On Sun, 3 Aug 2025 at 00:06, Richard Henderson
<[email protected]> wrote:
>
> While semihosting isn't really thread aware, the current
> implementation allocates space for the heap per-thread.
>
> Remove the heap_base and heap_limit fields from TaskState.
> Replace with static variables within do_common_semihosting.
>
> Signed-off-by: Richard Henderson <[email protected]>
> @@ -492,19 +489,20 @@ void target_cpu_copy_regs(CPUArchState *env,
> target_pt_regs *regs)
> for(i = 0; i < 16; i++) {
> env->regs[i] = regs->uregs[i];
> }
> -#if TARGET_BIG_ENDIAN
> - /* Enable BE8. */
> - if (EF_ARM_EABI_VERSION(info->elf_flags) >= EF_ARM_EABI_VER4
> - && (info->elf_flags & EF_ARM_BE8)) {
> - env->uncached_cpsr |= CPSR_E;
> - env->cp15.sctlr_el[1] |= SCTLR_E0E;
> - } else {
> - env->cp15.sctlr_el[1] |= SCTLR_B;
> - }
> - arm_rebuild_hflags(env);
> -#endif
>
> - ts->heap_base = info->brk;
> - /* This will be filled in on the first SYS_HEAPINFO call. */
> - ts->heap_limit = 0;
> + if (TARGET_BIG_ENDIAN) {
> + CPUState *cpu = env_cpu(env);
> + TaskState *ts = get_task_state(cpu);
> + struct image_info *info = ts->info;
> +
> + /* Enable BE8. */
> + if (EF_ARM_EABI_VERSION(info->elf_flags) >= EF_ARM_EABI_VER4
> + && (info->elf_flags & EF_ARM_BE8)) {
> + env->uncached_cpsr |= CPSR_E;
> + env->cp15.sctlr_el[1] |= SCTLR_E0E;
> + } else {
> + env->cp15.sctlr_el[1] |= SCTLR_B;
> + }
> + arm_rebuild_hflags(env);
> + }
This change to the big-endian handling code seems unrelated.
Otherwise
Reviewed-by: Peter Maydell <[email protected]>
> @@ -678,24 +678,20 @@ void do_common_semihosting(CPUState *cs)
> * Some C libraries assume the heap immediately follows .bss, so
> * allocate it using sbrk.
> */
> - if (!ts->heap_limit) {
> - abi_ulong ret;
> -
> - ts->heap_base = do_brk(0);
> - limit = ts->heap_base + COMMON_SEMI_HEAP_SIZE;
> + if (!heaplimit) {
> + heapbase = do_brk(0);
> /* Try a big heap, and reduce the size if that fails. */
> - for (;;) {
> - ret = do_brk(limit);
> + for (abi_ulong size = COMMON_SEMI_HEAP_SIZE; ; size >>= 1) {
> + abi_ulong limit = heapbase + size;
> + abi_ulong ret = do_brk(limit);
> if (ret >= limit) {
> + heaplimit = limit;
> break;
> }
> - limit = (ts->heap_base >> 1) + (limit >> 1);
The old code was doing this in a very weird way; what you
have here is much clearer...
> }
> - ts->heap_limit = limit;
> }
-- PMM
