efi/loongarch: Use load address to calculate kernel entry address

The efi_relocate_kernel() may load the PIE kernel to anywhere, the
loaded address may not be equal to link address or
EFI_KIMG_PREFERRED_ADDRESS.

Acked-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: Wang Yao <wangyao@lemote.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

Author: AlooGS

arch/loongarch/include/asm/efi.h

@@ -32,6 +32,6 @@ static inline unsigned long efi_get_kimg_min_align(void)
 
 #define EFI_KIMG_PREFERRED_ADDRESS	PHYSADDR(VMLINUX_LOAD_ADDRESS)
 
-unsigned long kernel_entry_address(void);
+unsigned long kernel_entry_address(unsigned long kernel_addr);
 
 #endif /* _ASM_LOONGARCH_EFI_H */

drivers/firmware/efi/libstub/loongarch-stub.c

@@ -35,9 +35,9 @@ efi_status_t handle_kernel_image(unsigned long *image_addr,
 	return status;
 }
 
-unsigned long kernel_entry_address(void)
+unsigned long kernel_entry_address(unsigned long kernel_addr)
 {
 	unsigned long base = (unsigned long)&kernel_offset - kernel_offset;
 
-	return (unsigned long)&kernel_entry - base + VMLINUX_LOAD_ADDRESS;
+	return (unsigned long)&kernel_entry - base + kernel_addr;
 }

drivers/firmware/efi/libstub/loongarch.c

@@ -37,9 +37,9 @@ static efi_status_t exit_boot_func(struct efi_boot_memmap *map, void *priv)
 	return EFI_SUCCESS;
 }
 
-unsigned long __weak kernel_entry_address(void)
+unsigned long __weak kernel_entry_address(unsigned long kernel_addr)
 {
-	return *(unsigned long *)(PHYSADDR(VMLINUX_LOAD_ADDRESS) + 8);
+	return *(unsigned long *)(kernel_addr + 8) - VMLINUX_LOAD_ADDRESS + kernel_addr;
 }
 
 efi_status_t efi_boot_kernel(void *handle, efi_loaded_image_t *image,
@@ -73,7 +73,7 @@ efi_status_t efi_boot_kernel(void *handle, efi_loaded_image_t *image,
 	csr_write64(CSR_DMW0_INIT, LOONGARCH_CSR_DMWIN0);
 	csr_write64(CSR_DMW1_INIT, LOONGARCH_CSR_DMWIN1);
 
-	real_kernel_entry = (void *)kernel_entry_address();
+	real_kernel_entry = (void *)kernel_entry_address(kernel_addr);
 
 	real_kernel_entry(true, (unsigned long)cmdline_ptr,
 			  (unsigned long)efi_system_table);