On 06/21/16 at 04:48pm, Thiago Jung Bauermann wrote:
> kexec_locate_mem_hole will be used by the PowerPC kexec_file_load
> implementation to find free memory for the purgatory stack.
>
> Signed-off-by: Thiago Jung Bauermann <bauerman at linux.vnet.ibm.com>
> Cc: Eric Biederman <ebiederm at xmission.com>
> Cc: Dave Young <dyoung at redhat.com>
> Cc: kexec at lists.infradead.org
> Cc: linux-kernel at vger.kernel.org
> ---
> include/linux/kexec.h | 4 ++++
> kernel/kexec_file.c | 66 ++++++++++++++++++++++++++++++++++++++-------------
> 2 files changed, 53 insertions(+), 17 deletions(-)
>
> diff --git a/include/linux/kexec.h b/include/linux/kexec.h
> index 3d91bcfc180d..4ca6f5f95d66 100644
> --- a/include/linux/kexec.h
> +++ b/include/linux/kexec.h
> @@ -227,6 +227,10 @@ extern asmlinkage long sys_kexec_load(unsigned long entry,
> struct kexec_segment __user *segments,
> unsigned long flags);
> extern int kernel_kexec(void);
> +int kexec_locate_mem_hole(struct kimage *image, unsigned long size,
> + unsigned long align, unsigned long min_addr,
> + unsigned long max_addr, bool top_down,
> + unsigned long *addr);
> extern int kexec_add_buffer(struct kimage *image, char *buffer,
> unsigned long bufsz, unsigned long memsz,
> unsigned long buf_align, unsigned long buf_min,
> diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
> index b1f1f6402518..85a515511925 100644
> --- a/kernel/kexec_file.c
> +++ b/kernel/kexec_file.c
> @@ -449,6 +449,46 @@ int __weak arch_kexec_walk_mem(struct kexec_buf *kbuf,
> return walk_system_ram_res(0, ULONG_MAX, kbuf, func);
> }
>
> +/**
> + * kexec_locate_mem_hole - find free memory to load segment or use in purgatory
> + * @image: kexec image being updated.
> + * @size: Memory size.
> + * @align: Minimum alignment needed.
> + * @min_addr: Minimum starting address.
> + * @max_addr: Maximum end address.
> + * @top_down Find the highest free memory region?
> + * @addr On success, will have start address of the memory region found.
> + *
> + * Return: 0 on success, negative errno on error.
> + */
> +int kexec_locate_mem_hole(struct kimage *image, unsigned long size,
> + unsigned long align, unsigned long min_addr,
> + unsigned long max_addr, bool top_down,
> + unsigned long *addr)
> +{
> + int ret;
> + struct kexec_buf buf;
> +
> + memset(&buf, 0, sizeof(struct kexec_buf));
> + buf.image = image;
> +
> + buf.memsz = size;
> + buf.buf_align = align;
> + buf.buf_min = min_addr;
> + buf.buf_max = max_addr;
> + buf.top_down = top_down;
Since patch 2/9 moved kexec_buf from internal header file to kexec.h it
will be natural to passing a kexec_buf pointer intead of passing all
these arguments in kexec_locate_mem_hole.
kbuf.mem can be used for addr.
> +
> + ret = arch_kexec_walk_mem(&buf, locate_mem_hole_callback);
> + if (ret != 1) {
> + /* A suitable memory range could not be found for buffer */
> + return -EADDRNOTAVAIL;
> + }
> +
> + *addr = buf.mem;
> +
> + return 0;
> +}
> +
> /*
> * Helper function for placing a buffer in a kexec segment. This assumes
> * that kexec_mutex is held.
> @@ -460,8 +500,8 @@ int kexec_add_buffer(struct kimage *image, char *buffer, unsigned long bufsz,
> {
>
> struct kexec_segment *ksegment;
> - struct kexec_buf buf, *kbuf;
> int ret;
> + unsigned long addr, align, size;
>
> /* Currently adding segment this way is allowed only in file mode */
> if (!image->file_mode)
> @@ -482,29 +522,21 @@ int kexec_add_buffer(struct kimage *image, char *buffer, unsigned long bufsz,
> return -EINVAL;
> }
>
> - memset(&buf, 0, sizeof(struct kexec_buf));
> - kbuf = &buf;
> - kbuf->image = image;
> -
> - 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;
> + size = ALIGN(memsz, PAGE_SIZE);
> + align = max(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);
> - if (ret != 1) {
> - /* A suitable memory range could not be found for buffer */
> - return -EADDRNOTAVAIL;
> - }
> + ret = kexec_locate_mem_hole(image, size, align, buf_min, buf_max,
> + top_down, &addr);
> + if (ret)
> + return ret;
>
> /* Found a suitable memory range */
> ksegment = &image->segment[image->nr_segments];
> ksegment->kbuf = buffer;
> ksegment->bufsz = bufsz;
> - ksegment->mem = kbuf->mem;
> - ksegment->memsz = kbuf->memsz;
> + ksegment->mem = addr;
> + ksegment->memsz = size;
> image->nr_segments++;
> *load_addr = ksegment->mem;
> return 0;
Thanks
Dave
