arm64/head: avoid symbol names pointing into first 64 KB of kernel image

We no longer map the first 64 KB of the kernel image, as there is nothing
there that we ever need to refer back to once the kernel has booted. Even
though facilities like kallsyms are very careful to only refer to the
region that starts at _stext when mapping virtual addresses to symbol
names, let's avoid any confusion by switching to local .L prefixed symbol
names for the EFI header, as none of them have any significance to the
rest of the kernel.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20201117124729.12642-3-ardb@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

diff --git a/arch/arm64/kernel/efi-header.S b/arch/arm64/kernel/efi-header.S
index 3ad4aecff03370a0377933e81603a189ed3936d9..ddaf57d825b5c759159cd23122bcdfdae5157082 100644 (file)
--- a/arch/arm64/kernel/efi-header.S
+++ b/arch/arm64/kernel/efi-header.S
@@ -9,28 +9,26 @@
 
        .macro  __EFI_PE_HEADER
        .long   PE_MAGIC
-coff_header:
        .short  IMAGE_FILE_MACHINE_ARM64                // Machine
-       .short  section_count                           // NumberOfSections
+       .short  .Lsection_count                         // NumberOfSections
        .long   0                                       // TimeDateStamp
        .long   0                                       // PointerToSymbolTable
        .long   0                                       // NumberOfSymbols
-       .short  section_table - optional_header         // SizeOfOptionalHeader
+       .short  .Lsection_table - .Loptional_header     // SizeOfOptionalHeader
        .short  IMAGE_FILE_DEBUG_STRIPPED | \
                IMAGE_FILE_EXECUTABLE_IMAGE | \
                IMAGE_FILE_LINE_NUMS_STRIPPED           // Characteristics
 
-optional_header:
+.Loptional_header:
        .short  PE_OPT_MAGIC_PE32PLUS                   // PE32+ format
        .byte   0x02                                    // MajorLinkerVersion
        .byte   0x14                                    // MinorLinkerVersion
-       .long   __initdata_begin - efi_header_end       // SizeOfCode
+       .long   __initdata_begin - .Lefi_header_end     // SizeOfCode
        .long   __pecoff_data_size                      // SizeOfInitializedData
        .long   0                                       // SizeOfUninitializedData
        .long   __efistub_efi_pe_entry - _head          // AddressOfEntryPoint
-       .long   efi_header_end - _head                  // BaseOfCode
+       .long   .Lefi_header_end - _head                // BaseOfCode
 
-extra_header_fields:
        .quad   0                                       // ImageBase
        .long   SEGMENT_ALIGN                           // SectionAlignment
        .long   PECOFF_FILE_ALIGNMENT                   // FileAlignment
@@ -45,7 +43,7 @@ extra_header_fields:
        .long   _end - _head                            // SizeOfImage
 
        // Everything before the kernel image is considered part of the header
-       .long   efi_header_end - _head                  // SizeOfHeaders
+       .long   .Lefi_header_end - _head                // SizeOfHeaders
        .long   0                                       // CheckSum
        .short  IMAGE_SUBSYSTEM_EFI_APPLICATION         // Subsystem
        .short  0                                       // DllCharacteristics
@@ -54,7 +52,7 @@ extra_header_fields:
        .quad   0                                       // SizeOfHeapReserve
        .quad   0                                       // SizeOfHeapCommit
        .long   0                                       // LoaderFlags
-       .long   (section_table - .) / 8                 // NumberOfRvaAndSizes
+       .long   (.Lsection_table - .) / 8               // NumberOfRvaAndSizes
 
        .quad   0                                       // ExportTable
        .quad   0                                       // ImportTable
@@ -64,17 +62,17 @@ extra_header_fields:
        .quad   0                                       // BaseRelocationTable
 
 #ifdef CONFIG_DEBUG_EFI
-       .long   efi_debug_table - _head                 // DebugTable
-       .long   efi_debug_table_size
+       .long   .Lefi_debug_table - _head               // DebugTable
+       .long   .Lefi_debug_table_size
 #endif
 
        // Section table
-section_table:
+.Lsection_table:
        .ascii  ".text\0\0\0"
-       .long   __initdata_begin - efi_header_end       // VirtualSize
-       .long   efi_header_end - _head                  // VirtualAddress
-       .long   __initdata_begin - efi_header_end       // SizeOfRawData
-       .long   efi_header_end - _head                  // PointerToRawData
+       .long   __initdata_begin - .Lefi_header_end     // VirtualSize
+       .long   .Lefi_header_end - _head                // VirtualAddress
+       .long   __initdata_begin - .Lefi_header_end     // SizeOfRawData
+       .long   .Lefi_header_end - _head                // PointerToRawData
 
        .long   0                                       // PointerToRelocations
        .long   0                                       // PointerToLineNumbers
@@ -98,7 +96,7 @@ section_table:
                IMAGE_SCN_MEM_READ | \
                IMAGE_SCN_MEM_WRITE                     // Characteristics
 
-       .set    section_count, (. - section_table) / 40
+       .set    .Lsection_count, (. - .Lsection_table) / 40
 
 #ifdef CONFIG_DEBUG_EFI
        /*
@@ -114,21 +112,21 @@ section_table:
        __INITRODATA
 
        .align  2
-efi_debug_table:
+.Lefi_debug_table:
        // EFI_IMAGE_DEBUG_DIRECTORY_ENTRY
        .long   0                                       // Characteristics
        .long   0                                       // TimeDateStamp
        .short  0                                       // MajorVersion
        .short  0                                       // MinorVersion
        .long   IMAGE_DEBUG_TYPE_CODEVIEW               // Type
-       .long   efi_debug_entry_size                    // SizeOfData
+       .long   .Lefi_debug_entry_size                  // SizeOfData
        .long   0                                       // RVA
-       .long   efi_debug_entry - _head                 // FileOffset
+       .long   .Lefi_debug_entry - _head               // FileOffset
 
-       .set    efi_debug_table_size, . - efi_debug_table
+       .set    .Lefi_debug_table_size, . - .Lefi_debug_table
        .previous
 
-efi_debug_entry:
+.Lefi_debug_entry:
        // EFI_IMAGE_DEBUG_CODEVIEW_NB10_ENTRY
        .ascii  "NB10"                                  // Signature
        .long   0                                       // Unknown
@@ -137,9 +135,9 @@ efi_debug_entry:
 
        .asciz  VMLINUX_PATH
 
-       .set    efi_debug_entry_size, . - efi_debug_entry
+       .set    .Lefi_debug_entry_size, . - .Lefi_debug_entry
 #endif
 
        .balign SEGMENT_ALIGN
-efi_header_end:
+.Lefi_header_end:
        .endm