ARM: hw_breakpoint: fix warnings generated by sparse

sparse doesn't like per-cpu accesses such as:

static DEFINE_PER_CPU(struct perf_event *, foo[MAXLEN]);
struct perf_event **bar = __get_cpu_var(foo);

and shouts quite loudly about it:

| warning: incorrect type in assignment (different modifiers)
|    expected struct perf_event **slots
|    got struct perf_event *[noderef] *<noident>

This patch adds casts to these sorts of assignments in hw_breakpoint.c
in order to silence the warnings.

Reported-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Will Deacon <will.deacon@arm.com>

diff --git a/arch/arm/kernel/hw_breakpoint.c b/arch/arm/kernel/hw_breakpoint.c
index eef1b1e..56ed9a6 100644 (file)
--- a/arch/arm/kernel/hw_breakpoint.c
+++ b/arch/arm/kernel/hw_breakpoint.c
@@ -337,7 +337,7 @@ int arch_install_hw_breakpoint(struct perf_event *bp)
                /* Breakpoint */
                ctrl_base = ARM_BASE_BCR;
                val_base = ARM_BASE_BVR;
-               slots = __get_cpu_var(bp_on_reg);
+               slots = (struct perf_event **)__get_cpu_var(bp_on_reg);
                max_slots = core_num_brps;
                if (info->step_ctrl.enabled) {
                        /* Override the breakpoint data with the step data. */
@@ -357,7 +357,7 @@ int arch_install_hw_breakpoint(struct perf_event *bp)
                        ctrl_base = ARM_BASE_WCR;
                        val_base = ARM_BASE_WVR;
                }
-               slots = __get_cpu_var(wp_on_reg);
+               slots = (struct perf_event **)__get_cpu_var(wp_on_reg);
                max_slots = core_num_wrps;
        }
 
@@ -394,7 +394,7 @@ void arch_uninstall_hw_breakpoint(struct perf_event *bp)
        if (info->ctrl.type == ARM_BREAKPOINT_EXECUTE) {
                /* Breakpoint */
                base = ARM_BASE_BCR;
-               slots = __get_cpu_var(bp_on_reg);
+               slots = (struct perf_event **)__get_cpu_var(bp_on_reg);
                max_slots = core_num_brps;
        } else {
                /* Watchpoint */
@@ -402,7 +402,7 @@ void arch_uninstall_hw_breakpoint(struct perf_event *bp)
                        base = ARM_BASE_BCR + core_num_brps;
                else
                        base = ARM_BASE_WCR;
-               slots = __get_cpu_var(wp_on_reg);
+               slots = (struct perf_event **)__get_cpu_var(wp_on_reg);
                max_slots = core_num_wrps;
        }
 
@@ -662,9 +662,11 @@ static void disable_single_step(struct perf_event *bp)
 static void watchpoint_handler(unsigned long unknown, struct pt_regs *regs)
 {
        int i;
-       struct perf_event *wp, **slots = __get_cpu_var(wp_on_reg);
+       struct perf_event *wp, **slots;
        struct arch_hw_breakpoint *info;
 
+       slots = (struct perf_event **)__get_cpu_var(wp_on_reg);
+
        /* Without a disassembler, we can only handle 1 watchpoint. */
        BUG_ON(core_num_wrps > 1);
 
@@ -703,9 +705,11 @@ static void watchpoint_handler(unsigned long unknown, struct pt_regs *regs)
 static void watchpoint_single_step_handler(unsigned long pc)
 {
        int i;
-       struct perf_event *wp, **slots = __get_cpu_var(wp_on_reg);
+       struct perf_event *wp, **slots;
        struct arch_hw_breakpoint *info;
 
+       slots = (struct perf_event **)__get_cpu_var(wp_on_reg);
+
        for (i = 0; i < core_num_reserved_brps; ++i) {
                rcu_read_lock();
 
@@ -734,10 +738,12 @@ static void breakpoint_handler(unsigned long unknown, struct pt_regs *regs)
 {
        int i;
        u32 ctrl_reg, val, addr;
-       struct perf_event *bp, **slots = __get_cpu_var(bp_on_reg);
+       struct perf_event *bp, **slots;
        struct arch_hw_breakpoint *info;
        struct arch_hw_breakpoint_ctrl ctrl;
 
+       slots = (struct perf_event **)__get_cpu_var(bp_on_reg);
+
        /* The exception entry code places the amended lr in the PC. */
        addr = regs->ARM_pc;