Hi,
On 25/08/2020 11:08, Wei Chen wrote:
Arm ID_AA64PFR0_EL1 register provides two fields to describe CPU
FP/SIMD implementations. Currently, we exactly know the meaning of
0x0, 0x1 and 0xf of these fields. Xen treats value < 8 as FP/SIMD
features presented. If there is a value 0x2 bumped in the future,
Xen behaviors for value <= 0x1 can also take effect. But what Xen
done for value <= 0x1 may not always cover new value 0x2 required.
We throw these messages to break the silence when Xen detected
unknown FP/SIMD IDs to notice user to check.
Signed-off-by: Wei Chen <wei.c...@arm.com>
Reviewed-by: Bertrand Marquis <bertrand.marq...@arm.com>
OOI, is this reviewed-by coming from internal review?
---
xen/arch/arm/setup.c | 12 ++++++++++++
xen/include/asm-arm/cpufeature.h | 2 ++
2 files changed, 14 insertions(+)
diff --git a/xen/arch/arm/setup.c b/xen/arch/arm/setup.c
index 7968cee47d..ef39ce1ec6 100644
--- a/xen/arch/arm/setup.c
+++ b/xen/arch/arm/setup.c
@@ -133,6 +133,18 @@ static void __init processor_id(void)
cpu_has_simd ? " AdvancedSIMD" : "",
cpu_has_gicv3 ? " GICv3-SysReg" : "");
+ /* Warn user if we find unknown floating-point features */
+ if ( cpu_has_unknown_fp )
+ printk(XENLOG_WARNING "WARNING: Unknown Floating-point ID:%d, "
+ "this may result to corruption on the platform\n",
+ boot_cpu_feature64(fp));
+
+ /* Warn user if we find unknown AdvancedSIMD features */
+ if ( cpu_has_unknown_simd )
+ printk(XENLOG_WARNING "WARNING: Unknown AdvancedSIMD ID:%d, "
+ "this may result to corruption on the platform\n",
+ boot_cpu_feature64(simd));
+
printk(" Debug Features: %016"PRIx64" %016"PRIx64"\n",
boot_cpu_data.dbg64.bits[0], boot_cpu_data.dbg64.bits[1]);
printk(" Auxiliary Features: %016"PRIx64" %016"PRIx64"\n",
diff --git a/xen/include/asm-arm/cpufeature.h b/xen/include/asm-arm/cpufeature.h
index 10878ead8a..a32309986e 100644
--- a/xen/include/asm-arm/cpufeature.h
+++ b/xen/include/asm-arm/cpufeature.h
@@ -16,6 +16,8 @@
#define cpu_has_fp (boot_cpu_feature64(fp) < 8)
#define cpu_has_simd (boot_cpu_feature64(simd) < 8)
#define cpu_has_gicv3 (boot_cpu_feature64(gic) == 1)
+#define cpu_has_unknown_fp (cpu_has_fp && (boot_cpu_feature64(fp) >= 2))
+#define cpu_has_unknown_simd (cpu_has_simd && (boot_cpu_feature64(simd) >= 2))
I would rather prefer if we don't introduce cpu_has_unknown_{fp, simd}
but open-code directly in the 'if'.
Other than that the code looks ok to me.
Cheers,
--
Julien Grall
