kernel_optimize_test/arch/parisc/include/asm/special_insns.h
John David Anglin 116d753308 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>
2019-06-06 14:12:22 +02:00

69 lines
1.4 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#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__( \
"mfctl " #reg ",%0" : \
"=r" (cr) \
); \
cr; \
})
#define mtctl(gr, cr) \
__asm__ __volatile__("mtctl %0,%1" \
: /* no outputs */ \
: "r" (gr), "i" (cr) : "memory")
/* these are here to de-mystefy the calling code, and to provide hooks */
/* which I needed for debugging EIEM problems -PB */
#define get_eiem() mfctl(15)
static inline void set_eiem(unsigned long val)
{
mtctl(val, 15);
}
#define mfsp(reg) ({ \
unsigned long cr; \
__asm__ __volatile__( \
"mfsp " #reg ",%0" : \
"=r" (cr) \
); \
cr; \
})
#define mtsp(val, cr) \
{ if (__builtin_constant_p(val) && ((val) == 0)) \
__asm__ __volatile__("mtsp %%r0,%0" : : "i" (cr) : "memory"); \
else \
__asm__ __volatile__("mtsp %0,%1" \
: /* no outputs */ \
: "r" (val), "i" (cr) : "memory"); }
#endif /* __PARISC_SPECIAL_INSNS_H */