diff options
| author | Nicholas Piggin <npiggin@gmail.com> | 2022-06-20 18:48:37 -0700 |
|---|---|---|
| committer | Richard Henderson <richard.henderson@linaro.org> | 2022-06-21 09:28:41 -0700 |
| commit | c79a8e840c435bc26a251e34b043318e8b2081db (patch) | |
| tree | 47c9954564787ad2abb3c37b01df9be199530351 /util/cacheflush.c | |
| parent | bdd50dc7d09c90525b80da4f056b849049893732 (diff) | |
util/cacheflush: Optimize flushing when ppc host has coherent icache
On linux, the AT_HWCAP bit PPC_FEATURE_ICACHE_SNOOP indicates
that we can use a simplified 3 instruction flush sequence.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Message-Id: <20220519141131.29839-1-npiggin@gmail.com>
[rth: update after merging cacheflush.c and cacheinfo.c]
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Message-Id: <20220621014837.189139-4-richard.henderson@linaro.org>
Diffstat (limited to 'util/cacheflush.c')
| -rw-r--r-- | util/cacheflush.c | 25 |
1 files changed, 23 insertions, 2 deletions
diff --git a/util/cacheflush.c b/util/cacheflush.c index 01b6cb7583..2c2c73e085 100644 --- a/util/cacheflush.c +++ b/util/cacheflush.c @@ -117,6 +117,10 @@ static void sys_cache_info(int *isize, int *dsize) * Architecture (+ OS) specific cache detection mechanisms. */ +#if defined(__powerpc__) +static bool have_coherent_icache; +#endif + #if defined(__aarch64__) && !defined(CONFIG_DARWIN) /* Apple does not expose CTR_EL0, so we must use system interfaces. */ static uint64_t save_ctr_el0; @@ -156,6 +160,7 @@ static void arch_cache_info(int *isize, int *dsize) if (*dsize == 0) { *dsize = qemu_getauxval(AT_DCACHEBSIZE); } + have_coherent_icache = qemu_getauxval(AT_HWCAP) & PPC_FEATURE_ICACHE_SNOOP; } #else @@ -298,8 +303,24 @@ void flush_idcache_range(uintptr_t rx, uintptr_t rw, size_t len) void flush_idcache_range(uintptr_t rx, uintptr_t rw, size_t len) { uintptr_t p, b, e; - size_t dsize = qemu_dcache_linesize; - size_t isize = qemu_icache_linesize; + size_t dsize, isize; + + /* + * Some processors have coherent caches and support a simplified + * flushing procedure. See + * POWER9 UM, 4.6.2.2 Instruction Cache Block Invalidate (icbi) + * https://ibm.ent.box.com/s/tmklq90ze7aj8f4n32er1mu3sy9u8k3k + */ + if (have_coherent_icache) { + asm volatile ("sync\n\t" + "icbi 0,%0\n\t" + "isync" + : : "r"(rx) : "memory"); + return; + } + + dsize = qemu_dcache_linesize; + isize = qemu_icache_linesize; b = rw & ~(dsize - 1); e = (rw + len + dsize - 1) & ~(dsize - 1); |