Messages in this thread Patch in this message | | | From | Xi Ruoyao <> | Subject | [PATCH 2/8] LoongArch: Only use -Wa,-mla-* options for !CONFIG_CC_HAS_EXPLICIT_RELOCS | Date | Sun, 28 Aug 2022 01:54:30 +0800 |
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If explicit relocation hints is used by the toolchain, -Wa,-mla-* options will be useless for C code. Only use them for !CONFIG_CC_HAS_EXPLICIT_RELOCS.
Replace "la" with "la.pcrel" in head.S to keep the semantic consistent with new and old toolchains for the low level startup code.
Signed-off-by: Xi Ruoyao <xry111@xry111.site> --- arch/loongarch/Makefile | 15 ++++++++++++++- arch/loongarch/kernel/head.S | 10 +++++----- 2 files changed, 19 insertions(+), 6 deletions(-)
diff --git a/arch/loongarch/Makefile b/arch/loongarch/Makefile index 415e09bdf31a..bd0ea6623245 100644 --- a/arch/loongarch/Makefile +++ b/arch/loongarch/Makefile @@ -40,10 +40,23 @@ endif cflags-y += -G0 -pipe -msoft-float LDFLAGS_vmlinux += -G0 -static -n -nostdlib + +ifdef CONFIG_CC_HAS_EXPLICIT_RELOCS +# GCC may have -mexplicit-relocs off by default if it was built with an old +# assembler. But with CONFIG_CC_HAS_EXPLICIT_RELOCS we are sure explicit +# relocation hints are supported by the assembler, so force it. +cflags-y += -mexplicit-relocs +else +# Likewise, disable -mexplicit-relocs if GCC enables by default but the +# assembler does not support it. +cflags-y += $(call cc-option,-mno-explicit-relocs) +# With -mno-explicit-relocs, use assembler options to adjust code generation +# for symbol address. KBUILD_AFLAGS_KERNEL += -Wa,-mla-global-with-pcrel KBUILD_CFLAGS_KERNEL += -Wa,-mla-global-with-pcrel KBUILD_AFLAGS_MODULE += -Wa,-mla-global-with-abs -KBUILD_CFLAGS_MODULE += -fplt -Wa,-mla-global-with-abs,-mla-local-with-abs +KBUILD_CFLAGS_MODULE += -Wa,-mla-global-with-abs,-mla-local-with-abs +endif cflags-y += -ffreestanding cflags-y += $(call cc-option, -mno-check-zero-division) diff --git a/arch/loongarch/kernel/head.S b/arch/loongarch/kernel/head.S index 01bac62a6442..eb3f641d5915 100644 --- a/arch/loongarch/kernel/head.S +++ b/arch/loongarch/kernel/head.S @@ -55,17 +55,17 @@ SYM_CODE_START(kernel_entry) # kernel entry point li.w t0, 0x00 # FPE=0, SXE=0, ASXE=0, BTE=0 csrwr t0, LOONGARCH_CSR_EUEN - la t0, __bss_start # clear .bss + la.pcrel t0, __bss_start # clear .bss st.d zero, t0, 0 - la t1, __bss_stop - LONGSIZE + la.pcrel t1, __bss_stop - LONGSIZE 1: addi.d t0, t0, LONGSIZE st.d zero, t0, 0 bne t0, t1, 1b - la t0, fw_arg0 + la.pcrel t0, fw_arg0 st.d a0, t0, 0 # firmware arguments - la t0, fw_arg1 + la.pcrel t0, fw_arg1 st.d a1, t0, 0 /* KSave3 used for percpu base, initialized as 0 */ @@ -73,7 +73,7 @@ SYM_CODE_START(kernel_entry) # kernel entry point /* GPR21 used for percpu base (runtime), initialized as 0 */ move u0, zero - la tp, init_thread_union + la.pcrel tp, init_thread_union /* Set the SP after an empty pt_regs. */ PTR_LI sp, (_THREAD_SIZE - 32 - PT_SIZE) PTR_ADD sp, sp, tp -- 2.37.0
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