ARM: 7862/1: pcpu: replace __get_cpu_var_uses

This is the ARM part of Christoph's patchset cleaning up the various
uses of __get_cpu_var across the tree.

The idea is to convert __get_cpu_var into either an explicit address
calculation using this_cpu_ptr() or into a use of this_cpu operations
that use the offset. Thereby address calculations are avoided and fewer
registers are used when code is generated.

[will: fixed debug ref counting checks and pcpu array accesses]

Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

3 files changed, 19 insertions, 20 deletions

diff --git a/arch/arm64/kernel/debug-monitors.c b/arch/arm64/kernel/debug-monitors.c
index cbfacf7fb438..6a0a9b132d7a 100644
--- a/arch/arm64/kernel/debug-monitors.c
+++ b/arch/arm64/kernel/debug-monitors.c
@@ -27,7 +27,6 @@
 #include <linux/uaccess.h>
 
 #include <asm/debug-monitors.h>
-#include <asm/local.h>
 #include <asm/cputype.h>
 #include <asm/system_misc.h>
 
@@ -89,8 +88,8 @@ early_param("nodebugmon", early_debug_disable);
  * Keep track of debug users on each core.
  * The ref counts are per-cpu so we use a local_t type.
  */
-static DEFINE_PER_CPU(local_t, mde_ref_count);
-static DEFINE_PER_CPU(local_t, kde_ref_count);
+static DEFINE_PER_CPU(int, mde_ref_count);
+static DEFINE_PER_CPU(int, kde_ref_count);
 
 void enable_debug_monitors(enum debug_el el)
 {
@@ -98,11 +97,11 @@ void enable_debug_monitors(enum debug_el el)
 
         WARN_ON(preemptible());
 
-        if (local_inc_return(&__get_cpu_var(mde_ref_count)) == 1)
+        if (this_cpu_inc_return(mde_ref_count) == 1)
                 enable = DBG_MDSCR_MDE;
 
         if (el == DBG_ACTIVE_EL1 &&
-            local_inc_return(&__get_cpu_var(kde_ref_count)) == 1)
+            this_cpu_inc_return(kde_ref_count) == 1)
                 enable |= DBG_MDSCR_KDE;
 
         if (enable && debug_enabled) {
@@ -118,11 +117,11 @@ void disable_debug_monitors(enum debug_el el)
 
         WARN_ON(preemptible());
 
-        if (local_dec_and_test(&__get_cpu_var(mde_ref_count)))
+        if (this_cpu_dec_return(mde_ref_count) == 0)
                 disable = ~DBG_MDSCR_MDE;
 
         if (el == DBG_ACTIVE_EL1 &&
-            local_dec_and_test(&__get_cpu_var(kde_ref_count)))
+            this_cpu_dec_return(kde_ref_count) == 0)
                 disable &= ~DBG_MDSCR_KDE;
 
         if (disable) {
diff --git a/arch/arm64/kernel/hw_breakpoint.c b/arch/arm64/kernel/hw_breakpoint.c
index 329218ca9ffb..ff516f6691e4 100644
--- a/arch/arm64/kernel/hw_breakpoint.c
+++ b/arch/arm64/kernel/hw_breakpoint.c
@@ -184,14 +184,14 @@ int arch_install_hw_breakpoint(struct perf_event *bp)
                 /* Breakpoint */
                 ctrl_reg = AARCH64_DBG_REG_BCR;
                 val_reg = AARCH64_DBG_REG_BVR;
-                slots = __get_cpu_var(bp_on_reg);
+                slots = this_cpu_ptr(bp_on_reg);
                 max_slots = core_num_brps;
                 reg_enable = !debug_info->bps_disabled;
         } else {
                 /* Watchpoint */
                 ctrl_reg = AARCH64_DBG_REG_WCR;
                 val_reg = AARCH64_DBG_REG_WVR;
-                slots = __get_cpu_var(wp_on_reg);
+                slots = this_cpu_ptr(wp_on_reg);
                 max_slots = core_num_wrps;
                 reg_enable = !debug_info->wps_disabled;
         }
@@ -230,12 +230,12 @@ void arch_uninstall_hw_breakpoint(struct perf_event *bp)
         if (info->ctrl.type == ARM_BREAKPOINT_EXECUTE) {
                 /* Breakpoint */
                 base = AARCH64_DBG_REG_BCR;
-                slots = __get_cpu_var(bp_on_reg);
+                slots = this_cpu_ptr(bp_on_reg);
                 max_slots = core_num_brps;
         } else {
                 /* Watchpoint */
                 base = AARCH64_DBG_REG_WCR;
-                slots = __get_cpu_var(wp_on_reg);
+                slots = this_cpu_ptr(wp_on_reg);
                 max_slots = core_num_wrps;
         }
 
@@ -505,11 +505,11 @@ static void toggle_bp_registers(int reg, enum debug_el el, int enable)
 
         switch (reg) {
         case AARCH64_DBG_REG_BCR:
-                slots = __get_cpu_var(bp_on_reg);
+                slots = this_cpu_ptr(bp_on_reg);
                 max_slots = core_num_brps;
                 break;
         case AARCH64_DBG_REG_WCR:
-                slots = __get_cpu_var(wp_on_reg);
+                slots = this_cpu_ptr(wp_on_reg);
                 max_slots = core_num_wrps;
                 break;
         default:
@@ -546,7 +546,7 @@ static int breakpoint_handler(unsigned long unused, unsigned int esr,
         struct debug_info *debug_info;
         struct arch_hw_breakpoint_ctrl ctrl;
 
-        slots = (struct perf_event **)__get_cpu_var(bp_on_reg);
+        slots = this_cpu_ptr(bp_on_reg);
         addr = instruction_pointer(regs);
         debug_info = &current->thread.debug;
 
@@ -596,7 +596,7 @@ unlock:
                         user_enable_single_step(current);
         } else {
                 toggle_bp_registers(AARCH64_DBG_REG_BCR, DBG_ACTIVE_EL1, 0);
-                kernel_step = &__get_cpu_var(stepping_kernel_bp);
+                kernel_step = this_cpu_ptr(&stepping_kernel_bp);
 
                 if (*kernel_step != ARM_KERNEL_STEP_NONE)
                         return 0;
@@ -623,7 +623,7 @@ static int watchpoint_handler(unsigned long addr, unsigned int esr,
         struct arch_hw_breakpoint *info;
         struct arch_hw_breakpoint_ctrl ctrl;
 
-        slots = (struct perf_event **)__get_cpu_var(wp_on_reg);
+        slots = this_cpu_ptr(wp_on_reg);
         debug_info = &current->thread.debug;
 
         for (i = 0; i < core_num_wrps; ++i) {
@@ -698,7 +698,7 @@ unlock:
                         user_enable_single_step(current);
         } else {
                 toggle_bp_registers(AARCH64_DBG_REG_WCR, DBG_ACTIVE_EL1, 0);
-                kernel_step = &__get_cpu_var(stepping_kernel_bp);
+                kernel_step = this_cpu_ptr(&stepping_kernel_bp);
 
                 if (*kernel_step != ARM_KERNEL_STEP_NONE)
                         return 0;
@@ -722,7 +722,7 @@ int reinstall_suspended_bps(struct pt_regs *regs)
         struct debug_info *debug_info = &current->thread.debug;
         int handled_exception = 0, *kernel_step;
 
-        kernel_step = &__get_cpu_var(stepping_kernel_bp);
+        kernel_step = this_cpu_ptr(&stepping_kernel_bp);
 
         /*
          * Called from single-step exception handler.
diff --git a/arch/arm64/kernel/perf_event.c b/arch/arm64/kernel/perf_event.c
index cea1594ff933..6983ed5a351a 100644
--- a/arch/arm64/kernel/perf_event.c
+++ b/arch/arm64/kernel/perf_event.c
@@ -1044,7 +1044,7 @@ static irqreturn_t armv8pmu_handle_irq(int irq_num, void *dev)
          */
         regs = get_irq_regs();
 
-        cpuc = &__get_cpu_var(cpu_hw_events);
+        cpuc = this_cpu_ptr(&cpu_hw_events);
         for (idx = 0; idx < cpu_pmu->num_events; ++idx) {
                 struct perf_event *event = cpuc->events[idx];
                 struct hw_perf_event *hwc;
@@ -1257,7 +1257,7 @@ device_initcall(register_pmu_driver);
 
 static struct pmu_hw_events *armpmu_get_cpu_events(void)
 {
-        return &__get_cpu_var(cpu_hw_events);
+        return this_cpu_ptr(&cpu_hw_events);
 }
 
 static void __init cpu_pmu_init(struct arm_pmu *armpmu)