MIPS requires some extra instructions to set up the $gp register for the
with a pointer to the global data area.
This isn't needed for non-PIC builds, but this patch enables the code
unconditionally to prevent bitrot.
Also enable PIC in one of the test configurations for ongoing
validation.
Signed-off-by: Thomas Weißschuh <linux@xxxxxxxxxxxxxx>
---
tools/include/nolibc/arch-mips.h | 7 ++++++-
tools/testing/selftests/nolibc/Makefile | 2 +-
2 files changed, 7 insertions(+), 2 deletions(-)
diff --git a/tools/include/nolibc/arch-mips.h b/tools/include/nolibc/arch-mips.h
index 3a2c76716b83..e9a01847c2b8 100644
--- a/tools/include/nolibc/arch-mips.h
+++ b/tools/include/nolibc/arch-mips.h
@@ -184,10 +184,15 @@ void __attribute__((weak, noreturn, optimize("Os", "omit-frame-pointer"))) __no_
__asm__ volatile (
".set push\n"
".set noreorder\n"
- ".option pic0\n"
+ "bal 1f\n" /* prime $ra for .cpload */
+ "nop\n"
+ "1:\n"
+ ".cpload $ra\n"
"move $a0, $sp\n" /* save stack pointer to $a0, as arg1 of _start_c */
"li $t0, -8\n"
"and $sp, $sp, $t0\n" /* $sp must be 8-byte aligned */
+ "addiu $sp, $sp, -4\n" /* space for .cprestore to store $gp */
+ ".cprestore 0\n"
"addiu $sp, $sp, -16\n" /* the callee expects to save a0..a3 there */
"jal _start_c\n" /* transfer to c runtime */
" nop\n" /* delayed slot */
diff --git a/tools/testing/selftests/nolibc/Makefile b/tools/testing/selftests/nolibc/Makefile
index 508435b8ac2a..484bb02d8e6c 100644
--- a/tools/testing/selftests/nolibc/Makefile
+++ b/tools/testing/selftests/nolibc/Makefile
@@ -144,7 +144,7 @@ CFLAGS_ppc = -m32 -mbig-endian -mno-vsx $(call cc-option,-mmultiple)
CFLAGS_ppc64 = -m64 -mbig-endian -mno-vsx $(call cc-option,-mmultiple)
CFLAGS_ppc64le = -m64 -mlittle-endian -mno-vsx $(call cc-option,-mabi=elfv2)
CFLAGS_s390 = -m64
-CFLAGS_mips32le = -EL -mabi=32
+CFLAGS_mips32le = -EL -mabi=32 -fPIC
CFLAGS_mips32be = -EB -mabi=32
CFLAGS_STACKPROTECTOR ?= $(call cc-option,-mstack-protector-guard=global $(call cc-option,-fstack-protector-all))
CFLAGS ?= -Os -fno-ident -fno-asynchronous-unwind-tables -std=c89 -W -Wall -Wextra \
---
base-commit: ba335752620565c25c3028fff9496bb8ef373602
change-id: 20770914-nolibc-pic-30043ffb0403
Best regards,
--
Thomas Weißschuh <linux@xxxxxxxxxxxxxx>
