Здравствуйте, Pzz, Вы писали:

Pzz>В защищенных режимах, когда происходит прерывание, то обычно сначала аппаратура переключает стек на стек ядра, а потом уже в него гадит.

В оригинальном сообщении нигде не сказано что речь идет о пользовательской программе. Как известно операционные системы тоже пишутся на C. И если мы уже в ядре то фраза "переключает стек на стек ядра" становится непонятной.

А при работе в режиме ядра возможны прерывания как с переключением стека так и без него о чем я уже писал в сообщении выше.

https://software.intel.com/sites/default/files/managed/a4/60/325384-sdm-vol-3abcd.pdf

6.12.1

If the handler procedure is going to be executed at a numerically lower privilege level, a stack switch occurs.
When the stack switch occurs:
a. The segment selector and stack pointer for the stack to be used by the handler are obtained from the TSS for the currently executing task. On this new stack, the processor pushes the stack segment selector and stack pointer of the interrupted procedure.
b. The processor then saves the current state of the EFLAGS, CS, and EIP registers on the new stack (see Figures 6-4).
c. If an exception causes an error code to be saved, it is pushed on the new stack after the EIP value.
• If the handler procedure is going to be executed at the same privilege level as the interrupted procedure:
a. The processor saves the current state of the EFLAGS, CS, and EIP registers on the current stack (see Figures 6-4).
b. If an exception causes an error code to be saved, it is pushed on the current stack after the EIP value.

...

To return from an exception- or interrupt-handler procedure, the handler must use the IRET (or IRETD) instruction.
The IRET instruction is similar to the RET instruction except that it restores the saved flags into the EFLAGS register. The IOPL field of the EFLAGS register is restored only if the CPL is 0. The IF flag is changed only if the CPL is less than or equal to the IOPL. See Chapter 3, "Instruction Set Reference, A-L," of the Intel® 64 and IA-32 Architectures Software Developer’s Manual, Volume 2A, for a description of the complete operation performed by the IRET instruction.
If a stack switch occurred when calling the handler procedure, the IRET instruction switches back to the interrupted procedure’s stack on the return.

Здравствуйте, Pzz, Вы писали:

Pzz>В защищенных режимах, когда происходит прерывание, то обычно сначала аппаратура переключает стек на стек ядра, а потом уже в него гадит.

В оригинальном сообщении нигде не сказано что речь идет о пользовательской программе. Как известно операционные системы тоже пишутся на C. И если мы уже в ядре то фраза "переключает стек на стек ядра" становится непонятной.

А при работе в режиме ядра возможны прерывания как с переключением стека так и без него о чем я уже писал в сообщении выше.

https://software.intel.com/sites/default/files/managed/a4/60/325384-sdm-vol-3abcd.pdf

6.12.1

• If the handler procedure is going to be executed at a numerically lower privilege level, a stack switch occurs.
When the stack switch occurs:
a. The segment selector and stack pointer for the stack to be used by the handler are obtained from the TSS for the currently executing task. On this new stack, the processor pushes the stack segment selector and stack pointer of the interrupted procedure.
b. The processor then saves the current state of the EFLAGS, CS, and EIP registers on the new stack (see Figures 6-4).
c. If an exception causes an error code to be saved, it is pushed on the new stack after the EIP value.
• If the handler procedure is going to be executed at the same privilege level as the interrupted procedure:
a. The processor saves the current state of the EFLAGS, CS, and EIP registers on the current stack (see Figures 6-4).
b. If an exception causes an error code to be saved, it is pushed on the current stack after the EIP value.

...

To return from an exception- or interrupt-handler procedure, the handler must use the IRET (or IRETD) instruction.
The IRET instruction is similar to the RET instruction except that it restores the saved flags into the EFLAGS register. The IOPL field of the EFLAGS register is restored only if the CPL is 0. The IF flag is changed only if the CPL is less than or equal to the IOPL. See Chapter 3, "Instruction Set Reference, A-L," of the Intel® 64 and IA-32 Architectures Software Developer’s Manual, Volume 2A, for a description of the complete operation performed by the IRET instruction.
If a stack switch occurred when calling the handler procedure, the IRET instruction switches back to the interrupted procedure’s stack on the return.