pmm: Implement tryalloc() for NBBS.

Signed-off-by: TunaCici <[email protected]>
TunaCici · May 11, 2024 · 3c86119 · 3c86119
1 parent 02f91ad
commit 3c86119
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Showing 4 changed files with 65 additions and 21 deletions.
diff --git a/Kernel/Include/Memory/NBBS.h b/Kernel/Include/Memory/NBBS.h
@@ -23,16 +23,18 @@
  * +---------+----------+------------+------------+----------+----------+
  */
 
-#define OCC_RIGHT       0x1
-#define OCC_LEFT        0x2
-#define COAL_RIGHT      0x4
-#define COAL_LEFT       0x8
-#define OCC             0x10
+#define OCC_RIGHT       ((uint8_t) 0x1)
+#define OCC_LEFT        ((uint8_t) 0x2)
+#define COAL_RIGHT      ((uint8_t) 0x4)
+#define COAL_LEFT       ((uint8_t) 0x8)
+#define OCC             ((uint8_t) 0x10)
 #define BUSY            (OCC | OCC_LEFT | OCC_RIGHT)
 
-#define EXP2(n) (0x1 << (n))
-#define LOG2_LOWER(n) (64 - __builtin_clzll(n) - 1) // 64 bit
-#define CAS(addr, cmp, val) __atomic_compare_exchange (addr, cmp, val, __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST)
+#define EXP2(n) (0x1ULL << (n))
+#define LOG2_LOWER(n) (64ULL - __builtin_clzll(n) - 1ULL) // 64 bit
+#define CAS(addr, cmp, val) __atomic_compare_exchange_n(addr, cmp, val, 0, __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST)
+
+#define LEVEL(n) LOG2_LOWER(n)
 
 /*
  * Public APIs
@@ -42,7 +44,7 @@
 
 int  nb_init(uint64_t base_addr, uint64_t size);
 void* nb_alloc(uint64_t size);
-void* nb_free(void *addr);
+void nb_free(void *addr);
 
 /*
  * Private APIs
@@ -51,6 +53,8 @@ void* nb_free(void *addr);
  */
 
 uint32_t try_alloc(uint32_t node);
+void freenode(uint32_t node, uint32_t level);
+
 
 /*
  * Helpers

diff --git a/Kernel/Main.c b/Kernel/Main.c
@@ -81,22 +81,27 @@ void kmain(boot_sysinfo* boot_params)
         /* 2. Init NBBS */
         klog("[kmain] Initializing NBBS...\n");
 
-        if (nb_init(mem_start, 32 * 1024)) {
+        if (nb_init(mem_start + 0x1000000, 32 * 1024)) {
                 klog("[kmain] Failed to initialize NBBS ;(\n");
         } else {
                 klog("[kmain] Initialized NBBS (%u KiB)!\n", 64u);
         }
 
         klog("[kmain] nb_alloc\n");
 
-        uint64_t *bruh = nb_alloc(4096);
+        for (int i = 0; i < 10; i++) {
+                uint64_t *bruh = nb_alloc(4096);
 
-        if (bruh) {
-                klog("[kmain] nb_alloc ok\n");
-        } else {
-                klog("[kmain] nb_alloc fail\n");
+                if (bruh) {
+                        klog("[kmain] nb_alloc ok (0x%p)\n", bruh);
+                } else {
+                        klog("[kmain] nb_alloc fail\n");
+                }
+
+                ksleep(1000);
         }
 
+
         /* 2. Init PMM */
         // klog("[kmain] Initializing physical memory manager...\n");
         // 

diff --git a/Kernel/Memory/NBBS.c b/Kernel/Memory/NBBS.c
@@ -80,7 +80,37 @@ int nb_init(uint64_t base, uint64_t size)
 
 uint32_t try_alloc(uint32_t node)
 {
-        return 1;
+        /* Try to mark as BUSY */
+        uint8_t free = 0;
+        if (!CAS(&tree[node], &free, BUSY)) {
+                return node;
+        }
+
+        uint32_t current = node;
+        uint32_t child = 0;
+
+        /* Propagate info about the occupancy up to the ancestor node(s) */
+        while (max_level < LEVEL(current)) {
+                child = current;
+                current = current >> 1;
+
+                uint8_t curr_val = 0;
+                uint8_t new_val = 0;
+
+                do {
+                        curr_val = tree[current];
+
+                        if (curr_val & OCC) {
+                                freenode(node, LEVEL(child));
+                                return current;
+                        }
+
+                        new_val = clean_coal(curr_val, child);
+                        new_val = mark(new_val, child);
+                } while (!CAS(&tree[current], &curr_val, new_val));
+        }
+
+        return 0;
 }
 
 void* nb_alloc(uint64_t size)
@@ -115,8 +145,8 @@ void* nb_alloc(uint64_t size)
                                 return (void*) (base_address + leaf * min_size);
                         } else {
                                 /* Skip the entire subtree [of failed] */
-                                uint32_t curr_level = LOG2_LOWER(i);
-                                uint32_t fail_level = LOG2_LOWER(failed_at);
+                                uint32_t curr_level = LEVEL(i);
+                                uint32_t fail_level = LEVEL(failed_at);
 
                                 uint32_t d = EXP2(curr_level - fail_level);
                                 i = (failed_at + 1) * d;
@@ -128,9 +158,14 @@ void* nb_alloc(uint64_t size)
 
 }
 
-void* nb_free(void *addr)
+void freenode(uint32_t node, uint32_t level)
 {
-
+
+}
+
+void nb_free(void *addr)
+{
+
 }
 
 

diff --git a/Makefile b/Makefile
@@ -41,7 +41,7 @@ HOST_AR = ar
 INCLUDES = \
 	-I Kernel/Include -I Kernel/Arch \
 	-I Tests/googletest/googletest/include
-CCFLAGS = ${INCLUDES} -march=armv8-a -mtune=cortex-a72 -g \
+CCFLAGS = ${INCLUDES} -march=armv8-a -mtune=cortex-a72 -mno-outline-atomics -g \
 	-Wall -Wextra -ffreestanding -nostdlib -std=gnu99 -DDEBUG
 CXXFLAGS = ${INCLUDES} -march=armv8-a -mtune=cortex-a72 -g \
 	-Wall -Wextra -ffreestanding -nostdlib -std=c++20 -DDEBUG