From 7c4b74e4f62c1ab0905c9fbac9ad0df06ad5d540 Mon Sep 17 00:00:00 2001 From: patacongo Date: Wed, 1 Sep 2010 23:52:38 +0000 Subject: [PATCH] Initial allocated page must be read/write/non-cacheable git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@2909 42af7a65-404d-4744-a932-0658087f49c3 --- arch/arm/src/arm/pg_macros.h | 1 + arch/arm/src/arm/up_allocpage.c | 14 +++++++++++--- 2 files changed, 12 insertions(+), 3 deletions(-) diff --git a/arch/arm/src/arm/pg_macros.h b/arch/arm/src/arm/pg_macros.h index a4d4dd5222..d30adeb106 100644 --- a/arch/arm/src/arm/pg_macros.h +++ b/arch/arm/src/arm/pg_macros.h @@ -93,6 +93,7 @@ # define MMU_L2_TEXTFLAGS (PTE_TYPE_TINY|PTE_EXT_AP_UNO_SRO|PTE_CACHEABLE) # define MMU_L1_DATAFLAGS (PMD_TYPE_FINE|PMD_BIT4) # define MMU_L2_DATAFLAGS (PTE_TYPE_TINY|PTE_EXT_AP_UNO_SRW|PTE_CACHEABLE|PTE_BUFFERABLE) +# define MMU_L2_ALLOCFLAGS (PTE_TYPE_TINY|PTE_EXT_AP_UNO_SRW) # define MMU_L1_PGTABFLAGS (PMD_TYPE_FINE|PMD_BIT4) # define MMU_L2_PGTABFLAGS (PTE_TYPE_TINY|PTE_EXT_AP_UNO_SRW) diff --git a/arch/arm/src/arm/up_allocpage.c b/arch/arm/src/arm/up_allocpage.c index 15309f61be..1db32592c6 100755 --- a/arch/arm/src/arm/up_allocpage.c +++ b/arch/arm/src/arm/up_allocpage.c @@ -133,12 +133,19 @@ static bool g_pgwrap; * available pages are in-use (the typical case), then this function will * select a page in-use, un-map it, and make it available. * - * NOTE 2: Allocating and filling a page is a two step process. up_allocpage() + * NOTE 2: If an in-use page is un-mapped, it may be necessary to flush the + * instruction cache in some architectures. + * + * NOTE 3: Allocating and filling a page is a two step process. up_allocpage() * allocates the page, and up_fillpage() fills it with data from some non- * volatile storage device. This distinction is made because up_allocpage() * can probably be implemented in board-independent logic whereas up_fillpage() * probably must be implemented as board-specific logic. * + * NOTE 4: The initial mapping of vpage should be read-able and write- + * able (but not cached). No special actions will be required of + * up_fillpage() in order to write into this allocated page. + * * Input Parameters: * tcb - A reference to the task control block of the task that needs to * have a page fill. Architecture-specific logic can retrieve page @@ -210,11 +217,12 @@ int up_allocpage(FAR _TCB *tcb, FAR void **vpage) /* Now setup up the new mapping. Get a pointer to the L2 entry * corresponding to the new mapping. Then set it map to the newly - * allocated page address. + * allocated page address. The inital mapping is read/write but + * non-cached (MMU_L2_ALLOCFLAGS) */ pte = up_va2pte(vaddr); - *pte = (paddr | MMU_L2_TEXTFLAGS); + *pte = (paddr | MMU_L2_ALLOCFLAGS); /* And save the new L1 index */