powerpc: Put exception configuration in a common place

The various calls to establish exception endianness and AIL are
now done from a single point using already established CPU and FW
feature bits to decide what to do.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

1 files changed, 42 insertions, 14 deletions

diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c
index 155dbcce8ef8..4ffd090633de 100644
--- a/arch/powerpc/kernel/setup_64.c
+++ b/arch/powerpc/kernel/setup_64.c
@@ -69,6 +69,7 @@
 #include <asm/kvm_ppc.h>
 #include <asm/hugetlb.h>
 #include <asm/livepatch.h>
+#include <asm/opal.h>
 
 #ifdef DEBUG
 #define DBG(fmt...) udbg_printf(fmt)
@@ -205,23 +206,50 @@ static void fixup_boot_paca(void)
         get_paca()->data_offset = 0;
 }
 
-static void cpu_ready_for_interrupts(void)
+static void configure_exceptions(void)
 {
-        /* Set IR and DR in PACA MSR */
-        get_paca()->kernel_msr = MSR_KERNEL;
-
         /*
-         * Enable AIL if supported, and we are in hypervisor mode. If we are
-         * not in hypervisor mode, we enable relocation-on interrupts later
-         * in pSeries_setup_arch() using the H_SET_MODE hcall.
+         * Setup the trampolines from the lowmem exception vectors
+         * to the kdump kernel when not using a relocatable kernel.
          */
-        if (cpu_has_feature(CPU_FTR_HVMODE) &&
-            cpu_has_feature(CPU_FTR_ARCH_207S)) {
-                unsigned long lpcr = mfspr(SPRN_LPCR);
-                mtspr(SPRN_LPCR, lpcr | LPCR_AIL_3);
+        setup_kdump_trampoline();
+
+        /* Under a PAPR hypervisor, we need hypercalls */
+        if (firmware_has_feature(FW_FEATURE_SET_MODE)) {
+                /* Enable AIL if possible */
+                pseries_enable_reloc_on_exc();
+
+                /*
+                 * Tell the hypervisor that we want our exceptions to
+                 * be taken in little endian mode.
+                 *
+                 * We don't call this for big endian as our calling convention
+                 * makes us always enter in BE, and the call may fail under
+                 * some circumstances with kdump.
+                 */
+#ifdef __LITTLE_ENDIAN__
+                pseries_little_endian_exceptions();
+#endif
+        } else {
+                /* Set endian mode using OPAL */
+                if (firmware_has_feature(FW_FEATURE_OPAL))
+                        opal_configure_cores();
+
+                /* Enable AIL if supported, and we are in hypervisor mode */
+                if (cpu_has_feature(CPU_FTR_HVMODE) &&
+                    cpu_has_feature(CPU_FTR_ARCH_207S)) {
+                        unsigned long lpcr = mfspr(SPRN_LPCR);
+                        mtspr(SPRN_LPCR, lpcr | LPCR_AIL_3);
+                }
         }
 }
 
+static void cpu_ready_for_interrupts(void)
+{
+        /* Set IR and DR in PACA MSR */
+        get_paca()->kernel_msr = MSR_KERNEL;
+}
+
 /*
  * Early initialization entry point. This is called by head.S
  * with MMU translation disabled. We rely on the "feature" of
@@ -277,10 +305,10 @@ void __init early_setup(unsigned long dt_ptr)
         probe_machine();
 
         /*
-         * Setup the trampolines from the lowmem exception vectors
-         * to the kdump kernel when not using a relocatable kernel.
+         * Configure exception handlers. This include setting up trampolines
+         * if needed, setting exception endian mode, etc...
          */
-        setup_kdump_trampoline();
+        configure_exceptions();
 
         /* Initialize the hash table or TLB handling */
         early_init_mmu();