On 12/12/2016 2:35 AM, James Morse wrote:
Hi Ard,
On 09/12/16 18:24, Ard Biesheuvel wrote:
As reported by James, the current libstub code involving the annotated
memory map only works somewhat correctly by accident, due to the fact
that a pool allocation happens to be reused immediately, retaining its
former contents.
Instead of juggling memory maps, which makes the code more complex than
it needs to be, simply put a placholder value into the FDT, and only
write the actual value after ExitBootServices() has been called.
diff --git a/drivers/firmware/efi/libstub/fdt.c b/drivers/firmware/efi/libstub/fdt.c
index a6a93116a8f0..5d39dff77f17 100644
--- a/drivers/firmware/efi/libstub/fdt.c
+++ b/drivers/firmware/efi/libstub/fdt.c
@@ -101,7 +101,7 @@ efi_status_t update_fdt(efi_system_table_t *sys_table, void *orig_fdt,
if (status)
goto fdt_set_fail;
- fdt_val64 = cpu_to_fdt64((u64)(unsigned long)memory_map);
+ fdt_val64 = U64_MAX; /* placeholder */
status = fdt_setprop(fdt, node, "linux,uefi-mmap-start",
&fdt_val64, sizeof(fdt_val64));
if (status)
@@ -148,6 +148,24 @@ efi_status_t update_fdt(efi_system_table_t *sys_table, void *orig_fdt,
return EFI_LOAD_ERROR;
}
+static efi_status_t update_fdt_memmap(void *fdt, u64 memmap)
+{
+ int node = fdt_path_offset(fdt, "/chosen");
+ efi_status_t status;
+
+ if (node < 0)
+ return EFI_LOAD_ERROR;
+
+ memmap = cpu_to_fdt64(memmap);
+ status = fdt_setprop_inplace(fdt, node, "linux,uefi-mmap-start",
+ &memmap, sizeof(memmap));
+
+ if (status)
+ return EFI_LOAD_ERROR;
+
+ return EFI_SUCCESS;
+}
v4.9.0 with this patch doesn't boot on my Seattle (with known buggy UEFI FW)
[0]. It looks like the memory map is truncated (and missing a runtime region,
compare with [1]). Should 'linux,uefi-mmap-size' be updated too? (Otherwise its
the size when we retrieved the runtime mapping, but before we allocated the FDT)
Overall this fails for me as well. It appears to work, until I trigger
the race condition I fixed, then OOM killer gets triggered the instant
rootfs starts to initialize. Since I see James has a number of
comments, I did not investigate further to determine why the patch is
not working on my system.
--
Jeffrey Hugo
Qualcomm Datacenter Technologies as an affiliate of Qualcomm
Technologies, Inc.
Qualcomm Technologies, Inc. is a member of the
Code Aurora Forum, a Linux Foundation Collaborative Project.
--
To unsubscribe from this list: send the line "unsubscribe linux-efi" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
