linux_dsm_epyc7002/arch/arm/include
Russell King 846a136881 ARM: vfp: fix saving d16-d31 vfp registers on v6+ kernels
Michael Olbrich reported that his test program fails when built with
-O2 -mcpu=cortex-a8 -mfpu=neon, and a kernel which supports v6 and v7
CPUs:

volatile int x = 2;
volatile int64_t y = 2;

int main() {
	volatile int a = 0;
	volatile int64_t b = 0;
	while (1) {
		a = (a + x) % (1 << 30);
		b = (b + y) % (1 << 30);
		assert(a == b);
	}
}

and two instances are run.  When built for just v7 CPUs, this program
works fine.  It uses the "vadd.i64 d19, d18, d16" VFP instruction.

It appears that we do not save the high-16 double VFP registers across
context switches when the kernel is built for v6 CPUs.  Fix that.

Cc: <stable@vger.kernel.org>
Tested-By: Michael Olbrich <m.olbrich@pengutronix.de>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2012-10-09 12:16:46 +01:00
..
asm ARM: vfp: fix saving d16-d31 vfp registers on v6+ kernels 2012-10-09 12:16:46 +01:00
debug ARM: picoxcell: move debug macros to include/debug 2012-09-14 09:22:03 -05:00
uapi/asm UAPI: (Scripted) Set up UAPI Kbuild files 2012-10-02 18:01:35 +01:00