xen/arm: vreg: Introduce vreg_emulate_cp{32,64}

Factorize the code to emulate 32-bit and 64-bit access to a co-processor
in specific helpers.

The new helpers will be used in different components to simplify the
emulation.

Finally, the prototypes for the callbacks to emulate 32-bit and 64-bit
co-processor access are the same as the sysreg one. Rather than
introducing new ones, repurpose the existent prototypes.

Signed-off-by: Julien Grall <julien.grall@arm.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>

xen/arch/arm/vtimer.c

@@ -252,49 +252,28 @@ static bool vtimer_cntp_cval(struct cpu_user_regs *regs, uint64_t *r,
 static bool vtimer_emulate_cp32(struct cpu_user_regs *regs, union hsr hsr)
 {
     struct hsr_cp32 cp32 = hsr.cp32;
-    /*
-     * Initialize to zero to avoid leaking data if there is an
-     * implementation error in the emulation (such as not correctly
-     * setting r).
-     */
-    uint32_t r = 0;
-    bool res;
-
 
     if ( cp32.read )
         perfc_incr(vtimer_cp32_reads);
     else
         perfc_incr(vtimer_cp32_writes);
 
-    if ( !cp32.read )
-        r = get_user_reg(regs, cp32.reg);
-
     switch ( hsr.bits & HSR_CP32_REGS_MASK )
     {
     case HSR_CPREG32(CNTP_CTL):
-        res = vtimer_cntp_ctl(regs, &r, cp32.read);
-        break;
+        return vreg_emulate_cp32(regs, hsr, vtimer_cntp_ctl);
 
     case HSR_CPREG32(CNTP_TVAL):
-        res = vtimer_cntp_tval(regs, &r, cp32.read);
-        break;
+        return vreg_emulate_cp32(regs, hsr, vtimer_cntp_tval);
 
     default:
         return false;
     }
-
-    if ( res && cp32.read )
-        set_user_reg(regs, cp32.reg, r);
-
-    return res;
 }
 
 static bool vtimer_emulate_cp64(struct cpu_user_regs *regs, union hsr hsr)
 {
     struct hsr_cp64 cp64 = hsr.cp64;
-    uint32_t r1 = get_user_reg(regs, cp64.reg1);
-    uint32_t r2 = get_user_reg(regs, cp64.reg2);
-    uint64_t x = (uint64_t)r1 | ((uint64_t)r2 << 32);
 
     if ( cp64.read )
         perfc_incr(vtimer_cp64_reads);
@@ -304,21 +283,11 @@ static bool vtimer_emulate_cp64(struct cpu_user_regs *regs, union hsr hsr)
     switch ( hsr.bits & HSR_CP64_REGS_MASK )
     {
     case HSR_CPREG64(CNTP_CVAL):
-        if ( !vtimer_cntp_cval(regs, &x, cp64.read) )
-            return false;
-        break;
+        return vreg_emulate_cp64(regs, hsr, vtimer_cntp_cval);
 
     default:
         return false;
     }
-
-    if ( cp64.read )
-    {
-        set_user_reg(regs, cp64.reg1, x & 0xffffffff);
-        set_user_reg(regs, cp64.reg2, x >> 32);
-    }
-
-    return true;
 }
 
 #ifdef CONFIG_ARM_64

xen/include/asm-arm/vreg.h

@@ -4,14 +4,68 @@
 #ifndef __ASM_ARM_VREG__
 #define __ASM_ARM_VREG__
 
-#ifdef CONFIG_ARM_64
-typedef bool (*vreg_sysreg32_fn_t)(struct cpu_user_regs *regs, uint32_t *r,
+typedef bool (*vreg_reg32_fn_t)(struct cpu_user_regs *regs, uint32_t *r,
                                    bool read);
-typedef bool (*vreg_sysreg64_fn_t)(struct cpu_user_regs *regs, uint64_t *r,
+typedef bool (*vreg_reg64_fn_t)(struct cpu_user_regs *regs, uint64_t *r,
                                    bool read);
 
+static inline bool vreg_emulate_cp32(struct cpu_user_regs *regs, union hsr hsr,
+                                     vreg_reg32_fn_t fn)
+{
+    struct hsr_cp32 cp32 = hsr.cp32;
+    /*
+     * Initialize to zero to avoid leaking data if there is an
+     * implementation error in the emulation (such as not correctly
+     * setting r).
+     */
+    uint32_t r = 0;
+    bool ret;
+
+    if ( !cp32.read )
+        r = get_user_reg(regs, cp32.reg);
+
+    ret = fn(regs, &r, cp32.read);
+
+    if ( ret && cp32.read )
+        set_user_reg(regs, cp32.reg, r);
+
+    return ret;
+}
+
+static inline bool vreg_emulate_cp64(struct cpu_user_regs *regs, union hsr hsr,
+                                     vreg_reg64_fn_t fn)
+{
+    struct hsr_cp64 cp64 = hsr.cp64;
+    /*
+     * Initialize to zero to avoid leaking data if there is an
+     * implementation error in the emulation (such as not correctly
+     * setting x).
+     */
+    uint64_t x = 0;
+    bool ret;
+
+    if ( !cp64.read )
+    {
+        uint32_t r1 = get_user_reg(regs, cp64.reg1);
+        uint32_t r2 = get_user_reg(regs, cp64.reg2);
+
+        x = (uint64_t)r1 | ((uint64_t)r2 << 32);
+    }
+
+    ret = fn(regs, &x, cp64.read);
+
+    if ( ret && cp64.read )
+    {
+        set_user_reg(regs, cp64.reg1, x & 0xffffffff);
+        set_user_reg(regs, cp64.reg2, x >> 32);
+    }
+
+    return ret;
+}
+
+#ifdef CONFIG_ARM_64
 static inline bool vreg_emulate_sysreg32(struct cpu_user_regs *regs, union hsr hsr,
-                                         vreg_sysreg32_fn_t fn)
+                                         vreg_reg32_fn_t fn)
 {
     struct hsr_sysreg sysreg = hsr.sysreg;
     uint32_t r = 0;
@@ -29,7 +83,7 @@ static inline bool vreg_emulate_sysreg32(struct cpu_user_regs *regs, union hsr h
 }
 
 static inline bool vreg_emulate_sysreg64(struct cpu_user_regs *regs, union hsr hsr,
-                                         vreg_sysreg64_fn_t fn)
+                                         vreg_reg64_fn_t fn)
 {
     struct hsr_sysreg sysreg = hsr.sysreg;
     /*