tile: don't assume user privilege is zero

Technically, user privilege is anything less than kernel
privilege.  We modify the existing user_mode() macro to have
this semantic (and use it in a couple of places it wasn't being
used before), and add an IS_KERNEL_EX1() macro to the assembly
code as well.

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

5 files changed, 23 insertions, 12 deletions

diff --git a/arch/tile/include/asm/processor.h b/arch/tile/include/asm/processor.h
index 230b830e94d4..c72fcba7016a 100644
--- a/arch/tile/include/asm/processor.h
+++ b/arch/tile/include/asm/processor.h
@@ -15,6 +15,8 @@
 #ifndef _ASM_TILE_PROCESSOR_H
 #define _ASM_TILE_PROCESSOR_H
 
+#include <arch/chip.h>
+
 #ifndef __ASSEMBLY__
 
 /*
@@ -25,7 +27,6 @@
 #include <asm/ptrace.h>
 #include <asm/percpu.h>
 
-#include <arch/chip.h>
 #include <arch/spr_def.h>
 
 struct task_struct;
@@ -347,7 +348,6 @@ extern int kdata_huge;
 
 /*
  * Provide symbolic constants for PLs.
- * Note that assembly code assumes that USER_PL is zero.
  */
 #define USER_PL 0
 #if CONFIG_KERNEL_PL == 2
diff --git a/arch/tile/include/asm/ptrace.h b/arch/tile/include/asm/ptrace.h
index 0d25c21bcd61..b9620c077abc 100644
--- a/arch/tile/include/asm/ptrace.h
+++ b/arch/tile/include/asm/ptrace.h
@@ -39,7 +39,7 @@ typedef unsigned long pt_reg_t;
 #define user_stack_pointer(regs) ((regs)->sp)
 
 /* Does the process account for user or for system time? */
-#define user_mode(regs) (EX1_PL((regs)->ex1) == USER_PL)
+#define user_mode(regs) (EX1_PL((regs)->ex1) < KERNEL_PL)
 
 /* Fill in a struct pt_regs with the current kernel registers. */
 struct pt_regs *get_pt_regs(struct pt_regs *);
diff --git a/arch/tile/kernel/intvec_64.S b/arch/tile/kernel/intvec_64.S
index 3b35bb490d3e..f020f01960cf 100644
--- a/arch/tile/kernel/intvec_64.S
+++ b/arch/tile/kernel/intvec_64.S
@@ -34,6 +34,16 @@
 
 #define PTREGS_OFFSET_SYSCALL PTREGS_OFFSET_REG(TREG_SYSCALL_NR)
 
+#if CONFIG_KERNEL_PL == 1 || CONFIG_KERNEL_PL == 2
+/*
+ * Set "result" non-zero if ex1 holds the PL of the kernel
+ * (with or without ICS being set).  Note this works only
+ * because we never find the PL at level 3.
+ */
+# define IS_KERNEL_EX1(result, ex1) andi result, ex1, CONFIG_KERNEL_PL
+#else
+# error Recode IS_KERNEL_EX1 for CONFIG_KERNEL_PL
+#endif
 
         .macro  push_reg reg, ptr=sp, delta=-8
         {
@@ -308,7 +318,7 @@ intvec_\vecname:
          */
         {
          blbs   sp, 2f
-         andi   r0, r0, SPR_EX_CONTEXT_1_1__PL_MASK  /* mask off ICS */
+         IS_KERNEL_EX1(r0, r0)
         }
 
         .ifc    \vecnum, INT_DOUBLE_FAULT
@@ -641,11 +651,12 @@ intvec_\vecname:
         /*
          * If we will be returning to the kernel, we will need to
          * reset the interrupt masks to the state they had before.
-         * Set DISABLE_IRQ in flags iff we came from PL1 with irqs disabled.
+         * Set DISABLE_IRQ in flags iff we came from kernel pl with
+         * irqs disabled.
          */
         mfspr   r32, SPR_EX_CONTEXT_K_1
         {
-         andi   r32, r32, SPR_EX_CONTEXT_1_1__PL_MASK  /* mask off ICS */
+         IS_KERNEL_EX1(r22, r22)
          PTREGS_PTR(r21, PTREGS_OFFSET_FLAGS)
         }
         beqzt   r32, 1f       /* zero if from user space */
@@ -812,7 +823,7 @@ STD_ENTRY(interrupt_return)
          PTREGS_PTR(r29, PTREGS_OFFSET_EX1)
         }
         ld      r29, r29
-        andi    r29, r29, SPR_EX_CONTEXT_1_1__PL_MASK  /* mask off ICS */
+        IS_KERNEL_EX1(r29, r29)
         {
          beqzt  r29, .Lresume_userspace
          move   r29, sp
@@ -936,7 +947,7 @@ STD_ENTRY(interrupt_return)
          PTREGS_PTR(r32, PTREGS_OFFSET_FLAGS)
         }
         {
-         andi   r0, r0, SPR_EX_CONTEXT_1_1__PL_MASK
+         IS_KERNEL_EX1(r0, r0)
          ld     r32, r32
         }
         bnez    r0, 1f
@@ -1007,7 +1018,7 @@ STD_ENTRY(interrupt_return)
         pop_reg r21, sp, PTREGS_OFFSET_REG(31) - PTREGS_OFFSET_PC
         {
          mtspr  SPR_EX_CONTEXT_K_1, lr
-         andi   lr, lr, SPR_EX_CONTEXT_1_1__PL_MASK  /* mask off ICS */
+         IS_KERNEL_EX1(lr, lr)
         }
         {
          mtspr  SPR_EX_CONTEXT_K_0, r21
diff --git a/arch/tile/kernel/stack.c b/arch/tile/kernel/stack.c
index 24fd223df65d..362284af3afd 100644
--- a/arch/tile/kernel/stack.c
+++ b/arch/tile/kernel/stack.c
@@ -103,7 +103,7 @@ static struct pt_regs *valid_fault_handler(struct KBacktraceIterator* kbt)
             p->sp >= sp) {
                 if (kbt->verbose)
                         pr_err("  <%s while in kernel mode>\n", fault);
-        } else if (EX1_PL(p->ex1) == USER_PL &&
+        } else if (user_mode(p) &&
                    p->sp < PAGE_OFFSET && p->sp != 0) {
                 if (kbt->verbose)
                         pr_err("  <%s while in user mode>\n", fault);
diff --git a/arch/tile/mm/fault.c b/arch/tile/mm/fault.c
index 64eec3f9584f..39c48cbe0a96 100644
--- a/arch/tile/mm/fault.c
+++ b/arch/tile/mm/fault.c
@@ -283,7 +283,7 @@ static int handle_page_fault(struct pt_regs *regs,
         flags = (FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE |
                  (write ? FAULT_FLAG_WRITE : 0));
 
-        is_kernel_mode = (EX1_PL(regs->ex1) != USER_PL);
+        is_kernel_mode = !user_mode(regs);
 
         tsk = validate_current();
 
@@ -824,7 +824,7 @@ void do_page_fault(struct pt_regs *regs, int fault_num,
         }
 
 #if CHIP_HAS_TILE_DMA() || CHIP_HAS_SN_PROC()
-        if (EX1_PL(regs->ex1) != USER_PL) {
+        if (!user_mode(regs)) {
                 struct async_tlb *async;
                 switch (fault_num) {
 #if CHIP_HAS_TILE_DMA()