diff options
Diffstat (limited to 'arch/x86/entry/entry_32.S')
| -rw-r--r-- | arch/x86/entry/entry_32.S | 109 |
1 files changed, 37 insertions, 72 deletions
diff --git a/arch/x86/entry/entry_32.S b/arch/x86/entry/entry_32.S index ccb9d32768f3..92c0b4a94e0a 100644 --- a/arch/x86/entry/entry_32.S +++ b/arch/x86/entry/entry_32.S @@ -268,19 +268,16 @@ 1: popl %ds 2: popl %es 3: popl %fs - addl $(4 + \pop), %esp /* pop the unused "gs" slot */ +4: addl $(4 + \pop), %esp /* pop the unused "gs" slot */ IRET_FRAME -.pushsection .fixup, "ax" -4: movl $0, (%esp) - jmp 1b -5: movl $0, (%esp) - jmp 2b -6: movl $0, (%esp) - jmp 3b -.popsection - _ASM_EXTABLE(1b, 4b) - _ASM_EXTABLE(2b, 5b) - _ASM_EXTABLE(3b, 6b) + + /* + * There is no _ASM_EXTABLE_TYPE_REG() for ASM, however since this is + * ASM the registers are known and we can trivially hard-code them. + */ + _ASM_EXTABLE_TYPE(1b, 2b, EX_TYPE_POP_ZERO|EX_REG_DS) + _ASM_EXTABLE_TYPE(2b, 3b, EX_TYPE_POP_ZERO|EX_REG_ES) + _ASM_EXTABLE_TYPE(3b, 4b, EX_TYPE_POP_ZERO|EX_REG_FS) .endm .macro RESTORE_ALL_NMI cr3_reg:req pop=0 @@ -308,7 +305,7 @@ .macro CHECK_AND_APPLY_ESPFIX #ifdef CONFIG_X86_ESPFIX32 #define GDT_ESPFIX_OFFSET (GDT_ENTRY_ESPFIX_SS * 8) -#define GDT_ESPFIX_SS PER_CPU_VAR(gdt_page) + GDT_ESPFIX_OFFSET +#define GDT_ESPFIX_SS PER_CPU_VAR(gdt_page + GDT_ESPFIX_OFFSET) ALTERNATIVE "jmp .Lend_\@", "", X86_BUG_ESPFIX @@ -652,10 +649,6 @@ SYM_CODE_START_LOCAL(asm_\cfunc) SYM_CODE_END(asm_\cfunc) .endm -.macro idtentry_sysvec vector cfunc - idtentry \vector asm_\cfunc \cfunc has_error_code=0 -.endm - /* * Include the defines which emit the idt entries which are shared * shared between 32 and 64 bit and emit the __irqentry_text_* markers @@ -701,7 +694,6 @@ SYM_CODE_START(__switch_to_asm) movl %ebx, PER_CPU_VAR(__stack_chk_guard) #endif -#ifdef CONFIG_RETPOLINE /* * When switching from a shallower to a deeper call stack * the RSB may either underflow or use entries populated @@ -710,7 +702,6 @@ SYM_CODE_START(__switch_to_asm) * speculative execution to prevent attack. */ FILL_RETURN_BUFFER %ebx, RSB_CLEAR_LOOPS, X86_FEATURE_RSB_CTXSW -#endif /* Restore flags or the incoming task to restore AC state. */ popfl @@ -725,26 +716,6 @@ SYM_CODE_END(__switch_to_asm) .popsection /* - * The unwinder expects the last frame on the stack to always be at the same - * offset from the end of the page, which allows it to validate the stack. - * Calling schedule_tail() directly would break that convention because its an - * asmlinkage function so its argument has to be pushed on the stack. This - * wrapper creates a proper "end of stack" frame header before the call. - */ -.pushsection .text, "ax" -SYM_FUNC_START(schedule_tail_wrapper) - FRAME_BEGIN - - pushl %eax - call schedule_tail - popl %eax - - FRAME_END - ret -SYM_FUNC_END(schedule_tail_wrapper) -.popsection - -/* * A newly forked process directly context switches into this address. * * eax: prev task we switched from @@ -752,29 +723,22 @@ SYM_FUNC_END(schedule_tail_wrapper) * edi: kernel thread arg */ .pushsection .text, "ax" -SYM_CODE_START(ret_from_fork) - call schedule_tail_wrapper +SYM_CODE_START(ret_from_fork_asm) + movl %esp, %edx /* regs */ - testl %ebx, %ebx - jnz 1f /* kernel threads are uncommon */ + /* return address for the stack unwinder */ + pushl $.Lsyscall_32_done -2: - /* When we fork, we trace the syscall return in the child, too. */ - movl %esp, %eax - call syscall_exit_to_user_mode - jmp .Lsyscall_32_done + FRAME_BEGIN + /* prev already in EAX */ + movl %ebx, %ecx /* fn */ + pushl %edi /* fn_arg */ + call ret_from_fork + addl $4, %esp + FRAME_END - /* kernel thread */ -1: movl %edi, %eax - CALL_NOSPEC ebx - /* - * A kernel thread is allowed to return here after successfully - * calling kernel_execve(). Exit to userspace to complete the execve() - * syscall. - */ - movl $0, PT_EAX(%esp) - jmp 2b -SYM_CODE_END(ret_from_fork) + RET +SYM_CODE_END(ret_from_fork_asm) .popsection SYM_ENTRY(__begin_SYSENTER_singlestep_region, SYM_L_GLOBAL, SYM_A_NONE) @@ -869,7 +833,7 @@ SYM_FUNC_START(entry_SYSENTER_32) movl %esp, %eax call do_SYSENTER_32 - testl %eax, %eax + testb %al, %al jz .Lsyscall_32_done STACKLEAK_ERASE @@ -907,6 +871,8 @@ SYM_FUNC_START(entry_SYSENTER_32) /* Now ready to switch the cr3 */ SWITCH_TO_USER_CR3 scratch_reg=%eax + /* Clobbers ZF */ + CLEAR_CPU_BUFFERS /* * Restore all flags except IF. (We restore IF separately because @@ -925,10 +891,8 @@ SYM_FUNC_START(entry_SYSENTER_32) sti sysexit -.pushsection .fixup, "ax" -2: movl $0, PT_FS(%esp) - jmp 1b -.popsection +2: movl $0, PT_FS(%esp) + jmp 1b _ASM_EXTABLE(1b, 2b) .Lsysenter_fix_flags: @@ -988,6 +952,7 @@ restore_all_switch_stack: /* Restore user state */ RESTORE_REGS pop=4 # skip orig_eax/error_code + CLEAR_CPU_BUFFERS .Lirq_return: /* * ARCH_HAS_MEMBARRIER_SYNC_CORE rely on IRET core serialization @@ -996,8 +961,7 @@ restore_all_switch_stack: */ iret -.section .fixup, "ax" -SYM_CODE_START(asm_iret_error) +.Lasm_iret_error: pushl $0 # no error code pushl $iret_error @@ -1014,9 +978,8 @@ SYM_CODE_START(asm_iret_error) #endif jmp handle_exception -SYM_CODE_END(asm_iret_error) -.previous - _ASM_EXTABLE(.Lirq_return, asm_iret_error) + + _ASM_EXTABLE(.Lirq_return, .Lasm_iret_error) SYM_FUNC_END(entry_INT80_32) .macro FIXUP_ESPFIX_STACK @@ -1202,6 +1165,7 @@ SYM_CODE_START(asm_exc_nmi) CHECK_AND_APPLY_ESPFIX RESTORE_ALL_NMI cr3_reg=%edi pop=4 + CLEAR_CPU_BUFFERS jmp .Lirq_return #ifdef CONFIG_X86_ESPFIX32 @@ -1243,19 +1207,20 @@ SYM_CODE_START(asm_exc_nmi) * 1 - orig_ax */ lss (1+5+6)*4(%esp), %esp # back to espfix stack + CLEAR_CPU_BUFFERS jmp .Lirq_return #endif SYM_CODE_END(asm_exc_nmi) .pushsection .text, "ax" -SYM_CODE_START(rewind_stack_do_exit) +SYM_CODE_START(rewind_stack_and_make_dead) /* Prevent any naive code from trying to unwind to our caller. */ xorl %ebp, %ebp movl PER_CPU_VAR(cpu_current_top_of_stack), %esi leal -TOP_OF_KERNEL_STACK_PADDING-PTREGS_SIZE(%esi), %esp - call do_exit + call make_task_dead 1: jmp 1b -SYM_CODE_END(rewind_stack_do_exit) +SYM_CODE_END(rewind_stack_and_make_dead) .popsection |