linux-toradex.git/arch/riscv/kernel/cpu_ops.c, branch v6.10

riscv: Use the same CPU operations for all CPUs

2024-01-04T23:03:07+00:00

RISC-V provides no binding (ACPI or DT) to describe per-cpu start/stop
operations, so cpu_set_ops() will always detect the same operations for
every CPU. Replace the cpu_ops array with a single pointer to save space
and reduce boot time.

Signed-off-by: Samuel Holland 
Reviewed-by: Conor Dooley 
Link: https://lore.kernel.org/r/20231121234736.3489608-4-samuel.holland@sifive.com
Signed-off-by: Palmer Dabbelt

riscv: Remove unused members from struct cpu_operations

2024-01-04T23:03:06+00:00

name is not used anywhere at all. cpu_prepare and cpu_disable do nothing
and always return 0 if implemented.

Signed-off-by: Samuel Holland 
Reviewed-by: Conor Dooley 
Link: https://lore.kernel.org/r/20231121234736.3489608-3-samuel.holland@sifive.com
Signed-off-by: Palmer Dabbelt

RISC-V: Align SBI probe implementation with spec

2023-04-29T20:04:50+00:00

sbi_probe_extension() is specified with "Returns 0 if the given SBI
extension ID (EID) is not available, or 1 if it is available unless
defined as any other non-zero value by the implementation."
Additionally, sbiret.value is a long. Fix the implementation to
ensure any nonzero long value is considered a success, rather
than only positive int values.

Fixes: b9dcd9e41587 ("RISC-V: Add basic support for SBI v0.2")
Signed-off-by: Andrew Jones 
Reviewed-by: Conor Dooley 
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20230427163626.101042-1-ajones@ventanamicro.com
Signed-off-by: Palmer Dabbelt

riscv: ensure cpu_ops_sbi is declared

2022-08-11T20:46:51+00:00

Sparse complains that cpu_ops_sbi is used undeclared:
arch/riscv/kernel/cpu_ops_sbi.c:17:29: warning: symbol 'cpu_ops_sbi' was not declared. Should it be static?

Fix the warning by adding cpu_ops_sbi to cpu_ops_sbi.h & including that
where used.

Signed-off-by: Conor Dooley 
Link: https://lore.kernel.org/r/20220714080235.3853374-1-conor.dooley@microchip.com
Signed-off-by: Palmer Dabbelt

RISC-V: Declare cpu_ops_spinwait in

2022-08-11T20:06:47+00:00

The cpu_ops_spinwait is used in a couple of places in arch/riscv
and is causing a sparse warning due to no declaration. Add this
to  with the others to fix the following:

arch/riscv/kernel/cpu_ops_spinwait.c:16:29: warning: symbol 'cpu_ops_spinwait' was not declared. Should it be static?

Signed-off-by: Ben Dooks 
Link: https://lore.kernel.org/r/20220714071811.187491-1-ben.dooks@sifive.com
[Palmer: Drop the extern from cpu_ops.c]
Fixes: 2ffc48fc7071 ("RISC-V: Move spinwait booting method to its own config")
Cc: stable@vger.kernel.org
Signed-off-by: Palmer Dabbelt

RISC-V: Move spinwait booting method to its own config

2022-01-20T17:27:16+00:00

The spinwait booting method should only be used for platforms with older
firmware without SBI HSM extension or M-mode firmware because spinwait
method can't support cpu hotplug, kexec or sparse hartid. It is better
to move the entire spinwait implementation to its own config which can
be disabled if required. It is enabled by default to maintain backward
compatibility and M-mode Linux.

Reviewed-by: Anup Patel 
Signed-off-by: Atish Patra 
Signed-off-by: Palmer Dabbelt

RISC-V: Use __cpu_up_stack/task_pointer only for spinwait method

2022-01-20T17:27:08+00:00

The __cpu_up_stack/task_pointer array is only used for spinwait method
now. The per cpu array based lookup is also fragile for platforms with
discontiguous/sparse hartids. The spinwait method is only used for
M-mode Linux or older firmwares without SBI HSM extension. For general
Linux systems, ordered booting method is preferred anyways to support
cpu hotplug and kexec.

Make sure that __cpu_up_stack/task_pointer is only used for spinwait
method. Take this opportunity to rename it to
__cpu_spinwait_stack/task_pointer to emphasize the purpose as well.

Reviewed-by: Anup Patel 
Signed-off-by: Atish Patra 
Signed-off-by: Palmer Dabbelt

RISC-V: Do not print the SBI version during HSM extension boot print

2022-01-20T17:27:03+00:00

The HSM extension information log also prints the SBI version v0.2. This
is misleading as the underlying firmware SBI version may be different
from v0.2.

Remove the unncessary printing of SBI version.

Signed-off-by: Atish Patra 
Reviewed-by: Anup Patel 
Signed-off-by: Palmer Dabbelt

treewide: Convert macro and uses of section(foo) to section("foo")

2020-10-25T21:51:49+00:00

Use a more generic form for __section that requires quotes to avoid
complications with clang and gcc differences.

Remove the quote operator # from compiler_attributes.h __section macro.

Convert all unquoted __section(foo) uses to quoted __section("foo").
Also convert __attribute__((section("foo"))) uses to __section("foo")
even if the __attribute__ has multiple list entry forms.

Conversion done using the script at:

    https://lore.kernel.org/lkml/75393e5ddc272dc7403de74d645e6c6e0f4e70eb.camel@perches.com/2-convert_section.pl

Signed-off-by: Joe Perches 
Reviewed-by: Nick Desaulniers 
Reviewed-by: Miguel Ojeda 
Signed-off-by: Linus Torvalds

riscv: force __cpu_up_ variables to put in data section

2020-05-04T22:03:25+00:00

Put __cpu_up_stack_pointer and __cpu_up_task_pointer in data section.
Currently, these two variables are put in bss section, there is a
potential risk that secondary harts get the uninitialized value before
main hart finishing the bss clearing. In this case, all secondary
harts would pass the waiting loop and enable the MMU before main hart
set up the page table.

This issue happens on random booting of multiple harts, which means
it will manifest for BBL and OpenSBI v0.6 (or older version). In OpenSBI
v0.7 (or higher version), we have HSM extension so all the secondary harts
are brought-up by Linux kernel in an orderly fashion. This means we don't
need this change for OpenSBI v0.7 (or higher version).

Signed-off-by: Zong Li 
Reviewed-by: Greentime Hu 
Reviewed-by: Anup Patel 
Reviewed-by: Atish Patra 
Signed-off-by: Palmer Dabbelt