On 2/7/2017 11:15 AM, Mark Rutland wrote:
Hi,
On Tue, Feb 07, 2017 at 10:59:50AM -0700, Jeffrey Hugo wrote:
From: Sameer Goel <sgoel@xxxxxxxxxxxxxx>
In cases where a device tree is not provided (ie ACPI based system), an
empty fdt is generated by efistub. Sets the address and size cell values
in a generated fdt to support 64 bit addressing.
This enables kexec/kdump on Qualcomm Technologies QDF24XX platforms as those
utilities will read the address/size values from the fdt, and such values
may exceed the range provided by the 32 bit default.
The description here doesn't state why this is a problem for ACPI.
What values are being read by the tools, and for what purpose?
Are they extracting data from the DTB, or is this part of inserting a
new property?
Why does this adversely affect ACPI?
I think the response I am about to send to Ard will address these questions.
Change-Id: Ie7f3637e375bd6631c6bda1f7b3c9003765ff4a5
Please remove this kind of tags from upstream patches. It's irrelevant.
Yep, sorry about that. I should know better.
Signed-off-by: Sameer Goel <sgoel@xxxxxxxxxxxxxx>
Signed-off-by: Jeffrey Hugo <jhugo@xxxxxxxxxxxxxx>
---
drivers/firmware/efi/libstub/fdt.c | 38 +++++++++++++++++++++++++++++++++++++-
1 file changed, 37 insertions(+), 1 deletion(-)
diff --git a/drivers/firmware/efi/libstub/fdt.c b/drivers/firmware/efi/libstub/fdt.c
index 921dfa0..def5c9c 100644
--- a/drivers/firmware/efi/libstub/fdt.c
+++ b/drivers/firmware/efi/libstub/fdt.c
@@ -16,6 +16,34 @@
#include "efistub.h"
+#define EFI_DT_ADDR_CELLS_DEFAULT 2
+#define EFI_DT_SIZE_CELLS_DEFAULT 2
+
+static void fdt_update_cell_size(efi_system_table_t *sys_table, void *fdt)
+{
+ int offset;
+ int status;
+
+ offset = fdt_path_offset(fdt, "/");
+ /* Set the #address-cells and #size-cells values for an empty tree */
+
+ status = fdt_setprop_u32(fdt, offset, "#address-cells",
+ EFI_DT_ADDR_CELLS_DEFAULT);
+ if (status) {
+ pr_efi(sys_table,
+ "Failed to set #address-cells for empty dtb\n");
+ return;
+ }
+
+ status = fdt_setprop_u32(fdt, offset, "#size-cells",
+ EFI_DT_SIZE_CELLS_DEFAULT);
+ if (status) {
+ pr_efi(sys_table,
+ "Failed to set #size-cells for empty dtb\n");
+ return;
+ }
+}
We don't seem to log anything for most other failures within
update_fdt() where this is called.
Are these really much more special?
static efi_status_t update_fdt(efi_system_table_t *sys_table, void *orig_fdt,
unsigned long orig_fdt_size,
void *fdt, int new_fdt_size, char *cmdline_ptr,
@@ -44,8 +72,16 @@ static efi_status_t update_fdt(efi_system_table_t *sys_table, void *orig_fdt,
if (orig_fdt)
status = fdt_open_into(orig_fdt, fdt, new_fdt_size);
- else
+ else {
Nit: if one side of an if-else has braces, the other should too per the
usual kernel coding style.
Will fix.
Thanks,
Mark.
--
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.
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