[PATCH 6.1.y] riscv/efistub: Ensure GP-relative addressing is not used

[PATCH 6.1.y] riscv/efistub: Ensure GP-relative addressing is not used

[Jan Kiszka]

From: Jan Kiszka <jan.kiszka@siemens.com>

commit afb2a4fb84555ef9e61061f6ea63ed7087b295d5 upstream.

The cflags for the RISC-V efistub were missing -mno-relax, thus were
under the risk that the compiler could use GP-relative addressing. That
happened for _edata with binutils-2.41 and kernel 6.1, causing the
relocation to fail due to an invalid kernel_size in handle_kernel_image.
It was not yet observed with newer versions, but that may just be luck.

Cc: <stable@vger.kernel.org>
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/firmware/efi/libstub/Makefile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile
index ef5045a53ce0..b6e1dcb98a64 100644
--- a/drivers/firmware/efi/libstub/Makefile
+++ b/drivers/firmware/efi/libstub/Makefile
@@ -25,7 +25,7 @@ cflags-$(CONFIG_ARM)		:= $(subst $(CC_FLAGS_FTRACE),,$(KBUILD_CFLAGS)) \
 				   -fno-builtin -fpic \
 				   $(call cc-option,-mno-single-pic-base)
 cflags-$(CONFIG_RISCV)		:= $(subst $(CC_FLAGS_FTRACE),,$(KBUILD_CFLAGS)) \
-				   -fpic
+				   -fpic -mno-relax
 cflags-$(CONFIG_LOONGARCH)	:= $(subst $(CC_FLAGS_FTRACE),,$(KBUILD_CFLAGS)) \
 				   -fpie
 
-- 
2.35.3

Re: [PATCH 6.1.y] riscv/efistub: Ensure GP-relative addressing is not used

[Greg Kroah-Hartman]

On Wed, Feb 21, 2024 at 11:21:24PM +0100, Jan Kiszka wrote:
> From: Jan Kiszka <jan.kiszka@siemens.com>
> 
> commit afb2a4fb84555ef9e61061f6ea63ed7087b295d5 upstream.
> 
> The cflags for the RISC-V efistub were missing -mno-relax, thus were
> under the risk that the compiler could use GP-relative addressing. That
> happened for _edata with binutils-2.41 and kernel 6.1, causing the
> relocation to fail due to an invalid kernel_size in handle_kernel_image.
> It was not yet observed with newer versions, but that may just be luck.
> 
> Cc: <stable@vger.kernel.org>
> Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
> Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> ---
>  drivers/firmware/efi/libstub/Makefile | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

Both now queued up, thanks.

greg k-h