[PATCH v2] efi/libstub: arm*: Pass latest memory map to the kernel

On 19 December 2016 at 21:38, Matt Fleming [off-list ref] wrote:

On Mon, 19 Dec, at 02:24:19PM, James Morse wrote:

quoted

From: Ard Biesheuvel <redacted>

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.

Reported-by: James Morse <james.morse@arm.com>
Signed-off-by: Ard Biesheuvel <redacted>
[Update mmap-size too, remove updated_fdt()s unused params and header entry]
Signed-off-by: James Morse <james.morse@arm.com>
---
Hi Ard,

This is a v2 of your patch that updates the mmap-size too. This solves the
truncated memmap problem I saw with v1 on Seattle.

The original patch was CC-stable, so I think this should also have:
Cc: <redacted>
Fixes: ed9cc156c42f ("efi/libstub: Use efi_exit_boot_services() in FDT")


Thanks,

James

 drivers/firmware/efi/libstub/efistub.h |  8 ----
 drivers/firmware/efi/libstub/fdt.c     | 75 +++++++++++++++++++++-------------
 2 files changed, 47 insertions(+), 36 deletions(-)

Thanks James. I've queued this one up in the 'urgent' queue and tagged
it for stable. I'll send it to tip before the end of the week.

Could we fold the hunk below, please?

diff --git a/drivers/firmware/efi/libstub/fdt.c

b/drivers/firmware/efi/libstub/fdt.c
index 9b11b0559a23..90ab96845937 100644

--- a/drivers/firmware/efi/libstub/fdt.c
+++ b/drivers/firmware/efi/libstub/fdt.c

@@ -149,26 +149,25 @@ static efi_status_t

update_fdt(efi_system_table_t *sys_table, void *orig_fdt,
 static efi_status_t update_fdt_memmap(void *fdt, u64 memmap, u32 map_size)
 {
        int node = fdt_path_offset(fdt, "/chosen");
-       efi_status_t status;
+       int err;

        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));
+       err = fdt_setprop_inplace(fdt, node, "linux,uefi-mmap-start",
+                                 &memmap, sizeof(memmap));

        if (status)
                return EFI_LOAD_ERROR;

        map_size = cpu_to_fdt32(map_size);
-       status = fdt_setprop_inplace(fdt, node, "linux,uefi-mmap-size",
-                                    &map_size, sizeof(map_size));
+       err = fdt_setprop_inplace(fdt, node, "linux,uefi-mmap-size",
+                                 &map_size, sizeof(map_size));

        if (status)
                return EFI_LOAD_ERROR;

-
        return EFI_SUCCESS;
 }

My mistake, and harmless in practice, but sloppy nonetheless