powerpc/pseries: Query hypervisor for RFI flush settings

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@neuling.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

1 files changed, 35 insertions, 0 deletions

diff --git a/arch/powerpc/platforms/pseries/setup.c b/arch/powerpc/platforms/pseries/setup.c
index a8531e012658..ae4f596273b5 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);