target/arm: Export arm_v7m_get_sp_ptr

Allow the function to be used outside of m_helper.c.
Move to be outside of ifndef CONFIG_USER_ONLY block.
Rename from get_v7m_sp_ptr.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: David Reiss <dreiss@meta.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20230227213329.793795-14-richard.henderson@linaro.org
[rth: Split out of a larger patch]
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

2 files changed, 51 insertions, 43 deletions

diff --git a/target/arm/internals.h b/target/arm/internals.h
index 086e88e..b1ef059 100644
--- a/target/arm/internals.h
+++ b/target/arm/internals.h
@@ -1360,6 +1360,16 @@ void arm_cpu_lpa2_finalize(ARMCPU *cpu, Error **errp);
 /* Read the CONTROL register as the MRS instruction would. */
 uint32_t arm_v7m_mrs_control(CPUARMState *env, uint32_t secure);
 
+/*
+ * Return a pointer to the location where we currently store the
+ * stack pointer for the requested security state and thread mode.
+ * This pointer will become invalid if the CPU state is updated
+ * such that the stack pointers are switched around (eg changing
+ * the SPSEL control bit).
+ */
+uint32_t *arm_v7m_get_sp_ptr(CPUARMState *env, bool secure,
+                             bool threadmode, bool spsel);
+
 #ifdef CONFIG_USER_ONLY
 static inline void define_cortex_a72_a57_a53_cp_reginfo(ARMCPU *cpu) { }
 #else
diff --git a/target/arm/tcg/m_helper.c b/target/arm/tcg/m_helper.c
index 03be79e..081fc3f 100644
--- a/target/arm/tcg/m_helper.c
+++ b/target/arm/tcg/m_helper.c
@@ -650,42 +650,6 @@ void HELPER(v7m_blxns)(CPUARMState *env, uint32_t dest)
     arm_rebuild_hflags(env);
 }
 
-static uint32_t *get_v7m_sp_ptr(CPUARMState *env, bool secure, bool threadmode,
-                                bool spsel)
-{
-    /*
-     * Return a pointer to the location where we currently store the
-     * stack pointer for the requested security state and thread mode.
-     * This pointer will become invalid if the CPU state is updated
-     * such that the stack pointers are switched around (eg changing
-     * the SPSEL control bit).
-     * Compare the v8M ARM ARM pseudocode LookUpSP_with_security_mode().
-     * Unlike that pseudocode, we require the caller to pass us in the
-     * SPSEL control bit value; this is because we also use this
-     * function in handling of pushing of the callee-saves registers
-     * part of the v8M stack frame (pseudocode PushCalleeStack()),
-     * and in the tailchain codepath the SPSEL bit comes from the exception
-     * return magic LR value from the previous exception. The pseudocode
-     * opencodes the stack-selection in PushCalleeStack(), but we prefer
-     * to make this utility function generic enough to do the job.
-     */
-    bool want_psp = threadmode && spsel;
-
-    if (secure == env->v7m.secure) {
-        if (want_psp == v7m_using_psp(env)) {
-            return &env->regs[13];
-        } else {
-            return &env->v7m.other_sp;
-        }
-    } else {
-        if (want_psp) {
-            return &env->v7m.other_ss_psp;
-        } else {
-            return &env->v7m.other_ss_msp;
-        }
-    }
-}
-
 static bool arm_v7m_load_vector(ARMCPU *cpu, int exc, bool targets_secure,
                                 uint32_t *pvec)
 {
@@ -810,8 +774,8 @@ static bool v7m_push_callee_stack(ARMCPU *cpu, uint32_t lr, bool dotailchain,
             !mode;
 
         mmu_idx = arm_v7m_mmu_idx_for_secstate_and_priv(env, M_REG_S, priv);
-        frame_sp_p = get_v7m_sp_ptr(env, M_REG_S, mode,
-                                    lr & R_V7M_EXCRET_SPSEL_MASK);
+        frame_sp_p = arm_v7m_get_sp_ptr(env, M_REG_S, mode,
+                                        lr & R_V7M_EXCRET_SPSEL_MASK);
         want_psp = mode && (lr & R_V7M_EXCRET_SPSEL_MASK);
         if (want_psp) {
             limit = env->v7m.psplim[M_REG_S];
@@ -1656,10 +1620,8 @@ static void do_v7m_exception_exit(ARMCPU *cpu)
          * use 'frame_sp_p' after we do something that makes it invalid.
          */
         bool spsel = env->v7m.control[return_to_secure] & R_V7M_CONTROL_SPSEL_MASK;
-        uint32_t *frame_sp_p = get_v7m_sp_ptr(env,
-                                              return_to_secure,
-                                              !return_to_handler,
-                                              spsel);
+        uint32_t *frame_sp_p = arm_v7m_get_sp_ptr(env, return_to_secure,
+                                                  !return_to_handler, spsel);
         uint32_t frameptr = *frame_sp_p;
         bool pop_ok = true;
         ARMMMUIdx mmu_idx;
@@ -1965,7 +1927,7 @@ static bool do_v7m_function_return(ARMCPU *cpu)
         threadmode = !arm_v7m_is_handler_mode(env);
         spsel = env->v7m.control[M_REG_S] & R_V7M_CONTROL_SPSEL_MASK;
 
-        frame_sp_p = get_v7m_sp_ptr(env, true, threadmode, spsel);
+        frame_sp_p = arm_v7m_get_sp_ptr(env, true, threadmode, spsel);
         frameptr = *frame_sp_p;
 
         /*
@@ -2900,3 +2862,39 @@ uint32_t HELPER(v7m_tt)(CPUARMState *env, uint32_t addr, uint32_t op)
 }
 
 #endif /* !CONFIG_USER_ONLY */
+
+uint32_t *arm_v7m_get_sp_ptr(CPUARMState *env, bool secure, bool threadmode,
+                             bool spsel)
+{
+    /*
+     * Return a pointer to the location where we currently store the
+     * stack pointer for the requested security state and thread mode.
+     * This pointer will become invalid if the CPU state is updated
+     * such that the stack pointers are switched around (eg changing
+     * the SPSEL control bit).
+     * Compare the v8M ARM ARM pseudocode LookUpSP_with_security_mode().
+     * Unlike that pseudocode, we require the caller to pass us in the
+     * SPSEL control bit value; this is because we also use this
+     * function in handling of pushing of the callee-saves registers
+     * part of the v8M stack frame (pseudocode PushCalleeStack()),
+     * and in the tailchain codepath the SPSEL bit comes from the exception
+     * return magic LR value from the previous exception. The pseudocode
+     * opencodes the stack-selection in PushCalleeStack(), but we prefer
+     * to make this utility function generic enough to do the job.
+     */
+    bool want_psp = threadmode && spsel;
+
+    if (secure == env->v7m.secure) {
+        if (want_psp == v7m_using_psp(env)) {
+            return &env->regs[13];
+        } else {
+            return &env->v7m.other_sp;
+        }
+    } else {
+        if (want_psp) {
+            return &env->v7m.other_ss_psp;
+        } else {
+            return &env->v7m.other_ss_msp;
+        }
+    }
+}