From 8a5e4cf53d981e793fca90d9b51bd395265cf4db Mon Sep 17 00:00:00 2001
From: Kimplul <kimi.h.kuparinen@gmail.com>
Date: Thu, 26 Jan 2023 15:53:16 +0200
Subject: add req_page syscall

---
 include/apos/mem.h      |  8 ++++++++
 include/apos/syscalls.h |  3 +++
 include/apos/types.h    |  1 +
 include/apos/uapi.h     | 26 ++++++++++++++++++++++++++
 include/apos/vmem.h     | 13 +++++++++++++
 5 files changed, 51 insertions(+)

(limited to 'include')

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
@@ -195,6 +195,14 @@ extern size_t __mm_page_shift;
 /** Gives access to global maximum order size. \global */
 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.
  *
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
@@ -319,6 +319,32 @@ 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.
  *
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
@@ -27,6 +27,19 @@
  */
 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.
  *
-- 
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