lib: sbi: Enable Ssqosid Ext using mstateen0

The QoS Identifiers extension (Ssqosid) introduces the srmcfg register,
which configures a hart with two identifiers: a Resource Control ID
(RCID) and a Monitoring Counter ID (MCID). These identifiers accompany
each request issued by the hart to shared resource controllers.

If extension Smstateen is implemented together with Ssqosid, then
Ssqosid also requires the SRMCFG bit in mstateen0 to be implemented. If
mstateen0.SRMCFG is 0, attempts to access srmcfg in privilege modes less
privileged than M-mode raise an illegal-instruction exception. If
mstateen0.SRMCFG is 1 or if extension Smstateen is not implemented,
attempts to access srmcfg when V=1 raise a virtual-instruction exception.

This extension can be found in the RISC-V Instruction Set Manual:
https://github.com/riscv/riscv-isa-manual

Changes in v5:
 - Remove SBI_HART_EXT_SSQOSID dependency SBI_HART_PRIV_VER_1_12

Changes in v4:
 - Remove extraneous parentheses around SMSTATEEN0_SRMCFG

Changes in v3:
 - Check SBI_HART_EXT_SSQOSID when swapping SRMCFG

Changes in v2:
 - Remove trap-n-detect
 - Context switch CSR_SRMCFG

Signed-off-by: Chen Pei <cp0613@linux.alibaba.com>
Reviewed-by: Radim Krčmář <rkrcmar@ventanamicro.com>
Link: https://lore.kernel.org/r/20251114115722.1831-1-cp0613@linux.alibaba.com
Signed-off-by: Anup Patel <anup@brainfault.org>

0 files changed, 0 insertions, 0 deletions