Am Donnerstag, 16 Juni 2016, 09:58:53 schrieb Dave Young:
> On 06/15/16 at 01:21pm, Thiago Jung Bauermann wrote:
> > +/**
> > + * arch_kexec_walk_mem - call func(data) on free memory regions
> > + * @image_type:    kimage.type
> > + * @top_down:      Start from the highest address?
> > + * @data:  Argument to pass 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(unsigned int image_type, bool top_down,
> > +                          void *data, int (*func)(u64, u64, void *))
> > +{
> 
> top_down is also not used?

It's unused in the default implementation, but the powerpc implementation in 
patch 8 uses it:

int arch_kexec_walk_mem(unsigned int type, bool top_down, void *data,
                        int (*func)(u64, u64, void *))
{
        int ret = 0;
        u64 i;
        phys_addr_t mstart, mend;

        if (top_down) {
                for_each_free_mem_range_reverse(i, NUMA_NO_NODE, 0,
                                                &mstart, &mend, NULL) {
                        ret = func(mstart, mend, data);
                        if (ret)
                                break;
                }
        } else {
                for_each_free_mem_range(i, NUMA_NO_NODE, 0, &mstart, &mend,
                                        NULL) {
                        ret = func(mstart, mend, data);
                        if (ret)
                                break;
                }
        }

        return ret;
}

> Rethink about the argument name type should be better than image_type,
> it is obvious in the comments and the code and simpler.

Ok, renamed in the patch below.

[]'s
Thiago Jung Bauermann
IBM Linux Technology Center


    kexec_file: Generalize kexec_add_buffer.
    
    Allow architectures to specify different memory walking functions for
    kexec_add_buffer. Intel uses iomem to track reserved memory ranges,
    but PowerPC uses the memblock subsystem.
    
    Signed-off-by: Thiago Jung Bauermann <bauer...@linux.vnet.ibm.com>
    Cc: Eric Biederman <ebied...@xmission.com>
    Cc: Dave Young <dyo...@redhat.com>
    Cc: ke...@lists.infradead.org
    Cc: linux-ker...@vger.kernel.org

diff --git a/include/linux/kexec.h b/include/linux/kexec.h
index e8acb2b43dd9..42b31f2e1d88 100644
--- a/include/linux/kexec.h
+++ b/include/linux/kexec.h
@@ -315,6 +315,8 @@ int __weak arch_kexec_apply_relocations_add(const Elf_Ehdr 
*ehdr,
                                        Elf_Shdr *sechdrs, unsigned int relsec);
 int __weak arch_kexec_apply_relocations(const Elf_Ehdr *ehdr, Elf_Shdr 
*sechdrs,
                                        unsigned int relsec);
+int __weak arch_kexec_walk_mem(unsigned int type, bool top_down, void *data,
+                              int (*func)(u64, u64, void *));
 void arch_kexec_protect_crashkres(void);
 void arch_kexec_unprotect_crashkres(void);
 
diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
index b6eec7527e9f..989647a324f2 100644
--- a/kernel/kexec_file.c
+++ b/kernel/kexec_file.c
@@ -428,6 +428,29 @@ 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
+ * @type:      kimage.type
+ * @top_down:  Start from the highest address?
+ * @data:      Argument to pass 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(unsigned int type, bool top_down, void *data,
+                              int (*func)(u64, u64, void *))
+{
+       if (type == KEXEC_TYPE_CRASH)
+               return walk_iomem_res_desc(crashk_res.desc,
+                                          IORESOURCE_SYSTEM_RAM | 
IORESOURCE_BUSY,
+                                          crashk_res.start, crashk_res.end,
+                                          data, func);
+       else
+               return walk_system_ram_res(0, ULONG_MAX, data, func);
+}
+
 /*
  * Helper function for placing a buffer in a kexec segment. This assumes
  * that kexec_mutex is held.
@@ -472,14 +495,8 @@ 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(image->type, top_down, kbuf,
+                                  locate_mem_hole_callback);
        if (ret != 1) {
                /* A suitable memory range could not be found for buffer */
                return -EADDRNOTAVAIL;

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