kexec_file: Change kexec_add_buffer to take kexec_buf as argument.

This is done to simplify the kexec_add_buffer argument list.
Adapt all callers to set up a kexec_buf to pass to kexec_add_buffer.

In addition, change the type of kexec_buf.buffer from char * to void *.
There is no particular reason for it to be a char *, and the change
allows us to get rid of 3 existing casts to char * in the code.

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, 40 insertions, 48 deletions

diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
index f865674bff51..efd2c094af7e 100644
--- a/kernel/kexec_file.c
+++ b/kernel/kexec_file.c
@@ -449,25 +449,27 @@ int __weak arch_kexec_walk_mem(struct kexec_buf *kbuf,
 		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.
+/**
+ * kexec_add_buffer - place a buffer in a kexec segment
+ * @kbuf:	Buffer contents and memory parameters.
+ *
+ * This function assumes that kexec_mutex is held.
+ * On successful return, @kbuf->mem will have the physical address of
+ * the buffer in memory.
+ *
+ * Return: 0 on success, negative errno on error.
  */
-int kexec_add_buffer(struct kimage *image, char *buffer, unsigned long bufsz,
-		     unsigned long memsz, unsigned long buf_align,
-		     unsigned long buf_min, unsigned long buf_max,
-		     bool top_down, unsigned long *load_addr)
+int kexec_add_buffer(struct kexec_buf *kbuf)
 {
 
 	struct kexec_segment *ksegment;
-	struct kexec_buf buf, *kbuf;
 	int ret;
 
 	/* Currently adding segment this way is allowed only in file mode */
-	if (!image->file_mode)
+	if (!kbuf->image->file_mode)
 		return -EINVAL;
 
-	if (image->nr_segments >= KEXEC_SEGMENT_MAX)
+	if (kbuf->image->nr_segments >= KEXEC_SEGMENT_MAX)
 		return -EINVAL;
 
 	/*
@@ -477,22 +479,14 @@ int kexec_add_buffer(struct kimage *image, char *buffer, unsigned long bufsz,
 	 * logic goes through list of segments to make sure there are
 	 * no destination overlaps.
 	 */
-	if (!list_empty(&image->control_pages)) {
+	if (!list_empty(&kbuf->image->control_pages)) {
 		WARN_ON(1);
 		return -EINVAL;
 	}
 
-	memset(&buf, 0, sizeof(struct kexec_buf));
-	kbuf = &buf;
-	kbuf->image = image;
-	kbuf->buffer = buffer;
-	kbuf->bufsz = bufsz;
-
-	kbuf->memsz = ALIGN(memsz, PAGE_SIZE);
-	kbuf->buf_align = max(buf_align, PAGE_SIZE);
-	kbuf->buf_min = buf_min;
-	kbuf->buf_max = buf_max;
-	kbuf->top_down = top_down;
+	/* Ensure minimum alignment needed for segments. */
+	kbuf->memsz = ALIGN(kbuf->memsz, PAGE_SIZE);
+	kbuf->buf_align = max(kbuf->buf_align, PAGE_SIZE);
 
 	/* Walk the RAM ranges and allocate a suitable range for the buffer */
 	ret = arch_kexec_walk_mem(kbuf, locate_mem_hole_callback);
@@ -502,13 +496,12 @@ int kexec_add_buffer(struct kimage *image, char *buffer, unsigned long bufsz,
 	}
 
 	/* Found a suitable memory range */
-	ksegment = &image->segment[image->nr_segments];
+	ksegment = &kbuf->image->segment[kbuf->image->nr_segments];
 	ksegment->kbuf = kbuf->buffer;
 	ksegment->bufsz = kbuf->bufsz;
 	ksegment->mem = kbuf->mem;
 	ksegment->memsz = kbuf->memsz;
-	image->nr_segments++;
-	*load_addr = ksegment->mem;
+	kbuf->image->nr_segments++;
 	return 0;
 }
 
@@ -630,13 +623,15 @@ static int __kexec_load_purgatory(struct kimage *image, unsigned long min,
 				  unsigned long max, int top_down)
 {
 	struct purgatory_info *pi = &image->purgatory_info;
-	unsigned long align, buf_align, bss_align, buf_sz, bss_sz, bss_pad;
-	unsigned long memsz, entry, load_addr, curr_load_addr, bss_addr, offset;
+	unsigned long align, bss_align, bss_sz, bss_pad;
+	unsigned long entry, load_addr, curr_load_addr, bss_addr, offset;
 	unsigned char *buf_addr, *src;
 	int i, ret = 0, entry_sidx = -1;
 	const Elf_Shdr *sechdrs_c;
 	Elf_Shdr *sechdrs = NULL;
-	void *purgatory_buf = NULL;
+	struct kexec_buf kbuf = { .image = image, .bufsz = 0, .buf_align = 1,
+				  .buf_min = min, .buf_max = max,
+				  .top_down = top_down };
 
 	/*
 	 * sechdrs_c points to section headers in purgatory and are read
@@ -702,9 +697,7 @@ static int __kexec_load_purgatory(struct kimage *image, unsigned long min,
 	}
 
 	/* Determine how much memory is needed to load relocatable object. */
-	buf_align = 1;
 	bss_align = 1;
-	buf_sz = 0;
 	bss_sz = 0;
 
 	for (i = 0; i < pi->ehdr->e_shnum; i++) {
@@ -713,10 +706,10 @@ static int __kexec_load_purgatory(struct kimage *image, unsigned long min,
 
 		align = sechdrs[i].sh_addralign;
 		if (sechdrs[i].sh_type != SHT_NOBITS) {
-			if (buf_align < align)
-				buf_align = align;
-			buf_sz = ALIGN(buf_sz, align);
-			buf_sz += sechdrs[i].sh_size;
+			if (kbuf.buf_align < align)
+				kbuf.buf_align = align;
+			kbuf.bufsz = ALIGN(kbuf.bufsz, align);
+			kbuf.bufsz += sechdrs[i].sh_size;
 		} else {
 			/* bss section */
 			if (bss_align < align)
@@ -728,32 +721,31 @@ static int __kexec_load_purgatory(struct kimage *image, unsigned long min,
 
 	/* Determine the bss padding required to align bss properly */
 	bss_pad = 0;
-	if (buf_sz & (bss_align - 1))
-		bss_pad = bss_align - (buf_sz & (bss_align - 1));
+	if (kbuf.bufsz & (bss_align - 1))
+		bss_pad = bss_align - (kbuf.bufsz & (bss_align - 1));
 
-	memsz = buf_sz + bss_pad + bss_sz;
+	kbuf.memsz = kbuf.bufsz + bss_pad + bss_sz;
 
 	/* Allocate buffer for purgatory */
-	purgatory_buf = vzalloc(buf_sz);
-	if (!purgatory_buf) {
+	kbuf.buffer = vzalloc(kbuf.bufsz);
+	if (!kbuf.buffer) {
 		ret = -ENOMEM;
 		goto out;
 	}
 
-	if (buf_align < bss_align)
-		buf_align = bss_align;
+	if (kbuf.buf_align < bss_align)
+		kbuf.buf_align = bss_align;
 
 	/* Add buffer to segment list */
-	ret = kexec_add_buffer(image, purgatory_buf, buf_sz, memsz,
-				buf_align, min, max, top_down,
-				&pi->purgatory_load_addr);
+	ret = kexec_add_buffer(&kbuf);
 	if (ret)
 		goto out;
+	pi->purgatory_load_addr = kbuf.mem;
 
 	/* Load SHF_ALLOC sections */
-	buf_addr = purgatory_buf;
+	buf_addr = kbuf.buffer;
 	load_addr = curr_load_addr = pi->purgatory_load_addr;
-	bss_addr = load_addr + buf_sz + bss_pad;
+	bss_addr = load_addr + kbuf.bufsz + bss_pad;
 
 	for (i = 0; i < pi->ehdr->e_shnum; i++) {
 		if (!(sechdrs[i].sh_flags & SHF_ALLOC))
@@ -799,11 +791,11 @@ static int __kexec_load_purgatory(struct kimage *image, unsigned long min,
 	 * Used later to identify which section is purgatory and skip it
 	 * from checksumming.
 	 */
-	pi->purgatory_buf = purgatory_buf;
+	pi->purgatory_buf = kbuf.buffer;
 	return ret;
 out:
 	vfree(sechdrs);
-	vfree(purgatory_buf);
+	vfree(kbuf.buffer);
 	return ret;
 }