linux/arch/mips/lib/ashldi3.c
Harvey Hunt aedcfbe065 MIPS: lib: Mark intrinsics notrace
On certain MIPS32 devices, the ftrace tracer "function_graph" uses
__lshrdi3() during the capturing of trace data. ftrace then attempts to
trace __lshrdi3() which leads to infinite recursion and a stack overflow.
Fix this by marking __lshrdi3() as notrace. Mark the other compiler
intrinsics as notrace in case the compiler decides to use them in the
ftrace path.

Signed-off-by: Harvey Hunt <harvey.hunt@imgtec.com>
Cc: <linux-mips@linux-mips.org>
Cc: <linux-kernel@vger.kernel.org>
Cc: <stable@vger.kernel.org> # 4.2.x-
Patchwork: https://patchwork.linux-mips.org/patch/13354/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2016-05-28 12:35:11 +02:00

30 lines
483 B
C

#include <linux/module.h>
#include "libgcc.h"
long long notrace __ashldi3(long long u, word_type b)
{
DWunion uu, w;
word_type bm;
if (b == 0)
return u;
uu.ll = u;
bm = 32 - b;
if (bm <= 0) {
w.s.low = 0;
w.s.high = (unsigned int) uu.s.low << -bm;
} else {
const unsigned int carries = (unsigned int) uu.s.low >> bm;
w.s.low = (unsigned int) uu.s.low << b;
w.s.high = ((unsigned int) uu.s.high << b) | carries;
}
return w.ll;
}
EXPORT_SYMBOL(__ashldi3);