ARM: fiq_glue: Add custom fiq return handler api.

Change-Id: I5ff2764e85151ca0a88576542fda07c2d33dd065
Signed-off-by: Arve Hjønnevåg <arve@android.com>

diff --git a/arch/arm/common/fiq_glue.S b/arch/arm/common/fiq_glue.S
index 9e3455a09f8fa36c1cfd27ba42ef83dec8e71fe9..24b42cec4813fa45f9abe0974cb9a3880500d4f8 100644 (file)
--- a/arch/arm/common/fiq_glue.S
+++ b/arch/arm/common/fiq_glue.S
@@ -22,13 +22,14 @@
                /* fiq stack: r0-r15,cpsr,spsr of interrupted mode */
 
 ENTRY(fiq_glue)
-               /* store pc, cpsr from previous mode */
+               /* store pc, cpsr from previous mode, reserve space for spsr */
                mrs     r12, spsr
-               sub     r11, lr, #4
+               sub     lr, lr, #4
                subs    r10, #1
                bne     nested_fiq
 
-               stmfd   sp!, {r11-r12, lr}
+               str     r12, [sp, #-8]!
+               str     lr, [sp, #-4]!
 
                /* store r8-r14 from previous mode */
                sub     sp, sp, #(7 * 4)
@@ -85,12 +86,15 @@ fiq_from_usr_mode_exit:
                msr     cpsr_c, #(FIQ_MODE | PSR_I_BIT | PSR_F_BIT)
 
                ldmfd   sp!, {r0-r7}
-               add     sp, sp, #(7 * 4)
-               ldmfd   sp!, {r11-r12, lr}
+               ldr     lr, [sp, #(4 * 7)]
+               ldr     r12, [sp, #(4 * 8)]
+               add     sp, sp, #(10 * 4)
 exit_fiq:
                msr     spsr_cxsf, r12
                add     r10, #1
-               movs    pc, r11
+               cmp     r11, #0
+               moveqs  pc, lr
+               bx      r11 /* jump to custom fiq return function */
 
 nested_fiq:
                orr     r12, r12, #(PSR_F_BIT)
@@ -98,14 +102,17 @@ nested_fiq:
 
 fiq_glue_end:
 
-ENTRY(fiq_glue_setup) /* func, data, sp */
-               mrs             r3, cpsr
+ENTRY(fiq_glue_setup) /* func, data, sp, smc call number */
+               stmfd           sp!, {r4}
+               mrs             r4, cpsr
                msr             cpsr_c, #(FIQ_MODE | PSR_I_BIT | PSR_F_BIT)
                movs            r8, r0
                mov             r9, r1
                mov             sp, r2
+               mov             r11, r3
                moveq           r10, #0
                movne           r10, #1
-               msr             cpsr_c, r3
+               msr             cpsr_c, r4
+               ldmfd           sp!, {r4}
                bx              lr
 

diff --git a/arch/arm/common/fiq_glue_setup.c b/arch/arm/common/fiq_glue_setup.c
index 4044c7db95c8c94c131aab30a44d5c9d44d9f1db..8cb1b611c6d57d0ae47e985432f04a3b1834d49d 100644 (file)
--- a/arch/arm/common/fiq_glue_setup.c
+++ b/arch/arm/common/fiq_glue_setup.c
@@ -18,20 +18,23 @@
 #include <asm/fiq_glue.h>
 
 extern unsigned char fiq_glue, fiq_glue_end;
-extern void fiq_glue_setup(void *func, void *data, void *sp);
+extern void fiq_glue_setup(void *func, void *data, void *sp,
+                          fiq_return_handler_t fiq_return_handler);
 
 static struct fiq_handler fiq_debbuger_fiq_handler = {
        .name = "fiq_glue",
 };
 DEFINE_PER_CPU(void *, fiq_stack);
 static struct fiq_glue_handler *current_handler;
+static fiq_return_handler_t fiq_return_handler;
 static DEFINE_MUTEX(fiq_glue_lock);
 
 static void fiq_glue_setup_helper(void *info)
 {
        struct fiq_glue_handler *handler = info;
        fiq_glue_setup(handler->fiq, handler,
-               __get_cpu_var(fiq_stack) + THREAD_START_SP);
+               __get_cpu_var(fiq_stack) + THREAD_START_SP,
+               fiq_return_handler);
 }
 
 int fiq_glue_register_handler(struct fiq_glue_handler *handler)
@@ -80,6 +83,49 @@ err_busy:
        return ret;
 }
 
+static void fiq_glue_update_return_handler(void (*fiq_return)(void))
+{
+       fiq_return_handler = fiq_return;
+       if (current_handler)
+               on_each_cpu(fiq_glue_setup_helper, current_handler, true);
+}
+
+int fiq_glue_set_return_handler(void (*fiq_return)(void))
+{
+       int ret;
+
+       mutex_lock(&fiq_glue_lock);
+       if (fiq_return_handler) {
+               ret = -EBUSY;
+               goto err_busy;
+       }
+       fiq_glue_update_return_handler(fiq_return);
+       ret = 0;
+err_busy:
+       mutex_unlock(&fiq_glue_lock);
+
+       return ret;
+}
+EXPORT_SYMBOL(fiq_glue_set_return_handler);
+
+int fiq_glue_clear_return_handler(void (*fiq_return)(void))
+{
+       int ret;
+
+       mutex_lock(&fiq_glue_lock);
+       if (WARN_ON(fiq_return_handler != fiq_return)) {
+               ret = -EINVAL;
+               goto err_inval;
+       }
+       fiq_glue_update_return_handler(NULL);
+       ret = 0;
+err_inval:
+       mutex_unlock(&fiq_glue_lock);
+
+       return ret;
+}
+EXPORT_SYMBOL(fiq_glue_clear_return_handler);
+
 /**
  * fiq_glue_resume - Restore fiqs after suspend or low power idle states
  *
@@ -93,7 +139,8 @@ void fiq_glue_resume(void)
        if (!current_handler)
                return;
        fiq_glue_setup(current_handler->fiq, current_handler,
-               __get_cpu_var(fiq_stack) + THREAD_START_SP);
+               __get_cpu_var(fiq_stack) + THREAD_START_SP,
+               fiq_return_handler);
        if (current_handler->resume)
                current_handler->resume(current_handler);
 }

diff --git a/arch/arm/include/asm/fiq_glue.h b/arch/arm/include/asm/fiq_glue.h
index d54c29db97a8345f87015c033f67101fc4fe8c94..a9e244f9f197c8cfd80d706a2a02c48cfb3f8f98 100644 (file)
--- a/arch/arm/include/asm/fiq_glue.h
+++ b/arch/arm/include/asm/fiq_glue.h
@@ -18,8 +18,11 @@ struct fiq_glue_handler {
        void (*fiq)(struct fiq_glue_handler *h, void *regs, void *svc_sp);
        void (*resume)(struct fiq_glue_handler *h);
 };
+typedef void (*fiq_return_handler_t)(void);
 
 int fiq_glue_register_handler(struct fiq_glue_handler *handler);
+int fiq_glue_set_return_handler(fiq_return_handler_t fiq_return);
+int fiq_glue_clear_return_handler(fiq_return_handler_t fiq_return);
 
 #ifdef CONFIG_FIQ_GLUE
 void fiq_glue_resume(void);