kexec_file: Allow arch-specific memory walking for kexec_add_buffer

Allow architectures to specify a different memory walking function for
kexec_add_buffer. x86 uses iomem to track reserved memory ranges, but
PowerPC uses the memblock subsystem.

Signed-off-by: Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>
Acked-by: Dave Young <dyoung@redhat.com>
Acked-by: Balbir Singh <bsingharora@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

1 files changed, 22 insertions, 8 deletions

diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
index 037c321c5618..f865674bff51 100644
--- a/kernel/kexec_file.c
+++ b/kernel/kexec_file.c
@@ -428,6 +428,27 @@ static int locate_mem_hole_callback(u64 start, u64 end, void *arg)
         return locate_mem_hole_bottom_up(start, end, kbuf);
 }
 
+/**
+ * arch_kexec_walk_mem - 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.
+ *
+ * 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 __weak arch_kexec_walk_mem(struct kexec_buf *kbuf,
+                               int (*func)(u64, u64, void *))
+{
+        if (kbuf->image->type == KEXEC_TYPE_CRASH)
+                return walk_iomem_res_desc(crashk_res.desc,
+                                           IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY,
+                                           crashk_res.start, crashk_res.end,
+                                           kbuf, func);
+        else
+                return walk_system_ram_res(0, ULONG_MAX, kbuf, func);
+}
+
 /*
  * Helper function for placing a buffer in a kexec segment. This assumes
  * that kexec_mutex is held.
@@ -474,14 +495,7 @@ int kexec_add_buffer(struct kimage *image, char *buffer, unsigned long bufsz,
         kbuf->top_down = top_down;
 
         /* Walk the RAM ranges and allocate a suitable range for the buffer */
-        if (image->type == KEXEC_TYPE_CRASH)
-                ret = walk_iomem_res_desc(crashk_res.desc,
-                                IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY,
-                                crashk_res.start, crashk_res.end, kbuf,
-                                locate_mem_hole_callback);
-        else
-                ret = walk_system_ram_res(0, -1, kbuf,
-                                          locate_mem_hole_callback);
+        ret = arch_kexec_walk_mem(kbuf, locate_mem_hole_callback);
         if (ret != 1) {
                 /* A suitable memory range could not be found for buffer */
                 return -EADDRNOTAVAIL;