Messages in this thread | | | Subject | Re: [PATCH] MIPS: Fix IRQ tracing when call handle_fpe() | From | yuanjunqing <> | Date | Tue, 26 May 2020 15:07:16 +0800 |
| |
在 2020/5/25 下午4:42, Thomas Bogendoerfer 写道: > On Mon, May 25, 2020 at 11:31:23AM +0800, YuanJunQing wrote: >> Register "a1" is unsaved in this function, >> when CONFIG_TRACE_IRQFLAGS is enabled, >> the TRACE_IRQS_OFF macro will call trace_hardirqs_off(), >> and this may change register "a1". >> The variment of register "a1" may send SIGFPE signal >> to task when call do_fpe(),and this may kill the task. >> >> Signed-off-by: YuanJunQing <yuanjunqing66@163.com> >> --- >> arch/mips/kernel/genex.S | 6 ++++-- >> 1 file changed, 4 insertions(+), 2 deletions(-) >> >> diff --git a/arch/mips/kernel/genex.S b/arch/mips/kernel/genex.S >> index 8236fb291e3f..956a76429773 100644 >> --- a/arch/mips/kernel/genex.S >> +++ b/arch/mips/kernel/genex.S >> @@ -480,16 +480,18 @@ NESTED(nmi_handler, PT_SIZE, sp) >> /* gas fails to assemble cfc1 for some archs (octeon).*/ \ >> .set mips1 >> SET_HARDFLOAT >> - cfc1 a1, fcr31 >> + cfc1 s0, fcr31 >> .set pop >> CLI >> TRACE_IRQS_OFF >> + move a1,s0 >> .endm > do we realy need to read fcr31 that early ? Wouldn't it work to > just move the cfc1 below TRACE_IRQS_OFF ? > > Thomas.
yes, it can work when we just move the cfc1 below TRACE_IRQS_OFF, and the code is written as follows.
CLI TRACE_IRQS_OFF .set mips1 SET_HARDFLOAT cfc1 a1, fcr31 .set pop .endm
| |