diff options
Diffstat (limited to 'Documentation/x86/x86_64/kernel-stacks')
| -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 a01eec5d1d0b..e3c8a49d1a2f 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 | |||
| 40 | interrupt-gate descriptor. When an interrupt occurs and the hardware | 40 | interrupt-gate descriptor. When an interrupt occurs and the hardware |
| 41 | loads such a descriptor, the hardware automatically sets the new stack | 41 | loads such a descriptor, the hardware automatically sets the new stack |
| 42 | pointer based on the IST value, then invokes the interrupt handler. If | 42 | pointer based on the IST value, then invokes the interrupt handler. If |
| 43 | software wants to allow nested IST interrupts then the handler must | 43 | the interrupt came from user mode, then the interrupt handler prologue |
| 44 | adjust the IST values on entry to and exit from the interrupt handler. | 44 | will switch back to the per-thread stack. If software wants to allow |
| 45 | (This is occasionally done, e.g. for debug exceptions.) | 45 | nested IST interrupts then the handler must adjust the IST values on |
| 46 | entry to and exit from the interrupt handler. (This is occasionally | ||
| 47 | done, e.g. for debug exceptions.) | ||
| 46 | 48 | ||
| 47 | Events with different IST codes (i.e. with different stacks) can be | 49 | Events with different IST codes (i.e. with different stacks) can be |
| 48 | nested. For example, a debug interrupt can safely be interrupted by an | 50 | nested. For example, a debug interrupt can safely be interrupted by an |