riscv: Prepare EFI header for relocatable kernels

ld does not handle relocations correctly as explained here [1],
a fix for that was proposed by Nelson there but we have to support older
toolchains and then provide this fix.

Note that llvm does not need this fix and is then excluded.

[1] https://sourceware.org/pipermail/binutils/2023-March/126690.html

Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Link: https://lore.kernel.org/r/20230329045329.64565-2-alexghiti@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

Author: Alexandre Ghiti

arch/riscv/include/asm/set_memory.h

@@ -56,4 +56,7 @@ bool kernel_page_present(struct page *page);
 #define SECTION_ALIGN L1_CACHE_BYTES
 #endif /* CONFIG_STRICT_KERNEL_RWX */
 
+#define PECOFF_SECTION_ALIGNMENT        0x1000
+#define PECOFF_FILE_ALIGNMENT           0x200
+
 #endif /* _ASM_RISCV_SET_MEMORY_H */

arch/riscv/kernel/efi-header.S

@@ -6,6 +6,7 @@
 
 #include <linux/pe.h>
 #include <linux/sizes.h>
+#include <asm/set_memory.h>
 
 	.macro	__EFI_PE_HEADER
 	.long	PE_MAGIC
@@ -33,7 +34,11 @@ optional_header:
 	.byte	0x02					// MajorLinkerVersion
 	.byte	0x14					// MinorLinkerVersion
 	.long	__pecoff_text_end - efi_header_end	// SizeOfCode
-	.long	__pecoff_data_virt_size			// SizeOfInitializedData
+#ifdef __clang__
+	.long   __pecoff_data_virt_size			// SizeOfInitializedData
+#else
+	.long	__pecoff_data_virt_end - __pecoff_text_end	// SizeOfInitializedData
+#endif
 	.long	0					// SizeOfUninitializedData
 	.long	__efistub_efi_pe_entry - _start		// AddressOfEntryPoint
 	.long	efi_header_end - _start			// BaseOfCode
@@ -91,9 +96,17 @@ section_table:
 		IMAGE_SCN_MEM_EXECUTE			// Characteristics
 
 	.ascii	".data\0\0\0"
-	.long	__pecoff_data_virt_size			// VirtualSize
+#ifdef __clang__
+	.long   __pecoff_data_virt_size			// VirtualSize
+#else
+	.long	__pecoff_data_virt_end - __pecoff_text_end	// VirtualSize
+#endif
 	.long	__pecoff_text_end - _start		// VirtualAddress
-	.long	__pecoff_data_raw_size			// SizeOfRawData
+#ifdef __clang__
+	.long   __pecoff_data_raw_size			// SizeOfRawData
+#else
+	.long	__pecoff_data_raw_end - __pecoff_text_end	// SizeOfRawData
+#endif
 	.long	__pecoff_text_end - _start		// PointerToRawData
 
 	.long	0					// PointerToRelocations

arch/riscv/kernel/vmlinux.lds.S

@@ -27,9 +27,6 @@ ENTRY(_start)
 
 jiffies = jiffies_64;
 
-PECOFF_SECTION_ALIGNMENT = 0x1000;
-PECOFF_FILE_ALIGNMENT = 0x200;
-
 SECTIONS
 {
 	/* Beginning of code and text segment */
@@ -132,6 +129,7 @@ SECTIONS
 #ifdef CONFIG_EFI
 	.pecoff_edata_padding : { BYTE(0); . = ALIGN(PECOFF_FILE_ALIGNMENT); }
 	__pecoff_data_raw_size = ABSOLUTE(. - __pecoff_text_end);
+	__pecoff_data_raw_end = ABSOLUTE(.);
 #endif
 
 	/* End of data section */
@@ -142,6 +140,7 @@ SECTIONS
 #ifdef CONFIG_EFI
 	. = ALIGN(PECOFF_SECTION_ALIGNMENT);
 	__pecoff_data_virt_size = ABSOLUTE(. - __pecoff_text_end);
+	__pecoff_data_virt_end = ABSOLUTE(.);
 #endif
 	_end = .;