Thread (20 messages) 20 messages, 3 authors, 2016-06-20

Re: [PATCH v2 2/9] kexec_file: Generalize kexec_add_buffer.

From: Dave Young <hidden>
Date: 2016-06-17 07:35:32
Also in: kexec, lkml

On 06/16/16 at 05:39pm, Thiago Jung Bauermann wrote:
Am Donnerstag, 16 Juni 2016, 09:58:53 schrieb Dave Young:
quoted
On 06/15/16 at 01:21pm, Thiago Jung Bauermann wrote:
quoted
+/**
+ * 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:
Well, arch_kexec_walk_mem use kbuf as "data", you can even drop
"image_type" since kbuf has all you want kbuf->image->type, and
kbuf->top_down 

int __weak arch_kexec_walk_mem(struct kexec_buf *kbuf,
			       int (*func)(u64, u64, void *))
quoted hunk ↗ jump to hunk
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;
}
quoted
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 [off-list ref]
    Cc: Eric Biederman [off-list ref]
    Cc: Dave Young [off-list ref]
    Cc: kexec@lists.infradead.org
    Cc: linux-kernel@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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Thanks
Dave
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