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>

diff --git a/include/linux/kexec.h b/include/linux/kexec.h
index 406c33dcae137a62af7e7d78edf11938270a45c9..5e320ddaaa829cb2ffef93b34cf6ceeaf46b2341 100644 (file)
--- a/include/linux/kexec.h
+++ b/include/linux/kexec.h
@@ -148,7 +148,34 @@ struct kexec_file_ops {
        kexec_verify_sig_t *verify_sig;
 #endif
 };
-#endif
+
+/**
+ * struct kexec_buf - parameters for finding a place for a buffer in memory
+ * @image:     kexec image in which memory to search.
+ * @buffer:    Contents which will be copied to the allocated memory.
+ * @bufsz:     Size of @buffer.
+ * @mem:       On return will have address of the buffer in memory.
+ * @memsz:     Size for the buffer in memory.
+ * @buf_align: Minimum alignment needed.
+ * @buf_min:   The buffer can't be placed below this address.
+ * @buf_max:   The buffer can't be placed above this address.
+ * @top_down:  Allocate from top of memory.
+ */
+struct kexec_buf {
+       struct kimage *image;
+       char *buffer;
+       unsigned long bufsz;
+       unsigned long mem;
+       unsigned long memsz;
+       unsigned long buf_align;
+       unsigned long buf_min;
+       unsigned long buf_max;
+       bool top_down;
+};
+
+int __weak arch_kexec_walk_mem(struct kexec_buf *kbuf,
+                              int (*func)(u64, u64, void *));
+#endif /* CONFIG_KEXEC_FILE */
 
 struct kimage {
        kimage_entry_t head;

diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
index 037c321c56188f9fbb35193072f08052d6e4771f..f865674bff51addc5d6bc4f6955d5a1470096623 100644 (file)
--- 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;

diff --git a/kernel/kexec_internal.h b/kernel/kexec_internal.h
index 0a52315d9c626abf5e17db2b348291e09efb6e15..4cef7e4706b098d7918b53ff1e1b931d1a5ec8dc 100644 (file)
--- a/kernel/kexec_internal.h
+++ b/kernel/kexec_internal.h
@@ -20,22 +20,6 @@ struct kexec_sha_region {
        unsigned long len;
 };
 
-/*
- * Keeps track of buffer parameters as provided by caller for requesting
- * memory placement of buffer.
- */
-struct kexec_buf {
-       struct kimage *image;
-       char *buffer;
-       unsigned long bufsz;
-       unsigned long mem;
-       unsigned long memsz;
-       unsigned long buf_align;
-       unsigned long buf_min;
-       unsigned long buf_max;
-       bool top_down;          /* allocate from top of memory hole */
-};
-
 void kimage_file_post_load_cleanup(struct kimage *image);
 #else /* CONFIG_KEXEC_FILE */
 static inline void kimage_file_post_load_cleanup(struct kimage *image) { }