There is currently no helper for iterating through the harts in a
system, and code must choose between sbi_scratch_last_hartindex() and
sbi_platform_hart_count() for the loop condition.
sbi_scratch_last_hartindex() has unusual semantics, leading to the
likelihood of off-by-one errors, and sbi_platform_hart_count() is
provided by the platform and so may not be properly bounded.
Add a new helper which definitively reports the number of harts managed
by this OpenSBI instance, i.e. the number of valid hart indexes, and a
convenient iterator macro.
Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
The compiler generates much better code for sbi_hartindex_to_hartid()
and sbi_hartindex_to_scratch() when using a constant for the bounds
check. This works out nicely because the underlying arrays are already
a constant size, so the only change needed is to fill the remainder of
each array with the appropriate default/out-of-bounds value. The
ellipsis in the designated initializer is a GCC extension (also
supported by Clang), but avoids runtime initialization of the array.
Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
The internal limit on the number of harts is SBI_HARTMASK_MAX_BITS, as
this value determines the size of various bitmaps and arrays (including
hartindex_to_hartid_table and hartindex_to_scratch_table). Clamp the
value provided by the platform, and drop the extra array element.
Update the documentation to indicate that hart_index2id must be sized
based on hart_count, and that hart indexes must be contiguous. As of
commit 5e90e54a1a ("lib: utils:Check that hartid is valid"), there is
no restriction on the valid hart ID values.
Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
The sbi_scratch_last_hartid() macro is not of much use on platforms
with really sparse hartids so let us replace use of this macro with
other approaches.
Signed-off-by: Anup Patel <apatel@ventanamicro.com>
We introduce HART index and related helper functions in sbi_scratch
where HART index is contiguous and each HART index maps to a physical
HART id such that 0 <= HART index and HART index < SBI_HARTMASK_MAX_BITS.
The HART index to HART id mapping follows the index2id mapping provided
by the platform. If the platform does not provide index2id mapping then
identity mapping is assumed.
Signed-off-by: Anup Patel <apatel@ventanamicro.com>
The scratch space being a scarce resource so let us print it's
size and usage at boot time.
Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
In sbi_scratch_init() we determine the last hart. The index of the last
hart cannot exceed SBI_HARTMASK_MAX_BITS - 1. We should not initialize
last_hartid_having_scratch to a higher number to avoid buffer overflows
when using this value before calling sbi_scratch_init().
When allocating scratch memory in sbi_scratch_alloc_offset() we zero out
the allocated memory for all harts except for the last one. We should not
skip the last hart.
Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Reviewed-by: Anup Patel <anup.patel@wdc.com>
The parameter owner of function sbi_scratch_alloc_offset() is never used.
The scratch memory is small. We should not use it for debug information in
future. Hence eliminate the parameter.
Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Reviewed-by: Xiang W <wxjstz@126.com>
Reviewed-by: Anup Patel <anup.patel@wdc.com>
The patch adds sbi_scratch_last_hartid() API which returns
last HART id having a scratch space. We can use this new API
to optimize places where we iterate over HART id from 0 to
SBI_HARTMASK_MAX_BITS.
Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>
A platform can have discontinuous and/or sparse HART ids so we
cannot always assume a set of HARTs with continuous HART ids.
This patch adds support for discontinuous and sparse HART ids by
introducing HART index to HART id table. This table has platform
hart_count entries and it maps HART index to HART id.
The HART index to HART id table has only two restrictions:
1. HART index < sbi_platform hart_count
2. HART id < SBI_HARTMASK_MAX_BITS
Example1:
Let's say we have a platform with 2 HART ids 11 and 22, for such a
a platform:
hart_count = 2
hart_index2id[0] = 11
hart_index2id[1] = 22
Example2:
Let's say we have a platform with 5 HARTs ids 0, 1, 2, 3, and 4
but out of these HART with id 0 is not usable so for such a platform:
hart_count = 5
hart_index2id[0] = -1U
hart_index2id[1] = 1
hart_index2id[2] = 2
hart_index2id[3] = 3
hart_index2id[4] = 4
OR
hart_count = 4
hart_index2id[0] = 1
hart_index2id[1] = 2
hart_index2id[2] = 3
hart_index2id[3] = 4
With HART index to HART id table in place, the hart_disabled()
callback is now redundant so we remove it as well.
Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>
We don't need to use sbi_platform_hart_count() in sbi_init and
sbi_scratch because checking sbi_platform_hart_disabled() or
return value of sbi_hartid_to_scratch() is sufficient.
Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>
As a step towards supporting discontinuous and sparse HART ids, we
don't set hartid_to_scratch table for disabled HARTs.
Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>
The sbi_hartid_to_scratch() API can fail for non-existent HARTs so
all uses of sbi_hartid_to_scratch() API should check return value.
Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>
This patch simplify HART id to scratch macro as follows:
1. Remove current "scratch" pointer argument because now we
use HART id to scratch table
2. Rename sbi_hart_id_to_scratch() to sbi_hartid_to_scratch()
to have macro name consistent with the name of callback
in struct sbi_scratch
Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>
Instead of calling hartid_to_scratch() callback every time when
we want sbi_scratch pointer from HART id, we create a table of
sbi_scratch pointers and use that to get sbi_scratch pointer.
As a result of HART id to scratch table, the conversion of
HART id to sbi_scratch pointer is just 2-3 instructions which
was 9 instructions previously.
Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>
We should zero-out memory allocated from extra scratch space using
sbi_scratch_alloc_offset() API hence this patch. This will not
impact performance because we mostly allocate from extra scratch
space only at cold boot time.
Signed-off-by: Anup Patel <anup@brainfault.org>
Reviewed-by: Atish Patra <atish.patra@wdc.com>
