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Groups > linux.kernel > #1718968

[PATCH 03/14] resource: add walk_system_ram_res_rev()

From AKASHI Takahiro <takahiro.akashi@linaro.org>
Newsgroups linux.kernel
Subject [PATCH 03/14] resource: add walk_system_ram_res_rev()
Date 2017-08-24 10:30 +0200
Message-ID <uhVGy-405-19@gated-at.bofh.it> (permalink)
References <uhVwR-3Wx-1@gated-at.bofh.it>
Organization linux.* mail to news gateway

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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.

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      | 48 ++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 51 insertions(+)

diff --git a/include/linux/ioport.h b/include/linux/ioport.h
index 6230064d7f95..9a212266299f 100644
--- a/include/linux/ioport.h
+++ b/include/linux/ioport.h
@@ -271,6 +271,9 @@ extern int
 walk_system_ram_res(u64 start, u64 end, void *arg,
 		    int (*func)(u64, u64, void *));
 extern int
+walk_system_ram_res_rev(u64 start, u64 end, void *arg,
+			int (*func)(u64, u64, void *));
+extern int
 walk_iomem_res_desc(unsigned long desc, unsigned long flags, u64 start, u64 end,
 		    void *arg, int (*func)(u64, u64, void *));
 
diff --git a/kernel/resource.c b/kernel/resource.c
index 9b5f04404152..1d6d734c75ac 100644
--- a/kernel/resource.c
+++ b/kernel/resource.c
@@ -23,6 +23,7 @@
 #include <linux/pfn.h>
 #include <linux/mm.h>
 #include <linux/resource_ext.h>
+#include <linux/vmalloc.h>
 #include <asm/io.h>
 
 
@@ -469,6 +470,53 @@ int walk_system_ram_res(u64 start, u64 end, void *arg,
 	return ret;
 }
 
+int walk_system_ram_res_rev(u64 start, u64 end, void *arg,
+				int (*func)(u64, u64, void *))
+{
+	struct resource res, *rams;
+	u64 orig_end;
+	int count, i;
+	int ret = -1;
+
+	count = 16; /* initial */
+again:
+	/* create a list */
+	rams = vmalloc(sizeof(struct resource) * count);
+	if (!rams)
+		return ret;
+
+	res.start = start;
+	res.end = end;
+	res.flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
+	orig_end = res.end;
+	i = 0;
+	while ((res.start < res.end) &&
+		(!find_next_iomem_res(&res, IORES_DESC_NONE, true))) {
+		if (i >= count) {
+			/* unlikely but */
+			vfree(rams);
+			count += 16;
+			goto again;
+		}
+
+		rams[i].start = res.start;
+		rams[i++].end = res.end;
+
+		res.start = res.end + 1;
+		res.end = orig_end;
+	}
+
+	/* go reverse */
+	for (i--; i >= 0; i--) {
+		ret = (*func)(rams[i].start, rams[i].end, arg);
+		if (ret)
+			break;
+	}
+
+	vfree(rams);
+	return ret;
+}
+
 #if !defined(CONFIG_ARCH_HAS_WALK_MEMORY)
 
 /*
-- 
2.14.1

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Thread

[PATCH 00/14] arm64: kexec: add kexec_file_load support AKASHI Takahiro <takahiro.akashi@linaro.org> - 2017-08-24 10:20 +0200
  [PATCH 14/14] arm64: kexec_file: add vmlinux format support AKASHI Takahiro <takahiro.akashi@linaro.org> - 2017-08-24 10:20 +0200
    Re: [PATCH 14/14] arm64: kexec_file: add vmlinux format support Mark Rutland <mark.rutland@arm.com> - 2017-08-24 19:40 +0200
      Re: [PATCH 14/14] arm64: kexec_file: add vmlinux format support AKASHI Takahiro <takahiro.akashi@linaro.org> - 2017-08-25 04:10 +0200
        Re: [PATCH 14/14] arm64: kexec_file: add vmlinux format support Dave Young <dyoung@redhat.com> - 2017-08-25 08:20 +0200
  [PATCH 08/14] arm64: kexec_file: create purgatory AKASHI Takahiro <takahiro.akashi@linaro.org> - 2017-08-24 10:20 +0200
    Re: [PATCH 08/14] arm64: kexec_file: create purgatory Ard Biesheuvel <ard.biesheuvel@linaro.org> - 2017-08-24 11:20 +0200
      Re: [PATCH 08/14] arm64: kexec_file: create purgatory AKASHI Takahiro <takahiro.akashi@linaro.org> - 2017-08-25 03:20 +0200
    Re: [PATCH 08/14] arm64: kexec_file: create purgatory Mark Rutland <mark.rutland@arm.com> - 2017-08-24 19:00 +0200
      Re: [PATCH 08/14] arm64: kexec_file: create purgatory AKASHI Takahiro <takahiro.akashi@linaro.org> - 2017-08-25 03:10 +0200
        Re: [PATCH 08/14] arm64: kexec_file: create purgatory Mark Rutland <mark.rutland@arm.com> - 2017-08-25 12:30 +0200
  [PATCH 02/14] include: pe.h: remove message[] from mz header definition AKASHI Takahiro <takahiro.akashi@linaro.org> - 2017-08-24 10:20 +0200
    Re: [PATCH 02/14] include: pe.h: remove message[] from mz header definition Ard Biesheuvel <ard.biesheuvel@linaro.org> - 2017-08-24 11:10 +0200
  [PATCH 01/14] MODSIGN: Export module signature definitions AKASHI Takahiro <takahiro.akashi@linaro.org> - 2017-08-24 10:20 +0200
  [PATCH 09/14] arm64: kexec_file: add sha256 digest check in purgatory AKASHI Takahiro <takahiro.akashi@linaro.org> - 2017-08-24 10:30 +0200
    Re: [PATCH 09/14] arm64: kexec_file: add sha256 digest check in purgatory Ard Biesheuvel <ard.biesheuvel@linaro.org> - 2017-08-24 11:20 +0200
      Re: [PATCH 09/14] arm64: kexec_file: add sha256 digest check in  purgatory AKASHI Takahiro <takahiro.akashi@linaro.org> - 2017-08-25 03:30 +0200
    Re: [PATCH 09/14] arm64: kexec_file: add sha256 digest check in  purgatory Mark Rutland <mark.rutland@arm.com> - 2017-08-24 19:10 +0200
      Re: [PATCH 09/14] arm64: kexec_file: add sha256 digest check in  purgatory AKASHI Takahiro <takahiro.akashi@linaro.org> - 2017-08-25 03:30 +0200
        Re: [PATCH 09/14] arm64: kexec_file: add sha256 digest check in  purgatory Mark Rutland <mark.rutland@arm.com> - 2017-08-25 12:50 +0200
  [PATCH 07/14] asm-generic: add kexec_file_load system call to unistd.h AKASHI Takahiro <takahiro.akashi@linaro.org> - 2017-08-24 10:30 +0200
    Re: [PATCH 07/14] asm-generic: add kexec_file_load system call to unistd.h Arnd Bergmann <arnd@arndb.de> - 2017-08-24 13:00 +0200
  [PATCH 13/14] arm64: kexec_file: add Image format support AKASHI Takahiro <takahiro.akashi@linaro.org> - 2017-08-24 10:30 +0200
    Re: [PATCH 13/14] arm64: kexec_file: add Image format support Mark Rutland <mark.rutland@arm.com> - 2017-08-24 19:30 +0200
      Re: [PATCH 13/14] arm64: kexec_file: add Image format support AKASHI Takahiro <takahiro.akashi@linaro.org> - 2017-08-25 04:00 +0200
  [PATCH 03/14] resource: add walk_system_ram_res_rev() AKASHI Takahiro <takahiro.akashi@linaro.org> - 2017-08-24 10:30 +0200
    Re: [PATCH 03/14] resource: add walk_system_ram_res_rev() Ard Biesheuvel <ard.biesheuvel@linaro.org> - 2017-08-24 11:10 +0200
      Re: [PATCH 03/14] resource: add walk_system_ram_res_rev() AKASHI Takahiro <takahiro.akashi@linaro.org> - 2017-08-25 03:00 +0200
  [PATCH 10/14] arm64: kexec_file: load initrd, device-tree and purgatory segments AKASHI Takahiro <takahiro.akashi@linaro.org> - 2017-08-24 10:30 +0200
    Re: [PATCH 10/14] arm64: kexec_file: load initrd, device-tree and  purgatory segments Mark Rutland <mark.rutland@arm.com> - 2017-08-24 19:20 +0200
      Re: [PATCH 10/14] arm64: kexec_file: load initrd, device-tree and  purgatory segments AKASHI Takahiro <takahiro.akashi@linaro.org> - 2017-08-25 03:40 +0200
  [PATCH 04/14] kexec_file: factor out vmlinux (elf) parser from powerpc AKASHI Takahiro <takahiro.akashi@linaro.org> - 2017-08-24 10:30 +0200
  [PATCH 05/14] kexec_file: factor out crashdump elf header function from x86 AKASHI Takahiro <takahiro.akashi@linaro.org> - 2017-08-24 10:30 +0200
    Re: [PATCH 05/14] kexec_file: factor out crashdump elf header  function from x86 Dave Young <dyoung@redhat.com> - 2017-08-25 07:50 +0200
  [PATCH 06/14] kexec_file: add kexec_add_segment() AKASHI Takahiro <takahiro.akashi@linaro.org> - 2017-08-24 10:30 +0200
  [PATCH 12/14] arm64: enable KEXEC_FILE config AKASHI Takahiro <takahiro.akashi@linaro.org> - 2017-08-24 10:30 +0200
  [PATCH 11/14] arm64: kexec_file: set up for crash dump adding elf core header AKASHI Takahiro <takahiro.akashi@linaro.org> - 2017-08-24 10:30 +0200

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