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Date: Mon, 17 Jun 2013 17:55:03 -0600
From: Toshi Kani <toshi.kani@...com>
To: Yinghai Lu <yinghai@...nel.org>
Cc: "H. Peter Anvin" <hpa@...or.com>,
Thomas Gleixner <tglx@...utronix.de>,
Ingo Molnar <mingo@...e.hu>,
Andrew Morton <akpm@...ux-foundation.org>,
Tejun Heo <tj@...nel.org>, Thomas Renninger <trenn@...e.de>,
Tang Chen <tangchen@...fujitsu.com>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
"Rafael J. Wysocki" <rjw@...k.pl>, Jacob Shin <jacob.shin@....com>,
Pekka Enberg <penberg@...nel.org>,
ACPI Devel Maling List <linux-acpi@...r.kernel.org>
Subject: Re: [PATCH v5 03/22] x86, ACPI, mm: Kill max_low_pfn_mapped
On Mon, 2013-06-17 at 16:36 -0700, Yinghai Lu wrote:
> On Mon, Jun 17, 2013 at 4:19 PM, Toshi Kani <toshi.kani@...com> wrote:
> > On Fri, 2013-06-14 at 17:56 -0700, Yinghai Lu wrote:
> >> Now we have arch_pfn_mapped array, and max_low_pfn_mapped should not
> >> be used anymore.
> >
> > Can you describe why max_low_pfn_mapped should not be used? Is this to
> > allow moving the code of acpi_initrd_override() up before
> > init_mem_mapping() in a succeeding patch, or is there also another
> > reason behind it? Also, I think arch_pfn_mapped should be pfn_mapped[].
>
> ok, assumption that from [0, max_low_pfn_mapped) all mapped.
>
> Now we only map the RAM or KERNL_RESERVED, to prevent user from
> taking it granted that only check it is below max_low_pfn_mapped to assume
> it mapped.
Oh, I see. So, it is not necessary any more.
> Yes, is should be pfn_mapped[]
OK.
Please update the change log per the info you described here. With
that:
Acked-by: Toshi Kani <toshi.kani@...com>
Thanks,
-Toshi
> >
> > Thanks,
> > -Toshi
> >
> >
> >> User should use arch_pfn_mapped or just 1UL<<(32-PAGE_SHIFT) instead.
> >>
> >> Only user is ACPI_INITRD_TABLE_OVERRIDE, and it should not use that,
> >> as later accessing is using early_ioremap(). We could change to use
> >> 1U<<(32_PAGE_SHIFT) with it, aka under 4G.
> >>
> >> -v2: Leave alone max_low_pfn_mapped in i915 code according to tj.
> >>
> >> Suggested-by: H. Peter Anvin <hpa@...or.com>
> >> Signed-off-by: Yinghai Lu <yinghai@...nel.org>
> >> Cc: "Rafael J. Wysocki" <rjw@...k.pl>
> >> Cc: Jacob Shin <jacob.shin@....com>
> >> Cc: Pekka Enberg <penberg@...nel.org>
> >> Cc: linux-acpi@...r.kernel.org
> >> Tested-by: Thomas Renninger <trenn@...e.de>
> >> Reviewed-by: Tang Chen <tangchen@...fujitsu.com>
> >> Tested-by: Tang Chen <tangchen@...fujitsu.com>
> >> ---
> >> arch/x86/include/asm/page_types.h | 1 -
> >> arch/x86/kernel/setup.c | 4 +---
> >> arch/x86/mm/init.c | 4 ----
> >> drivers/acpi/osl.c | 6 +++---
> >> 4 files changed, 4 insertions(+), 11 deletions(-)
> >>
> >> diff --git a/arch/x86/include/asm/page_types.h b/arch/x86/include/asm/page_types.h
> >> index 54c9787..b012b82 100644
> >> --- a/arch/x86/include/asm/page_types.h
> >> +++ b/arch/x86/include/asm/page_types.h
> >> @@ -43,7 +43,6 @@
> >>
> >> extern int devmem_is_allowed(unsigned long pagenr);
> >>
> >> -extern unsigned long max_low_pfn_mapped;
> >> extern unsigned long max_pfn_mapped;
> >>
> >> static inline phys_addr_t get_max_mapped(void)
> >> diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
> >> index 66ab495..6ca5f2c 100644
> >> --- a/arch/x86/kernel/setup.c
> >> +++ b/arch/x86/kernel/setup.c
> >> @@ -112,13 +112,11 @@
> >> #include <asm/prom.h>
> >>
> >> /*
> >> - * max_low_pfn_mapped: highest direct mapped pfn under 4GB
> >> - * max_pfn_mapped: highest direct mapped pfn over 4GB
> >> + * max_pfn_mapped: highest direct mapped pfn
> >> *
> >> * The direct mapping only covers E820_RAM regions, so the ranges and gaps are
> >> * represented by pfn_mapped
> >> */
> >> -unsigned long max_low_pfn_mapped;
> >> unsigned long max_pfn_mapped;
> >>
> >> #ifdef CONFIG_DMI
> >> diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
> >> index eaac174..8554656 100644
> >> --- a/arch/x86/mm/init.c
> >> +++ b/arch/x86/mm/init.c
> >> @@ -313,10 +313,6 @@ static void add_pfn_range_mapped(unsigned long start_pfn, unsigned long end_pfn)
> >> nr_pfn_mapped = clean_sort_range(pfn_mapped, E820_X_MAX);
> >>
> >> max_pfn_mapped = max(max_pfn_mapped, end_pfn);
> >> -
> >> - if (start_pfn < (1UL<<(32-PAGE_SHIFT)))
> >> - max_low_pfn_mapped = max(max_low_pfn_mapped,
> >> - min(end_pfn, 1UL<<(32-PAGE_SHIFT)));
> >> }
> >>
> >> bool pfn_range_is_mapped(unsigned long start_pfn, unsigned long end_pfn)
> >> diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c
> >> index e721863..93e3194 100644
> >> --- a/drivers/acpi/osl.c
> >> +++ b/drivers/acpi/osl.c
> >> @@ -624,9 +624,9 @@ void __init acpi_initrd_override(void *data, size_t size)
> >> if (table_nr == 0)
> >> return;
> >>
> >> - acpi_tables_addr =
> >> - memblock_find_in_range(0, max_low_pfn_mapped << PAGE_SHIFT,
> >> - all_tables_size, PAGE_SIZE);
> >> + /* under 4G at first, then above 4G */
> >> + acpi_tables_addr = memblock_find_in_range(0, (1ULL<<32) - 1,
> >> + all_tables_size, PAGE_SIZE);
> >> if (!acpi_tables_addr) {
> >> WARN_ON(1);
> >> return;
> >
> >
> > --
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