Re: [PATCH 3/3] kselftest/arm64: Add lsfe to the hwcaps test

[Ben Horgan]

Hi Mark,

On 6/27/25 18:20, Mark Brown wrote:

This feature has no traps associated with it so the SIGILL is not reliable.

Signed-off-by: Mark Brown <broo...@kernel.org>
---
  tools/testing/selftests/arm64/abi/hwcap.c | 21 +++++++++++++++++++++
  1 file changed, 21 insertions(+)

diff --git a/tools/testing/selftests/arm64/abi/hwcap.c 
b/tools/testing/selftests/arm64/abi/hwcap.c
index 35f521e5f41c..9dfca2eb7c41 100644
--- a/tools/testing/selftests/arm64/abi/hwcap.c
+++ b/tools/testing/selftests/arm64/abi/hwcap.c
@@ -17,6 +17,8 @@
  #include <asm/sigcontext.h>
  #include <asm/unistd.h>

+#include <linux/auxvec.h>

+
  #include "../../kselftest.h"

#define TESTS_PER_HWCAP 3

@@ -165,6 +167,18 @@ static void lse128_sigill(void)
                     : "cc", "memory");
  }

+static void lsfe_sigill(void)

+{
+       float __attribute__ ((aligned (16))) mem = 0;
+       register float *memp asm ("x0") = &mem;
+
+       /* LDFADD H0, H0, [X0] */
+       asm volatile(".inst 0x7c600000"

Same effect, but isn't this the release variant, LDFADDL?

+                    : "+r" (memp)
+                    :
+                    : "cc", "memory");
+}
+
  static void lut_sigill(void)
  {
        /* LUTI2 V0.16B, { V0.16B }, V[0] */
@@ -758,6 +772,13 @@ static const struct hwcap_data {
                .cpuinfo = "lse128",
                .sigill_fn = lse128_sigill,
        },
+       {
+               .name = "LSFE",
+               .at_hwcap = AT_HWCAP3,
+               .hwcap_bit = HWCAP3_LSFE,
+               .cpuinfo = "lsfe",
+               .sigill_fn = lsfe_sigill,
+       },
        {
                .name = "LUT",
                .at_hwcap = AT_HWCAP2,

Thanks,

Ben