9 files changed, 331 insertions, 4 deletions

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 446e49b56e6a..67f8303d513d 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -2041,6 +2041,25 @@ config AUTO_ZRELADDR
           0xf8000000. This assumes the zImage being placed in the first 128MB
           from start of memory.
 
+config EFI_STUB
+        bool
+
+config EFI
+        bool "UEFI runtime support"
+        depends on OF && !CPU_BIG_ENDIAN && MMU && AUTO_ZRELADDR && !XIP_KERNEL
+        select UCS2_STRING
+        select EFI_PARAMS_FROM_FDT
+        select EFI_STUB
+        select EFI_ARMSTUB
+        select EFI_RUNTIME_WRAPPERS
+        ---help---
+          This option provides support for runtime services provided
+          by UEFI firmware (such as non-volatile variables, realtime
+          clock, and platform reset). A UEFI stub is also provided to
+          allow the kernel to be booted as an EFI application. This
+          is only useful for kernels that may run on systems that have
+          UEFI firmware.
+
 endmenu
 
 menu "CPU Power Management"
diff --git a/arch/arm/boot/compressed/Makefile b/arch/arm/boot/compressed/Makefile
index 3f9a9ebc77c3..4c23a68a0917 100644
--- a/arch/arm/boot/compressed/Makefile
+++ b/arch/arm/boot/compressed/Makefile
@@ -167,9 +167,11 @@ if [ $(words $(ZRELADDR)) -gt 1 -a "$(CONFIG_AUTO_ZRELADDR)" = "" ]; then \
         false; \
 fi
 
+efi-obj-$(CONFIG_EFI_STUB) := $(objtree)/drivers/firmware/efi/libstub/lib.a
+
 $(obj)/vmlinux: $(obj)/vmlinux.lds $(obj)/$(HEAD) $(obj)/piggy.$(suffix_y).o \
                 $(addprefix $(obj)/, $(OBJS)) $(lib1funcs) $(ashldi3) \
-                $(bswapsdi2) FORCE
+                $(bswapsdi2) $(efi-obj-y) FORCE
         @$(check_for_multiple_zreladdr)
         $(call if_changed,ld)
         @$(check_for_bad_syms)
diff --git a/arch/arm/boot/compressed/efi-header.S b/arch/arm/boot/compressed/efi-header.S
new file mode 100644
index 000000000000..9d5dc4fda3c1
--- /dev/null
+++ b/arch/arm/boot/compressed/efi-header.S
@@ -0,0 +1,130 @@
+/*
+ * Copyright (C) 2013-2015 Linaro Ltd
+ * Authors: Roy Franz <roy.franz@linaro.org>
+ *          Ard Biesheuvel <ard.biesheuvel@linaro.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+                .macro  __nop
+#ifdef CONFIG_EFI_STUB
+                @ This is almost but not quite a NOP, since it does clobber the
+                @ condition flags. But it is the best we can do for EFI, since
+                @ PE/COFF expects the magic string "MZ" at offset 0, while the
+                @ ARM/Linux boot protocol expects an executable instruction
+                @ there.
+                .inst   'M' | ('Z' << 8) | (0x1310 << 16)   @ tstne r0, #0x4d000
+#else
+                mov     r0, r0
+#endif
+                .endm
+
+                .macro  __EFI_HEADER
+#ifdef CONFIG_EFI_STUB
+                b       __efi_start
+
+                .set    start_offset, __efi_start - start
+                .org    start + 0x3c
+                @
+                @ The PE header can be anywhere in the file, but for
+                @ simplicity we keep it together with the MSDOS header
+                @ The offset to the PE/COFF header needs to be at offset
+                @ 0x3C in the MSDOS header.
+                @ The only 2 fields of the MSDOS header that are used are this
+                @ PE/COFF offset, and the "MZ" bytes at offset 0x0.
+                @
+                .long   pe_header - start       @ Offset to the PE header.
+
+pe_header:
+                .ascii  "PE\0\0"
+
+coff_header:
+                .short  0x01c2                  @ ARM or Thumb
+                .short  2                       @ nr_sections
+                .long   0                       @ TimeDateStamp
+                .long   0                       @ PointerToSymbolTable
+                .long   1                       @ NumberOfSymbols
+                .short  section_table - optional_header
+                                                @ SizeOfOptionalHeader
+                .short  0x306                   @ Characteristics.
+                                                @ IMAGE_FILE_32BIT_MACHINE |
+                                                @ IMAGE_FILE_DEBUG_STRIPPED |
+                                                @ IMAGE_FILE_EXECUTABLE_IMAGE |
+                                                @ IMAGE_FILE_LINE_NUMS_STRIPPED
+
+optional_header:
+                .short  0x10b                   @ PE32 format
+                .byte   0x02                    @ MajorLinkerVersion
+                .byte   0x14                    @ MinorLinkerVersion
+                .long   _end - __efi_start      @ SizeOfCode
+                .long   0                       @ SizeOfInitializedData
+                .long   0                       @ SizeOfUninitializedData
+                .long   efi_stub_entry - start  @ AddressOfEntryPoint
+                .long   start_offset            @ BaseOfCode
+                .long   0                       @ data
+
+extra_header_fields:
+                .long   0                       @ ImageBase
+                .long   0x200                   @ SectionAlignment
+                .long   0x200                   @ FileAlignment
+                .short  0                       @ MajorOperatingSystemVersion
+                .short  0                       @ MinorOperatingSystemVersion
+                .short  0                       @ MajorImageVersion
+                .short  0                       @ MinorImageVersion
+                .short  0                       @ MajorSubsystemVersion
+                .short  0                       @ MinorSubsystemVersion
+                .long   0                       @ Win32VersionValue
+
+                .long   _end - start            @ SizeOfImage
+                .long   start_offset            @ SizeOfHeaders
+                .long   0                       @ CheckSum
+                .short  0xa                     @ Subsystem (EFI application)
+                .short  0                       @ DllCharacteristics
+                .long   0                       @ SizeOfStackReserve
+                .long   0                       @ SizeOfStackCommit
+                .long   0                       @ SizeOfHeapReserve
+                .long   0                       @ SizeOfHeapCommit
+                .long   0                       @ LoaderFlags
+                .long   0x6                     @ NumberOfRvaAndSizes
+
+                .quad   0                       @ ExportTable
+                .quad   0                       @ ImportTable
+                .quad   0                       @ ResourceTable
+                .quad   0                       @ ExceptionTable
+                .quad   0                       @ CertificationTable
+                .quad   0                       @ BaseRelocationTable
+
+section_table:
+                @
+                @ The EFI application loader requires a relocation section
+                @ because EFI applications must be relocatable. This is a
+                @ dummy section as far as we are concerned.
+                @
+                .ascii  ".reloc\0\0"
+                .long   0                       @ VirtualSize
+                .long   0                       @ VirtualAddress
+                .long   0                       @ SizeOfRawData
+                .long   0                       @ PointerToRawData
+                .long   0                       @ PointerToRelocations
+                .long   0                       @ PointerToLineNumbers
+                .short  0                       @ NumberOfRelocations
+                .short  0                       @ NumberOfLineNumbers
+                .long   0x42100040              @ Characteristics
+
+                .ascii  ".text\0\0\0"
+                .long   _end - __efi_start      @ VirtualSize
+                .long   __efi_start             @ VirtualAddress
+                .long   _edata - __efi_start    @ SizeOfRawData
+                .long   __efi_start             @ PointerToRawData
+                .long   0                       @ PointerToRelocations
+                .long   0                       @ PointerToLineNumbers
+                .short  0                       @ NumberOfRelocations
+                .short  0                       @ NumberOfLineNumbers
+                .long   0xe0500020              @ Characteristics
+
+                .align  9
+__efi_start:
+#endif
+                .endm
diff --git a/arch/arm/boot/compressed/head.S b/arch/arm/boot/compressed/head.S
index 06e983f59980..af11c2f8f3b7 100644
--- a/arch/arm/boot/compressed/head.S
+++ b/arch/arm/boot/compressed/head.S
@@ -12,6 +12,8 @@
 #include <asm/assembler.h>
 #include <asm/v7m.h>
 
+#include "efi-header.S"
+
  AR_CLASS(      .arch   armv7-a )
  M_CLASS(       .arch   armv7-m )
 
@@ -126,7 +128,7 @@
 start:
                 .type   start,#function
                 .rept   7
-                mov     r0, r0
+                __nop
                 .endr
    ARM(         mov     r0, r0          )
    ARM(         b       1f              )
@@ -139,7 +141,8 @@ start:
                 .word   0x04030201      @ endianness flag
 
  THUMB(         .thumb                  )
-1:
+1:              __EFI_HEADER
+
  ARM_BE8(       setend  be              )       @ go BE8 if compiled for BE8
  AR_CLASS(      mrs     r9, cpsr        )
 #ifdef CONFIG_ARM_VIRT_EXT
@@ -1353,6 +1356,53 @@ __enter_kernel:
 
 reloc_code_end:
 
+#ifdef CONFIG_EFI_STUB
+                .align  2
+_start:         .long   start - .
+
+ENTRY(efi_stub_entry)
+                @ allocate space on stack for passing current zImage address
+                @ and for the EFI stub to return of new entry point of
+                @ zImage, as EFI stub may copy the kernel. Pointer address
+                @ is passed in r2. r0 and r1 are passed through from the
+                @ EFI firmware to efi_entry
+                adr     ip, _start
+                ldr     r3, [ip]
+                add     r3, r3, ip
+                stmfd   sp!, {r3, lr}
+                mov     r2, sp                  @ pass zImage address in r2
+                bl      efi_entry
+
+                @ Check for error return from EFI stub. r0 has FDT address
+                @ or error code.
+                cmn     r0, #1
+                beq     efi_load_fail
+
+                @ Preserve return value of efi_entry() in r4
+                mov     r4, r0
+                bl      cache_clean_flush
+                bl      cache_off
+
+                @ Set parameters for booting zImage according to boot protocol
+                @ put FDT address in r2, it was returned by efi_entry()
+                @ r1 is the machine type, and r0 needs to be 0
+                mov     r0, #0
+                mov     r1, #0xFFFFFFFF
+                mov     r2, r4
+
+                @ Branch to (possibly) relocated zImage that is in [sp]
+                ldr     lr, [sp]
+                ldr     ip, =start_offset
+                add     lr, lr, ip
+                mov     pc, lr                          @ no mode switch
+
+efi_load_fail:
+                @ Return EFI_LOAD_ERROR to EFI firmware on error.
+                ldr     r0, =0x80000001
+                ldmfd   sp!, {ip, pc}
+ENDPROC(efi_stub_entry)
+#endif
+
                 .align
                 .section ".stack", "aw", %nobits
 .L_user_stack:  .space  4096
diff --git a/arch/arm/boot/compressed/vmlinux.lds.S b/arch/arm/boot/compressed/vmlinux.lds.S
index 2b60b843ac5e..81c493156ce8 100644
--- a/arch/arm/boot/compressed/vmlinux.lds.S
+++ b/arch/arm/boot/compressed/vmlinux.lds.S
@@ -48,6 +48,13 @@ SECTIONS
     *(.rodata)
     *(.rodata.*)
   }
+  .data : {
+    /*
+     * The EFI stub always executes from RAM, and runs strictly before the
+     * decompressor, so we can make an exception for its r/w data, and keep it
+     */
+    *(.data.efistub)
+  }
   .piggydata : {
     *(.piggydata)
   }
diff --git a/arch/arm/include/asm/efi.h b/arch/arm/include/asm/efi.h
index c91e330616ad..e0eea72deb87 100644
--- a/arch/arm/include/asm/efi.h
+++ b/arch/arm/include/asm/efi.h
@@ -57,4 +57,27 @@ void efi_virtmap_unload(void);
 #define efi_init()
 #endif /* CONFIG_EFI */
 
+/* arch specific definitions used by the stub code */
+
+#define efi_call_early(f, ...) sys_table_arg->boottime->f(__VA_ARGS__)
+
+/*
+ * A reasonable upper bound for the uncompressed kernel size is 32 MBytes,
+ * so we will reserve that amount of memory. We have no easy way to tell what
+ * the actuall size of code + data the uncompressed kernel will use.
+ * If this is insufficient, the decompressor will relocate itself out of the
+ * way before performing the decompression.
+ */
+#define MAX_UNCOMP_KERNEL_SIZE  SZ_32M
+
+/*
+ * The kernel zImage should preferably be located between 32 MB and 128 MB
+ * from the base of DRAM. The min address leaves space for a maximal size
+ * uncompressed image, and the max address is due to how the zImage decompressor
+ * picks a destination address.
+ */
+#define ZIMAGE_OFFSET_LIMIT     SZ_128M
+#define MIN_ZIMAGE_OFFSET       MAX_UNCOMP_KERNEL_SIZE
+#define MAX_FDT_OFFSET          ZIMAGE_OFFSET_LIMIT
+
 #endif /* _ASM_ARM_EFI_H */
diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile
index 3c0467d3688c..8cf9ccbf42d5 100644
--- a/drivers/firmware/efi/libstub/Makefile
+++ b/drivers/firmware/efi/libstub/Makefile
@@ -34,6 +34,7 @@ $(obj)/lib-%.o: $(srctree)/lib/%.c FORCE
 lib-$(CONFIG_EFI_ARMSTUB)       += arm-stub.o fdt.o string.o \
                                    $(patsubst %.c,lib-%.o,$(arm-deps))
 
+lib-$(CONFIG_ARM)               += arm32-stub.o
 lib-$(CONFIG_ARM64)             += arm64-stub.o
 CFLAGS_arm64-stub.o             := -DTEXT_OFFSET=$(TEXT_OFFSET)
 
@@ -67,3 +68,11 @@ quiet_cmd_stubcopy = STUBCPY $@
                      $(OBJDUMP) -r $@ | grep $(STUBCOPY_RELOC-y)        \
                      && (echo >&2 "$@: absolute symbol references not allowed in the EFI stub"; \
                          rm -f $@; /bin/false); else /bin/false; fi
+
+#
+# ARM discards the .data section because it disallows r/w data in the
+# decompressor. So move our .data to .data.efistub, which is preserved
+# explicitly by the decompressor linker script.
+#
+STUBCOPY_FLAGS-$(CONFIG_ARM)    += --rename-section .data=.data.efistub
+STUBCOPY_RELOC-$(CONFIG_ARM)    := R_ARM_ABS
diff --git a/drivers/firmware/efi/libstub/arm-stub.c b/drivers/firmware/efi/libstub/arm-stub.c
index 950c87f5d279..3397902e4040 100644
--- a/drivers/firmware/efi/libstub/arm-stub.c
+++ b/drivers/firmware/efi/libstub/arm-stub.c
@@ -303,8 +303,10 @@ fail:
  * The value chosen is the largest non-zero power of 2 suitable for this purpose
  * both on 32-bit and 64-bit ARM CPUs, to maximize the likelihood that it can
  * be mapped efficiently.
+ * Since 32-bit ARM could potentially execute with a 1G/3G user/kernel split,
+ * map everything below 1 GB.
  */
-#define EFI_RT_VIRTUAL_BASE     0x40000000
+#define EFI_RT_VIRTUAL_BASE     SZ_512M
 
 static int cmp_mem_desc(const void *l, const void *r)
 {
diff --git a/drivers/firmware/efi/libstub/arm32-stub.c b/drivers/firmware/efi/libstub/arm32-stub.c
new file mode 100644
index 000000000000..495ebd657e38
--- /dev/null
+++ b/drivers/firmware/efi/libstub/arm32-stub.c
@@ -0,0 +1,85 @@
+/*
+ * Copyright (C) 2013 Linaro Ltd;  <roy.franz@linaro.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ */
+#include <linux/efi.h>
+#include <asm/efi.h>
+
+efi_status_t handle_kernel_image(efi_system_table_t *sys_table,
+                                 unsigned long *image_addr,
+                                 unsigned long *image_size,
+                                 unsigned long *reserve_addr,
+                                 unsigned long *reserve_size,
+                                 unsigned long dram_base,
+                                 efi_loaded_image_t *image)
+{
+        unsigned long nr_pages;
+        efi_status_t status;
+        /* Use alloc_addr to tranlsate between types */
+        efi_physical_addr_t alloc_addr;
+
+        /*
+         * Verify that the DRAM base address is compatible with the ARM
+         * boot protocol, which determines the base of DRAM by masking
+         * off the low 27 bits of the address at which the zImage is
+         * loaded. These assumptions are made by the decompressor,
+         * before any memory map is available.
+         */
+        dram_base = round_up(dram_base, SZ_128M);
+
+        /*
+         * Reserve memory for the uncompressed kernel image. This is
+         * all that prevents any future allocations from conflicting
+         * with the kernel. Since we can't tell from the compressed
+         * image how much DRAM the kernel actually uses (due to BSS
+         * size uncertainty) we allocate the maximum possible size.
+         * Do this very early, as prints can cause memory allocations
+         * that may conflict with this.
+         */
+        alloc_addr = dram_base;
+        *reserve_size = MAX_UNCOMP_KERNEL_SIZE;
+        nr_pages = round_up(*reserve_size, EFI_PAGE_SIZE) / EFI_PAGE_SIZE;
+        status = sys_table->boottime->allocate_pages(EFI_ALLOCATE_ADDRESS,
+                                                     EFI_LOADER_DATA,
+                                                     nr_pages, &alloc_addr);
+        if (status != EFI_SUCCESS) {
+                *reserve_size = 0;
+                pr_efi_err(sys_table, "Unable to allocate memory for uncompressed kernel.\n");
+                return status;
+        }
+        *reserve_addr = alloc_addr;
+
+        /*
+         * Relocate the zImage, so that it appears in the lowest 128 MB
+         * memory window.
+         */
+        *image_size = image->image_size;
+        status = efi_relocate_kernel(sys_table, image_addr, *image_size,
+                                     *image_size,
+                                     dram_base + MAX_UNCOMP_KERNEL_SIZE, 0);
+        if (status != EFI_SUCCESS) {
+                pr_efi_err(sys_table, "Failed to relocate kernel.\n");
+                efi_free(sys_table, *reserve_size, *reserve_addr);
+                *reserve_size = 0;
+                return status;
+        }
+
+        /*
+         * Check to see if we were able to allocate memory low enough
+         * in memory. The kernel determines the base of DRAM from the
+         * address at which the zImage is loaded.
+         */
+        if (*image_addr + *image_size > dram_base + ZIMAGE_OFFSET_LIMIT) {
+                pr_efi_err(sys_table, "Failed to relocate kernel, no low memory available.\n");
+                efi_free(sys_table, *reserve_size, *reserve_addr);
+                *reserve_size = 0;
+                efi_free(sys_table, *image_size, *image_addr);
+                *image_size = 0;
+                return EFI_LOAD_ERROR;
+        }
+        return EFI_SUCCESS;
+}