On Tue, Jun 10, 2008 at 12:47:38PM -0400, Warren Togami wrote:
The attached patch by Peter Jones pjones@redhat.com implements intelligent placement of the ramdisk in memory during boot of an ELF image created by mkelfimage.
I appreciate this patch!
But can you (or Peter) please describe the algorithm in english?
I don't like a commit message that claims code to be intelligent.. :p
This patch allows a wrapped Fedora i586 kernel to boot on both KVM and Artec Group's Thincan DBE61C (coreboot). It probably needs more testing in other circumstances.
Thanks again for the patch. See below for some comments.
diff -up mkelfImage-2.7/linux-i386/convert_params.c.ramdisk_base mkelfImage-2.7/linux-i386/convert_params.c --- mkelfImage-2.7/linux-i386/convert_params.c.ramdisk_base 2006-03-27 18:44:59.000000000 -0500 +++ mkelfImage-2.7/linux-i386/convert_params.c 2008-05-21 12:55:44.000000000 -0400 @@ -1301,6 +1301,44 @@ static void query_firmware_values(struct
}
+static void relocate_ramdisk(struct param_info *info) +{
- struct e820entry *e820_map;
- struct e820entry *highest = 0;
- unsigned long load_addr;
- int i;
- e820_map = info->real_mode->e820_map;
+#if 0
- printf("initrd_start = 0x%lx\n", info->real_mode->initrd_start);
- printf("real_mode->e820_map_nr: %d\n", info->real_mode->e820_map_nr);
+#endif
I think these debugging messages should either be hooked to some verbose option or simply removed.
- for (i = 0; i < info->real_mode->e820_map_nr; i++) {
if (e820_map[i].type != E820_RAM)continue;+#if 0
printf("addr: 0x%lx len: %x\n", e820_map[i].addr, e820_map[i].size);+#endif
..as should this.
if (highest && e820_map[i].addr < highest->addr)continue;if (e820_map[i].size < info->real_mode->initrd_size)continue;
Find the highest free RAM block in the e820 map which is big enough to hold the initrd..
if (e820_map[i].addr + info->real_mode->initrd_size >= 0x38000000)continue;
..what is this 3.5MB limit about? Also might this condition be sensitive to an overflow error?
highest = &e820_map[i];- }
- if (highest == 0)
return;- load_addr = highest->addr + highest->size;
- load_addr -= info->real_mode->initrd_size;
- load_addr &= ~0xfffUL;
Load the initrd to the top of this RAM block on a 4k boundary.
- memcpy((void *)load_addr, (void *)info->real_mode->initrd_start, info->real_mode->initrd_size);
- printf("relocating ramdisk to 0x%lx\n", load_addr);
- info->real_mode->initrd_start = load_addr;
+} /*
- Debug
- =============================================================================
@@ -1533,6 +1571,10 @@ void *convert_params(unsigned type, void query_firmware_class(&info); query_firmware_values(&info); query_bootloader_values(&info);
if (info.real_mode->initrd_size) {
/* Make sure the initrd is in a relatively safe place. */relocate_ramdisk(&info);}
/* Do the hardware setup that linux might forget... */ hardware_setup(&info);
diff -up mkelfImage-2.7/linux-i386/mkelf-linux-i386.c.ramdisk_base mkelfImage-2.7/linux-i386/mkelf-linux-i386.c --- mkelfImage-2.7/linux-i386/mkelf-linux-i386.c.ramdisk_base 2006-03-17 09:08:22.000000000 -0500 +++ mkelfImage-2.7/linux-i386/mkelf-linux-i386.c 2008-05-21 10:47:42.000000000 -0400 @@ -352,6 +352,9 @@ int linux_i386_mkelf(int argc, char **ar */ params->initrd_start = params->initrd_size = 0; if (ramdisk_size) {
while (ramdisk_base <= kernel_size)ramdisk_base <<= 1;
Does this start with 1MB, then try 2MB, 4MB and so on?
phdr[index].p_paddr = ramdisk_base; phdr[index].p_vaddr = ramdisk_base; phdr[index].p_filesz = ramdisk_size;
Please keep in mind to also include Signed-off-by: lines from all who have touched the patch. Please see http://www.coreboot.org/Development_Guidelines#Sign-off_Procedure
Thanks again for your contribution!
//Peter