x86, efi: Break up large initrd reads

The efi boot stub tries to read the entire initrd in 1 go, however
some efi implementations hang if too much if asked to read too much
data at the same time. After some experimentation I found out that my
asrock p67 board will hang if asked to read chunks of 4MiB, so use a
safe value.

elilo reads in chunks of 16KiB, but since that requires many read
calls I use a value of 1 MiB.  hpa suggested adding individual
blacklists for when systems are found where this value causes a crash.

Signed-off-by: Maarten Lankhorst <m.b.lankhorst@gmail.com>
Link: http://lkml.kernel.org/r/4EEB3A02.3090201@gmail.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

diff --git a/arch/x86/boot/compressed/eboot.c b/arch/x86/boot/compressed/eboot.c
index 4055e63..fec216f 100644 (file)
--- a/arch/x86/boot/compressed/eboot.c
+++ b/arch/x86/boot/compressed/eboot.c
@@ -643,14 +643,22 @@ grow:
                        u64 size;
 
                        size = initrds[j].size;
-                       status = efi_call_phys3(fh->read, initrds[j].handle,
-                                               &size, addr);
-                       if (status != EFI_SUCCESS)
-                               goto free_initrd_total;
+                       while (size) {
+                               u64 chunksize;
+                               if (size > EFI_READ_CHUNK_SIZE)
+                                       chunksize = EFI_READ_CHUNK_SIZE;
+                               else
+                                       chunksize = size;
+                               status = efi_call_phys3(fh->read,
+                                                       initrds[j].handle,
+                                                       &chunksize, addr);
+                               if (status != EFI_SUCCESS)
+                                       goto free_initrd_total;
+                               addr += chunksize;
+                               size -= chunksize;
+                       }
 
                        efi_call_phys1(fh->close, initrds[j].handle);
-
-                       addr += size;
                }
 
        }

diff --git a/arch/x86/boot/compressed/eboot.h b/arch/x86/boot/compressed/eboot.h
index f66d023..3925166 100644 (file)
--- a/arch/x86/boot/compressed/eboot.h
+++ b/arch/x86/boot/compressed/eboot.h
@@ -12,6 +12,7 @@
 #define DESC_TYPE_CODE_DATA    (1 << 0)
 
 #define EFI_PAGE_SIZE          (1UL << EFI_PAGE_SHIFT)
+#define EFI_READ_CHUNK_SIZE    (1024 * 1024)
 
 #define PIXEL_RGB_RESERVED_8BIT_PER_COLOR              0
 #define PIXEL_BGR_RESERVED_8BIT_PER_COLOR              1