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author | Linus Torvalds <torvalds@linux-foundation.org> | 2011-03-17 19:34:12 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2011-03-17 19:34:12 -0700 |
commit | 08351fc6a75731226e1112fc7254542bd3a2912e (patch) | |
tree | 8b25bd168e0663c766f0332c8be082aa7d6ed265 /arch/tile/lib/cacheflush.c | |
parent | 0df0914d414a504b975f3cc66ace0c16ef55b7f3 (diff) | |
parent | 0dccb0489f9a5a13a33e828ab965aa49685d12f8 (diff) |
Merge git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile
* git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile: (27 commits)
arch/tile: support newer binutils assembler shift semantics
arch/tile: fix deadlock bugs in rwlock implementation
drivers/edac: provide support for tile architecture
tile on-chip network driver: sync up with latest fixes
arch/tile: support 4KB page size as well as 64KB
arch/tile: add some more VMSPLIT options and use consistent naming
arch/tile: fix some comments and whitespace
arch/tile: export some additional module symbols
arch/tile: enhance existing finv_buffer_remote() routine
arch/tile: fix two bugs in the backtracer code
arch/tile: use extended assembly to inline __mb_incoherent()
arch/tile: use a cleaner technique to enable interrupt for cpu_idle()
arch/tile: sync up with <arch/sim.h> and <arch/sim_def.h> changes
arch/tile: fix reversed test of strict_strtol() return value
arch/tile: avoid a simulator warning during bootup
arch/tile: export <asm/hardwall.h> to userspace
arch/tile: warn and retry if an IPI is not accepted by the target cpu
arch/tile: stop disabling INTCTRL_1 interrupts during hypervisor downcalls
arch/tile: fix __ndelay etc to work better
arch/tile: bug fix: exec'ed task thought it was still single-stepping
...
Fix up trivial conflict in arch/tile/kernel/vmlinux.lds.S (percpu
alignment vs section naming convention fix)
Diffstat (limited to 'arch/tile/lib/cacheflush.c')
-rw-r--r-- | arch/tile/lib/cacheflush.c | 102 |
1 files changed, 102 insertions, 0 deletions
diff --git a/arch/tile/lib/cacheflush.c b/arch/tile/lib/cacheflush.c index 11b6164c209..35c1d8ca5f3 100644 --- a/arch/tile/lib/cacheflush.c +++ b/arch/tile/lib/cacheflush.c @@ -21,3 +21,105 @@ void __flush_icache_range(unsigned long start, unsigned long end) { invalidate_icache((const void *)start, end - start, PAGE_SIZE); } + + +/* Force a load instruction to issue. */ +static inline void force_load(char *p) +{ + *(volatile char *)p; +} + +/* + * Flush and invalidate a VA range that is homed remotely on a single + * core (if "!hfh") or homed via hash-for-home (if "hfh"), waiting + * until the memory controller holds the flushed values. + */ +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; + + /* + * Flush and invalidate the buffer out of the local L1/L2 + * and request the home cache to flush and invalidate as well. + */ + __finv_buffer(buffer, size); + + /* + * Wait for the home cache to acknowledge that it has processed + * all the flush-and-invalidate requests. This does not mean + * that the flushed data has reached the memory controller yet, + * but it does mean the home cache is processing the flushes. + */ + __insn_mf(); + + /* + * Issue a load to the last cache line, which can't complete + * until all the previously-issued flushes to the same memory + * controller have also completed. If we weren't striping + * memory, that one load would be sufficient, but since we may + * be, we also need to back up to the last load issued to + * another memory controller, which would be the point where + * we crossed an 8KB boundary (the granularity of striping + * across memory controllers). Keep backing up and doing this + * until we are before the beginning of the buffer, or have + * hit all the controllers. + * + * If we are flushing a hash-for-home buffer, it's even worse. + * Each line may be homed on a different tile, and each tile + * may have up to four lines that are on different + * controllers. So as we walk backwards, we have to touch + * enough cache lines to satisfy these constraints. In + * practice this ends up being close enough to "load from + * every cache line on a full memory stripe on each + * controller" that we simply do that, to simplify the logic. + * + * FIXME: See bug 9535 for some issues with this code. + */ + if (hfh) { + step_size = L2_CACHE_BYTES; + load_count = (STRIPE_WIDTH / L2_CACHE_BYTES) * + (1 << CHIP_LOG_NUM_MSHIMS()); + } else { + step_size = STRIPE_WIDTH; + load_count = (1 << CHIP_LOG_NUM_MSHIMS()); + } + + /* Load the last byte of the buffer. */ + p = (char *)buffer + size - 1; + force_load(p); + + /* Bump down to the end of the previous stripe or cache line. */ + p -= step_size; + p = (char *)((unsigned long)p | (step_size - 1)); + + /* Figure out how far back we need to go. */ + base = p - (step_size * (load_count - 2)); + if ((long)base < (long)buffer) + base = buffer; + + /* + * Fire all the loads we need. The MAF only has eight entries + * so we can have at most eight outstanding loads, so we + * unroll by that amount. + */ +#pragma unroll 8 + for (; p >= base; p -= step_size) + force_load(p); + + /* + * Repeat, but with inv's instead of loads, to get rid of the + * data we just loaded into our own cache and the old home L3. + * No need to unroll since inv's don't target a register. + */ + p = (char *)buffer + size - 1; + __insn_inv(p); + p -= step_size; + p = (char *)((unsigned long)p | (step_size - 1)); + for (; p >= base; p -= step_size) + __insn_inv(p); + + /* Wait for the load+inv's (and thus finvs) to have completed. */ + __insn_mf(); +} |