MIPS: Truncate link address into 32bit for 32bit kernel

[ Upstream commit ff487d41036035376e47972c7c522490b839ab37 ]

LLD failed to link vmlinux with 64bit load address for 32bit ELF
while bfd will strip 64bit address into 32bit silently.
To fix LLD build, we should truncate load address provided by platform
into 32bit for 32bit kernel.

Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Link: https://github.com/ClangBuiltLinux/linux/issues/786
Link: https://sourceware.org/bugzilla/show_bug.cgi?id=25784
Reviewed-by: Fangrui Song <maskray@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Tested-by: Nathan Chancellor <natechancellor@gmail.com>
Cc: Maciej W. Rozycki <macro@linux-mips.org>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/arch/mips/Makefile b/arch/mips/Makefile
index ad0a92f95af108ce86c0f852723f04e6c7e52632..63e2ad43bd6adc266be4b432096eb9323454336c 100644 (file)
--- a/arch/mips/Makefile
+++ b/arch/mips/Makefile
@@ -290,12 +290,23 @@ ifdef CONFIG_64BIT
   endif
 endif
 
+# When linking a 32-bit executable the LLVM linker cannot cope with a
+# 32-bit load address that has been sign-extended to 64 bits.  Simply
+# remove the upper 32 bits then, as it is safe to do so with other
+# linkers.
+ifdef CONFIG_64BIT
+       load-ld                 = $(load-y)
+else
+       load-ld                 = $(subst 0xffffffff,0x,$(load-y))
+endif
+
 KBUILD_AFLAGS  += $(cflags-y)
 KBUILD_CFLAGS  += $(cflags-y)
-KBUILD_CPPFLAGS += -DVMLINUX_LOAD_ADDRESS=$(load-y)
+KBUILD_CPPFLAGS += -DVMLINUX_LOAD_ADDRESS=$(load-y) -DLINKER_LOAD_ADDRESS=$(load-ld)
 KBUILD_CPPFLAGS += -DDATAOFFSET=$(if $(dataoffset-y),$(dataoffset-y),0)
 
 bootvars-y     = VMLINUX_LOAD_ADDRESS=$(load-y) \
+                 LINKER_LOAD_ADDRESS=$(load-ld) \
                  VMLINUX_ENTRY_ADDRESS=$(entry-y) \
                  PLATFORM="$(platform-y)" \
                  ITS_INPUTS="$(its-y)"

diff --git a/arch/mips/boot/compressed/Makefile b/arch/mips/boot/compressed/Makefile
index d859f079b771a158208b0cef571a22a22c3f67ac..378cbfb31ee70ffe6ebe80c4f4905b12e26fc091 100644 (file)
--- a/arch/mips/boot/compressed/Makefile
+++ b/arch/mips/boot/compressed/Makefile
@@ -90,7 +90,7 @@ ifneq ($(zload-y),)
 VMLINUZ_LOAD_ADDRESS := $(zload-y)
 else
 VMLINUZ_LOAD_ADDRESS = $(shell $(obj)/calc_vmlinuz_load_addr \
-               $(obj)/vmlinux.bin $(VMLINUX_LOAD_ADDRESS))
+               $(obj)/vmlinux.bin $(LINKER_LOAD_ADDRESS))
 endif
 UIMAGE_LOADADDR = $(VMLINUZ_LOAD_ADDRESS)
 

diff --git a/arch/mips/kernel/vmlinux.lds.S b/arch/mips/kernel/vmlinux.lds.S
index 36f2e860ba3eade90e3c1f535c18713d257ebaff..be63fff95b2abb64c8e766807927d823b3bee940 100644 (file)
--- a/arch/mips/kernel/vmlinux.lds.S
+++ b/arch/mips/kernel/vmlinux.lds.S
@@ -50,7 +50,7 @@ SECTIONS
        /* . = 0xa800000000300000; */
        . = 0xffffffff80300000;
 #endif
-       . = VMLINUX_LOAD_ADDRESS;
+       . = LINKER_LOAD_ADDRESS;
        /* read-only */
        _text = .;      /* Text and read-only data */
        .text : {