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Message-ID: <20160613072939.GD4974@dhcp-128-65.nay.redhat.com>
Date: Mon, 13 Jun 2016 15:29:39 +0800
From: Dave Young <dyoung@...hat.com>
To: Thiago Jung Bauermann <bauerman@...ux.vnet.ibm.com>
Cc: linuxppc-dev@...ts.ozlabs.org, kexec@...ts.infradead.org,
linux-kernel@...r.kernel.org,
Eric Biederman <ebiederm@...ssion.com>
Subject: Re: [PATCH 2/8] kexec_file: Generalize kexec_add_buffer.
On 06/12/16 at 12:10am, Thiago Jung Bauermann wrote:
> 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.
Can the crashk_res be inserted to iomem_resource so that only one
weak function for system ram is needed?
>
> Also, factor kexec_locate_mem_hole out of kexec_add_buffer. It will be
> used by the PowerPC kexec_file_load implementation to find free memory
> for the purgatory stack.
>
> Cc: Eric Biederman <ebiederm@...ssion.com>
> Cc: kexec@...ts.infradead.org
> Cc: linux-kernel@...r.kernel.org
> ---
> include/linux/kexec.h | 10 ++++++
> kernel/kexec_file.c | 96 +++++++++++++++++++++++++++++++++++++--------------
> 2 files changed, 81 insertions(+), 25 deletions(-)
>
> diff --git a/include/linux/kexec.h b/include/linux/kexec.h
> index e8acb2b43dd9..920e2cbe5bdd 100644
> --- a/include/linux/kexec.h
> +++ b/include/linux/kexec.h
> @@ -210,6 +210,10 @@ 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 start,
> + unsigned long end, 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,
> @@ -315,6 +319,12 @@ 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_walk_iomem(unsigned long desc, unsigned long start,
> + unsigned long end, bool top_down, void *data,
> + int (*func)(u64, u64, void *));
> +int __weak arch_walk_system_ram(unsigned long start, unsigned long end,
> + 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..300f71cb4f72 100644
> --- a/kernel/kexec_file.c
> +++ b/kernel/kexec_file.c
> @@ -428,6 +428,68 @@ static int locate_mem_hole_callback(u64 start, u64 end, void *arg)
> return locate_mem_hole_bottom_up(start, end, kbuf);
> }
>
> +int __weak arch_walk_iomem(unsigned long desc, unsigned long start,
> + unsigned long end, bool top_down, void *data,
> + int (*func)(u64, u64, void *))
> +{
> + return walk_iomem_res_desc(desc,
> + IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY,
> + start, end, data, func);
> +}
> +
> +int __weak arch_walk_system_ram(unsigned long start, unsigned long end,
> + bool top_down, void *data,
> + int (*func)(u64, u64, void *))
> +{
> + return walk_system_ram_res(start, end, data, 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.
> + * @start: Minimum starting address.
> + * @end: 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 erro on failure.
> + */
> +int kexec_locate_mem_hole(struct kimage *image, unsigned long size,
> + unsigned long align, unsigned long start,
> + unsigned long end, 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 = start;
> + buf.buf_max = end;
> + buf.top_down = top_down;
> +
> + /* Walk the RAM ranges and allocate a suitable range for the buffer */
> + if (image->type == KEXEC_TYPE_CRASH)
> + ret = arch_walk_iomem(crashk_res.desc, crashk_res.start,
> + crashk_res.end, top_down, &buf,
> + locate_mem_hole_callback);
> + else
> + ret = arch_walk_system_ram(0, -1, top_down, &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.
> @@ -439,8 +501,8 @@ 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)
> @@ -461,36 +523,20 @@ 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 */
> - 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);
> - 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;
> --
> 1.9.1
>
>
> _______________________________________________
> kexec mailing list
> kexec@...ts.infradead.org
> http://lists.infradead.org/mailman/listinfo/kexec
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