A-Team_Digital_Solutions/android_kernel_motorola_sm6375
Watch
2
0
Fork
You've already forked android_kernel_motorola_sm6375
 0
mirror of https://github.com/BobTheBlinker/android_kernel_motorola_sm6375.git synced 2026-10-28 02:32:09 -04:00
Code Issues Projects Releases Packages Wiki Activity

parisc: Use lpa instruction to load physical addresses in driver code

Browse source 
Most I/O in the kernel is done using the kernel offset mapping.
However, there is one API that uses aliased kernel address ranges:

> The final category of APIs is for I/O to deliberately aliased address
> ranges inside the kernel.  Such aliases are set up by use of the
> vmap/vmalloc API.  Since kernel I/O goes via physical pages, the I/O
> subsystem assumes that the user mapping and kernel offset mapping are
> the only aliases.  This isn't true for vmap aliases, so anything in
> the kernel trying to do I/O to vmap areas must manually manage
> coherency.  It must do this by flushing the vmap range before doing
> I/O and invalidating it after the I/O returns.

For this reason, we should use the hardware lpa instruction to load the
physical address of kernel virtual addresses in the driver code.

I believe we only use the vmap/vmalloc API with old PA 1.x processors
which don't have a sba, so we don't hit this problem.

Tested on c3750, c8000 and rp3440.

Signed-off-by: John David Anglin <[email protected]>
Signed-off-by: Helge Deller <[email protected]>
This commit is contained in:
John David Anglin 2019-06-02 19:12:40 -04:00 • committed by Helge Deller
commit 116d753308
3 changed files with 26 additions and 2 deletions
Download patch file Download diff file Expand all files Collapse all files

2
drivers/parisc/ccio-dma.c
View file

@ -570,7 +570,7 @@ ccio_io_pdir_entry(u64 *pdir_ptr, space_t sid, unsigned long vba,
** "hints" parm includes the VALID bit!
** "dep" clobbers the physical address offset bits as well.
*/
pa = virt_to_phys(vba);
pa = lpa(vba);
asm volatile("depw %1,31,12,%0" : "+r" (pa) : "r" (hints));
((u32 *)pdir_ptr)[1] = (u32) pa;

2
drivers/parisc/sba_iommu.c
View file

@ -572,7 +572,7 @@ sba_io_pdir_entry(u64 *pdir_ptr, space_t sid, unsigned long vba,
u64 pa; /* physical address */
register unsigned ci; /* coherent index */
pa = virt_to_phys(vba);
pa = lpa(vba);
pa &= IOVP_MASK;
asm("lci 0(%1), %0" : "=r" (ci) : "r" (vba));