On Thu, 10 Feb 2022 at 11:30, Alex Bennée <alex.ben...@linaro.org> wrote:
>
> The previous numbers were a guess at best and rather arbitrary without
> taking into account anything that might be loaded. Instead of using
> guesses based on the state of registers implement a new function that:
>
> a) scans the MemoryRegions for the largest RAM block
> b) iterates through all "ROM" blobs looking for the biggest gap
>
> The "ROM" blobs include all code loaded via -kernel and the various
> -device loader techniques.
>
> Signed-off-by: Alex Bennée <alex.ben...@linaro.org>
> Cc: Andrew Strauss <astraus...@gmail.com>
> Cc: Keith Packard <kei...@keithp.com>
> Message-Id: <20210601090715.22330-1-alex.ben...@linaro.org>
>
> +/*
> + * Sort into address order. We break ties between rom-startpoints
> + * and rom-endpoints in favour of the startpoint, by sorting the 0->1
> + * transition before the 1->0 transition. Either way round would
> + * work, but this way saves a little work later by avoiding
> + * dealing with "gaps" of 0 length.
> + */
> +static gint sort_secs(gconstpointer a, gconstpointer b)
> +{
> + RomSec *ra = (RomSec *) a;
> + RomSec *rb = (RomSec *) b;
> +
> + if (ra->base == rb->base) {
> + return ra->se - rb->se;
> + }
> + return ra->base > rb->base ? 1 : -1;
> +}
This sort comparator still doesn't report the equality
case as actually equal.
> /*
> - * Find the chunk of R/W memory containing the address. This is
> - * used for the SYS_HEAPINFO semihosting call, which should
> - * probably be using information from the loaded application.
> + * If we have found the RAM lets iterate through the ROM blobs to
> + * workout the best place for the remainder of RAM and split it
"work out"
> + * equally between stack and heap.
> */
> @@ -1201,12 +1205,15 @@ target_ulong do_common_semihosting(CPUState *cs)
> retvals[2] = ts->stack_base;
> retvals[3] = 0; /* Stack limit. */
> #else
> - limit = current_machine->ram_size;
> - /* TODO: Make this use the limit of the loaded application. */
> - retvals[0] = rambase + limit / 2;
> - retvals[1] = rambase + limit;
> - retvals[2] = rambase + limit; /* Stack base */
> - retvals[3] = rambase; /* Stack limit. */
> + /*
> + * Reporting 0 indicates we couldn't calculate the real
> + * values which should force most software to fall back to
> + * using information it has.
> + */
What is this comment referring to? We aren't obviously
reporting 0 here...
> + retvals[0] = info.heapbase; /* Heap Base */
> + retvals[1] = info.heaplimit; /* Heap Limit */
> + retvals[2] = info.heaplimit; /* Stack base */
> + retvals[3] = info.heapbase; /* Stack limit. */
> #endif
>
> for (i = 0; i < ARRAY_SIZE(retvals); i++) {
Otherwise
Reviewed-by: Peter Maydell <peter.mayd...@linaro.org>
-- PMM
