diff mbox

[PULL,5/7] target-arm: Fix handling of STM (user) with r15 in register list

Message ID 1426509618-27416-6-git-send-email-peter.maydell@linaro.org
State New
Headers show

Commit Message

Peter Maydell March 16, 2015, 12:40 p.m. UTC
The A32 encoding of LDM distinguishes LDM (user) from LDM (exception
return) based on whether r15 is in the register list. However for
STM (user) there is no equivalent distinction. We were incorrectly
treating "r15 in list" as indicating exception return for both LDM
and STM, with the result that an STM (user) involving r15 went into
an infinite loop. Fix this; note that the value stored for r15
in this case is the current PC regardless of our current mode.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 1426015125-5521-1-git-send-email-peter.maydell@linaro.org
---
 target-arm/translate.c | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)
diff mbox

Patch

diff --git a/target-arm/translate.c b/target-arm/translate.c
index 381d896..9116529 100644
--- a/target-arm/translate.c
+++ b/target-arm/translate.c
@@ -8859,17 +8859,23 @@  static void disas_arm_insn(DisasContext *s, unsigned int insn)
         case 0x08:
         case 0x09:
             {
-                int j, n, user, loaded_base;
+                int j, n, loaded_base;
+                bool exc_return = false;
+                bool is_load = extract32(insn, 20, 1);
+                bool user = false;
                 TCGv_i32 loaded_var;
                 /* load/store multiple words */
                 /* XXX: store correct base if write back */
-                user = 0;
                 if (insn & (1 << 22)) {
+                    /* LDM (user), LDM (exception return) and STM (user) */
                     if (IS_USER(s))
                         goto illegal_op; /* only usable in supervisor mode */
 
-                    if ((insn & (1 << 15)) == 0)
-                        user = 1;
+                    if (is_load && extract32(insn, 15, 1)) {
+                        exc_return = true;
+                    } else {
+                        user = true;
+                    }
                 }
                 rn = (insn >> 16) & 0xf;
                 addr = load_reg(s, rn);
@@ -8903,7 +8909,7 @@  static void disas_arm_insn(DisasContext *s, unsigned int insn)
                 j = 0;
                 for(i=0;i<16;i++) {
                     if (insn & (1 << i)) {
-                        if (insn & (1 << 20)) {
+                        if (is_load) {
                             /* load */
                             tmp = tcg_temp_new_i32();
                             gen_aa32_ld32u(tmp, addr, get_mem_index(s));
@@ -8968,7 +8974,7 @@  static void disas_arm_insn(DisasContext *s, unsigned int insn)
                 if (loaded_base) {
                     store_reg(s, rn, loaded_var);
                 }
-                if ((insn & (1 << 22)) && !user) {
+                if (exc_return) {
                     /* Restore CPSR from SPSR.  */
                     tmp = load_cpu_field(spsr);
                     gen_set_cpsr(tmp, CPSR_ERET_MASK);