+cc Tony, linux-ia64
On Sat, Jan 21, 2012 at 8:04 AM, Bjorn Helgaas <bhelgaas@xxxxxxxxxx> wrote:
> On Fri, Jan 20, 2012 at 7:13 PM, Myron Stowe <myron.stowe@xxxxxxxxxx> wrote:
>> From: Myron Stowe <mstowe@xxxxxxxxxx>
>>
>> This patch adds support for RAM to ACPI's mapping capabilities in order
>> to support APEI error injection (EINJ) actions.
>>
>> This patch re-factors similar functionality introduced in commit
>> 76da3fb3575, bringing it into osl.c in preparation for removing
>> ./drivers/acpi/atomicio.[ch].
>>
>> Signed-off-by: Myron Stowe <myron.stowe@xxxxxxxxxx>
>> ---
>>
>> drivers/acpi/osl.c | 36 ++++++++++++++++++++++++++++++++++--
>> 1 files changed, 34 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c
>> index f363a55..8ee64ea 100644
>> --- a/drivers/acpi/osl.c
>> +++ b/drivers/acpi/osl.c
>> @@ -31,6 +31,7 @@
>> #include <linux/kernel.h>
>> #include <linux/slab.h>
>> #include <linux/mm.h>
>> +#include <linux/highmem.h>
>> #include <linux/pci.h>
>> #include <linux/interrupt.h>
>> #include <linux/kmod.h>
>> @@ -321,6 +322,37 @@ acpi_map_lookup_virt(void __iomem *virt, acpi_size size)
>> return NULL;
>> }
>>
>> +#ifndef CONFIG_IA64
>> +#define should_use_kmap(pfn) page_is_ram(pfn)
>> +#else
>> +/* ioremap will take care of cache attributes */
>> +#define should_use_kmap(pfn) 0
>> +#endif
>> +
>> +static void __iomem *acpi_map(acpi_physical_address pg_off, unsigned long pg_sz)
>> +{
>> + unsigned long pfn;
>> +
>> + pfn = pg_off >> PAGE_SHIFT;
>> + if (should_use_kmap(pfn)) {
>> + if (pg_sz > PAGE_SIZE)
>> + return NULL;
>> + return (void __iomem __force *)kmap(pfn_to_page(pfn));
>> + } else
>> + return acpi_os_ioremap(pg_off, pg_sz);
>
> This implies that ioremap() works differently on ia64 than on x86.
> Apparently one can ioremap() RAM on x86, but not on ia64. Why is this
> different? Shouldn't we instead fix ioremap() on ia64 so it works the
> same as on x86?
>
> I looked at the ia64 ioremap(), and I can't see the reason it fails
> for RAM. Huang, do you remember the details from 76da3fb3575?
>
>> +}
>> +
>> +static void acpi_unmap(acpi_physical_address pg_off, void __iomem *vaddr)
>> +{
>> + unsigned long pfn;
>> +
>> + pfn = pg_off >> PAGE_SHIFT;
>> + if (page_is_ram(pfn))
>> + kunmap(pfn_to_page(pfn));
>> + else
>> + iounmap(vaddr);
>
> I hope we can resolve the ioremap() question so we don't need this
> patch at all. But if we do need this, I don't like the asymmetry here
> -- on x86 RAM, I think we use ioremap() and kunmap(), which seems
> wrong. We should be able to use ioremap() and iounmap().
>
>> +}
>> +
>> void __iomem *__init_refok
>> acpi_os_map_memory(acpi_physical_address phys, acpi_size size)
>> {
>> @@ -353,7 +385,7 @@ acpi_os_map_memory(acpi_physical_address phys, acpi_size size)
>>
>> pg_off = round_down(phys, PAGE_SIZE);
>> pg_sz = round_up(phys + size, PAGE_SIZE) - pg_off;
>> - virt = acpi_os_ioremap(pg_off, pg_sz);
>> + virt = acpi_map(pg_off, pg_sz);
>> if (!virt) {
>> mutex_unlock(&acpi_ioremap_lock);
>> kfree(map);
>> @@ -384,7 +416,7 @@ static void acpi_os_map_cleanup(struct acpi_ioremap *map)
>> {
>> if (!map->refcount) {
>> synchronize_rcu();
>> - iounmap(map->virt);
>> + acpi_unmap(map->phys, map->virt);
>> kfree(map);
>> }
>> }
>>
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