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@xxxxxxx>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
---
drivers/firmware/efi/libstub/fdt.c | 51 ++++++++++++++++++++++++--------------
1 file changed, 32 insertions(+), 19 deletions(-)
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;
+}
+
#ifndef EFI_FDT_ALIGN
#define EFI_FDT_ALIGN EFI_PAGE_SIZE
#endif
@@ -243,15 +261,6 @@ efi_status_t allocate_new_fdt_and_exit_boot(efi_system_table_t *sys_table,
goto fail;
}
- /*
- * Now that we have done our final memory allocation (and free)
- * we can get the memory map key needed for
- * exit_boot_services().
- */
- status = efi_get_memory_map(sys_table, &map);
- if (status != EFI_SUCCESS)
- goto fail_free_new_fdt;
-
status = update_fdt(sys_table,
(void *)fdt_addr, fdt_size,
(void *)*new_fdt_addr, new_fdt_size,
@@ -266,20 +275,16 @@ efi_status_t allocate_new_fdt_and_exit_boot(efi_system_table_t *sys_table,
/*
* We need to allocate more space for the new
* device tree, so free existing buffer that is
- * too small. Also free memory map, as we will need
- * to get new one that reflects the free/alloc we do
- * on the device tree buffer.
+ * too small.
*/
efi_free(sys_table, new_fdt_size, *new_fdt_addr);
- sys_table->boottime->free_pool(memory_map);
new_fdt_size += EFI_PAGE_SIZE;
} else {
pr_efi_err(sys_table, "Unable to construct new device tree.\n");
- goto fail_free_mmap;
+ goto fail_free_new_fdt;
}
}
- sys_table->boottime->free_pool(memory_map);
priv.runtime_map = runtime_map;
priv.runtime_entry_count = &runtime_entry_count;
status = efi_exit_boot_services(sys_table, handle, &map, &priv,
@@ -288,6 +293,17 @@ efi_status_t allocate_new_fdt_and_exit_boot(efi_system_table_t *sys_table,
if (status == EFI_SUCCESS) {
efi_set_virtual_address_map_t *svam;
+ status = update_fdt_memmap((void *)*new_fdt_addr,
+ (u64)memory_map);
+ if (status != EFI_SUCCESS) {
+ /*
+ * The kernel won't get far without the memory map, but
+ * may still be able to print something meaningful so
+ * return success here.
+ */
+ return EFI_SUCCESS;
+ }
+
/* Install the new virtual address map */
svam = sys_table->runtime->set_virtual_address_map;
status = svam(runtime_entry_count * desc_size, desc_size,
@@ -319,9 +335,6 @@ efi_status_t allocate_new_fdt_and_exit_boot(efi_system_table_t *sys_table,
pr_efi_err(sys_table, "Exit boot services failed.\n");
-fail_free_mmap:
- sys_table->boottime->free_pool(memory_map);
-
fail_free_new_fdt:
efi_free(sys_table, new_fdt_size, *new_fdt_addr);
--
2.7.4
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