On 2013-07-18, Ingo Molnar wrote:
>
> * Qiaowei Ren <qiaowei....@intel.com> wrote:
>
>> Current code doesn't use specific interface to access I/O space.
>> So some potential bugs can be caused. We can fix this by using
>> specific API.
>
> This is still very vague.
>
>>
>> Signed-off-by: Qiaowei Ren <qiaowei....@intel.com>
>> ---
>> arch/x86/kernel/tboot.c | 21 ++++++++++++---------
>> 1 file changed, 12 insertions(+), 9 deletions(-)
>> diff --git a/arch/x86/kernel/tboot.c b/arch/x86/kernel/tboot.c index
>> 3ff42d2..afe8cf8 100644
>> --- a/arch/x86/kernel/tboot.c
>> +++ b/arch/x86/kernel/tboot.c
>> @@ -466,9 +466,12 @@ struct sinit_mle_data {
>> u32 vtd_dmars_off;
>> } __packed;
>> +#define SINIT_MLE_DATA_VTD_DMAR_OFF 140
>> +
>> struct acpi_table_header *tboot_get_dmar_table(struct
>> acpi_table_header *dmar_tbl) {
>> - void *heap_base, *heap_ptr, *config;
>> + void __iomem *heap_base, *heap_ptr, *config;
>> + u32 dmar_tbl_off;
>>
>> if (!tboot_enabled())
>> return dmar_tbl;
>> @@ -485,25 +488,25 @@ struct acpi_table_header
> *tboot_get_dmar_table(struct acpi_table_header *dmar_tb
>> return NULL;
>>
>> /* now map TXT heap */
>> - heap_base = ioremap(*(u64 *)(config + TXTCR_HEAP_BASE),
>> - *(u64 *)(config + TXTCR_HEAP_SIZE));
>> + heap_base = ioremap(readl(config + TXTCR_HEAP_BASE),
>> + readl(config + TXTCR_HEAP_SIZE));
>> iounmap(config);
>> if (!heap_base)
>> return NULL;
>>
>> /* walk heap to SinitMleData */
>> /* skip BiosData */
>> - heap_ptr = heap_base + *(u64 *)heap_base;
>> + heap_ptr = heap_base + readq(heap_base);
>> /* skip OsMleData */
>> - heap_ptr += *(u64 *)heap_ptr;
>> + heap_ptr += readq(heap_ptr);
>> /* skip OsSinitData */
>> - heap_ptr += *(u64 *)heap_ptr;
>> + heap_ptr += readq(heap_ptr);
>> /* now points to SinitMleDataSize; set to SinitMleData */
>> heap_ptr += sizeof(u64);
>> /* get addr of DMAR table */
>> - dmar_tbl = (struct acpi_table_header *)(heap_ptr +
>> - ((struct sinit_mle_data *)heap_ptr)->vtd_dmars_off -
>> - sizeof(u64));
>> + dmar_tbl_off = readl(heap_ptr + SINIT_MLE_DATA_VTD_DMAR_OFF);
>> + memcpy_fromio(dmar_tbl, heap_ptr + dmar_tbl_off - sizeof(u64),
>> + sizeof(struct acpi_table_header));
>
> That memcpy (or an equivalent of it) was not in the code before, AFAICS.
>
> How can this be an 'interface fix'? It adds in new code...
>
Sorry, current code only need to get addr of DMAR table, so memcpy_fromio may
be removed, even though this will also work.
So "memcpy_fromio" line will be changed to
dmar_tbl = (struct acpi_table_header *)(heap_ptr + dmar_tbl_off + -
sizeof(u64));
If so, no new interface will be added, and the changelog at the beginning of
this patch is engouch?
Thanks,
Qiaowei
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