From: Matthias Kruk <m@m10k.eu>
Date: Thu, 12 Dec 2019 09:33:11 +0000 (+0900)
Subject: Smaller fixes to the paging code:
X-Git-Url: https://git.corax.cc/?a=commitdiff_plain;h=9caa512fd4c77ecaeb0c1191bf3cb843929bc1ef;p=corax

Smaller fixes to the paging code:
 - Make pg_dir_sbrk() return the address where the heap would start, if there is no heap
 - Don't map any segments but the kernel BSS and TEXT segments into process page directories
---

diff --git a/kernel/arch/paging.c b/kernel/arch/paging.c
index fd64607..23a36e6 100644
--- a/kernel/arch/paging.c
+++ b/kernel/arch/paging.c
@@ -770,6 +770,47 @@ cleanup:
 	return(ret_val);
 }
 
+static void* _pg_dir_heap_start(pg_dir_t *pd)
+{
+	u32_t ret_val;
+	int i;
+
+	for(i = 0, ret_val = (u32_t)-1; i < CONFIG_PAGING_DIR_MAXREGIONS; i++) {
+		struct region *reg;
+		u32_t limit;
+
+		reg = pd->pd_regions[i];
+
+		switch(reg->reg_type) {
+		case REGION_HEAP:
+			ret_val = (u32_t)reg->reg_base;
+			i = CONFIG_PAGING_DIR_MAXREGIONS;
+
+			break;
+
+		case REGION_TEXT:
+		case REGION_BSS:
+		case REGION_DATA:
+		case REGION_RODATA:
+			limit = ALIGN((u32_t)reg->reg_base + reg->reg_size,
+						  reg->reg_pgsize);
+
+			if(limit > ret_val) {
+			    ret_val = limit;
+			}
+
+			break;
+
+		default:
+		case REGION_STACK:
+		case REGION_KSTACK:
+			break;
+		}
+	}
+
+	return((void*)ret_val);
+}
+
 static int _pg_dir_heap_map(pg_dir_t *pd, u32_t heap_size)
 {
 	/*
@@ -887,6 +928,17 @@ int _clone_kernel_region(pg_dir_t *kdir, region_t *reg, void *data)
 	dir = (pg_dir_t*)data;
 
 	switch(reg->reg_type) {
+	case REGION_TEXT:
+	case REGION_BSS:
+		ret_val = pg_dir_map_region(dir, kdir, reg);
+		break;
+
+	default:
+		/* don't map anything else */
+		ret_val = 0;
+		break;
+
+#if 0
 	case REGION_DATA:
 		ret_val = pg_dir_clone_region(dir, kdir, reg);
 		break;
@@ -966,6 +1018,7 @@ int _clone_kernel_region(pg_dir_t *kdir, region_t *reg, void *data)
 #endif /* 0 */
 	default:
 		break;
+#endif
 	}
 
 	return(ret_val);
@@ -1454,6 +1507,12 @@ void* pg_dir_sbrk(pg_dir_t *pd, i32_t increment)
 			}
 		}
 
+		/*
+		 * If we're still here, we should return the address where
+		 * the program break would have been if there was a heap.
+		 */
+		ret_val = _pg_dir_heap_start(pd);
+
 		return(ret_val);
 	}