except for the thread_info structure at the bottom.
In addition to the per thread stacks, there are specialized stacks
except for the thread_info structure at the bottom.
In addition to the per thread stacks, there are specialized stacks
-associated with each cpu. These stacks are only used while the kernel
-is in control on that cpu, when a cpu returns to user space the
-specialized stacks contain no useful data. The main cpu stacks is
+associated with each CPU. These stacks are only used while the kernel
+is in control on that CPU; when a CPU returns to user space the
+specialized stacks contain no useful data. The main CPU stacks are:
to automatically switch to a new stack for designated events such as
double fault or NMI, which makes it easier to handle these unusual
events on x86_64. This feature is called the Interrupt Stack Table
to automatically switch to a new stack for designated events such as
double fault or NMI, which makes it easier to handle these unusual
events on x86_64. This feature is called the Interrupt Stack Table
-(IST). There can be up to 7 IST entries per cpu. The IST code is an
-index into the Task State Segment (TSS), the IST entries in the TSS
-point to dedicated stacks, each stack can be a different size.
+(IST). There can be up to 7 IST entries per CPU. The IST code is an
+index into the Task State Segment (TSS). The IST entries in the TSS
+point to dedicated stacks; each stack can be a different size.
interrupt-gate descriptor. When an interrupt occurs and the hardware
loads such a descriptor, the hardware automatically sets the new stack
pointer based on the IST value, then invokes the interrupt handler. If
software wants to allow nested IST interrupts then the handler must
adjust the IST values on entry to and exit from the interrupt handler.
interrupt-gate descriptor. When an interrupt occurs and the hardware
loads such a descriptor, the hardware automatically sets the new stack
pointer based on the IST value, then invokes the interrupt handler. If
software wants to allow nested IST interrupts then the handler must
adjust the IST values on entry to and exit from the interrupt handler.
Events with different IST codes (i.e. with different stacks) can be
nested. For example, a debug interrupt can safely be interrupted by an
Events with different IST codes (i.e. with different stacks) can be
nested. For example, a debug interrupt can safely be interrupted by an
happens.
* DOUBLEFAULT_STACK. EXCEPTION_STKSZ (PAGE_SIZE).
Used for interrupt 8 - Double Fault Exception (#DF).
happens.
* DOUBLEFAULT_STACK. EXCEPTION_STKSZ (PAGE_SIZE).
Used for interrupt 8 - Double Fault Exception (#DF).
- Invoked when handling a exception causes another exception. Happens
- when the kernel is very confused (e.g. kernel stack pointer corrupt)
- Using a separate stack allows to recover from it well enough in many
- cases to still output an oops.
+ Invoked when handling one exception causes another exception. Happens
+ when the kernel is very confused (e.g. kernel stack pointer corrupt).
+ Using a separate stack allows the kernel to recover from it well enough
+ in many cases to still output an oops.