libhsakmt: Add mmap alloc aligned helper function

mmap alloc larger address range with align padding page plus guard
pages, then unmap the padding and guard pages at beginning and end
of the range, return aligned address range.

Change-Id: Iaf3c711a079c744289efbafee9b5e63aaf724765
Signed-off-by: Philip Yang <Philip.Yang@amd.com>


[ROCm/ROCR-Runtime commit: b7710a1dda]

projects/rocr-runtime/src/fmm.c

@@ -706,13 +706,60 @@ static void *reserved_aperture_allocate_aligned(manageable_aperture_t *app,
 	return start;
 }
 
+static void *mmap_allocate_aligned(int prot, int flags, uint64_t size,
+				   uint64_t align,  uint64_t guard_size,
+				   void *aper_base, void *aper_limit)
+{
+	void *addr, *aligned_addr, *aligned_end, *mapping_end;
+	uint64_t aligned_padded_size;
+
+	aligned_padded_size = size + guard_size * 2 + (align - PAGE_SIZE);
+
+	/* Map memory PROT_NONE to alloc address space only */
+	addr = mmap(0, aligned_padded_size, PROT_NONE, flags, -1, 0);
+	if (addr == MAP_FAILED) {
+		pr_err("mmap failed: %s\n", strerror(errno));
+		return NULL;
+	}
+
+	/* Adjust for alignment and guard pages */
+	aligned_addr = (void *)ALIGN_UP((uint64_t)addr + guard_size, align);
+	if (aligned_addr < aper_base ||
+	    VOID_PTR_ADD(aligned_addr, size - 1) > aper_limit) {
+		pr_err("mmap returned %p, out of range %p-%p\n", aligned_addr,
+		       aper_base, aper_limit);
+		munmap(addr, aligned_padded_size);
+		return NULL;
+	}
+
+	/* Unmap padding and guard pages */
+	if (aligned_addr > addr)
+		munmap(addr, VOID_PTRS_SUB(aligned_addr, addr));
+
+	aligned_end = VOID_PTR_ADD(aligned_addr, size);
+	mapping_end = VOID_PTR_ADD(addr, aligned_padded_size);
+	if (mapping_end > aligned_end)
+		munmap(aligned_end, VOID_PTRS_SUB(mapping_end, aligned_end));
+
+	if (prot == PROT_NONE)
+		return aligned_addr;
+
+	/*  MAP_FIXED to the aligned address with required prot */
+	addr = mmap(aligned_addr, size, prot, flags | MAP_FIXED, -1, 0);
+	if (addr == MAP_FAILED) {
+		pr_err("mmap failed: %s\n", strerror(errno));
+		return NULL;
+	}
+
+	return addr;
+}
+
 static void *mmap_aperture_allocate_aligned(manageable_aperture_t *aper,
 					    void *address,
 					    uint64_t size, uint64_t align)
 {
-	uint64_t aligned_padded_size, guard_size;
 	uint64_t alignment_size = PAGE_SIZE << svm.alignment_order;
-	void *addr, *aligned_addr, *aligned_end, *mapping_end;
+	uint64_t guard_size;
 
 	if (address)
 		return NULL;
@@ -736,37 +783,9 @@ static void *mmap_aperture_allocate_aligned(manageable_aperture_t *aper,
 	 * pages on both sides
 	 */
 	guard_size = (uint64_t)aper->guard_pages * PAGE_SIZE;
-	aligned_padded_size = size + align +
-		2*guard_size - PAGE_SIZE;
 
-	/* Map memory */
-	addr = mmap(0, aligned_padded_size, PROT_NONE,
-		    MAP_ANONYMOUS | MAP_NORESERVE | MAP_PRIVATE, -1, 0);
-	if (addr == MAP_FAILED) {
-		pr_err("mmap failed: %s\n", strerror(errno));
-		return NULL;
-	}
-
-	/* Adjust for alignment and guard pages, range-check the reslt */
-	aligned_addr = (void *)ALIGN_UP((uint64_t)addr + guard_size, align);
-	if (aligned_addr < aper->base ||
-	    VOID_PTR_ADD(aligned_addr, size - 1) > aper->limit) {
-		pr_err("mmap returned %p, out of range %p-%p\n", aligned_addr,
-		       aper->base, aper->limit);
-		munmap(addr, aligned_padded_size);
-		return NULL;
-	}
-
-	/* Unmap padding and guard pages */
-	if (aligned_addr > addr)
-		munmap(addr, VOID_PTRS_SUB(aligned_addr, addr));
-
-	aligned_end = VOID_PTR_ADD(aligned_addr, size);
-	mapping_end = VOID_PTR_ADD(addr, aligned_padded_size);
-	if (mapping_end > aligned_end)
-		munmap(aligned_end, VOID_PTRS_SUB(mapping_end, aligned_end));
-
-	return aligned_addr;
+	return mmap_allocate_aligned(PROT_NONE, MAP_ANONYMOUS | MAP_NORESERVE | MAP_PRIVATE,
+				     size, align, guard_size, aper->base, aper->limit);
 }
 
 static void mmap_aperture_release(manageable_aperture_t *aper,