The DCache clean & ICache invalidation requirements for instructions to be data coherence are discoverable through new fields in CTR_EL0. Let's support the two bits if they are enabled, the CPU core will not execute the unnecessary DCache clean or Icache Invalidation instructions.
2019-09-03 Shaokun Zhang <zhangshao...@hisilicon.com> * config/aarch64/sync-cache.c: Support CTR_EL0.IDC and CTR_EL0.DIC in __aarch64_sync_cache_range function. --- libgcc/config/aarch64/sync-cache.c | 57 ++++++++++++++++++++++++-------------- 1 file changed, 36 insertions(+), 21 deletions(-) diff --git a/libgcc/config/aarch64/sync-cache.c b/libgcc/config/aarch64/sync-cache.c index 791f5e42ff44..ea3da4be02b3 100644 --- a/libgcc/config/aarch64/sync-cache.c +++ b/libgcc/config/aarch64/sync-cache.c @@ -23,6 +23,9 @@ a copy of the GCC Runtime Library Exception along with this program; see the files COPYING3 and COPYING.RUNTIME respectively. If not, see <http://www.gnu.org/licenses/>. */ +#define CTR_IDC_SHIFT 28 +#define CTR_DIC_SHIFT 29 + void __aarch64_sync_cache_range (const void *, const void *); void @@ -41,32 +44,44 @@ __aarch64_sync_cache_range (const void *base, const void *end) icache_lsize = 4 << (cache_info & 0xF); dcache_lsize = 4 << ((cache_info >> 16) & 0xF); - /* Loop over the address range, clearing one cache line at once. - Data cache must be flushed to unification first to make sure the - instruction cache fetches the updated data. 'end' is exclusive, - as per the GNU definition of __clear_cache. */ + /* If CTR_EL0.IDC is enabled, Data cache clean to the Point of Unification is + not required for instruction to data coherence. */ + + if (((cache_info >> CTR_IDC_SHIFT) & 0x1) == 0x0) { + /* Loop over the address range, clearing one cache line at once. + Data cache must be flushed to unification first to make sure the + instruction cache fetches the updated data. 'end' is exclusive, + as per the GNU definition of __clear_cache. */ - /* Make the start address of the loop cache aligned. */ - address = (const char*) ((__UINTPTR_TYPE__) base - & ~ (__UINTPTR_TYPE__) (dcache_lsize - 1)); + /* Make the start address of the loop cache aligned. */ + address = (const char*) ((__UINTPTR_TYPE__) base + & ~ (__UINTPTR_TYPE__) (dcache_lsize - 1)); - for (; address < (const char *) end; address += dcache_lsize) - asm volatile ("dc\tcvau, %0" - : - : "r" (address) - : "memory"); + for (; address < (const char *) end; address += dcache_lsize) + asm volatile ("dc\tcvau, %0" + : + : "r" (address) + : "memory"); + } asm volatile ("dsb\tish" : : : "memory"); - /* Make the start address of the loop cache aligned. */ - address = (const char*) ((__UINTPTR_TYPE__) base - & ~ (__UINTPTR_TYPE__) (icache_lsize - 1)); + /* If CTR_EL0.DIC is enabled, Instruction cache cleaning to the Point of + Unification is not required for instruction to data coherence. */ + + if (((cache_info >> CTR_DIC_SHIFT) & 0x1) == 0x0) { + /* Make the start address of the loop cache aligned. */ + address = (const char*) ((__UINTPTR_TYPE__) base + & ~ (__UINTPTR_TYPE__) (icache_lsize - 1)); + + for (; address < (const char *) end; address += icache_lsize) + asm volatile ("ic\tivau, %0" + : + : "r" (address) + : "memory"); - for (; address < (const char *) end; address += icache_lsize) - asm volatile ("ic\tivau, %0" - : - : "r" (address) - : "memory"); + asm volatile ("dsb\tish" : : : "memory"); + } - asm volatile ("dsb\tish; isb" : : : "memory"); + asm volatile("isb" : : : "memory"); } -- 2.7.4