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Message-ID: <20121128170856.GL21266@phenom.dumpdata.com>
Date: Wed, 28 Nov 2012 12:08:56 -0500
From: Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
To: Yinghai Lu <yinghai@...nel.org>
Cc: Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...e.hu>,
"H. Peter Anvin" <hpa@...or.com>, Jacob Shin <jacob.shin@....com>,
Andrew Morton <akpm@...ux-foundation.org>,
Stefano Stabellini <stefano.stabellini@...citrix.com>,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH v8 14/46] x86, mm: use pfn_range_is_mapped() with
reserve_initrd
On Fri, Nov 16, 2012 at 07:38:51PM -0800, Yinghai Lu wrote:
> We are going to map ram only, so under max_low_pfn_mapped,
> between 4g and max_pfn_mapped does not mean mapped at all.
>
> Use pfn_range_is_mapped() to find out if range is mapped for initrd.
>
> That could happen bootloader put initrd in range but user could
^- 'if the' ^^^^^-'used'
> use memmap to carve some of range out.
^^^-> get rid of that. ^^^^->'ranges'
>
> Also during copying need to use early_memmap to map original initrd
> for accessing.
>
> Signed-off-by: Yinghai Lu <yinghai@...nel.org>
> ---
> arch/x86/kernel/setup.c | 52 +++++++++++++++++++++++++---------------------
> 1 files changed, 28 insertions(+), 24 deletions(-)
>
> diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
> index d85cbd9..bd52f9d 100644
> --- a/arch/x86/kernel/setup.c
> +++ b/arch/x86/kernel/setup.c
> @@ -317,20 +317,19 @@ static void __init relocate_initrd(void)
> u64 ramdisk_image = boot_params.hdr.ramdisk_image;
> u64 ramdisk_size = boot_params.hdr.ramdisk_size;
> u64 area_size = PAGE_ALIGN(ramdisk_size);
> - u64 end_of_lowmem = max_low_pfn_mapped << PAGE_SHIFT;
> u64 ramdisk_here;
> unsigned long slop, clen, mapaddr;
> char *p, *q;
>
> - /* We need to move the initrd down into lowmem */
> - ramdisk_here = memblock_find_in_range(0, end_of_lowmem, area_size,
> - PAGE_SIZE);
> + /* We need to move the initrd down into directly mapped mem */
> + ramdisk_here = memblock_find_in_range(0, PFN_PHYS(max_low_pfn_mapped),
> + area_size, PAGE_SIZE);
>
> if (!ramdisk_here)
> panic("Cannot find place for new RAMDISK of size %lld\n",
> ramdisk_size);
>
> - /* Note: this includes all the lowmem currently occupied by
> + /* Note: this includes all the mem currently occupied by
> the initrd, we rely on that fact to keep the data intact. */
> memblock_reserve(ramdisk_here, area_size);
> initrd_start = ramdisk_here + PAGE_OFFSET;
> @@ -340,17 +339,7 @@ static void __init relocate_initrd(void)
>
> q = (char *)initrd_start;
>
> - /* Copy any lowmem portion of the initrd */
> - if (ramdisk_image < end_of_lowmem) {
> - clen = end_of_lowmem - ramdisk_image;
> - p = (char *)__va(ramdisk_image);
> - memcpy(q, p, clen);
> - q += clen;
> - ramdisk_image += clen;
> - ramdisk_size -= clen;
> - }
> -
> - /* Copy the highmem portion of the initrd */
> + /* Copy the initrd */
> while (ramdisk_size) {
> slop = ramdisk_image & ~PAGE_MASK;
> clen = ramdisk_size;
> @@ -364,7 +353,7 @@ static void __init relocate_initrd(void)
> ramdisk_image += clen;
> ramdisk_size -= clen;
> }
> - /* high pages is not converted by early_res_to_bootmem */
> +
> ramdisk_image = boot_params.hdr.ramdisk_image;
> ramdisk_size = boot_params.hdr.ramdisk_size;
> printk(KERN_INFO "Move RAMDISK from [mem %#010llx-%#010llx] to"
> @@ -373,13 +362,27 @@ static void __init relocate_initrd(void)
> ramdisk_here, ramdisk_here + ramdisk_size - 1);
> }
>
> +static u64 __init get_mem_size(unsigned long limit_pfn)
> +{
> + int i;
> + u64 mapped_pages = 0;
> + unsigned long start_pfn, end_pfn;
> +
> + for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, NULL) {
> + start_pfn = min_t(unsigned long, start_pfn, limit_pfn);
> + end_pfn = min_t(unsigned long, end_pfn, limit_pfn);
> + mapped_pages += end_pfn - start_pfn;
> + }
> +
> + return mapped_pages << PAGE_SHIFT;
> +}
> static void __init reserve_initrd(void)
> {
> /* Assume only end is not page aligned */
> u64 ramdisk_image = boot_params.hdr.ramdisk_image;
> u64 ramdisk_size = boot_params.hdr.ramdisk_size;
> u64 ramdisk_end = PAGE_ALIGN(ramdisk_image + ramdisk_size);
> - u64 end_of_lowmem = max_low_pfn_mapped << PAGE_SHIFT;
> + u64 mapped_size;
>
> if (!boot_params.hdr.type_of_loader ||
> !ramdisk_image || !ramdisk_size)
> @@ -387,18 +390,19 @@ static void __init reserve_initrd(void)
>
> initrd_start = 0;
>
> - if (ramdisk_size >= (end_of_lowmem>>1)) {
> + mapped_size = get_mem_size(max_low_pfn_mapped);
> + if (ramdisk_size >= (mapped_size>>1))
> panic("initrd too large to handle, "
> "disabling initrd (%lld needed, %lld available)\n",
> - ramdisk_size, end_of_lowmem>>1);
> - }
> + ramdisk_size, mapped_size>>1);
>
> printk(KERN_INFO "RAMDISK: [mem %#010llx-%#010llx]\n", ramdisk_image,
> ramdisk_end - 1);
>
> -
> - if (ramdisk_end <= end_of_lowmem) {
> - /* All in lowmem, easy case */
> + if (ramdisk_end <= (max_low_pfn_mapped<<PAGE_SHIFT) &&
> + pfn_range_is_mapped(PFN_DOWN(ramdisk_image),
> + PFN_DOWN(ramdisk_end))) {
> + /* All are mapped, easy case */
> /*
> * don't need to reserve again, already reserved early
> * in i386_start_kernel
> --
> 1.7.7
--
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