From 9d422ed700c302b9923b4b8b10ccbfc93d153c9e Mon Sep 17 00:00:00 2001
From: Stefan Lankes <lankes@lfbs.rwth-aachen.de>
Date: Sun, 15 Jul 2012 05:57:39 -0700
Subject: [PATCH] define the function shmalloc to allocate a shared page

caution, the function returns the physical address
---
 arch/x86/include/asm/svm.h | 11 +++++++++--
 arch/x86/mm/svm.c          | 34 +++++++++++++++++++++++++---------
 2 files changed, 34 insertions(+), 11 deletions(-)

diff --git a/arch/x86/include/asm/svm.h b/arch/x86/include/asm/svm.h
index eb06b9d7..f2e3060d 100644
--- a/arch/x86/include/asm/svm.h
+++ b/arch/x86/include/asm/svm.h
@@ -55,7 +55,7 @@ int svm_init(void);
  *
  * @return Pointer to the new memory range
  */
-void* svm_malloc(size_t sizei, uint32_t flags);
+void* svm_malloc(size_t size, uint32_t flags);
 
 /** @brief Frees memory, which is managed by the SVM subsystem
  *
@@ -72,6 +72,13 @@ int svm_barrier(uint32_t flags);
  */
 int svm_access_request(size_t addr);
 
+/** @brief Allocate n shared pages
+ *
+ * @param n number of requested pages
+ * @return physical address of the shared pages
+ */
+size_t shmalloc(uint32_t n);
+
 int svm_alloc_page(size_t addr, page_table_t* pgt);
 
 /** @brief emit page to core ue
@@ -93,7 +100,7 @@ static inline void svm_invalidate(void)
 void svm_invalidate(void);
 #endif
 
-/* *brief flushs the cache for all SVM regions
+/* @brief flushs the cache for all SVM regions
  */
 #ifndef SVM_WB
 static inline void svm_flush(size_t unused)
diff --git a/arch/x86/mm/svm.c b/arch/x86/mm/svm.c
index 57dc1d49..68b62fbb 100644
--- a/arch/x86/mm/svm.c
+++ b/arch/x86/mm/svm.c
@@ -152,11 +152,11 @@ int svm_init(void)
 	return 0;
 }
 
-static size_t get_shpage(void)
+static size_t get_shpages(uint32_t n)
 {
 	int x = X_PID(RC_MY_COREID);
 	int y = Y_PID(RC_MY_COREID);
-	size_t i, j, start = SHM_X0_Y0;
+	size_t i, j = 0, k = 0, start = SHM_X0_Y0;
 	int diff, min = x + y;
 
 	diff = ABS(5 - x) + ABS(0 - y);
@@ -177,16 +177,32 @@ static size_t get_shpage(void)
 		start = SHM_X5_Y2;
 	}
 
-	for(i=0; i < SHARED_PAGES; i++) {
+	for(i=0; (i < SHARED_PAGES) && (k < n); i++) {
+		k = 0;
 		j = (((start - shmbegin) >> PAGE_SHIFT) + i) % SHARED_PAGES;
-		if (page_owner[j] >= RCCE_MAXNP) {
-			page_owner[j] = RCCE_IAM;
-			RCCE_release_lock(RC_COREID[LOCK_ID]);
-			return shmbegin + (j << PAGE_SHIFT);
+
+		while((k<n) && (i < SHARED_PAGES) && (page_owner[j+k] >= RCCE_MAXNP)) {
+			k++; i++;
 		}
 	}
 
-	return 0;
+	if (BUILTIN_EXPECT(i >= SHARED_PAGES, 0))
+		return 0;
+
+	memset((void*) (page_owner+j), RCCE_IAM, sizeof(uint8_t)*n);
+
+	return shmbegin + (j << PAGE_SHIFT);
+}
+
+size_t shmalloc(uint32_t n)
+{
+	size_t ret;
+
+	RCCE_acquire_lock(RC_COREID[LOCK_ID]);
+	ret = get_shpages(n);
+	RCCE_release_lock(RC_COREID[LOCK_ID]);
+
+	return ret;
 }
 
 /*
@@ -212,7 +228,7 @@ int svm_alloc_page(size_t addr, page_table_t* pgt)
 	if (!offset) {
 		int i;
 
-		phyaddr = get_shpage();
+		phyaddr = get_shpages(1);
 		offset = (uint16_t) ((phyaddr - shmbegin) >> PAGE_SHIFT);
 		for(i=0; i<RCCE_NP; i++)
 			iRCCE_put(mpb, (t_vcharp) &offset, sizeof(uint16_t), i);