diff options
Diffstat (limited to 'Documentation/x86/x86_64')
| -rw-r--r-- | Documentation/x86/x86_64/kernel-stacks | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/Documentation/x86/x86_64/kernel-stacks b/Documentation/x86/x86_64/kernel-stacks index a01eec5..e3c8a49 100644 --- a/Documentation/x86/x86_64/kernel-stacks +++ b/Documentation/x86/x86_64/kernel-stacks @@ -40,9 +40,11 @@ An IST is selected by a non-zero value in the IST field of an 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. -(This is occasionally done, e.g. for debug exceptions.) +the interrupt came from user mode, then the interrupt handler prologue +will switch back to the per-thread stack. 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. (This is occasionally +done, e.g. for debug exceptions.) Events with different IST codes (i.e. with different stacks) can be nested. For example, a debug interrupt can safely be interrupted by an |
