diff options
Diffstat (limited to 'arch/x86/entry/entry_64.S')
| -rw-r--r-- | arch/x86/entry/entry_64.S | 69 |
1 files changed, 2 insertions, 67 deletions
diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S index 7e82e553183a..0d728142467f 100644 --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -142,67 +142,6 @@ END(native_usergs_sysret64) * with them due to bugs in both AMD and Intel CPUs. */ - .pushsection .entry_trampoline, "ax" - -/* - * The code in here gets remapped into cpu_entry_area's trampoline. This means - * that the assembler and linker have the wrong idea as to where this code - * lives (and, in fact, it's mapped more than once, so it's not even at a - * fixed address). So we can't reference any symbols outside the entry - * trampoline and expect it to work. - * - * Instead, we carefully abuse %rip-relative addressing. - * _entry_trampoline(%rip) refers to the start of the remapped) entry - * trampoline. We can thus find cpu_entry_area with this macro: - */ - -#define CPU_ENTRY_AREA \ - _entry_trampoline - CPU_ENTRY_AREA_entry_trampoline(%rip) - -/* The top word of the SYSENTER stack is hot and is usable as scratch space. */ -#define RSP_SCRATCH CPU_ENTRY_AREA_entry_stack + \ - SIZEOF_entry_stack - 8 + CPU_ENTRY_AREA - -ENTRY(entry_SYSCALL_64_trampoline) - UNWIND_HINT_EMPTY - swapgs - - /* Stash the user RSP. */ - movq %rsp, RSP_SCRATCH - - /* Note: using %rsp as a scratch reg. */ - SWITCH_TO_KERNEL_CR3 scratch_reg=%rsp - - /* Load the top of the task stack into RSP */ - movq CPU_ENTRY_AREA_tss + TSS_sp1 + CPU_ENTRY_AREA, %rsp - - /* Start building the simulated IRET frame. */ - pushq $__USER_DS /* pt_regs->ss */ - pushq RSP_SCRATCH /* pt_regs->sp */ - pushq %r11 /* pt_regs->flags */ - pushq $__USER_CS /* pt_regs->cs */ - pushq %rcx /* pt_regs->ip */ - - /* - * x86 lacks a near absolute jump, and we can't jump to the real - * entry text with a relative jump. We could push the target - * address and then use retq, but this destroys the pipeline on - * many CPUs (wasting over 20 cycles on Sandy Bridge). Instead, - * spill RDI and restore it in a second-stage trampoline. - */ - pushq %rdi - movq $entry_SYSCALL_64_stage2, %rdi - JMP_NOSPEC %rdi -END(entry_SYSCALL_64_trampoline) - - .popsection - -ENTRY(entry_SYSCALL_64_stage2) - UNWIND_HINT_EMPTY - popq %rdi - jmp entry_SYSCALL_64_after_hwframe -END(entry_SYSCALL_64_stage2) - ENTRY(entry_SYSCALL_64) UNWIND_HINT_EMPTY /* @@ -212,13 +151,9 @@ ENTRY(entry_SYSCALL_64) */ swapgs - /* - * This path is only taken when PAGE_TABLE_ISOLATION is disabled so it - * is not required to switch CR3. - * - * tss.sp2 is scratch space. - */ + /* tss.sp2 is scratch space. */ movq %rsp, PER_CPU_VAR(cpu_tss_rw + TSS_sp2) + SWITCH_TO_KERNEL_CR3 scratch_reg=%rsp movq PER_CPU_VAR(cpu_current_top_of_stack), %rsp /* Construct struct pt_regs on stack */ |