arch/tile: parameterize system PLs to support KVM port

While not a port to KVM (yet), this change modifies the kernel
to be able to build either at PL1 or at PL2 with a suitable
config switch.  Pushing up this change avoids handling branch
merge issues going forward with the KVM work.

Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>

1 files changed, 11 insertions, 1 deletions

diff --git a/arch/tile/kernel/process.c b/arch/tile/kernel/process.c
index 221f12bd27fa..8430f45daea6 100644
--- a/arch/tile/kernel/process.c
+++ b/arch/tile/kernel/process.c
@@ -305,15 +305,25 @@ int dump_task_regs(struct task_struct *tsk, elf_gregset_t *regs)
 /* Allow user processes to access the DMA SPRs */
 void grant_dma_mpls(void)
 {
+#if CONFIG_KERNEL_PL == 2
+        __insn_mtspr(SPR_MPL_DMA_CPL_SET_1, 1);
+        __insn_mtspr(SPR_MPL_DMA_NOTIFY_SET_1, 1);
+#else
         __insn_mtspr(SPR_MPL_DMA_CPL_SET_0, 1);
         __insn_mtspr(SPR_MPL_DMA_NOTIFY_SET_0, 1);
+#endif
 }
 
 /* Forbid user processes from accessing the DMA SPRs */
 void restrict_dma_mpls(void)
 {
+#if CONFIG_KERNEL_PL == 2
+        __insn_mtspr(SPR_MPL_DMA_CPL_SET_2, 1);
+        __insn_mtspr(SPR_MPL_DMA_NOTIFY_SET_2, 1);
+#else
         __insn_mtspr(SPR_MPL_DMA_CPL_SET_1, 1);
         __insn_mtspr(SPR_MPL_DMA_NOTIFY_SET_1, 1);
+#endif
 }
 
 /* Pause the DMA engine, then save off its state registers. */
@@ -524,7 +534,7 @@ struct task_struct *__sched _switch_to(struct task_struct *prev,
          * Switch kernel SP, PC, and callee-saved registers.
          * In the context of the new task, return the old task pointer
          * (i.e. the task that actually called __switch_to).
-         * Pass the value to use for SYSTEM_SAVE_1_0 when we reset our sp.
+         * Pass the value to use for SYSTEM_SAVE_K_0 when we reset our sp.
          */
         return __switch_to(prev, next, next_current_ksp0(next));
 }