powerpc: Fix DSCR inheritance over fork()
Two DSCR tests have a hack in them:
/*
* XXX: Force a context switch out so that DSCR
* current value is copied into the thread struct
* which is required for the child to inherit the
* changed value.
*/
sleep(1);
We should not be working around this in the testcase, it is a kernel bug.
Fix it by copying the current DSCR to the child, instead of what we
had in the thread struct at last context switch.
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 9da7b5f..6f76f25 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -1287,7 +1287,7 @@
#ifdef CONFIG_PPC64
if (cpu_has_feature(CPU_FTR_DSCR)) {
p->thread.dscr_inherit = current->thread.dscr_inherit;
- p->thread.dscr = current->thread.dscr;
+ p->thread.dscr = mfspr(SPRN_DSCR);
}
if (cpu_has_feature(CPU_FTR_HAS_PPR))
p->thread.ppr = INIT_PPR;
diff --git a/tools/testing/selftests/powerpc/dscr/dscr_inherit_exec_test.c b/tools/testing/selftests/powerpc/dscr/dscr_inherit_exec_test.c
index 8265504..08a8b95 100644
--- a/tools/testing/selftests/powerpc/dscr/dscr_inherit_exec_test.c
+++ b/tools/testing/selftests/powerpc/dscr/dscr_inherit_exec_test.c
@@ -60,14 +60,6 @@
else
set_dscr(dscr);
- /*
- * XXX: Force a context switch out so that DSCR
- * current value is copied into the thread struct
- * which is required for the child to inherit the
- * changed value.
- */
- sleep(1);
-
pid = fork();
if (pid == -1) {
perror("fork() failed");
diff --git a/tools/testing/selftests/powerpc/dscr/dscr_inherit_test.c b/tools/testing/selftests/powerpc/dscr/dscr_inherit_test.c
index 4e414ca..3e5a6d1 100644
--- a/tools/testing/selftests/powerpc/dscr/dscr_inherit_test.c
+++ b/tools/testing/selftests/powerpc/dscr/dscr_inherit_test.c
@@ -40,14 +40,6 @@
else
set_dscr(dscr);
- /*
- * XXX: Force a context switch out so that DSCR
- * current value is copied into the thread struct
- * which is required for the child to inherit the
- * changed value.
- */
- sleep(1);
-
pid = fork();
if (pid == -1) {
perror("fork() failed");