[PATCH 4.9 032/120] efi/libstub/arm*: Pass latest memory map to the kernel

[Greg Kroah-Hartman]

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>

commit abfb7b686a3e5be27bf81db62f9c5c895b76f5d1 upstream.

As reported by James Morse, 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 on most implementations of the
UEFI boot services.

Instead of juggling memory maps, which makes the code more complex than
it needs to be, simply put placeholder values into the FDT for the memory
map parameters, and only write the actual values after ExitBootServices()
has been called.

Reported-by: James Morse <james.morse@xxxxxxx>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
Cc: Jeffrey Hugo <jhugo@xxxxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Matt Fleming <matt@xxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
Cc: linux-efi@xxxxxxxxxxxxxxx
Fixes: ed9cc156c42f ("efi/libstub: Use efi_exit_boot_services() in FDT")
Link: http://lkml.kernel.org/r/1482587963-20183-2-git-send-email-ard.biesheuvel@xxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/firmware/efi/libstub/efistub.h |    8 ---
 drivers/firmware/efi/libstub/fdt.c     |   87 +++++++++++++++++++++------------
 2 files changed, 56 insertions(+), 39 deletions(-)

--- a/drivers/firmware/efi/libstub/efistub.h
+++ b/drivers/firmware/efi/libstub/efistub.h
@@ -30,14 +30,6 @@ efi_status_t efi_file_close(void *handle
 
 unsigned long get_dram_base(efi_system_table_t *sys_table_arg);
 
-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,
-			u64 initrd_addr, u64 initrd_size,
-			efi_memory_desc_t *memory_map,
-			unsigned long map_size, unsigned long desc_size,
-			u32 desc_ver);
-
 efi_status_t allocate_new_fdt_and_exit_boot(efi_system_table_t *sys_table,
 					    void *handle,
 					    unsigned long *new_fdt_addr,
--- a/drivers/firmware/efi/libstub/fdt.c
+++ b/drivers/firmware/efi/libstub/fdt.c
@@ -16,13 +16,10 @@
 
 #include "efistub.h"
 
-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,
-			u64 initrd_addr, u64 initrd_size,
-			efi_memory_desc_t *memory_map,
-			unsigned long map_size, unsigned long desc_size,
-			u32 desc_ver)
+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,
+			       u64 initrd_addr, u64 initrd_size)
 {
 	int node, num_rsv;
 	int status;
@@ -101,25 +98,23 @@ efi_status_t update_fdt(efi_system_table
 	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)
 		goto fdt_set_fail;
 
-	fdt_val32 = cpu_to_fdt32(map_size);
+	fdt_val32 = U32_MAX; /* placeholder */
 	status = fdt_setprop(fdt, node, "linux,uefi-mmap-size",
 			     &fdt_val32,  sizeof(fdt_val32));
 	if (status)
 		goto fdt_set_fail;
 
-	fdt_val32 = cpu_to_fdt32(desc_size);
 	status = fdt_setprop(fdt, node, "linux,uefi-mmap-desc-size",
 			     &fdt_val32, sizeof(fdt_val32));
 	if (status)
 		goto fdt_set_fail;
 
-	fdt_val32 = cpu_to_fdt32(desc_ver);
 	status = fdt_setprop(fdt, node, "linux,uefi-mmap-desc-ver",
 			     &fdt_val32, sizeof(fdt_val32));
 	if (status)
@@ -148,6 +143,43 @@ fdt_set_fail:
 	return EFI_LOAD_ERROR;
 }
 
+static efi_status_t update_fdt_memmap(void *fdt, struct efi_boot_memmap *map)
+{
+	int node = fdt_path_offset(fdt, "/chosen");
+	u64 fdt_val64;
+	u32 fdt_val32;
+	int err;
+
+	if (node < 0)
+		return EFI_LOAD_ERROR;
+
+	fdt_val64 = cpu_to_fdt64((unsigned long)*map->map);
+	err = fdt_setprop_inplace(fdt, node, "linux,uefi-mmap-start",
+				  &fdt_val64, sizeof(fdt_val64));
+	if (err)
+		return EFI_LOAD_ERROR;
+
+	fdt_val32 = cpu_to_fdt32(*map->map_size);
+	err = fdt_setprop_inplace(fdt, node, "linux,uefi-mmap-size",
+				  &fdt_val32, sizeof(fdt_val32));
+	if (err)
+		return EFI_LOAD_ERROR;
+
+	fdt_val32 = cpu_to_fdt32(*map->desc_size);
+	err = fdt_setprop_inplace(fdt, node, "linux,uefi-mmap-desc-size",
+				  &fdt_val32, sizeof(fdt_val32));
+	if (err)
+		return EFI_LOAD_ERROR;
+
+	fdt_val32 = cpu_to_fdt32(*map->desc_ver);
+	err = fdt_setprop_inplace(fdt, node, "linux,uefi-mmap-desc-ver",
+				  &fdt_val32, sizeof(fdt_val32));
+	if (err)
+		return EFI_LOAD_ERROR;
+
+	return EFI_SUCCESS;
+}
+
 #ifndef EFI_FDT_ALIGN
 #define EFI_FDT_ALIGN EFI_PAGE_SIZE
 #endif
@@ -243,20 +275,10 @@ efi_status_t allocate_new_fdt_and_exit_b
 			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,
-				    cmdline_ptr, initrd_addr, initrd_size,
-				    memory_map, map_size, desc_size, desc_ver);
+				    cmdline_ptr, initrd_addr, initrd_size);
 
 		/* Succeeding the first time is the expected case. */
 		if (status == EFI_SUCCESS)
@@ -266,20 +288,16 @@ efi_status_t allocate_new_fdt_and_exit_b
 			/*
 			 * 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 +306,16 @@ efi_status_t allocate_new_fdt_and_exit_b
 	if (status == EFI_SUCCESS) {
 		efi_set_virtual_address_map_t *svam;
 
+		status = update_fdt_memmap((void *)*new_fdt_addr, &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 +347,6 @@ efi_status_t allocate_new_fdt_and_exit_b
 
 	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);