powerpc/64: Disable the speculation barrier from the command line

commit cf175dc315f90185128fb061dc05b6fbb211aa2f upstream.

The speculation barrier can be disabled from the command line
with the parameter: "nospectre_v1".

Signed-off-by: Diana Craciun <diana.craciun@nxp.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/arch/powerpc/kernel/security.c b/arch/powerpc/kernel/security.c
index bf298d0c475fa4785d568f0db249258ec49841ab..813e38ff81cec62bd14e359cb58a9d958aa2c813 100644 (file)
--- a/arch/powerpc/kernel/security.c
+++ b/arch/powerpc/kernel/security.c
@@ -17,6 +17,7 @@
 unsigned long powerpc_security_features __read_mostly = SEC_FTR_DEFAULT;
 
 bool barrier_nospec_enabled;
+static bool no_nospec;
 
 static void enable_barrier_nospec(bool enable)
 {
@@ -43,9 +44,18 @@ void setup_barrier_nospec(void)
        enable = security_ftr_enabled(SEC_FTR_FAVOUR_SECURITY) &&
                 security_ftr_enabled(SEC_FTR_BNDS_CHK_SPEC_BAR);
 
-       enable_barrier_nospec(enable);
+       if (!no_nospec)
+               enable_barrier_nospec(enable);
 }
 
+static int __init handle_nospectre_v1(char *p)
+{
+       no_nospec = true;
+
+       return 0;
+}
+early_param("nospectre_v1", handle_nospectre_v1);
+
 #ifdef CONFIG_DEBUG_FS
 static int barrier_nospec_set(void *data, u64 val)
 {