From: Dave Young <dyoung@redhat.com>
To: AKASHI Takahiro <takahiro.akashi@linaro.org>
Cc: catalin.marinas@arm.com, will.deacon@arm.com,
bauerman@linux.vnet.ibm.com, dhowells@redhat.com,
vgoyal@redhat.com, herbert@gondor.apana.org.au,
davem@davemloft.net, akpm@linux-foundation.org,
mpe@ellerman.id.au, bhe@redhat.com, arnd@arndb.de,
ard.biesheuvel@linaro.org, julien.thierry@arm.com,
kexec@lists.infradead.org, linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org,
Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [PATCH v8 01/13] resource: add walk_system_ram_res_rev()
Date: Fri, 23 Feb 2018 16:36:19 +0800 [thread overview]
Message-ID: <20180223083619.GA4433@dhcp-128-65.nay.redhat.com> (raw)
In-Reply-To: <20180222111732.23051-2-takahiro.akashi@linaro.org>
Hi AKASHI,
On 02/22/18 at 08:17pm, AKASHI Takahiro wrote:
> This function, being a variant of walk_system_ram_res() introduced in
> commit 8c86e70acead ("resource: provide new functions to walk through
> resources"), walks through a list of all the resources of System RAM
> in reversed order, i.e., from higher to lower.
>
> It will be used in kexec_file implementation on arm64.
I remember there was an old discussion about this, it should be added
in patch log why this is needed.
>
> Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
> Cc: Vivek Goyal <vgoyal@redhat.com>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Linus Torvalds <torvalds@linux-foundation.org>
> ---
> include/linux/ioport.h | 3 +++
> kernel/resource.c | 57 ++++++++++++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 60 insertions(+)
>
> diff --git a/include/linux/ioport.h b/include/linux/ioport.h
> index da0ebaec25f0..f12d95fe038b 100644
> --- a/include/linux/ioport.h
> +++ b/include/linux/ioport.h
> @@ -277,6 +277,9 @@ extern int
> walk_system_ram_res(u64 start, u64 end, void *arg,
> int (*func)(struct resource *, void *));
> extern int
> +walk_system_ram_res_rev(u64 start, u64 end, void *arg,
> + int (*func)(struct resource *, void *));
> +extern int
> walk_iomem_res_desc(unsigned long desc, unsigned long flags, u64 start, u64 end,
> void *arg, int (*func)(struct resource *, void *));
>
> diff --git a/kernel/resource.c b/kernel/resource.c
> index e270b5048988..bdaa93407f4c 100644
> --- a/kernel/resource.c
> +++ b/kernel/resource.c
> @@ -23,6 +23,8 @@
> #include <linux/pfn.h>
> #include <linux/mm.h>
> #include <linux/resource_ext.h>
> +#include <linux/string.h>
> +#include <linux/vmalloc.h>
> #include <asm/io.h>
>
>
> @@ -486,6 +488,61 @@ int walk_mem_res(u64 start, u64 end, void *arg,
> arg, func);
> }
>
> +int walk_system_ram_res_rev(u64 start, u64 end, void *arg,
> + int (*func)(struct resource *, void *))
> +{
> + struct resource res, *rams;
> + int rams_size = 16, i;
> + int ret = -1;
> +
> + /* create a list */
> + rams = vmalloc(sizeof(struct resource) * rams_size);
> + if (!rams)
> + return ret;
> +
> + res.start = start;
> + res.end = end;
> + res.flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
> + i = 0;
> + while ((res.start < res.end) &&
> + (!find_next_iomem_res(&res, IORES_DESC_NONE, true))) {
> + if (i >= rams_size) {
> + /* re-alloc */
> + struct resource *rams_new;
> + int rams_new_size;
> +
> + rams_new_size = rams_size + 16;
> + rams_new = vmalloc(sizeof(struct resource)
> + * rams_new_size);
> + if (!rams_new)
> + goto out;
> +
> + memcpy(rams_new, rams,
> + sizeof(struct resource) * rams_size);
> + vfree(rams);
> + rams = rams_new;
> + rams_size = rams_new_size;
> + }
> +
> + rams[i].start = res.start;
> + rams[i++].end = res.end;
> +
> + res.start = res.end + 1;
> + res.end = end;
> + }
> +
> + /* go reverse */
> + for (i--; i >= 0; i--) {
> + ret = (*func)(&rams[i], arg);
> + if (ret)
> + break;
> + }
> +
> +out:
> + vfree(rams);
> + return ret;
> +}
> +
> #if !defined(CONFIG_ARCH_HAS_WALK_MEMORY)
>
> /*
> --
> 2.16.2
>
Thanks
Dave
next prev parent reply other threads:[~2018-02-23 8:36 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-22 11:17 [PATCH v8 00/13] arm64: kexec: add kexec_file_load() support AKASHI Takahiro
2018-02-22 11:17 ` [PATCH v8 01/13] resource: add walk_system_ram_res_rev() AKASHI Takahiro
2018-02-23 8:36 ` Dave Young [this message]
2018-03-20 1:43 ` Baoquan He
2018-03-20 3:12 ` AKASHI Takahiro
2018-03-20 3:48 ` Baoquan He
2018-02-22 11:17 ` [PATCH v8 02/13] kexec_file: make an use of purgatory optional AKASHI Takahiro
2018-02-23 8:49 ` Dave Young
2018-02-26 10:24 ` AKASHI Takahiro
2018-02-28 12:33 ` Dave Young
2018-03-01 2:59 ` AKASHI Takahiro
2018-02-22 11:17 ` [PATCH v8 03/13] kexec_file,x86,powerpc: factor out kexec_file_ops functions AKASHI Takahiro
2018-02-23 9:24 ` Dave Young
2018-02-26 10:01 ` AKASHI Takahiro
2018-02-26 11:25 ` Philipp Rudo
2018-02-28 12:38 ` Dave Young
2018-03-01 3:18 ` AKASHI Takahiro
2018-02-26 11:17 ` [PATCH v8 03/13] kexec_file, x86, powerpc: " Philipp Rudo
2018-02-27 2:03 ` AKASHI Takahiro
2018-02-27 9:26 ` Philipp Rudo
2018-02-22 11:17 ` [PATCH v8 04/13] x86: kexec_file: factor out elf core header related functions AKASHI Takahiro
2018-02-24 3:15 ` Dave Young
2018-02-26 9:21 ` AKASHI Takahiro
2018-02-22 11:17 ` [PATCH v8 05/13] kexec_file, x86: move re-factored code to generic side AKASHI Takahiro
2018-02-22 11:17 ` [PATCH v8 06/13] asm-generic: add kexec_file_load system call to unistd.h AKASHI Takahiro
2018-02-22 11:17 ` [PATCH v8 07/13] arm64: kexec_file: invoke the kernel without purgatory AKASHI Takahiro
2018-02-22 11:17 ` [PATCH v8 08/13] arm64: kexec_file: load initrd and device-tree AKASHI Takahiro
2018-02-22 11:17 ` [PATCH v8 09/13] arm64: kexec_file: add crash dump support AKASHI Takahiro
2018-02-22 11:17 ` [PATCH v8 10/13] arm64: kexec_file: add Image format support AKASHI Takahiro
2018-02-22 11:17 ` [PATCH v8 11/13] arm64: kexec_file: enable KEXEC_FILE config AKASHI Takahiro
2018-02-22 11:17 ` [PATCH v8 12/13] include: pe.h: remove message[] from mz header definition AKASHI Takahiro
2018-02-22 11:17 ` [PATCH v8 13/13] arm64: kexec_file: enable KEXEC_VERIFY_SIG for Image AKASHI Takahiro
2018-02-27 4:56 ` [PATCH v8 00/13] arm64: kexec: add kexec_file_load() support AKASHI Takahiro
2018-02-28 12:25 ` Dave Young
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