From 49387dba910e485640b575e920ee463b7e611dc3 Mon Sep 17 00:00:00 2001 From: Shinya Kuribayashi Date: Tue, 6 May 2008 13:22:52 +0900 Subject: [MIPS] cpu/mips/cache.S: Fix build warning Some old GNU assemblers, such as v2.14 (ELDK 3.1.1), v2.16 (ELDK 4.1.0), warns illegal global symbol references by bal (and jal also) instruction. This does not happen with the latest binutils v2.18. Here's an example on gth2_config: mips_4KC-gcc -D__ASSEMBLY__ -g -Os -D__KERNEL__ -DTEXT_BASE=0x90000000 -I/home/skuribay/devel/u-boot.git/include -fno-builtin -ffreestanding -nostdinc -isy stem /opt/eldk311/usr/bin/../lib/gcc-lib/mips-linux/3.3.3/include -pipe -DCONFIG_MIPS -D__MIPS__ -G 0 -mabicalls -fpic -pipe -msoft-float -march=4kc -mtune=4k c -EB -c -o cache.o cache.S cache.S: Assembler messages: cache.S:243: Warning: Pretending global symbol used as branch target is local. cache.S:250: Warning: Pretending global symbol used as branch target is local. In principle, gas might be sensitive to global symbol references in PIC code because they should be processed through GOT (global offset table). But if `bal' instruction is used, it results in PC-based offset jump. This is the cause of this warning. In practice, we know it doesn't matter whether PC-based reference or GOT- based. As for this case, both will work before/after relocation. But let's fix the code. This patch explicitly sets up a target address, then jump there. Here's an example of disassembled code with/without this patch. 90000668: 1485ffef bne a0,a1,90000628 9000066c: ac80fffc sw zero,-4(a0) 90000670: 01402821 move a1,t2 -90000674: 0411ffba bal 90000560 -90000678: 01803021 move a2,t4 -9000067c: 01602821 move a1,t3 -90000680: 0411ffcc bal 900005b4 -90000684: 01a03021 move a2,t5 -90000688: 03000008 jr t8 -9000068c: 00000000 nop +90000674: 01803021 move a2,t4 +90000678: 8f8f83ec lw t7,-31764(gp) +9000067c: 01e0f809 jalr t7 +90000680: 00000000 nop +90000684: 01602821 move a1,t3 +90000688: 01a03021 move a2,t5 +9000068c: 8f8f81e0 lw t7,-32288(gp) +90000690: 01e0f809 jalr t7 +90000694: 00000000 nop +90000698: 03000008 jr t8 +9000069c: 00000000 nop Signed-off-by: Shinya Kuribayashi --- cpu/mips/cache.S | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) (limited to 'cpu') diff --git a/cpu/mips/cache.S b/cpu/mips/cache.S index 428d251..1b0efc3 100644 --- a/cpu/mips/cache.S +++ b/cpu/mips/cache.S @@ -240,14 +240,16 @@ NESTED(mips_cache_reset, 0, ra) */ move a1, t2 move a2, t4 - bal mips_init_icache + PTR_LA t7, mips_init_icache + jalr t7 /* * then initialize D-cache. */ move a1, t3 move a2, t5 - bal mips_init_dcache + PTR_LA t7, mips_init_dcache + jalr t7 jr RA END(mips_cache_reset) -- cgit v1.1