git: db79bf75ac9e - main - powerpc: cpuset: add local functions for copyin/copyout

The branch main has been updated by alfredo:

URL: https://cgit.FreeBSD.org/src/commit/?id=db79bf75ac9eb1b5678ccbaebb45fb88c0e0e1e3

commit db79bf75ac9eb1b5678ccbaebb45fb88c0e0e1e3
Author:     Alfredo Dal'Ava Junior <alfredo@FreeBSD.org>
AuthorDate: 2022-10-03 14:51:05 +0000
Commit:     Alfredo Dal'Ava Junior <alfredo@FreeBSD.org>
CommitDate: 2022-10-03 15:03:09 +0000

    powerpc: cpuset: add local functions for copyin/copyout
    
    Add local functions to workaround an instruction segment trap (panic)
    when the indirect functions copyin and copyout are called by an external
    loadable kernel module (i.e. pfsync, zfs and linuxulator). The crash
    was triggered by change 47a57144af25a7bd768b29272d50a36fdf2874ba, but
    kernel binary linked with LLD 9 works fine. LLVM bisect points that LLD
    behavior chaged after dc06b0bc9ad055d06535462d91bfc2a744b2f589.
    
    This is know to affect powerpc targets only and the final fix is still
    being discussed with the LLVM community.
    
    PR:     266730
    Reviewed by:    luporl, jhibbits (on IRC, previous version)
    MFC after:      2 days
    Sponsored by:   Instituto de Pesquisas Eldorado (eldorado.org.br)
    Differential Revision:  https://reviews.freebsd.org/D36234
---
 sys/kern/kern_cpuset.c | 36 ++++++++++++++++++++++++++++++++++--
 1 file changed, 34 insertions(+), 2 deletions(-)

diff --git a/sys/kern/kern_cpuset.c b/sys/kern/kern_cpuset.c
index ed0a666c460c..d89be2805759 100644
--- a/sys/kern/kern_cpuset.c
+++ b/sys/kern/kern_cpuset.c
@@ -1743,10 +1743,42 @@ cpuset_check_capabilities(struct thread *td, cpulevel_t level, cpuwhich_t which,
 	return (0);
 }
 
+#if defined(__powerpc__)
+/*
+ * TODO: At least powerpc64 and powerpc64le kernels panic with
+ * exception 0x480 (instruction segment exception) when copyin/copyout,
+ * are set as a function pointer in cpuset_copy_cb struct and called by
+ * an external module (like pfsync). Tip: copyin/copyout have an ifunc
+ * resolver function.
+ *
+ * Bisect of LLVM shows that the behavior changed on LLVM 10.0 with
+ * https://reviews.llvm.org/rGdc06b0bc9ad055d06535462d91bfc2a744b2f589
+ *
+ * This is a hack/workaround while problem is being discussed with LLVM
+ * community
+ */
+static int
+cpuset_copyin(const void *uaddr, void *kaddr, size_t len)
+{
+	return(copyin(uaddr, kaddr, len));
+}
+
+static int
+cpuset_copyout(const void *kaddr, void *uaddr, size_t len)
+{
+	return(copyout(kaddr, uaddr, len));
+}
+
 static const struct cpuset_copy_cb copy_set = {
-	.cpuset_copyin = copyin,
-	.cpuset_copyout = copyout
+	.cpuset_copyin = cpuset_copyin,
+	.cpuset_copyout = cpuset_copyout
 };
+#else
+static const struct cpuset_copy_cb copy_set = {
+        .cpuset_copyin = copyin,
+        .cpuset_copyout = copyout
+};
+#endif
 
 #ifndef _SYS_SYSPROTO_H_
 struct cpuset_args {