From 8e3c00db16fcedea0ea47d93c2acb6d7d5ba9164 Mon Sep 17 00:00:00 2001 From: Fredrik Noring Date: Thu, 1 Nov 2018 14:36:48 +0000 Subject: MIPS: Use `.set mips2' to emulate LL/SC for the R5900 too GAS treats the R5900 as MIPS III, with some modifications. The MIPS III designation means that the GNU C Library will try to assemble the LL and SC instructions, even though they are not implemented in the R5900. GAS will therefore produce the following errors: Error: opcode not supported on this processor: r5900 (mips3) `ll $2,0($4)' Error: opcode not supported on this processor: r5900 (mips3) `sc $6,0($4)' The MIPS II ISA override as used here enables the kernel to trap and emulate the LL and SC instructions, as required. This change has been tested by compiling the GNU C Library 2.27 with a GCC 8.2.0 cross-compiler for mipsr5900el-unknown-linux-gnu under Gentoo. * sysdeps/mips/sys/tas.h (_test_and_set): Handle the R5900 CPU with the ISA override. --- ChangeLog | 5 +++++ sysdeps/mips/sys/tas.h | 3 ++- 2 files changed, 7 insertions(+), 1 deletion(-) diff --git a/ChangeLog b/ChangeLog index 204af29..67abf14 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,8 @@ +2018-11-01 Fredrik Noring + + * sysdeps/mips/sys/tas.h (_test_and_set): Handle the R5900 CPU + with the ISA override. + 2018-10-31 Rafael Avila de Espindola * sysdeps/unix/sysv/linux/sysdep-vdso.h: Simplify an #if #else diff --git a/sysdeps/mips/sys/tas.h b/sysdeps/mips/sys/tas.h index d5ed013..22cee94 100644 --- a/sysdeps/mips/sys/tas.h +++ b/sysdeps/mips/sys/tas.h @@ -38,10 +38,11 @@ __NTH (_test_and_set (int *__p, int __v)) { int __r, __t; + /* The R5900 reports itself as MIPS III but it does not have LL/SC. */ __asm__ __volatile__ ("/* Inline test and set */\n" ".set push\n\t" -#if _MIPS_SIM == _ABIO32 && __mips < 2 +#if _MIPS_SIM == _ABIO32 && (__mips < 2 || defined (_MIPS_ARCH_R5900)) ".set mips2\n\t" #endif "sync\n\t" -- cgit v1.1