arch/tile: disable GX prefetcher during cache flush

Otherwise, it's possible to end up with the prefetcher pulling
data into cache that the code believes has been flushed.

Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
This commit is contained in:
Chris Metcalf 2011-05-02 15:54:32 -04:00
parent 43d9ebba93
commit dbb434214e

View File

@ -15,6 +15,7 @@
#include <asm/page.h>
#include <asm/cacheflush.h>
#include <arch/icache.h>
#include <arch/spr_def.h>
void __flush_icache_range(unsigned long start, unsigned long end)
@ -39,6 +40,18 @@ void finv_buffer_remote(void *buffer, size_t size, int hfh)
char *p, *base;
size_t step_size, load_count;
const unsigned long STRIPE_WIDTH = 8192;
#ifdef __tilegx__
/*
* On TILE-Gx, we must disable the dstream prefetcher before doing
* a cache flush; otherwise, we could end up with data in the cache
* that we don't want there. Note that normally we'd do an mf
* after the SPR write to disabling the prefetcher, but we do one
* below, before any further loads, so there's no need to do it
* here.
*/
uint_reg_t old_dstream_pf = __insn_mfspr(SPR_DSTREAM_PF);
__insn_mtspr(SPR_DSTREAM_PF, 0);
#endif
/*
* Flush and invalidate the buffer out of the local L1/L2
@ -122,4 +135,9 @@ void finv_buffer_remote(void *buffer, size_t size, int hfh)
/* Wait for the load+inv's (and thus finvs) to have completed. */
__insn_mf();
#ifdef __tilegx__
/* Reenable the prefetcher. */
__insn_mtspr(SPR_DSTREAM_PF, old_dstream_pf);
#endif
}