diff options
Diffstat (limited to 'arch/x86/entry/entry_64.S')
| -rw-r--r-- | arch/x86/entry/entry_64.S | 39 |
1 files changed, 39 insertions, 0 deletions
diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S index d983a0d4bc73..159737062611 100644 --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -1106,6 +1106,45 @@ SYM_CODE_START_LOCAL_NOALIGN(.Lbad_gs) SYM_CODE_END(.Lbad_gs) .previous +/* + * rdi: New stack pointer points to the top word of the stack + * rsi: Function pointer + * rdx: Function argument (can be NULL if none) + */ +SYM_FUNC_START(asm_call_on_stack) + /* + * Save the frame pointer unconditionally. This allows the ORC + * unwinder to handle the stack switch. + */ + pushq %rbp + mov %rsp, %rbp + + /* + * The unwinder relies on the word at the top of the new stack + * page linking back to the previous RSP. + */ + mov %rsp, (%rdi) + mov %rdi, %rsp + /* Move the argument to the right place */ + mov %rdx, %rdi + +1: + .pushsection .discard.instr_begin + .long 1b - . + .popsection + + CALL_NOSPEC rsi + +2: + .pushsection .discard.instr_end + .long 2b - . + .popsection + + /* Restore the previous stack pointer from RBP. */ + leaveq + ret +SYM_FUNC_END(asm_call_on_stack) + /* Call softirq on interrupt stack. Interrupts are off. */ .pushsection .text, "ax" SYM_FUNC_START(do_softirq_own_stack) |