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target-arm: A64: Implement DC ZVA

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Implement the DC ZVA instruction, which clears a block of memory.
The fast path obtains a pointer to the underlying RAM via the TCG TLB
data structure so we can do a direct memset(), with fallback to a
simple byte-store loop in the slow path.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Acked-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
This commit is contained in:
Peter Maydell 2014-04-15 19:18:41 +01:00
parent 9225d739e7
commit aca3f40b37
7 changed files with 180 additions and 6 deletions
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52
include/exec/softmmu_exec.h
View file

@ -162,3 +162,55 @@
#define stw(p, v) stw_data(p, v)
#define stl(p, v) stl_data(p, v)
#define stq(p, v) stq_data(p, v)
/**
* tlb_vaddr_to_host:
* @env: CPUArchState
* @addr: guest virtual address to look up
* @access_type: 0 for read, 1 for write, 2 for execute
* @mmu_idx: MMU index to use for lookup
*
* Look up the specified guest virtual index in the TCG softmmu TLB.
* If the TLB contains a host virtual address suitable for direct RAM
* access, then return it. Otherwise (TLB miss, TLB entry is for an
* I/O access, etc) return NULL.
*
* This is the equivalent of the initial fast-path code used by
* TCG backends for guest load and store accesses.
*/
static inline void *tlb_vaddr_to_host(CPUArchState *env, target_ulong addr,
int access_type, int mmu_idx)
{
int index = (addr >> TARGET_PAGE_BITS) & (CPU_TLB_SIZE - 1);
CPUTLBEntry *tlbentry = &env->tlb_table[mmu_idx][index];
target_ulong tlb_addr;
uintptr_t haddr;
switch (access_type) {
case 0:
tlb_addr = tlbentry->addr_read;
break;
case 1:
tlb_addr = tlbentry->addr_write;
break;
case 2:
tlb_addr = tlbentry->addr_code;
break;
default:
g_assert_not_reached();
}
if ((addr & TARGET_PAGE_MASK)
!= (tlb_addr & (TARGET_PAGE_MASK | TLB_INVALID_MASK))) {
/* TLB entry is for a different page */
return NULL;
}
if (tlb_addr & ~TARGET_PAGE_MASK) {
/* IO access */
return NULL;
}
haddr = addr + env->tlb_table[mmu_idx][index].addend;
return (void *)haddr;
}