[fuchsia] Simplify memory allocation

Previuously Fuchsia-specific memory allocation logic was trying to deal with non-page-aligned address returned from zx_vmar_map(), but it's no longer necessary because zx_vmap_map() is guaranteed to return page-aligned address. Also it was trying to unmap partial pages, but zx_vmar_unmap() now requires that len is page-aligned. This change fixes both issues by removing two redundant zx_vmar_unmap() calls. Also deallocateExecutable() has been updated to pass page-aligned size to zx_vmar_unmap(). This CL resolves test failures in some viz_unittests on Fuchsia. Bug: chromium:961455 Change-Id: Ib53e46af853802679a55dacc8546c3f67a3486c7 Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/34409Tested-by: Sergey Ulanov <sergeyu@chromium.org> Kokoro-Presubmit: kokoro <noreply+kokoro@google.com> Reviewed-by: Nicolas Capens <nicolascapens@google.com>

[fuchsia] Simplify memory allocation
0eb5c839 · Sergey Ulanov · Sergey Ulanov · 8cce70e1 · 0eb5c839
Commit 0eb5c839 authored Jul 26, 2019 by Sergey Ulanov Committed by Sergey Ulanov Jul 29, 2019
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Showing with 12 additions and 22 deletions

ExecutableMemory.cpp src/Reactor/ExecutableMemory.cpp +12 -22

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--- a/src/Reactor/ExecutableMemory.cpp
+++ b/src/Reactor/ExecutableMemory.cpp
@@ -233,25 +233,10 @@ void *allocateExecutable(size_t bytes)
 			return nullptr;
 		}
-		zx_vaddr_t alignedReservation = roundUp(reservation, pageSize);
+		// zx_vmar_map() returns page-aligned address.
-		mapping = reinterpret_cast<void*>(alignedReservation);
+		ASSERT(roundUp(reservation, pageSize) == reservation);
-		// Unmap extra memory reserved before the block.
-		if (alignedReservation != reservation) {
-			size_t prefix_size = alignedReservation - reservation;
-			status =
-				zx_vmar_unmap(zx_vmar_root_self(), reservation, prefix_size);
-			ASSERT(status == ZX_OK);
-			length -= prefix_size;
-		}
-		// Unmap extra memory at the end.
+		mapping = reinterpret_cast<void*>(reservation);
-		if (length > bytes) {
-			status = zx_vmar_unmap(
-				zx_vmar_root_self(), alignedReservation + bytes,
-				length - bytes);
-			ASSERT(status == ZX_OK);
-		}
 	#else
 		mapping = allocate(length, pageSize);
 	#endif
@@ -265,10 +250,12 @@ void markExecutable(void *memory, size_t bytes)
 		unsigned long oldProtection;
 		VirtualProtect(memory, bytes, PAGE_EXECUTE_READ, &oldProtection);
 	#elif defined(__Fuchsia__)
+		size_t pageSize = memoryPageSize();
+		size_t length = roundUp(bytes, pageSize);
 		zx_status_t status = zx_vmar_protect(
 			zx_vmar_root_self(), ZX_VM_PERM_READ | ZX_VM_PERM_EXECUTE,
-			reinterpret_cast<zx_vaddr_t>(memory), bytes);
+			reinterpret_cast<zx_vaddr_t>(memory), length);
-	    ASSERT(status != ZX_OK);
+		ASSERT(status == ZX_OK);
 	#else
 		mprotect(memory, bytes, PROT_READ | PROT_EXEC);
 	#endif
@@ -285,8 +272,11 @@ void deallocateExecutable(void *memory, size_t bytes)
 		size_t length = (bytes + pageSize - 1) & ~(pageSize - 1);
 		munmap(memory, length);
 	#elif defined(__Fuchsia__)
-	    zx_vmar_unmap(zx_vmar_root_self(), reinterpret_cast<zx_vaddr_t>(memory),
+		size_t pageSize = memoryPageSize();
-			          bytes);
+		size_t length = roundUp(bytes, pageSize);
+		zx_status_t status =  zx_vmar_unmap(
+		    zx_vmar_root_self(), reinterpret_cast<zx_vaddr_t>(memory), length);
+		ASSERT(status == ZX_OK);
 	#else
 		mprotect(memory, bytes, PROT_READ | PROT_WRITE);
 		deallocate(memory);