The branch main has been updated by kevans:
URL:
https://cgit.FreeBSD.org/src/commit/?id=ce5a210997da3c4064cfe162e760379f1fa8b587
commit ce5a210997da3c4064cfe162e760379f1fa8b587
Author: Kyle Evans <kev...@freebsd.org>
AuthorDate: 2023-04-26 17:23:48 +0000
Commit: Kyle Evans <kev...@freebsd.org>
CommitDate: 2023-04-26 17:24:00 +0000
openzfs: arm64: implement kfpu_begin/kfpu_end
This is part one of a fix for booting with ZFS on arm64 using
accelerated checksum implementations. Checksum benchmarking will
attempt to use the FPU, so we currently panic quickly on boot. BLAKE3
is still broken, as it clobbers x18 and we promptly discover that fact
as soon as we attempt to fetch curthread in kfpu_end().
Note that _STANDALONE is special-cased here, but ideally we wouldn't be
building the code that uses kfpu_begin()/kfpu_end() at all in the loader
environment.
Discussed with: imp (a bit)
Differential Revision: https://reviews.freebsd.org/D39448
---
.../include/os/freebsd/spl/sys/simd_aarch64.h | 28 +++++++++++++++++++++-
1 file changed, 27 insertions(+), 1 deletion(-)
diff --git a/sys/contrib/openzfs/include/os/freebsd/spl/sys/simd_aarch64.h
b/sys/contrib/openzfs/include/os/freebsd/spl/sys/simd_aarch64.h
index 7d2e2db28017..9edbc5f40455 100644
--- a/sys/contrib/openzfs/include/os/freebsd/spl/sys/simd_aarch64.h
+++ b/sys/contrib/openzfs/include/os/freebsd/spl/sys/simd_aarch64.h
@@ -44,13 +44,39 @@
#define _FREEBSD_SIMD_AARCH64_H
#include <sys/types.h>
+#include <sys/ucontext.h>
#include <machine/elf.h>
+#include <machine/fpu.h>
#include <machine/md_var.h>
+#include <machine/pcb.h>
+
+#ifdef _STANDALONE
#define kfpu_allowed() 0
-#define kfpu_initialize(tsk) do {} while (0)
#define kfpu_begin() do {} while (0)
#define kfpu_end() do {} while (0)
+
+#else
+
+/*
+ * XXX kfpu_allowed() should be 1, but this is pending a fix to the BLAKE3
+ * generated assembly to avoid clobbering x18. Turn it back on after that
+ * lands.
+ */
+#define kfpu_allowed() 0
+#define kfpu_begin() do {
\
+ if (__predict_false(!is_fpu_kern_thread(0))) \
+ fpu_kern_enter(curthread, NULL, FPU_KERN_NOCTX); \
+} while(0)
+
+#define kfpu_end() do {
\
+ if (__predict_false(curthread->td_pcb->pcb_fpflags & PCB_FP_NOSAVE))
\
+ fpu_kern_leave(curthread, NULL); \
+} while(0)
+
+#endif
+
+#define kfpu_initialize(tsk) do {} while (0)
#define kfpu_init() (0)
#define kfpu_fini() do {} while (0)
