rockbox/utils/hwstub/stub/system.h
Amaury Pouly 9bb6050d40 hwstub: rewrite exception catching
Since we can catch exceptions like data aborts on read/write, it takes very
little to also catch exceptions in calls. When extending this with the catching
of illegal instructions, the call instruction now becomes much more robust and
also for address and instruction probing. Since we can catch several types of
exception, rename set_data_abort_jmp to set_exception_jmp. At the same time,
simplify the logic in read/write request handlers. Also fix a bug in ARM
jump code: it was using
  stmia r1, {..., pc}
as if pc would get current pc + 8 but this is actually implementation defined
on older ARMs (typically pc + 12) and deprecated on newer ARMs, so rewrite the
code avoid that. The set_exception_jmp() function now also reports the exception
type.

Change-Id: Icd0dd52d2456b361b27c4776be09c3d13528ed93
2017-01-24 15:34:19 +01:00

135 lines
4.2 KiB
C

/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2012 by Amaury Pouly
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
****************************************************************************/
#ifndef __HWSTUB_SYSTEM__
#define __HWSTUB_SYSTEM__
#ifdef ARM_ARCH
#define IRQ_ENABLED 0x00
#define IRQ_DISABLED 0x80
#define IRQ_STATUS 0x80
#define FIQ_ENABLED 0x00
#define FIQ_DISABLED 0x40
#define FIQ_STATUS 0x40
#define IRQ_FIQ_ENABLED 0x00
#define IRQ_FIQ_DISABLED 0xc0
#define IRQ_FIQ_STATUS 0xc0
#define HIGHEST_IRQ_LEVEL IRQ_DISABLED
#define set_irq_level(status) \
set_interrupt_status((status), IRQ_STATUS)
#define set_fiq_status(status) \
set_interrupt_status((status), FIQ_STATUS)
#define disable_irq_save() \
disable_interrupt_save(IRQ_STATUS)
#define disable_fiq_save() \
disable_interrupt_save(FIQ_STATUS)
#define restore_irq(cpsr) \
restore_interrupt(cpsr)
#define restore_fiq(cpsr) \
restore_interrupt(cpsr)
#define disable_irq() \
disable_interrupt(IRQ_STATUS)
#define enable_irq() \
enable_interrupt(IRQ_STATUS)
#define disable_fiq() \
disable_interrupt(FIQ_STATUS)
#define enable_fiq() \
enable_interrupt(FIQ_STATUS)
#ifndef __ASSEMBLER__
static inline int set_interrupt_status(int status, int mask)
{
unsigned long cpsr;
int oldstatus;
/* Read the old levels and set the new ones */
asm volatile (
"mrs %1, cpsr \n"
"bic %0, %1, %[mask] \n"
"orr %0, %0, %2 \n"
"msr cpsr_c, %0 \n"
: "=&r,r"(cpsr), "=&r,r"(oldstatus)
: "r,i"(status & mask), [mask]"i,i"(mask));
return oldstatus;
}
static inline void restore_interrupt(int cpsr)
{
/* Set cpsr_c from value returned by disable_interrupt_save
* or set_interrupt_status */
asm volatile ("msr cpsr_c, %0" : : "r"(cpsr));
}
static inline void enable_interrupt(int mask)
{
/* Clear I and/or F disable bit */
int tmp;
asm volatile (
"mrs %0, cpsr \n"
"bic %0, %0, %1 \n"
"msr cpsr_c, %0 \n"
: "=&r"(tmp) : "i"(mask));
}
static inline void disable_interrupt(int mask)
{
/* Set I and/or F disable bit */
int tmp;
asm volatile (
"mrs %0, cpsr \n"
"orr %0, %0, %1 \n"
"msr cpsr_c, %0 \n"
: "=&r"(tmp) : "i"(mask));
}
static inline int disable_interrupt_save(int mask)
{
/* Set I and/or F disable bit and return old cpsr value */
int cpsr, tmp;
asm volatile (
"mrs %1, cpsr \n"
"orr %0, %1, %2 \n"
"msr cpsr_c, %0 \n"
: "=&r"(tmp), "=&r"(cpsr)
: "i"(mask));
return cpsr;
}
#endif /* __ASSEMBLER__ */
#endif /* ARM_ARCH */
/* Save the current context into a local buffer and return 0.
* When an exception occurs, typically read/write at invalid address or invalid
* instructions (the exact exceptions caught depend on the architecture), it will
* restore the context to what it was when the function was called except that
* it returns a nonzero value describing the error */
#define EXCEPTION_NONE 0 /* no exception, returned on the first call */
#define EXCEPTION_UNSP 1 /* some unspecified exception occured */
#define EXCEPTION_ADDR 2 /* read/write at an invalid address */
#define EXCEPTION_INSTR 3 /* invalid instruction */
#ifndef __ASSEMBLER__
int set_exception_jmp(void);
#endif /* __ASSEMBLER__ */
#endif /* __HWSTUB_SYSTEM__ */