arm64: move early boot code to the .init segment

Apart from the arm64/linux and EFI header data structures, there is nothing
in the .head.text section that must reside at the beginning of the Image.
So let's move it to the .init section where it belongs.

Note that this involves some minor tweaking of the EFI header, primarily
because the address of 'stext' no longer coincides with the start of the
.text section. It also requires a couple of relocated symbol references
to be slightly rewritten or their definition moved to the linker script.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>

diff --git a/arch/arm64/kernel/efi-entry.S b/arch/arm64/kernel/efi-entry.S
index cae3112f779122528545dc086549f9d82c688d52..e88c064b845c3a42985b1aa7b0940680ff356788 100644 (file)
--- a/arch/arm64/kernel/efi-entry.S
+++ b/arch/arm64/kernel/efi-entry.S
@@ -62,7 +62,7 @@ ENTRY(entry)
         */
        mov     x20, x0         // DTB address
        ldr     x0, [sp, #16]   // relocated _text address
-       movz    x21, #:abs_g0:stext_offset
+       ldr     w21, =stext_offset
        add     x21, x0, x21
 
        /*

diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S
index 4203d5f257bcf396f8cdadb4f613d7048b486f59..b434176188474db2f1c66248341146b6514da19e 100644 (file)
--- a/arch/arm64/kernel/head.S
+++ b/arch/arm64/kernel/head.S
@@ -102,8 +102,6 @@ _head:
 #endif
 
 #ifdef CONFIG_EFI
-       .globl  __efistub_stext_offset
-       .set    __efistub_stext_offset, stext - _head
        .align 3
 pe_header:
        .ascii  "PE"
@@ -123,11 +121,11 @@ optional_header:
        .short  0x20b                           // PE32+ format
        .byte   0x02                            // MajorLinkerVersion
        .byte   0x14                            // MinorLinkerVersion
-       .long   _end - stext                    // SizeOfCode
+       .long   _end - efi_header_end           // SizeOfCode
        .long   0                               // SizeOfInitializedData
        .long   0                               // SizeOfUninitializedData
        .long   __efistub_entry - _head         // AddressOfEntryPoint
-       .long   __efistub_stext_offset          // BaseOfCode
+       .long   efi_header_end - _head          // BaseOfCode
 
 extra_header_fields:
        .quad   0                               // ImageBase
@@ -144,7 +142,7 @@ extra_header_fields:
        .long   _end - _head                    // SizeOfImage
 
        // Everything before the kernel image is considered part of the header
-       .long   __efistub_stext_offset          // SizeOfHeaders
+       .long   efi_header_end - _head          // SizeOfHeaders
        .long   0                               // CheckSum
        .short  0xa                             // Subsystem (EFI application)
        .short  0                               // DllCharacteristics
@@ -188,10 +186,10 @@ section_table:
        .byte   0
        .byte   0
        .byte   0                       // end of 0 padding of section name
-       .long   _end - stext            // VirtualSize
-       .long   __efistub_stext_offset  // VirtualAddress
-       .long   _edata - stext          // SizeOfRawData
-       .long   __efistub_stext_offset  // PointerToRawData
+       .long   _end - efi_header_end   // VirtualSize
+       .long   efi_header_end - _head  // VirtualAddress
+       .long   _edata - efi_header_end // SizeOfRawData
+       .long   efi_header_end - _head  // PointerToRawData
 
        .long   0               // PointerToRelocations (0 for executables)
        .long   0               // PointerToLineNumbers (0 for executables)
@@ -200,15 +198,18 @@ section_table:
        .long   0xe0500020      // Characteristics (section flags)
 
        /*
-        * EFI will load stext onwards at the 4k section alignment
+        * EFI will load .text onwards at the 4k section alignment
         * described in the PE/COFF header. To ensure that instruction
         * sequences using an adrp and a :lo12: immediate will function
-        * correctly at this alignment, we must ensure that stext is
+        * correctly at this alignment, we must ensure that .text is
         * placed at a 4k boundary in the Image to begin with.
         */
        .align 12
+efi_header_end:
 #endif
 
+       __INIT
+
 ENTRY(stext)
        bl      preserve_boot_args
        bl      el2_setup                       // Drop to EL1, w20=cpu_boot_mode
@@ -223,12 +224,12 @@ ENTRY(stext)
         * the TCR will have been set.
         */
        ldr     x27, 0f                         // address to jump to after
-                                               // MMU has been enabled
+       neg     x27, x27                        // MMU has been enabled
        adr_l   lr, __enable_mmu                // return (PIC) address
        b       __cpu_setup                     // initialise processor
 ENDPROC(stext)
        .align  3
-0:     .quad   __mmap_switched - (_head - TEXT_OFFSET) + KIMAGE_VADDR
+0:     .quad   (_text - TEXT_OFFSET) - __mmap_switched - KIMAGE_VADDR
 
 /*
  * Preserve the arguments passed by the bootloader in x0 .. x3
@@ -397,7 +398,7 @@ __create_page_tables:
        ldr     x5, =KIMAGE_VADDR
        add     x5, x5, x23                     // add KASLR displacement
        create_pgd_entry x0, x5, x3, x6
-       ldr     w6, kernel_img_size
+       ldr     w6, =kernel_img_size
        add     x6, x6, x5
        mov     x3, x24                         // phys offset
        create_block_map x0, x7, x3, x5, x6
@@ -414,9 +415,6 @@ __create_page_tables:
 
        ret     x28
 ENDPROC(__create_page_tables)
-
-kernel_img_size:
-       .long   _end - (_head - TEXT_OFFSET)
        .ltorg
 
 /*

diff --git a/arch/arm64/kernel/image.h b/arch/arm64/kernel/image.h
index 5e360ce88f10ba4110697552a47ea8c42053a02f..4fd72da646a3e3a80e98c1314e82b292bf0bc5ec 100644 (file)
--- a/arch/arm64/kernel/image.h
+++ b/arch/arm64/kernel/image.h
@@ -71,8 +71,12 @@
        DEFINE_IMAGE_LE64(_kernel_offset_le, TEXT_OFFSET);      \
        DEFINE_IMAGE_LE64(_kernel_flags_le, __HEAD_FLAGS);
 
+kernel_img_size = _end - (_text - TEXT_OFFSET);
+
 #ifdef CONFIG_EFI
 
+__efistub_stext_offset = stext - _text;
+
 /*
  * Prevent the symbol aliases below from being emitted into the kallsyms
  * table, by forcing them to be absolute symbols (which are conveniently