From 37d0c7fcf10cd9107b71cb682b419e403e71f739 Mon Sep 17 00:00:00 2001
From: Peter Maydell <peter.maydell@linaro.org>
Date: Mon, 8 Oct 2018 14:22:07 -0400
Subject: [PATCH] target/arm: Add v8M stack checks for Thumb push/pop

Add v8M stack checks for the 16-bit Thumb push/pop
encodings: STMDB, STMFD, LDM, LDMIA, LDMFD.

Backports commit aa369e5c08bbe2748d2be96f13f4ef469a4d3080 from qemu
---
 qemu/target/arm/translate.c | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/qemu/target/arm/translate.c b/qemu/target/arm/translate.c
index 9ef0a2d7..fcabc8f5 100644
--- a/qemu/target/arm/translate.c
+++ b/qemu/target/arm/translate.c
@@ -12466,7 +12466,10 @@ static void disas_thumb_insn(DisasContext *s, uint32_t insn)
             store_reg(s, rd, tmp);
             break;
         case 4: case 5: case 0xc: case 0xd:
-            /* push/pop */
+            /*
+             * 0b1011_x10x_xxxx_xxxx
+             *  - push/pop
+             */
             addr = load_reg(s, 13);
             if (insn & (1 << 8))
                 offset = 4;
@@ -12479,6 +12482,17 @@ static void disas_thumb_insn(DisasContext *s, uint32_t insn)
             if ((insn & (1 << 11)) == 0) {
                 tcg_gen_addi_i32(tcg_ctx, addr, addr, -offset);
             }
+
+            if (s->v8m_stackcheck) {
+                /*
+                 * Here 'addr' is the lower of "old SP" and "new SP";
+                 * if this is a pop that starts below the limit and ends
+                 * above it, it is UNKNOWN whether the limit check triggers;
+                 * we choose to trigger.
+                 */
+                gen_helper_v8m_stackcheck(tcg_ctx, tcg_ctx->cpu_env, addr);
+            }
+
             for (i = 0; i < 8; i++) {
                 if (insn & (1 << i)) {
                     if (insn & (1 << 11)) {