add req_page syscall

11 files changed, 110 insertions, 0 deletions

diff --git a/arch/riscv64/conf/init b/arch/riscv64/conf/init
index b24a661..c77c048 100755
--- a/arch/riscv64/conf/init
+++ b/arch/riscv64/conf/init
diff --git a/arch/riscv64/conf/initrd b/arch/riscv64/conf/initrd
index 35cf825..fb6f525 100644
--- a/arch/riscv64/conf/initrd
+++ b/arch/riscv64/conf/initrd
diff --git a/common/mem.c b/common/mem.c
index 2cf72e3..f4a0919 100644
--- a/common/mem.c
+++ b/common/mem.c
@@ -17,6 +17,15 @@ size_t __mm_sizes[10];
 size_t __mm_page_shift;
 enum mm_order __mm_max_order;
 
+enum mm_order nearest_order(size_t size)
+{
+	for (enum mm_order order = max_order(); order >= MM_MIN; --order)
+		if (order_size(order) >= size)
+			return order;
+
+	return MM_O0;
+}
+
 void init_mem(size_t max_order, size_t bits[10], size_t page_shift)
 {
 	__mm_max_order = max_order;
diff --git a/common/uapi/dispatch.c b/common/uapi/dispatch.c
index d11e02e..b5cd51e 100644
--- a/common/uapi/dispatch.c
+++ b/common/uapi/dispatch.c
@@ -51,6 +51,7 @@ void handle_syscall(sys_arg_t syscall, sys_arg_t a, sys_arg_t b,
 	case SYS_NOOP: sys_noop(t, a, b, c, d, e); break;
 	case SYS_PUTCH: sys_putch(t, a, b, c, d, e); break;
 	case SYS_REQ_MEM: sys_req_mem(t, a, b, c, d, e); break;
+	case SYS_REQ_PAGE: sys_req_page(t, a, b, c, d, e); break;
 	case SYS_REQ_PMEM: sys_req_pmem(t, a, b, c, d, e); break;
 	case SYS_REQ_FIXMEM: sys_req_fixmem(t, a, b, c, d, e); break;
 	case SYS_REQ_SHAREDMEM: sys_req_sharedmem(t, a, b, c, d, e); break;
diff --git a/common/uapi/mem.c b/common/uapi/mem.c
index 099028e..41ebcca 100644
--- a/common/uapi/mem.c
+++ b/common/uapi/mem.c
@@ -33,6 +33,25 @@ SYSCALL_DEFINE2(req_mem)(struct tcb *t, sys_arg_t size, sys_arg_t flags)
 }
 
 /**
+ * Allocate single page to program.
+ *
+ * @param t Current tcb.
+ * @param size Size of the allocation.
+ * @param flags Flags of allocation.
+ * @return \ref ERR_OOMEM if unsucessful, otherwise \ref OK, virtual address,
+ * actual size, physical address, in that order.
+ */
+SYSCALL_DEFINE2(req_page)(struct tcb *t, sys_arg_t size, sys_arg_t flags)
+{
+	struct tcb *r = get_cproc(t);
+	vm_t start = 0; pm_t paddr = 0; size_t asize = size;
+	if (!(start = alloc_uvpage(r, asize, flags, &asize, &paddr)))
+		return_args(t, SYS_RET1(ERR_OOMEM));
+
+	return_args(t, SYS_RET4(OK, start, asize, paddr));
+}
+
+/**
  * Fixed memory request syscall handler.
  *
  * @param t Current tcb.
diff --git a/common/vmem.c b/common/vmem.c
index f1eed83..b28a3d6 100644
--- a/common/vmem.c
+++ b/common/vmem.c
@@ -200,6 +200,36 @@ vm_t alloc_uvmem(struct tcb *t, size_t size, vmflags_t flags)
 	return w;
 }
 
+vm_t alloc_uvpage(struct tcb *t, size_t size, vmflags_t flags, size_t *asize,
+                  pm_t *paddr)
+{
+	hard_assert(t && is_proc(t), ERR_INVAL);
+
+	enum mm_order order = nearest_order(size);
+	size_t actual_size = order_size(order);
+	stat_t status = OK;
+
+	const vm_t v = alloc_region(&t->sp_r, size, &size, flags);
+	const vm_t w = __addr(__page(v));
+
+	pm_t addr = alloc_page(order);
+	/** @todo should free region */
+	if (!addr)
+		return NULL;
+
+	status = map_vpage(t->proc.vmem, addr, w, flags, order);
+	if (is_rpc(t) && status == INFO_SEFF)
+		clone_rpc_maps(t);
+
+	if (asize)
+		*asize = actual_size;
+
+	if (paddr)
+		*paddr = addr;
+
+	return w;
+}
+
 vm_t alloc_fixed_uvmem(struct tcb *t, vm_t start, size_t size, vmflags_t flags)
 {
 	hard_assert(t && is_proc(t), ERR_INVAL);
diff --git a/include/apos/mem.h b/include/apos/mem.h
index 4db7a67..ea61aba 100644
--- a/include/apos/mem.h
+++ b/include/apos/mem.h
@@ -196,6 +196,14 @@ extern size_t __mm_page_shift;
 extern enum mm_order __mm_max_order;
 
 /**
+ * Find nearest order to size.
+ *
+ * @param size Size to map to an order.
+ * @return Nearest order larger than \p size.
+ */
+enum mm_order nearest_order(size_t size);
+
+/**
  * Initialize memory subsystem data. Populates __mm_* with data given.
  *
  * @param max_order Maximum order the current system supports.
diff --git a/include/apos/syscalls.h b/include/apos/syscalls.h
index 611765d..40e6504 100644
--- a/include/apos/syscalls.h
+++ b/include/apos/syscalls.h
@@ -38,6 +38,9 @@ enum {
 	/** Request memory from anywhere. */
 	SYS_REQ_MEM,
 
+	/** Request physical page from ram. */
+	SYS_REQ_PAGE,
+
 	/** Request memory with physical address. */
 	SYS_REQ_PMEM,
 
diff --git a/include/apos/types.h b/include/apos/types.h
index 431d551..36e918e 100644
--- a/include/apos/types.h
+++ b/include/apos/types.h
@@ -445,6 +445,7 @@ typedef int_fast8_t stat_t;
  * is with pids */
 typedef int_fast32_t id_t;
 
+/** Maximum ID number. */
 #define ID_MAX INT_FAST32_MAX
 
 /** Memory region flags. */
diff --git a/include/apos/uapi.h b/include/apos/uapi.h
index dda4391..fefd1bf 100644
--- a/include/apos/uapi.h
+++ b/include/apos/uapi.h
@@ -320,6 +320,32 @@ SYSCALL_DECLARE1(putch, ch);
 SYSCALL_DECLARE2(req_mem, size, flags);
 
 /**
+ * Request one page of memory. The nearest fitting size is chosen.
+ *
+ * This might be better implemented as some number of adjacent physical pages,
+ * but the underlying physical page allocator doesn't really handle it very
+ * well. This weird design decision is because I don't know if there are devices
+ * whose drivers need multiple adjacent physical pages, only that at least
+ * virtio devices need to be able to access the physical address of a single
+ * page. Basic adjacent physical pages can be made from higher order pages,
+ * just with a massive overhead. Still, probably good eough for now.
+ *
+ * For example, if you need two adjacent 4K pages, you pass size = 8K and you
+ * get back a 2M page, if one is available.
+ *
+ * @param t Current tcb.
+ * @param size Required size of region.
+ * @param flags Mapping flags to use.
+ * @param c Unused.
+ * @param d Unused.
+ * @param e Unused.
+ *
+ * Returns \ref ERR_OOMEM if no page is available, otherwise \c OK, virtual
+ * address, actual size, physical size in that order.
+ */
+SYSCALL_DECLARE2(req_page, size, flags);
+
+/**
  * Request physical memory syscall.
  *
  * Allocates at least the specified size of allocation which includes the
diff --git a/include/apos/vmem.h b/include/apos/vmem.h
index 38bad16..5cbe7db 100644
--- a/include/apos/vmem.h
+++ b/include/apos/vmem.h
@@ -28,6 +28,19 @@
 vm_t alloc_uvmem(struct tcb *r, size_t size, vmflags_t flags);
 
 /**
+ * Allocate one physical page for user virtual memory.
+ *
+ * @param r Process to allocate memory in.
+ * @param size Minimum size of allocation.
+ * @param flags Flags of allocation.
+ * @param asize Where to write actual size of allocation.
+ * @param paddr Where to write physical address of page.
+ * @return Start of allocation when succesful, \c NULL otherwise.
+ */
+vm_t alloc_uvpage(struct tcb *r, size_t size, vmflags_t flags,
+                  size_t *asize, pm_t *paddr);
+
+/**
  * Allocate fixed user virtual memory.
  *
  * Virtual memory start address is chosen so that \c start is within the