From 116d753308cf032159c7b7aa87c9605bb5354784 Mon Sep 17 00:00:00 2001 From: John David Anglin Date: Sun, 2 Jun 2019 19:12:40 -0400 Subject: parisc: Use lpa instruction to load physical addresses in driver code 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 Signed-off-by: Helge Deller --- arch/parisc/include/asm/special_insns.h | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+) (limited to 'arch/parisc/include') diff --git a/arch/parisc/include/asm/special_insns.h b/arch/parisc/include/asm/special_insns.h index 3d4dd68e181b..a303ae9a77f4 100644 --- a/arch/parisc/include/asm/special_insns.h +++ b/arch/parisc/include/asm/special_insns.h @@ -2,6 +2,30 @@ #ifndef __PARISC_SPECIAL_INSNS_H #define __PARISC_SPECIAL_INSNS_H +#define lpa(va) ({ \ + unsigned long pa; \ + __asm__ __volatile__( \ + "copy %%r0,%0\n\t" \ + "lpa %%r0(%1),%0" \ + : "=r" (pa) \ + : "r" (va) \ + : "memory" \ + ); \ + pa; \ +}) + +#define lpa_user(va) ({ \ + unsigned long pa; \ + __asm__ __volatile__( \ + "copy %%r0,%0\n\t" \ + "lpa %%r0(%%sr3,%1),%0" \ + : "=r" (pa) \ + : "r" (va) \ + : "memory" \ + ); \ + pa; \ +}) + #define mfctl(reg) ({ \ unsigned long cr; \ __asm__ __volatile__( \ -- cgit v1.2.3