;
+ }
+ }
+
+ return ret;
+}
+#endif
+
/**
- * arch_kexec_walk_mem - call func(data) on free memory regions
+ * kexec_walk_resources - call func(data) on free memory regions
* @kbuf: Context info for the search. Also passed to @func.
* @func: Function to call for each memory region.
*
@@ -508,8 +558,8 @@ static int locate_mem_hole_callback(struct resource *res, void *arg)
* and that value will be returned. If all free regions are visited without
* func returning non-zero, then zero will be returned.
*/
-int __weak arch_kexec_walk_mem(struct kexec_buf *kbuf,
- int (*func)(struct resource *, void *))
+static int kexec_walk_resources(struct kexec_buf *kbuf,
+ int (*func)(struct resource *, void *))
{
if (kbuf->image->type == KEXEC_TYPE_CRASH)
return walk_iomem_res_desc(crashk_res.desc,
@@ -536,7 +586,10 @@ int kexec_locate_mem_hole(struct kexec_buf *kbuf)
if (kbuf->mem != KEXEC_BUF_MEM_UNKNOWN)
return 0;

- ret = arch_kexec_walk_mem(kbuf, locate_mem_hole_callback);
+ if (IS_ENABLED(CONFIG_ARCH_DISCARD_MEMBLOCK))
+ ret = kexec_walk_resources(kbuf, locate_mem_hole_callback);
+ else
+ ret = kexec_walk_memblock(kbuf, locate_mem_hole_callback);

return ret == 1 ? 0 : -EADDRNOTAVAIL;
}
--
2.19.0