some binary, for example the output of golang, may be mark as FPXX, while in fact they are still FP32. Since FPXX binary can work with both FR=1 and FR=0, we force it to use FR=0 here. https://go-review.googlesource.com/c/go/+/239217 https://go-review.googlesource.com/c/go/+/237058 v2->v3: commit message: add Signed-off-by and Cc to stable. v1->v2: Fix bad commit message: in fact, we are switching to FR=0 Signed-off-by: YunQiang Su <yunqiang.su@xxxxxxxxxxxxx> Cc: stable@xxxxxxxxxxxxxxx # 4.19+ --- arch/mips/kernel/elf.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) diff --git a/arch/mips/kernel/elf.c b/arch/mips/kernel/elf.c index 7b045d2a0b51..bf798ce0ec0e 100644 --- a/arch/mips/kernel/elf.c +++ b/arch/mips/kernel/elf.c @@ -234,9 +234,10 @@ int arch_check_elf(void *_ehdr, bool has_interpreter, void *_interp_ehdr, * fpxx case. This is because, in any-ABI (or no-ABI) we have no FPU * instructions so we don't care about the mode. We will simply use * the one preferred by the hardware. In fpxx case, that ABI can - * handle both FR=1 and FR=0, so, again, we simply choose the one - * preferred by the hardware. Next, if we only use single-precision - * FPU instructions, and the default ABI FPU mode is not good + * handle both FR=1 and FR=0. Here, we use FR=0, because some + * binaries may be mark as FPXX by mistake (ie, output of golang). + * - If we only use single-precision FPU instructions, + * and the default ABI FPU mode is not good * (ie single + any ABI combination), we set again the FPU mode to the * one is preferred by the hardware. Next, if we know that the code * will only use single-precision instructions, shown by single being @@ -248,8 +249,9 @@ int arch_check_elf(void *_ehdr, bool has_interpreter, void *_interp_ehdr, */ if (prog_req.fre && !prog_req.frdefault && !prog_req.fr1) state->overall_fp_mode = FP_FRE; - else if ((prog_req.fr1 && prog_req.frdefault) || - (prog_req.single && !prog_req.frdefault)) + else if (prog_req.fr1 && prog_req.frdefault) + state->overall_fp_mode = FP_FR0; + else if (prog_req.single && !prog_req.frdefault) /* Make sure 64-bit MIPS III/IV/64R1 will not pick FR1 */ state->overall_fp_mode = ((raw_current_cpu_data.fpu_id & MIPS_FPIR_F64) && cpu_has_mips_r2_r6) ? -- 2.20.1
