> -----Original Message----- > From: linux-mips-bounce@xxxxxxxxxxxxxx [mailto:linux-mips-bounce@linux- > mips.org] On Behalf Of Viller Hsiao > Sent: 19 February 2014 14:55 > To: linux-mips@xxxxxxxxxxxxxx > Cc: Viller Hsiao; Steven Rostedt; Frederic Weisbecker; Ingo Molnar; Ralf Baechle > Subject: [PATCH] MIPS: ftrace: Fix icache flush range error > > > In 32-bit machine, the start address of flushing icache is wrong after calculated > address of 2nd modified instruction in function tracer. The start address is shifted > 4 bytes from ordinary calculation. > > This causes problem when the address of 1st instruction is the last word of one > cache line. It will not be flushed at this case. > > Signed-off-by: Viller Hsiao <villerhsiao@xxxxxxxxx> > --- > arch/mips/kernel/ftrace.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/arch/mips/kernel/ftrace.c b/arch/mips/kernel/ftrace.c index > 185ba25..5bdc535 100644 > --- a/arch/mips/kernel/ftrace.c > +++ b/arch/mips/kernel/ftrace.c > @@ -107,12 +107,12 @@ static int ftrace_modify_code_2(unsigned long ip, > unsigned int new_code1, > unsigned int new_code2) > { > int faulted; > + unsigned long ip2 = ip + 4; I think better to omit this variable... > > safe_store_code(new_code1, ip, faulted); > if (unlikely(faulted)) > return -EFAULT; > - ip += 4; > - safe_store_code(new_code2, ip, faulted); > + safe_store_code(new_code2, ip2, faulted); And just do the addition directly here instead. > if (unlikely(faulted)) > return -EFAULT; > flush_icache_range(ip, ip + 8); /* original ip + 12 */ Care to fix this comment by removing it? I can't rationalise it and made me confused for a bit. If you do remove it please mention the change in the commit message. Nice catch by the way. Cheers, Qais > -- > 1.8.4.3 >
