Messages in this thread Patch in this message | | | Subject | [PATCH] i386 bootmem restrictions | From | Andy Whitcroft <> | Date | Thu, 26 Aug 2004 10:54:38 +0100 |
| |
The bootmem allocator is initialised before the kernel virtual address space has been fully established. As a result, any allocations which are made before paging_init() has completed may point to invalid kernel addresses. This patch notes this limitation and indicates where the allocator is fully available.
Revision: $Rev: 572 $
Signed-off-by: Andy Whitcroft <apw@shadowen.org>
diffstat 100-ia32_bootmem --- setup.c | 11 ++++++++++- 1 files changed, 10 insertions(+), 1 deletion(-)
diff -X /home/apw/brief/lib/vdiff.excl -rupN reference/arch/i386/kernel/setup.c current/arch/i386/kernel/setup.c --- reference/arch/i386/kernel/setup.c 2004-08-25 12:13:32.000000000 +0100 +++ current/arch/i386/kernel/setup.c 2004-08-26 10:27:59.000000000 +0100 @@ -1350,7 +1350,12 @@ void __init setup_arch(char **cmdline_p) /* * NOTE: before this point _nobody_ is allowed to allocate - * any memory using the bootmem allocator. + * any memory using the bootmem allocator. Although the + * alloctor is now initialised only the first 8Mb of the kernel + * virtual address space has been mapped. All allocations before + * paging_init() has completed must use the alloc_bootmem_low_pages() + * variant (which allocates DMA'able memory) and care must be taken + * not to exceed the 8Mb limit. */ #ifdef CONFIG_SMP @@ -1358,6 +1363,10 @@ void __init setup_arch(char **cmdline_p) #endif paging_init(); + /* + * NOTE: at this point the bootmem allocator is fully available. + */ + #ifdef CONFIG_EARLY_PRINTK { char *s = strstr(*cmdline_p, "earlyprintk="); - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |