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[Qemu-devel] [PATCH 09/13] target/arm: Add v8M stack checks for Thumb2 L
From: |
Peter Maydell |
Subject: |
[Qemu-devel] [PATCH 09/13] target/arm: Add v8M stack checks for Thumb2 LDM/STM |
Date: |
Tue, 2 Oct 2018 17:35:52 +0100 |
Add the v8M stack checks for:
* LDM (T2 encoding)
* STM (T2 encoding)
This includes the 32-bit encodings of the instructions listed
in v8M ARM ARM rule R_YVWT as
* LDM, LDMIA, LDMFD
* LDMDB, LDMEA
* POP (multiple registers)
* PUSH (muliple registers)
* STM, STMIA, STMEA
* STMDB, STMFD
We perform the stack limit before doing any other part
of the load or store.
Signed-off-by: Peter Maydell <address@hidden>
---
target/arm/translate.c | 19 ++++++++++++++++++-
1 file changed, 18 insertions(+), 1 deletion(-)
diff --git a/target/arm/translate.c b/target/arm/translate.c
index c16d6075d94..3fb378a492d 100644
--- a/target/arm/translate.c
+++ b/target/arm/translate.c
@@ -10524,6 +10524,7 @@ static void disas_thumb2_insn(DisasContext *s, uint32_t
insn)
} else {
int i, loaded_base = 0;
TCGv_i32 loaded_var;
+ bool wback = extract32(insn, 21, 1);
/* Load/store multiple. */
addr = load_reg(s, rn);
offset = 0;
@@ -10531,10 +10532,26 @@ static void disas_thumb2_insn(DisasContext *s,
uint32_t insn)
if (insn & (1 << i))
offset += 4;
}
+
if (insn & (1 << 24)) {
tcg_gen_addi_i32(addr, addr, -offset);
}
+ if (s->v8m_stackcheck && rn == 13 && wback) {
+ /*
+ * If the writeback is incrementing SP rather than
+ * decrementing it, and the initial SP is below the
+ * stack limit but the final written-back SP would
+ * be above, then then we must not perform any memory
+ * accesses, but it is IMPDEF whether we generate
+ * an exception. We choose to do so in this case.
+ * At this point 'addr' is the lowest address, so
+ * either the original SP (if incrementing) or our
+ * final SP (if decrementing), so that's what we check.
+ */
+ gen_helper_v8m_stackcheck(cpu_env, addr);
+ }
+
loaded_var = NULL;
for (i = 0; i < 16; i++) {
if ((insn & (1 << i)) == 0)
@@ -10562,7 +10579,7 @@ static void disas_thumb2_insn(DisasContext *s, uint32_t
insn)
if (loaded_base) {
store_reg(s, rn, loaded_var);
}
- if (insn & (1 << 21)) {
+ if (wback) {
/* Base register writeback. */
if (insn & (1 << 24)) {
tcg_gen_addi_i32(addr, addr, -offset);
--
2.19.0
- Re: [Qemu-devel] [PATCH 01/13] target/arm: Define new TBFLAG for v8M stack checking, (continued)
- [Qemu-devel] [PATCH 02/13] target/arm: Define new EXCP type for v8M stack overflows, Peter Maydell, 2018/10/02
- [Qemu-devel] [PATCH 05/13] target/arm: Add some comments in Thumb decode, Peter Maydell, 2018/10/02
- [Qemu-devel] [PATCH 04/13] target/arm: Add v8M stack checks on ADD/SUB/MOV of SP, Peter Maydell, 2018/10/02
- [Qemu-devel] [PATCH 09/13] target/arm: Add v8M stack checks for Thumb2 LDM/STM,
Peter Maydell <=
- [Qemu-devel] [PATCH 06/13] target/arm: Add v8M stack checks on exception entry, Peter Maydell, 2018/10/02
- [Qemu-devel] [PATCH 07/13] target/arm: Add v8M stack limit checks on NS function calls, Peter Maydell, 2018/10/02
- [Qemu-devel] [PATCH 08/13] target/arm: Add v8M stack checks for LDRD/STRD (imm), Peter Maydell, 2018/10/02