v8/src/arm64/cpu-arm64.cc
jacob.bramley fec99c689b [arm64] Use 'dc civac' to work around some errata.
This addresses Cortex-A53 errata 819472, 826319, 827319 and 824069.

Note that using "civac" rather than "cvau" doesn't appear to affect
performance at all.

BUG=

Review-Url: https://codereview.chromium.org/1921173004
Cr-Commit-Position: refs/heads/master@{#35828}
2016-04-27 16:37:27 +00:00

117 lines
4.3 KiB
C++

// Copyright 2013 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
// CPU specific code for arm independent of OS goes here.
#if V8_TARGET_ARCH_ARM64
#include "src/arm64/utils-arm64.h"
#include "src/assembler.h"
namespace v8 {
namespace internal {
class CacheLineSizes {
public:
CacheLineSizes() {
#ifdef USE_SIMULATOR
cache_type_register_ = 0;
#else
// Copy the content of the cache type register to a core register.
__asm__ __volatile__("mrs %x[ctr], ctr_el0" // NOLINT
: [ctr] "=r"(cache_type_register_));
#endif
}
uint32_t icache_line_size() const { return ExtractCacheLineSize(0); }
uint32_t dcache_line_size() const { return ExtractCacheLineSize(16); }
private:
uint32_t ExtractCacheLineSize(int cache_line_size_shift) const {
// The cache type register holds the size of cache lines in words as a
// power of two.
return 4 << ((cache_type_register_ >> cache_line_size_shift) & 0xf);
}
uint32_t cache_type_register_;
};
void CpuFeatures::FlushICache(void* address, size_t length) {
#ifdef V8_HOST_ARCH_ARM64
// The code below assumes user space cache operations are allowed. The goal
// of this routine is to make sure the code generated is visible to the I
// side of the CPU.
uintptr_t start = reinterpret_cast<uintptr_t>(address);
// Sizes will be used to generate a mask big enough to cover a pointer.
CacheLineSizes sizes;
uintptr_t dsize = sizes.dcache_line_size();
uintptr_t isize = sizes.icache_line_size();
// Cache line sizes are always a power of 2.
DCHECK(CountSetBits(dsize, 64) == 1);
DCHECK(CountSetBits(isize, 64) == 1);
uintptr_t dstart = start & ~(dsize - 1);
uintptr_t istart = start & ~(isize - 1);
uintptr_t end = start + length;
__asm__ __volatile__ ( // NOLINT
// Clean every line of the D cache containing the target data.
"0: \n\t"
// dc : Data Cache maintenance
// c : Clean
// i : Invalidate
// va : by (Virtual) Address
// c : to the point of Coherency
// See ARM DDI 0406B page B2-12 for more information.
// We would prefer to use "cvau" (clean to the point of unification) here
// but we use "civac" to work around Cortex-A53 errata 819472, 826319,
// 827319 and 824069.
"dc civac, %[dline] \n\t"
"add %[dline], %[dline], %[dsize] \n\t"
"cmp %[dline], %[end] \n\t"
"b.lt 0b \n\t"
// Barrier to make sure the effect of the code above is visible to the rest
// of the world.
// dsb : Data Synchronisation Barrier
// ish : Inner SHareable domain
// The point of unification for an Inner Shareable shareability domain is
// the point by which the instruction and data caches of all the processors
// in that Inner Shareable shareability domain are guaranteed to see the
// same copy of a memory location. See ARM DDI 0406B page B2-12 for more
// information.
"dsb ish \n\t"
// Invalidate every line of the I cache containing the target data.
"1: \n\t"
// ic : instruction cache maintenance
// i : invalidate
// va : by address
// u : to the point of unification
"ic ivau, %[iline] \n\t"
"add %[iline], %[iline], %[isize] \n\t"
"cmp %[iline], %[end] \n\t"
"b.lt 1b \n\t"
// Barrier to make sure the effect of the code above is visible to the rest
// of the world.
"dsb ish \n\t"
// Barrier to ensure any prefetching which happened before this code is
// discarded.
// isb : Instruction Synchronisation Barrier
"isb \n\t"
: [dline] "+r" (dstart),
[iline] "+r" (istart)
: [dsize] "r" (dsize),
[isize] "r" (isize),
[end] "r" (end)
// This code does not write to memory but without the dependency gcc might
// move this code before the code is generated.
: "cc", "memory"
); // NOLINT
#endif // V8_HOST_ARCH_ARM64
}
} // namespace internal
} // namespace v8
#endif // V8_TARGET_ARCH_ARM64