linux-kernel - [PATCH 10/11] powerpc/pseries: Query hypervisor for RFI flush settings

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Message-Id: <20180108165453.26066-10-mpe@ellerman.id.au>
Date:   Tue,  9 Jan 2018 03:54:52 +1100
From:   Michael Ellerman <mpe@...erman.id.au>
To:     linuxppc-dev@...abs.org
Cc:     linux-kernel@...r.kernel.org, tglx@...utronix.de,
        peterz@...radead.org, npiggin@...il.com, anton@...ba.org,
        mikey@...ling.org, oohall@...il.com, paulus@...ba.org
Subject: [PATCH 10/11] powerpc/pseries: Query hypervisor for RFI flush settings

From: Michael Neuling <mikey@...ling.org>

A new hypervisor call is available which tells the guest settings
related to the RFI flush. Use it to query the appropriate flush
instruction(s), and whether the flush is required.

Signed-off-by: Michael Neuling <mikey@...ling.org>
Signed-off-by: Michael Ellerman <mpe@...erman.id.au>
---
 arch/powerpc/platforms/pseries/setup.c | 35 ++++++++++++++++++++++++++++++++++
 1 file changed, 35 insertions(+)

diff --git a/arch/powerpc/platforms/pseries/setup.c b/arch/powerpc/platforms/pseries/setup.c
index 28b286df0e91..db76963e693d 100644
--- a/arch/powerpc/platforms/pseries/setup.c
+++ b/arch/powerpc/platforms/pseries/setup.c
@@ -459,6 +459,39 @@ static void __init find_and_init_phbs(void)
 	of_pci_check_probe_only();
 }
 
+static void pseries_setup_rfi_flush(void)
+{
+	struct h_cpu_char_result result;
+	enum l1d_flush_type types;
+	bool enable;
+	long rc;
+
+	/* Enable by default */
+	enable = true;
+
+	rc = plpar_get_cpu_characteristics(&result);
+	if (rc == H_SUCCESS) {
+		types = L1D_FLUSH_NONE;
+
+		if (result.character & H_CPU_CHAR_L1D_FLUSH_TRIG2)
+			types |= L1D_FLUSH_MTTRIG;
+		if (result.character & H_CPU_CHAR_L1D_FLUSH_ORI30)
+			types |= L1D_FLUSH_ORI;
+
+		/* Use fallback if nothing set in hcall */
+		if (types == L1D_FLUSH_NONE)
+			types = L1D_FLUSH_FALLBACK;
+
+		if (!(result.behaviour & H_CPU_BEHAV_L1D_FLUSH_PR))
+			enable = false;
+	} else {
+		/* Default to fallback if case hcall is not available */
+		types = L1D_FLUSH_FALLBACK;
+	}
+
+	setup_rfi_flush(types, enable);
+}
+
 static void __init pSeries_setup_arch(void)
 {
 	set_arch_panic_timeout(10, ARCH_PANIC_TIMEOUT);
@@ -476,6 +509,8 @@ static void __init pSeries_setup_arch(void)
 
 	fwnmi_init();
 
+	pseries_setup_rfi_flush();
+
 	/* By default, only probe PCI (can be overridden by rtas_pci) */
 	pci_add_flags(PCI_PROBE_ONLY);
 
-- 
2.14.3