linux-kernel - [PATCH v5 01/13] kexec_file: Allow arch-specific memory walking for kexec_add

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Message-Id: <1470956898-5991-2-git-send-email-bauerman@linux.vnet.ibm.com>
Date:	Thu, 11 Aug 2016 20:08:06 -0300
From:	Thiago Jung Bauermann <bauerman@...ux.vnet.ibm.com>
To:	kexec@...ts.infradead.org
Cc:	linuxppc-dev@...ts.ozlabs.org, linux-kernel@...r.kernel.org,
	x86@...nel.org, Eric Biederman <ebiederm@...ssion.com>,
	Dave Young <dyoung@...hat.com>,
	Vivek Goyal <vgoyal@...hat.com>, Baoquan He <bhe@...hat.com>,
	Michael Ellerman <mpe@...erman.id.au>,
	Benjamin Herrenschmidt <benh@...nel.crashing.org>,
	Paul Mackerras <paulus@...ba.org>,
	Stewart Smith <stewart@...ux.vnet.ibm.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>,
	"H. Peter Anvin" <hpa@...or.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Thiago Jung Bauermann <bauerman@...ux.vnet.ibm.com>
Subject: [PATCH v5 01/13] 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@...ux.vnet.ibm.com>
Acked-by: Dave Young <dyoung@...hat.com>
---
 include/linux/kexec.h   | 26 ++++++++++++++++++++++++++
 kernel/kexec_file.c     | 30 ++++++++++++++++++++++--------
 kernel/kexec_internal.h | 16 ----------------
 3 files changed, 48 insertions(+), 24 deletions(-)

diff --git a/include/linux/kexec.h b/include/linux/kexec.h
index 29202935055d..5ffd0011395c 100644
--- a/include/linux/kexec.h
+++ b/include/linux/kexec.h
@@ -149,6 +149,32 @@ struct kexec_file_ops {
 #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 *));
 int __weak arch_kexec_verify_buffer(enum kexec_file_type type, const void *buf,
 				    unsigned long size);
 #endif /* CONFIG_KEXEC_FILE */
diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
index c32d1d65bb77..e63fd4592e20 100644
--- a/kernel/kexec_file.c
+++ b/kernel/kexec_file.c
@@ -502,6 +502,27 @@ 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.
@@ -548,14 +569,7 @@ 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 0a52315d9c62..4cef7e4706b0 100644
--- 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) { }
-- 
1.9.1