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authorJohn David Anglin <dave.anglin@bell.net>2019-06-02 19:12:40 -0400
committerHelge Deller <deller@gmx.de>2019-06-06 14:12:22 +0200
commit116d753308cf032159c7b7aa87c9605bb5354784 (patch)
treef2642cc73c48384f7b7934d0c794d27121018ffd /arch/parisc
parentec13c82d261b5a10e6f6e3273b60329d1146edbb (diff)
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 <dave.anglin@bell.net> Signed-off-by: Helge Deller <deller@gmx.de>
Diffstat (limited to 'arch/parisc')
-rw-r--r--arch/parisc/include/asm/special_insns.h24
1 files changed, 24 insertions, 0 deletions
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__( \