From: Diana Craciun <diana.craciun@nxp.com>
Date: Wed, 12 Dec 2018 14:03:04 +0000 (+0200)
Subject: powerpc/fsl: Add nospectre_v2 command line argument
X-Git-Tag: Ubuntu-4.15.0-49.53~89
X-Git-Url: https://git.proxmox.com/?p=mirror_ubuntu-bionic-kernel.git;a=commitdiff_plain;h=1f3934551ba8c8f87abcaee83f3662e56d8a279f

powerpc/fsl: Add nospectre_v2 command line argument

When the command line argument is present, the Spectre variant 2
mitigations are disabled.

BugLink: https://bugs.launchpad.net/bugs/1822870
Signed-off-by: Diana Craciun <diana.craciun@nxp.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
(backported from commit f633a8ad636efb5d4bba1a047d4a0f1ef719aa06)
Signed-off-by: Manoj Iyer <manoj.iyer@canonical.com>
Acked-by: Stefan Bader <stefan.bader@canonical.com>
Acked-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>
---

diff --git a/arch/powerpc/include/asm/setup.h b/arch/powerpc/include/asm/setup.h
index 0c78fc08f11a..8d36456e1766 100644
--- a/arch/powerpc/include/asm/setup.h
+++ b/arch/powerpc/include/asm/setup.h
@@ -65,6 +65,13 @@ void do_barrier_nospec_fixups_range(bool enable, void *start, void *end);
 static inline void do_barrier_nospec_fixups_range(bool enable, void *start, void *end) { };
 #endif
 
+#ifdef CONFIG_PPC_FSL_BOOK3E
+void setup_spectre_v2(void);
+#else
+static inline void setup_spectre_v2(void) {};
+#endif
+void do_btb_flush_fixups(void);
+
 #endif /* !__ASSEMBLY__ */
 
 #endif	/* _ASM_POWERPC_SETUP_H */
diff --git a/arch/powerpc/kernel/security.c b/arch/powerpc/kernel/security.c
index 1b395b85132b..4393a3834ec7 100644
--- a/arch/powerpc/kernel/security.c
+++ b/arch/powerpc/kernel/security.c
@@ -26,6 +26,10 @@ static enum count_cache_flush_type count_cache_flush_type = COUNT_CACHE_FLUSH_NO
 
 bool barrier_nospec_enabled;
 static bool no_nospec;
+static bool btb_flush_enabled;
+#ifdef CONFIG_PPC_FSL_BOOK3E
+static bool no_spectrev2;
+#endif
 
 static void enable_barrier_nospec(bool enable)
 {
@@ -101,6 +105,23 @@ static __init int barrier_nospec_debugfs_init(void)
 device_initcall(barrier_nospec_debugfs_init);
 #endif /* CONFIG_DEBUG_FS */
 
+#ifdef CONFIG_PPC_FSL_BOOK3E
+static int __init handle_nospectre_v2(char *p)
+{
+	no_spectrev2 = true;
+
+	return 0;
+}
+early_param("nospectre_v2", handle_nospectre_v2);
+void setup_spectre_v2(void)
+{
+	if (no_spectrev2)
+		do_btb_flush_fixups();
+	else
+		btb_flush_enabled = true;
+}
+#endif /* CONFIG_PPC_FSL_BOOK3E */
+
 #ifdef CONFIG_PPC_BOOK3S_64
 ssize_t cpu_show_meltdown(struct device *dev, struct device_attribute *attr, char *buf)
 {