[Qemu-devel] [PATCH 2/2] linux-user/arm: Adjust MAX_RESERVED_VA for M-profile

[Richard Henderson <richard.henderson@linaro.org>]

Limit the virtual address space for M-profile cpus to 2GB,
so that we avoid all of the magic addresses in the top half
of the M-profile system map.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 linux-user/arm/target_cpu.h | 24 +++++++++++++++++++++---
 1 file changed, 21 insertions(+), 3 deletions(-)

diff --git a/linux-user/arm/target_cpu.h b/linux-user/arm/target_cpu.h
index 279ea532d5..3f79356a07 100644
--- a/linux-user/arm/target_cpu.h
+++ b/linux-user/arm/target_cpu.h
@@ -19,9 +19,27 @@
 #ifndef ARM_TARGET_CPU_H
 #define ARM_TARGET_CPU_H
 
-/* We need to be able to map the commpage.
-   See validate_guest_space in linux-user/elfload.c.  */
-#define MAX_RESERVED_VA(CPU)  0xffff0000ul
+static inline unsigned long arm_max_reserved_va(CPUState *cs)
+{
+    ARMCPU *cpu = ARM_CPU(cs);
+
+    if (arm_feature(&cpu->env, ARM_FEATURE_M)) {
+        /*
+         * There are magic return addresses above 0xfe000000,
+         * and in general a lot of M-profile system stuff in
+         * the high addresses.  Restrict linux-user to the
+         * cached write-back RAM in the system map.
+         */
+        return 0x80000000ul;
+    } else {
+        /*
+         * We need to be able to map the commpage.
+         * See validate_guest_space in linux-user/elfload.c.
+         */
+        return 0xffff0000ul;
+    }
+}
+#define MAX_RESERVED_VA  arm_max_reserved_va
 
 static inline void cpu_clone_regs(CPUARMState *env, target_ulong newsp)
 {
-- 
2.17.1