[bootloader] Retry fixed allocation at 100000h w/ smaller size
Gigaboot allocates a fixed region at 10_0000h for the kernel text and
rodata/bss. By default it did a 6 MiB allocation, but certain platforms
(ex: GCE) were unable to allocate 6 contiguous megabytes.
Try a 6 MB allocation; if it fails, retry a 3 MB allocation at
the same fixed address. This allows 'fx gce' to work. This should
be safe for GCE builds -- 3 MiB runs from 10_0000h to 40_0000h.
A build of zircon.elf at head with gcc:
13 .bss 00083510 ffffffff80231000 ffffffff80231000 00131f50 2**12
size
... bss 537872
So BSS runs from 23_1000h - 2b_4510h, which fits within the 3 MB allocation.
A clang build of zx:
[14] .bss NOBITS ffffffff80251000 001515d0
BSS runs from 25_1000h to 2d_6000h, which also fits fine within the
3 MB alloc.
This will no longer be necessary when the kernel is relocatable.
Tested:
GCE: fx gce create-fuchsia-image instance && fx gce create instance;
tested that zx booted to shell.
...
Description: efi\boot\bootx64.efi
FilePath: efi\boot\bootx64.efi
OptionNumber: 0.
handle 0
boot: cannot obtain 6291456 bytes for kernel @ 0x100000
KALLOC DONE
...
NUC(NUC7i3BNH): Tested that was able to load gigaboot from the EFI
shell, kernel fixed allocation succeeds when bootx64.efi is run from
EFI (but not from GRUB), tested that zircon.elf / image were loadable.
https://screenshot.googleplex.com/gwddVFusYNR (with BSS size)
Acer Switch SA5-271: Tested that the updated loader can run from EFI
(no EFI shell available), can load zircon.elf / zircon.zbi from a GPT
formatted USB key.
Change-Id: Ie57e428a17a99951aaec9658830ae5feeca4ba54
diff --git a/bootloader/src/osboot.c b/bootloader/src/osboot.c
index df762d4..946e308 100644
--- a/bootloader/src/osboot.c
+++ b/bootloader/src/osboot.c
@@ -389,9 +389,24 @@
if (gBS->AllocatePages(AllocateAddress, EfiLoaderData,
BYTES_TO_PAGES(kernel_zone_size), &kernel_zone_base)) {
- printf("boot: cannot obtain memory for kernel @ %p\n", (void*) kernel_zone_base);
+ printf("boot: cannot obtain %zu bytes for kernel @ %p\n", kernel_zone_size,
+ (void*) kernel_zone_base);
kernel_zone_size = 0;
}
+ // HACK: Try again with a smaller size - certain platforms (ex: GCE) are unable
+ // to support a large fixed allocation at 0x100000.
+ if (kernel_zone_size == 0) {
+ kernel_zone_size = 3 * 1024 * 1024;
+ efi_status status = gBS->AllocatePages(AllocateAddress, EfiLoaderData,
+ BYTES_TO_PAGES(kernel_zone_size),
+ &kernel_zone_base);
+ if (status) {
+ printf("boot: cannot obtain %zu bytes for kernel @ %p\n",
+ kernel_zone_size,
+ (void*) kernel_zone_base);
+ kernel_zone_size = 0;
+ }
+ }
printf("KALLOC DONE\n");
// Default boot defaults to network
