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Message-ID: <CAE9FiQWrh5fOzAj_f03iqF+pQjGExvzppVoeJjwnp0p030jDPA@mail.gmail.com>
Date: Wed, 7 Mar 2012 10:14:15 -0800
From: Yinghai Lu <yinghai@...nel.org>
To: Matt Fleming <matt.fleming@...el.com>
Cc: "H. Peter Anvin" <hpa@...nel.org>, mingo@...hat.com,
mjg@...hat.com, linux-kernel@...r.kernel.org, keithp@...thp.com,
rui.zhang@...el.com, huang.ying.caritas@...il.com,
stable@...r.kernel.org, tglx@...utronix.de,
linux-tip-commits@...r.kernel.org
Subject: Re: [tip:x86/urgent] x86, efi: Delete efi_ioremap() and fix
CONFIG_X86_32 oops
On Wed, Mar 7, 2012 at 2:30 AM, Matt Fleming <matt.fleming@...el.com> wrote:
> On Mon, 2012-02-27 at 18:27 -0800, H. Peter Anvin wrote:
>> On 02/23/2012 08:47 PM, H. Peter Anvin wrote:
>> >>
>> >> please check attach patch for tip/efi branch.
>> >
>> > That doesn't do anything like what I noted above.
>> >
>> > We should get rid of dependencies on legacy PC memory layouts, not add
>> > more hacks. What is so hard about "when we create the initial mappings,
>> > only create for RAM/ACPI/EFI regions" (if we even need to do so for
>> > ACPI, I think ACPI might use ioremap() already)?
>> >
>>
>> Hi Yinghai,
>>
>> Can you please answer my question?
>
> Did you have something like this in mind? Note that it doesn't go all
> the way to removing the add_do_memmap boot parameter because I'm not
> sure how to do that for GPL exported symbols.
>
> The only testing I've done with this is to ensure that it boots under
> qemu (both for EFI and BIOS) on 32/64-bit.
>
> This is on top of tip/x86/efi.
>
> diff --git a/arch/x86/include/asm/page_types.h b/arch/x86/include/asm/page_types.h
> index bce688d..4f95f23 100644
> --- a/arch/x86/include/asm/page_types.h
> +++ b/arch/x86/include/asm/page_types.h
> @@ -51,8 +51,9 @@ static inline phys_addr_t get_max_mapped(void)
> return (phys_addr_t)max_pfn_mapped << PAGE_SHIFT;
> }
>
> -extern unsigned long init_memory_mapping(unsigned long start,
> - unsigned long end);
> +extern unsigned long init_memory_mapping(void);
> +extern unsigned long __init_memory_mapping(unsigned long start,
> + unsigned long end);
>
> extern void initmem_init(void);
> extern void free_initmem(void);
> diff --git a/arch/x86/kernel/amd_gart_64.c b/arch/x86/kernel/amd_gart_64.c
> index b1e7c7f..f52ced2 100644
> --- a/arch/x86/kernel/amd_gart_64.c
> +++ b/arch/x86/kernel/amd_gart_64.c
> @@ -769,7 +769,7 @@ int __init gart_iommu_init(void)
>
> if (end_pfn > max_low_pfn_mapped) {
> start_pfn = (aper_base>>PAGE_SHIFT);
> - init_memory_mapping(start_pfn<<PAGE_SHIFT, end_pfn<<PAGE_SHIFT);
> + __init_memory_mapping(start_pfn<<PAGE_SHIFT, end_pfn<<PAGE_SHIFT);
> }
>
> pr_info("PCI-DMA: using GART IOMMU.\n");
> diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
> index e22bb08..b65d287 100644
> --- a/arch/x86/kernel/setup.c
> +++ b/arch/x86/kernel/setup.c
> @@ -690,8 +690,6 @@ early_param("reservelow", parse_reservelow);
>
> void __init setup_arch(char **cmdline_p)
> {
> - unsigned long end_pfn;
> -
> #ifdef CONFIG_X86_32
> memcpy(&boot_cpu_data, &new_cpu_data, sizeof(new_cpu_data));
> visws_early_detect();
> @@ -927,31 +925,11 @@ void __init setup_arch(char **cmdline_p)
>
> init_gbpages();
>
> - /* max_pfn_mapped is updated here */
> - end_pfn = max_low_pfn;
> -
> -#ifdef CONFIG_X86_64
> - /*
> - * There may be regions after the last E820_RAM region that we
> - * want to include in the kernel direct mapping because their
> - * contents are needed at runtime.
> - */
> - if (efi_enabled) {
> - unsigned long efi_end;
> -
> - efi_end = e820_end_pfn(MAXMEM>>PAGE_SHIFT, E820_RESERVED_EFI);
> - if (efi_end > end_pfn)
> - end_pfn = efi_end;
> - }
> -#endif
> -
> - max_low_pfn_mapped = init_memory_mapping(0, end_pfn << PAGE_SHIFT);
> - max_pfn_mapped = max_low_pfn_mapped;
> + /* max_low_pfn_mapped is updated here */
> + max_pfn_mapped = init_memory_mapping();
>
> #ifdef CONFIG_X86_64
> if (max_pfn > max_low_pfn) {
> - max_pfn_mapped = init_memory_mapping(1UL<<32,
> - max_pfn<<PAGE_SHIFT);
> /* can we preseve max_low_pfn ?*/
> max_low_pfn = max_pfn;
> }
> diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
> index 6cabf65..f1835e9 100644
> --- a/arch/x86/mm/init.c
> +++ b/arch/x86/mm/init.c
> @@ -118,8 +118,8 @@ static int __meminit save_mr(struct map_range *mr, int nr_range,
> * This runs before bootmem is initialized and gets pages directly from
> * the physical memory. To access them they are temporarily mapped.
> */
> -unsigned long __init_refok init_memory_mapping(unsigned long start,
> - unsigned long end)
> +unsigned long __init_refok __init_memory_mapping(unsigned long start,
> + unsigned long end)
> {
> unsigned long page_size_mask = 0;
> unsigned long start_pfn, end_pfn;
> @@ -301,6 +301,59 @@ unsigned long __init_refok init_memory_mapping(unsigned long start,
> return ret >> PAGE_SHIFT;
> }
>
> +/*
> + * Traverse the E820 memory map and add RAM/ACPI/EFI regions to the
> + * initial memory mapping.
> + */
> +unsigned long __init_refok init_memory_mapping(void)
> +{
> + struct e820entry *entry;
> + unsigned long last_pfn_mapped = 0;
> + unsigned long start, end;
> + int i;
> +
> + /* Map the legacy region until we fix all drivers */
> + __init_memory_mapping(0, 1 << 20);
> +
> + for (i = 0; i < e820.nr_map; i++) {
> + entry = &e820.map[i];
> + start = entry->addr;
> + end = start + entry->size;
> +
> + /* We've already mapped below 1MB */
> + if (end < (1 << 20))
> + continue;
> +
> + if (start < (1 << 20))
> + start = 1 << 20;
> +#ifdef CONFIG_X86_32
> + /*
> + * The map is sorted, so bail once we hit a region
> + * that's above max_low_pfn.
> + */
> + if (start >= max_low_pfn << PAGE_SHIFT)
> + break;
> +
> + if (end > max_low_pfn << PAGE_SHIFT)
> + end = max_low_pfn << PAGE_SHIFT;
> +#endif
> + switch (entry->type) {
> + case E820_RAM:
> + case E820_RESERVED_EFI:
> + case E820_ACPI:
> + case E820_NVS:
> + last_pfn_mapped = __init_memory_mapping(start, end);
> + break;
> + default:
> + continue;
> + }
> +
> + if (end <= max_low_pfn << PAGE_SHIFT)
> + max_low_pfn_mapped = last_pfn_mapped;
those two line could be dropped if you have
last_pfn_mapped = 1<<(20 - 12);
before the loop
Also you can not use max_low_pfn here...
you need to update e820_end_pfn to search max pfn for several types like
> + case E820_RAM:
> + case E820_RESERVED_EFI:
> + case E820_ACPI:
> + case E820_NVS:
but my question is:
is there any system that will put EFI runtime, or ACPI or NVS above
4G? is that legal?
Yinghai
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