Hi Shaokun,
On 9/3/19 9:35 AM, Shaokun Zhang wrote:
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.
This version looks ok to me. I've checked the assembly generated for
sync-cache.c and it looks as expected.
Can you please confirm that you've bootstrapped and tested this patch on
an aarch64 system?
Thanks,
Kyrill
---
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
