On Fri, 5 Jun 2020 at 05:17, Richard Henderson
<richard.hender...@linaro.org> wrote:
>
> This data can be allocated by page_alloc_target_data() and
> released by page_set_flags(start, end, prot | PAGE_RESET).
>
> This data will be used to hold tag memory for AArch64 MTE.
>
> Signed-off-by: Richard Henderson <richard.hender...@linaro.org>
> ---
> @@ -289,6 +295,8 @@ int walk_memory_regions(void *, walk_memory_regions_fn);
> int page_get_flags(target_ulong address);
> void page_set_flags(target_ulong start, target_ulong end, int flags);
> int page_check_range(target_ulong start, target_ulong len, int flags);
> +void *page_get_target_data(target_ulong address);
> +void *page_alloc_target_data(target_ulong address, size_t size);
Could we have a doc comment for any new function that's got
global scope, please?
> #endif
>
> CPUArchState *cpu_copy(CPUArchState *env);
> +void *page_alloc_target_data(target_ulong address, size_t size)
> +{
> + PageDesc *p = page_find(address >> TARGET_PAGE_BITS);
> + void *ret = NULL;
> +
> + if (p) {
> + ret = p->target_data;
> + if (!ret && (p->flags & PAGE_VALID)) {
> + p->target_data = ret = g_malloc0(size);
> + }
> + }
> + return ret;
Can a PageDesc validly have p->target_data != NULL but
p->flags with PAGE_VALID not set ?
It's not clear to me why for a !PAGE_VALID page which
has target_data already we return that pointer but
if it doesn't have any we don't allocate: either
"always allocate" or "always return NULL for non-valid pages"
would seem more self-consistent.
> @@ -787,9 +788,11 @@ abi_long target_mremap(abi_ulong old_addr, abi_ulong
> old_size,
> new_addr = -1;
> } else {
> new_addr = h2g(host_addr);
> + /* FIXME: Move page flags and target_data for each page. */
Is this something we're going to address later in the patchset?
> prot = page_get_flags(old_addr);
> page_set_flags(old_addr, old_addr + old_size, 0);
> - page_set_flags(new_addr, new_addr + new_size, prot | PAGE_VALID);
> + page_set_flags(new_addr, new_addr + new_size,
> + prot | PAGE_VALID | PAGE_RESET);
> }
> tb_invalidate_phys_range(new_addr, new_addr + new_size);
> mmap_unlock();
thanks
-- PMM
