zephyr/arch/xtensa/core/gen_zsr.py

110 lines
3.7 KiB
Python
Executable File

#!/usr/bin/env python3
# Copyright (c) 2022 Intel corporation
# SPDX-License-Identifier: Apache-2.0
import argparse
import re
# Scratch register allocator. Zephyr uses multiple Xtensa SRs as
# scratch space for various special purposes. Unfortunately the
# configurable architecture means that not all registers will be the
# same on every device. This script parses a pre-cooked ("gcc -E
# -dM") core-isa.h file for the current architecture and assigns
# registers to usages.
def parse_args():
parser = argparse.ArgumentParser(allow_abbrev=False)
parser.add_argument("--coherence", action="store_true",
help="Enable scratch registers for CONFIG_KERNEL_COHERENCE")
parser.add_argument("--mmu", action="store_true",
help="Enable scratch registers for MMU usage")
parser.add_argument("--syscall-scratch", action="store_true",
help="Enable scratch registers for syscalls if needed")
parser.add_argument("coreisa",
help="Path to preprocessed core-isa.h")
parser.add_argument("outfile",
help="Output file")
return parser.parse_args()
args = parse_args()
NEEDED = ["A0SAVE", "CPU"]
if args.mmu:
NEEDED += ["DBLEXC", "DEPC_SAVE", "EXCCAUSE_SAVE"]
if args.coherence:
NEEDED += ["FLUSH"]
coreisa = args.coreisa
outfile = args.outfile
syms = {}
def get(s):
return syms[s] if s in syms else 0
with open(coreisa) as infile:
for line in infile.readlines():
m = re.match(r"^#define\s+([^ ]+)\s*(.*)", line.rstrip())
if m:
syms[m.group(1)] = m.group(2)
# Use MISC registers first if available, that's what they're for
regs = [ f"MISC{n}" for n in range(0, int(get("XCHAL_NUM_MISC_REGS"))) ]
if args.syscall_scratch:
# If there is no THREADPTR, we need to use syscall for
# arch_is_user_context() where the code needs a scratch
# register.
have_threadptr = int(get("XCHAL_HAVE_THREADPTR"))
if have_threadptr == 0:
NEEDED.append("SYSCALL_SCRATCH")
# Next come EXCSAVE. Also record our highest non-debug interrupt level.
maxint = 0
for il in range(1, 1 + int(get("XCHAL_NUM_INTLEVELS"))):
regs.append(f"EXCSAVE{il}")
if il != int(get("XCHAL_DEBUGLEVEL")):
maxint = max(il, maxint)
# Find the highest priority software interrupt. We'll use that for
# arch_irq_offload().
irqoff_level = -1
irqoff_int = -1
for sym, val in syms.items():
if val == "XTHAL_INTTYPE_SOFTWARE":
m = re.match(r"XCHAL_INT(\d+)_TYPE", sym)
if m:
intnum = int(m.group(1))
levelsym = f"XCHAL_INT{intnum}_LEVEL"
if levelsym in syms:
intlevel = int(syms[levelsym])
if intlevel > irqoff_level:
irqoff_int = intnum
irqoff_level = intlevel
# Now emit our output header with the assignments we chose
with open(outfile, "w") as f:
f.write("/* Generated File, see gen_zsr.py */\n")
f.write("#ifndef ZEPHYR_ZSR_H\n")
f.write("#define ZEPHYR_ZSR_H\n")
for i, need in enumerate(NEEDED):
f.write(f"# define ZSR_{need} {regs[i]}\n")
f.write(f"# define ZSR_{need}_STR \"{regs[i]}\"\n")
# Emit any remaining registers as generics
for i in range(len(NEEDED), len(regs)):
f.write(f"# define ZSR_EXTRA{i - len(NEEDED)} {regs[i]}\n")
f.write(f"# define ZSR_EXTRA{i - len(NEEDED)}_STR \"{regs[i]}\"\n")
# Also, our highest level EPC/EPS registers
f.write(f"# define ZSR_RFI_LEVEL {maxint}\n")
f.write(f"# define ZSR_EPC EPC{maxint}\n")
f.write(f"# define ZSR_EPS EPS{maxint}\n")
# And the irq offset interrupt
if irqoff_int >= 0:
f.write(f"# define ZSR_IRQ_OFFLOAD_INT {irqoff_int}\n")
f.write("#endif\n")