From b2e62d9a7b9a2eb10e451a57813bad168376e122 Mon Sep 17 00:00:00 2001 From: Peter Crosthwaite Date: Fri, 4 Mar 2016 11:30:19 +0000 Subject: [PATCH] arm: cpu: handle BE32 user-mode as BE endian with address manipulations on subword accesses (to give the illusion of BE). But user-mode cannot tell the difference and is already implemented as straight BE. So handle the difference in the endianess query, where USER mode is BE and system is not. Signed-off-by: Peter Crosthwaite Reviewed-by: Peter Maydell Signed-off-by: Peter Maydell --- target-arm/cpu.h | 17 ++++++++++++++++- 1 file changed, 16 insertions(+), 1 deletion(-) diff --git a/target-arm/cpu.h b/target-arm/cpu.h index 75e5ea0a43..ab0ea92baf 100644 --- a/target-arm/cpu.h +++ b/target-arm/cpu.h @@ -1915,7 +1915,22 @@ static inline bool arm_cpu_data_is_big_endian(CPUARMState *env) /* In 32bit endianness is determined by looking at CPSR's E bit */ if (!is_a64(env)) { - return (env->uncached_cpsr & CPSR_E) ? 1 : 0; + return +#ifdef CONFIG_USER_ONLY + /* In system mode, BE32 is modelled in line with the + * architecture (as word-invariant big-endianness), where loads + * and stores are done little endian but from addresses which + * are adjusted by XORing with the appropriate constant. So the + * endianness to use for the raw data access is not affected by + * SCTLR.B. + * In user mode, however, we model BE32 as byte-invariant + * big-endianness (because user-only code cannot tell the + * difference), and so we need to use a data access endianness + * that depends on SCTLR.B. + */ + arm_sctlr_b(env) || +#endif + ((env->uncached_cpsr & CPSR_E) ? 1 : 0); } cur_el = arm_current_el(env);