linux-kernel - [PATCH RFC rebase 8/9] powerpc/64s: barrier

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Date:   Thu, 15 Mar 2018 20:15:57 +0100
From:   Michal Suchanek <msuchanek@...e.de>
To:     linuxppc-dev@...ts.ozlabs.org
Cc:     Kate Stewart <kstewart@...uxfoundation.org>,
        Madhavan Srinivasan <maddy@...ux.vnet.ibm.com>,
        Paul Mackerras <paulus@...ba.org>,
        Michael Neuling <mikey@...ling.org>,
        "Bryant G. Ly" <bryantly@...ux.vnet.ibm.com>,
        Mahesh Salgaonkar <mahesh@...ux.vnet.ibm.com>,
        "Naveen N. Rao" <naveen.n.rao@...ux.vnet.ibm.com>,
        Daniel Axtens <dja@...ens.net>,
        Nicholas Piggin <npiggin@...il.com>,
        Al Viro <viro@...iv.linux.org.uk>,
        David Gibson <david@...son.dropbear.id.au>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        linux-kernel@...r.kernel.org,
        Sergey Senozhatsky <sergey.senozhatsky@...il.com>,
        Cédric Le Goater <clg@...d.org>,
        Masami Hiramatsu <mhiramat@...nel.org>,
        Andrew Donnellan <andrew.donnellan@....ibm.com>,
        Philippe Ombredanne <pombredanne@...b.com>,
        Joe Perches <joe@...ches.com>,
        Oliver O'Halloran <oohall@...il.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        "Tobin C. Harding" <me@...in.cc>,
        Michal Suchanek <msuchanek@...e.de>
Subject: [PATCH RFC rebase 8/9] powerpc/64s: barrier_nospec: Add hcall triggerr

Adapted from the RFI implementation

Signed-off-by: Michal Suchanek <msuchanek@...e.de>
---
 arch/powerpc/platforms/pseries/mobility.c |  2 +-
 arch/powerpc/platforms/pseries/pseries.h  |  2 +-
 arch/powerpc/platforms/pseries/setup.c    | 37 ++++++++++++++++++++++---------
 3 files changed, 29 insertions(+), 12 deletions(-)

diff --git a/arch/powerpc/platforms/pseries/mobility.c b/arch/powerpc/platforms/pseries/mobility.c
index 8a8033a249c7..9d506be1580e 100644
--- a/arch/powerpc/platforms/pseries/mobility.c
+++ b/arch/powerpc/platforms/pseries/mobility.c
@@ -349,7 +349,7 @@ void post_mobility_fixup(void)
 			"failed: %d\n", rc);
 
 	/* Possibly switch to a new RFI flush type */
-	pseries_setup_rfi_flush();
+	pseries_setup_rfi_nospec();
 
 	return;
 }
diff --git a/arch/powerpc/platforms/pseries/pseries.h b/arch/powerpc/platforms/pseries/pseries.h
index 27cdcb69fd18..d49670c67686 100644
--- a/arch/powerpc/platforms/pseries/pseries.h
+++ b/arch/powerpc/platforms/pseries/pseries.h
@@ -100,6 +100,6 @@ static inline unsigned long cmo_get_page_size(void)
 
 int dlpar_workqueue_init(void);
 
-void pseries_setup_rfi_flush(void);
+void pseries_setup_rfi_nospec(void);
 
 #endif /* _PSERIES_PSERIES_H */
diff --git a/arch/powerpc/platforms/pseries/setup.c b/arch/powerpc/platforms/pseries/setup.c
index 9877c3dfcdc8..4b899a4db6dd 100644
--- a/arch/powerpc/platforms/pseries/setup.c
+++ b/arch/powerpc/platforms/pseries/setup.c
@@ -459,30 +459,47 @@ static void __init find_and_init_phbs(void)
 	of_pci_check_probe_only();
 }
 
-void pseries_setup_rfi_flush(void)
+void pseries_setup_rfi_nospec(void)
 {
 	struct h_cpu_char_result result;
-	enum l1d_flush_type types;
-	bool enable;
+	enum l1d_flush_type flush_types;
+	enum spec_barrier_type barrier_type;
+	bool flush_enable;
+	bool barrier_enable;
 	long rc;
 
 	/* Enable by default */
-	enable = true;
-	types = L1D_FLUSH_FALLBACK;
+	flush_enable = true;
+	flush_types = L1D_FLUSH_FALLBACK;
+	barrier_enable = true;
+	/* no fallback available if the firmware does not tell us */
+	barrier_type = SPEC_BARRIER_NONE;
 
 	rc = plpar_get_cpu_characteristics(&result);
 	if (rc == H_SUCCESS) {
 		if (result.character & H_CPU_CHAR_L1D_FLUSH_TRIG2)
-			types |= L1D_FLUSH_MTTRIG;
+			flush_types |= L1D_FLUSH_MTTRIG;
 		if (result.character & H_CPU_CHAR_L1D_FLUSH_ORI30)
-			types |= L1D_FLUSH_ORI;
+			flush_types |= L1D_FLUSH_ORI;
+		if (result.character & H_CPU_CHAR_SPEC_BAR_ORI31)
+			barrier_type |= SPEC_BARRIER_ORI;
 
 		if ((!(result.behaviour & H_CPU_BEHAV_L1D_FLUSH_PR)) ||
 		    (!(result.behaviour & H_CPU_BEHAV_FAVOUR_SECURITY)))
-			enable = false;
+			flush_enable = false;
+		/*
+		 * Do not check H_CPU_BEHAV_BNDS_CHK_SPEC_BAR - the ORI does
+		 * nothing anyway when not supported.
+		 */
+		if ((!(result.behaviour & H_CPU_BEHAV_FAVOUR_SECURITY)))
+			barrier_enable = false;
+	} else {
+		/* Default to fallback if case hcall is not available */
+		flush_types = L1D_FLUSH_FALLBACK;
 	}
 
-	setup_rfi_flush(types, enable);
+	setup_barrier_nospec(barrier_type, barrier_enable);
+	setup_rfi_flush(flush_types, flush_enable);
 }
 
 #ifdef CONFIG_PCI_IOV
@@ -658,7 +675,7 @@ static void __init pSeries_setup_arch(void)
 
 	fwnmi_init();
 
-	pseries_setup_rfi_flush();
+	pseries_setup_rfi_nospec();
 
 	/* By default, only probe PCI (can be overridden by rtas_pci) */
 	pci_add_flags(PCI_PROBE_ONLY);
-- 
2.13.6