fef
7e6dbad05f
The old strategy was to only do context switching from within the PendSV handler. This worked fine until now because all syscalls were handled either atomically or just returned -EAGAIN if the resource was locked or busy. However, with the introduction of I/O wait, we need to be able to sleep directly from within the kernel by moving the context switching completely into the kernel.
138 lines
3.3 KiB
C
138 lines
3.3 KiB
C
/* See the end of this file for copyright, license, and warranty information. */
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#include <arch-generic/hardware.h>
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#include <arch/hardware.h>
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#include <arch/interrupt.h>
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#include <toolchain.h>
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static void uart_write_sync(const char *s)
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{
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char c;
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while ((c = *s++) != '\0') {
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mom_are_we_there_yet(UART->UART_SR & UART_SR_TXRDY);
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UART->UART_THR = c;
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}
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}
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/** Setup UART to manual byte-by-byte control */
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static inline void uart_emergency_setup(void)
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{
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UART->UART_IDR = 0xffffffff;
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mom_are_we_there_yet(UART->UART_SR & UART_SR_TXRDY);
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UART->UART_PTCR = UART_PTCR_RXTDIS | UART_PTCR_TXTDIS;
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UART->UART_CR = UART_CR_RXDIS | UART_CR_RSTRX
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| UART_CR_TXDIS | UART_CR_RSTTX;
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UART->UART_CR = UART_CR_TXEN;
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UART->UART_THR = '\0';
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}
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#pragma GCC diagnostic push
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#pragma GCC diagnostic ignored "-Wswitch"
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static inline void print_err_msg(enum irqno irqno)
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{
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uart_write_sync("\n\n########## SERIOUS BRUH MOMENT! ##########\n");
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switch (irqno) {
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case IRQNO_HARD_FAULT:
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uart_write_sync("Hard");
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break;
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case IRQNO_MM_FAULT:
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uart_write_sync("Memory Management");
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break;
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case IRQNO_BUS_FAULT:
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uart_write_sync("Bus");
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break;
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case IRQNO_USAGE_FAULT:
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uart_write_sync("Usage");
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break;
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}
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uart_write_sync(" Fault encountered, cannot continue\nRegister dump:\n");
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}
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#pragma GCC diagnostic pop /* -Wswitch */
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static void reg_to_str(char *dest, word_t val)
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{
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for (int i = 28; i >= 0; i -= 4) {
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uint8_t digit = (val >> i) & 0x0f;
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if (digit < 0x0a)
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digit += '0';
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else
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digit += 'a' - 0x0a;
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*dest++ = digit;
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}
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}
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static void print_reg(const char *name, word_t val)
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{
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/* static saves stack space, which might be limited */
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static char line[] = "???? = 0x????????\n";
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char c;
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char *name_pos = line;
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while ((c = *name++) != '\0')
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*name_pos++ = c;
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while (name_pos < &line[4])
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*name_pos++ = ' ';
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reg_to_str(&line[9], val);
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uart_write_sync(line);
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}
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static void print_regs(struct exc_context *context)
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{
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print_reg("R0", context->sp->r0);
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print_reg("R1", context->sp->r1);
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print_reg("R2", context->sp->r2);
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print_reg("R3", context->sp->r3);
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print_reg("R4", context->r4);
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print_reg("R5", context->r5);
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print_reg("R6", context->r6);
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print_reg("R7", context->r7);
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print_reg("R8", context->r8);
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print_reg("R9", context->r9);
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print_reg("R10", context->r10);
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print_reg("R11", context->r11);
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print_reg("R12", context->sp->r12);
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print_reg("SP", *(word_t *)&context->sp);
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print_reg("LR", *(word_t *)&context->sp->lr);
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print_reg("PC", *(word_t *)&context->sp->pc);
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print_reg("xPSR", context->sp->psr);
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}
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#include <arch/debug.h>
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__naked __noreturn void handle_fault(struct exc_context *context, enum irqno irqno)
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{
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uart_emergency_setup();
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print_err_msg(irqno);
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print_regs(context);
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if (SCB->HFSR & SCB_HFSR_FORCED_Msk)
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print_reg("CFSR", SCB->CFSR);
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uart_write_sync("\nSystem halted, goodbye\n\n");
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__breakpoint;
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while (1);
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}
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/*
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* This file is part of Ardix.
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* Copyright (c) 2020, 2021 Felix Kopp <owo@fef.moe>.
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*
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* Ardix is non-violent software: you may only use, redistribute,
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* and/or modify it under the terms of the CNPLv6+ as found in
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* the LICENSE file in the source code root directory or at
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* <https://git.pixie.town/thufie/CNPL>.
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*
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* Ardix comes with ABSOLUTELY NO WARRANTY, to the extent
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* permitted by applicable law. See the CNPLv6+ for details.
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*/
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