diff options
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/entry/entry_64.S | 55 |
1 files changed, 51 insertions, 4 deletions
diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S index 35b8e949ac2f..42a9379f7acb 100644 --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -326,8 +326,24 @@ syscall_return_via_sysret: popq %rsi /* skip rcx */ popq %rdx popq %rsi + + /* + * Now all regs are restored except RSP and RDI. + * Save old stack pointer and switch to trampoline stack. + */ + movq %rsp, %rdi + movq PER_CPU_VAR(cpu_tss + TSS_sp0), %rsp + + pushq RSP-RDI(%rdi) /* RSP */ + pushq (%rdi) /* RDI */ + + /* + * We are on the trampoline stack. All regs except RDI are live. + * We can do future final exit work right here. + */ + popq %rdi - movq RSP-ORIG_RAX(%rsp), %rsp + popq %rsp USERGS_SYSRET64 END(entry_SYSCALL_64) @@ -630,10 +646,41 @@ GLOBAL(swapgs_restore_regs_and_return_to_usermode) ud2 1: #endif - SWAPGS POP_EXTRA_REGS - POP_C_REGS - addq $8, %rsp /* skip regs->orig_ax */ + popq %r11 + popq %r10 + popq %r9 + popq %r8 + popq %rax + popq %rcx + popq %rdx + popq %rsi + + /* + * The stack is now user RDI, orig_ax, RIP, CS, EFLAGS, RSP, SS. + * Save old stack pointer and switch to trampoline stack. + */ + movq %rsp, %rdi + movq PER_CPU_VAR(cpu_tss + TSS_sp0), %rsp + + /* Copy the IRET frame to the trampoline stack. */ + pushq 6*8(%rdi) /* SS */ + pushq 5*8(%rdi) /* RSP */ + pushq 4*8(%rdi) /* EFLAGS */ + pushq 3*8(%rdi) /* CS */ + pushq 2*8(%rdi) /* RIP */ + + /* Push user RDI on the trampoline stack. */ + pushq (%rdi) + + /* + * We are on the trampoline stack. All regs except RDI are live. + * We can do future final exit work right here. + */ + + /* Restore RDI. */ + popq %rdi + SWAPGS INTERRUPT_RETURN |