From fe205bdd1321f95f8f3c35d243ea7cb22af8fbe1 Mon Sep 17 00:00:00 2001 From: Thomas Meyer Date: Fri, 3 Apr 2015 16:51:26 +0200 Subject: um: Print minimum physical memory requirement Print a more sensible message about the minimum physical memory requirement. Signed-off-by: Thomas Meyer Signed-off-by: Richard Weinberger --- arch/um/kernel/physmem.c | 41 +++++++++++++++++++++++++++++++++++------ 1 file changed, 35 insertions(+), 6 deletions(-) (limited to 'arch') diff --git a/arch/um/kernel/physmem.c b/arch/um/kernel/physmem.c index 549ecf3f5857..9034fc8056b4 100644 --- a/arch/um/kernel/physmem.c +++ b/arch/um/kernel/physmem.c @@ -57,22 +57,51 @@ void map_memory(unsigned long virt, unsigned long phys, unsigned long len, extern int __syscall_stub_start; +/** + * setup_physmem() - Setup physical memory for UML + * @start: Start address of the physical kernel memory, + * i.e start address of the executable image. + * @reserve_end: end address of the physical kernel memory. + * @len: Length of total physical memory that should be mapped/made + * available, in bytes. + * @highmem: Number of highmem bytes that should be mapped/made available. + * + * Creates an unlinked temporary file of size (len + highmem) and memory maps + * it on the last executable image address (uml_reserved). + * + * The offset is needed as the length of the total physical memory + * (len + highmem) includes the size of the memory used be the executable image, + * but the mapped-to address is the last address of the executable image + * (uml_reserved == end address of executable image). + * + * The memory mapped memory of the temporary file is used as backing memory + * of all user space processes/kernel tasks. + */ void __init setup_physmem(unsigned long start, unsigned long reserve_end, unsigned long len, unsigned long long highmem) { unsigned long reserve = reserve_end - start; - int pfn = PFN_UP(__pa(reserve_end)); - int delta = (len - reserve) >> PAGE_SHIFT; - int err, offset, bootmap_size; + unsigned long pfn = PFN_UP(__pa(reserve_end)); + unsigned long delta = (len - reserve) >> PAGE_SHIFT; + unsigned long offset, bootmap_size; + long map_size; + int err; + + offset = uml_reserved - uml_physmem; + map_size = len - offset; + if(map_size <= 0) { + printf("Too few physical memory! Needed=%d, given=%d\n", + offset, len); + exit(1); + } physmem_fd = create_mem_file(len + highmem); - offset = uml_reserved - uml_physmem; err = os_map_memory((void *) uml_reserved, physmem_fd, offset, - len - offset, 1, 1, 1); + map_size, 1, 1, 1); if (err < 0) { printf("setup_physmem - mapping %ld bytes of memory at 0x%p " - "failed - errno = %d\n", len - offset, + "failed - errno = %d\n", map_size, (void *) uml_reserved, err); exit(1); } -- cgit v1.2.3