[PATCH 16/21] efi: libstub: Factor out min alignment and preferred kernel load address

[Ard Biesheuvel <ardb@kernel.org>]

Factor out the expressions that describe the preferred placement of the
loaded image as well as the minimum alignment so we can reuse them in
the decompressor.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
 arch/arm64/include/asm/efi.h                  | 15 +++++++++++++++
 arch/loongarch/include/asm/efi.h              |  7 +++++++
 arch/riscv/include/asm/efi.h                  | 11 +++++++++++
 drivers/firmware/efi/libstub/arm64-stub.c     | 11 +----------
 drivers/firmware/efi/libstub/loongarch-stub.c |  3 ++-
 drivers/firmware/efi/libstub/riscv-stub.c     | 15 +++------------
 6 files changed, 39 insertions(+), 23 deletions(-)

diff --git a/arch/arm64/include/asm/efi.h b/arch/arm64/include/asm/efi.h
index af35ad671754..108b115dbf5b 100644
--- a/arch/arm64/include/asm/efi.h
+++ b/arch/arm64/include/asm/efi.h
@@ -76,6 +76,21 @@ static inline unsigned long efi_get_max_initrd_addr(unsigned long image_addr)
 	return (image_addr & ~(SZ_1G - 1UL)) + (1UL << (VA_BITS_MIN - 1));
 }
 
+static inline unsigned long efi_get_kimg_min_align(void)
+{
+	extern bool efi_nokaslr;
+
+	/*
+	 * Although relocatable kernels can fix up the misalignment with
+	 * respect to MIN_KIMG_ALIGN, the resulting virtual text addresses are
+	 * subtly out of sync with those recorded in the vmlinux when kaslr is
+	 * disabled but the image required relocation anyway. Therefore retain
+	 * 2M alignment if KASLR was explicitly disabled, even if it was not
+	 * going to be activated to begin with.
+	 */
+	return efi_nokaslr ? MIN_KIMG_ALIGN : EFI_KIMG_ALIGN;
+}
+
 #define EFI_ALLOC_ALIGN		SZ_64K
 
 /*
diff --git a/arch/loongarch/include/asm/efi.h b/arch/loongarch/include/asm/efi.h
index 60d6a170c18d..5a470c8d2bbc 100644
--- a/arch/loongarch/include/asm/efi.h
+++ b/arch/loongarch/include/asm/efi.h
@@ -24,4 +24,11 @@ static inline unsigned long efi_get_max_initrd_addr(unsigned long image_addr)
 	return ULONG_MAX;
 }
 
+static inline unsigned long efi_get_kimg_min_align(void)
+{
+	return SZ_2M;
+}
+
+#define EFI_KIMG_PREFERRED_ADDRESS	PHYSADDR(VMLINUX_LOAD_ADDRESS)
+
 #endif /* _ASM_LOONGARCH_EFI_H */
diff --git a/arch/riscv/include/asm/efi.h b/arch/riscv/include/asm/efi.h
index d0570936cb8c..a742868eb23c 100644
--- a/arch/riscv/include/asm/efi.h
+++ b/arch/riscv/include/asm/efi.h
@@ -31,6 +31,17 @@ static inline unsigned long efi_get_max_initrd_addr(unsigned long image_addr)
 	return ULONG_MAX;
 }
 
+static inline unsigned long efi_get_kimg_min_align(void)
+{
+	/*
+	 * RISC-V requires the kernel image to placed 2 MB aligned base for 64
+	 * bit and 4MB for 32 bit.
+	 */
+	return IS_ENABLED(CONFIG_64BIT) ? SZ_2M : SZ_4M;
+}
+
+#define EFI_KIMG_PREFERRED_ADDRESS	efi_get_kimg_min_align()
+
 void efi_virtmap_load(void);
 void efi_virtmap_unload(void);
 
diff --git a/drivers/firmware/efi/libstub/arm64-stub.c b/drivers/firmware/efi/libstub/arm64-stub.c
index e767a5ac8c3d..dd21b7b7309a 100644
--- a/drivers/firmware/efi/libstub/arm64-stub.c
+++ b/drivers/firmware/efi/libstub/arm64-stub.c
@@ -88,16 +88,7 @@ efi_status_t handle_kernel_image(unsigned long *image_addr,
 	efi_status_t status;
 	unsigned long kernel_size, kernel_memsize = 0;
 	u32 phys_seed = 0;
-
-	/*
-	 * Although relocatable kernels can fix up the misalignment with
-	 * respect to MIN_KIMG_ALIGN, the resulting virtual text addresses are
-	 * subtly out of sync with those recorded in the vmlinux when kaslr is
-	 * disabled but the image required relocation anyway. Therefore retain
-	 * 2M alignment if KASLR was explicitly disabled, even if it was not
-	 * going to be activated to begin with.
-	 */
-	u64 min_kimg_align = efi_nokaslr ? MIN_KIMG_ALIGN : EFI_KIMG_ALIGN;
+	u64 min_kimg_align = efi_get_kimg_min_align();
 
 	if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) {
 		efi_guid_t li_fixed_proto = LINUX_EFI_LOADED_IMAGE_FIXED_GUID;
diff --git a/drivers/firmware/efi/libstub/loongarch-stub.c b/drivers/firmware/efi/libstub/loongarch-stub.c
index 32329f2a92f9..a2e55e5c4003 100644
--- a/drivers/firmware/efi/libstub/loongarch-stub.c
+++ b/drivers/firmware/efi/libstub/loongarch-stub.c
@@ -35,7 +35,8 @@ efi_status_t handle_kernel_image(unsigned long *image_addr,
 	kernel_addr = (unsigned long)&kernel_offset - kernel_offset;
 
 	status = efi_relocate_kernel(&kernel_addr, kernel_fsize, kernel_asize,
-				     PHYSADDR(VMLINUX_LOAD_ADDRESS), SZ_2M, 0x0);
+				     EFI_KIMG_PREFERRED_ADDRESS,
+				     efi_get_kimg_min_align(), 0x0);
 
 	*image_addr = kernel_addr;
 	*image_size = kernel_asize;
diff --git a/drivers/firmware/efi/libstub/riscv-stub.c b/drivers/firmware/efi/libstub/riscv-stub.c
index b450ebf95977..c5a551f69a7f 100644
--- a/drivers/firmware/efi/libstub/riscv-stub.c
+++ b/drivers/firmware/efi/libstub/riscv-stub.c
@@ -12,16 +12,6 @@
 
 #include "efistub.h"
 
-/*
- * RISC-V requires the kernel image to placed 2 MB aligned base for 64 bit and
- * 4MB for 32 bit.
- */
-#ifdef CONFIG_64BIT
-#define MIN_KIMG_ALIGN		SZ_2M
-#else
-#define MIN_KIMG_ALIGN		SZ_4M
-#endif
-
 typedef void __noreturn (*jump_kernel_func)(unsigned long, unsigned long);
 
 static unsigned long hartid;
@@ -125,9 +115,10 @@ efi_status_t handle_kernel_image(unsigned long *image_addr,
 	 * lowest possible memory region as long as the address and size meets
 	 * the alignment constraints.
 	 */
-	preferred_addr = MIN_KIMG_ALIGN;
+	preferred_addr = EFI_KIMG_PREFERRED_ADDRESS;
 	status = efi_relocate_kernel(image_addr, kernel_size, *image_size,
-				     preferred_addr, MIN_KIMG_ALIGN, 0x0);
+				     preferred_addr, efi_get_kimg_min_align(),
+				     0x0);
 
 	if (status != EFI_SUCCESS) {
 		efi_err("Failed to relocate kernel\n");
-- 
2.35.1