67 lines
2.7 KiB
C
67 lines
2.7 KiB
C
//---
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// gint:exc - Exception handling
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//
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// This small module is used to display exceptions and configure when the
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// exception handler displays these messages. This is for advanced users
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// only!
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//---
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#ifndef GINT_EXC
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#define GINT_EXC
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#include <gint/defs/attributes.h>
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#include <stdint.h>
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/* gint_panic(): Panic handler function
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This function is called when an uncaught CPU exception is generated. By
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default, it displays a full-screen error message with the event code and
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basic debugging information. Some custom event codes may be used for kernel
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failure scenarios. This function never returns. */
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GNORETURN void gint_panic(uint32_t code);
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/* gint_panic_set(): Change the panic handler function
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Sets up a different panic function instead of the default. It the argument
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is NULL, restores the default. */
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void gint_panic_set(GNORETURN void (*panic)(uint32_t code));
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/* gint_exc_catch(): Set a function to catch exceptions
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Sets up an exception-catching function. If an exception occurs, before a
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panic is raised, the exception-catching function is executed in interrupt
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mode and is given a chance to handle the exception. Passing NULL disables
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this feature.
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The exception-catching function can do anything that does not use interrupts
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or causes an exception, such as logging the exception or any other useful
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mechanism.
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What happens next depends on the return value:
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* If it returns 0, the exception is considered handled and execution
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continues normally at or after the offending instruction.
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* If it returns nonzero, a panic is raised.
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Please be aware that many exceptions are of re-execution type. When
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execution restarts after such an exception is handled, the offending
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instruction if re-executed. This can cause the exception handling mechanism
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to loop. Use gint_exc_skip() to skip over the offending instruction when
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needed. Whether an exception is of re-execution type depends on the
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exception code. */
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void gint_exc_catch(int (*handler)(uint32_t code));
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/* gint_exc_skip(): Skip pending exception instructions
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Many exceptions re-execute the offending instruction after the exception is
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handled. For instance the TLB miss handler is supposed to load the required
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page into memory, so that the instruction that accessed unmapped memory can
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be successfully re-executed.
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When an exception-catching function records an exception without solving it,
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this re-execution will fail again and the exception handling process will
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loop. In such a situation, gint_exc_skip() can be used to manually skip the
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offending instruction.
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@instructions Number of instructions to skip (usually only one) */
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void gint_exc_skip(int instructions);
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#endif /* GINT_EXC */
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