diff options
Diffstat (limited to 'arch/x86/entry/entry_32.S')
| -rw-r--r-- | arch/x86/entry/entry_32.S | 95 |
1 files changed, 4 insertions, 91 deletions
diff --git a/arch/x86/entry/entry_32.S b/arch/x86/entry/entry_32.S index ff0034740900..ccb9d32768f3 100644 --- a/arch/x86/entry/entry_32.S +++ b/arch/x86/entry/entry_32.S @@ -20,7 +20,7 @@ * 1C(%esp) - %ds * 20(%esp) - %es * 24(%esp) - %fs - * 28(%esp) - %gs saved iff !CONFIG_X86_32_LAZY_GS + * 28(%esp) - unused -- was %gs on old stackprotector kernels * 2C(%esp) - orig_eax * 30(%esp) - %eip * 34(%esp) - %cs @@ -53,83 +53,6 @@ #define PTI_SWITCH_MASK (1 << PAGE_SHIFT) -/* - * User gs save/restore - * - * %gs is used for userland TLS and kernel only uses it for stack - * canary which is required to be at %gs:20 by gcc. Read the comment - * at the top of stackprotector.h for more info. - * - * Local labels 98 and 99 are used. - */ -#ifdef CONFIG_X86_32_LAZY_GS - - /* unfortunately push/pop can't be no-op */ -.macro PUSH_GS - pushl $0 -.endm -.macro POP_GS pop=0 - addl $(4 + \pop), %esp -.endm -.macro POP_GS_EX -.endm - - /* all the rest are no-op */ -.macro PTGS_TO_GS -.endm -.macro PTGS_TO_GS_EX -.endm -.macro GS_TO_REG reg -.endm -.macro REG_TO_PTGS reg -.endm -.macro SET_KERNEL_GS reg -.endm - -#else /* CONFIG_X86_32_LAZY_GS */ - -.macro PUSH_GS - pushl %gs -.endm - -.macro POP_GS pop=0 -98: popl %gs - .if \pop <> 0 - add $\pop, %esp - .endif -.endm -.macro POP_GS_EX -.pushsection .fixup, "ax" -99: movl $0, (%esp) - jmp 98b -.popsection - _ASM_EXTABLE(98b, 99b) -.endm - -.macro PTGS_TO_GS -98: mov PT_GS(%esp), %gs -.endm -.macro PTGS_TO_GS_EX -.pushsection .fixup, "ax" -99: movl $0, PT_GS(%esp) - jmp 98b -.popsection - _ASM_EXTABLE(98b, 99b) -.endm - -.macro GS_TO_REG reg - movl %gs, \reg -.endm -.macro REG_TO_PTGS reg - movl \reg, PT_GS(%esp) -.endm -.macro SET_KERNEL_GS reg - movl $(__KERNEL_STACK_CANARY), \reg - movl \reg, %gs -.endm - -#endif /* CONFIG_X86_32_LAZY_GS */ - /* Unconditionally switch to user cr3 */ .macro SWITCH_TO_USER_CR3 scratch_reg:req ALTERNATIVE "jmp .Lend_\@", "", X86_FEATURE_PTI @@ -282,7 +205,7 @@ .macro SAVE_ALL pt_regs_ax=%eax switch_stacks=0 skip_gs=0 unwind_espfix=0 cld .if \skip_gs == 0 - PUSH_GS + pushl $0 .endif pushl %fs @@ -307,9 +230,6 @@ movl $(__USER_DS), %edx movl %edx, %ds movl %edx, %es -.if \skip_gs == 0 - SET_KERNEL_GS %edx -.endif /* Switch to kernel stack if necessary */ .if \switch_stacks > 0 SWITCH_TO_KERNEL_STACK @@ -348,7 +268,7 @@ 1: popl %ds 2: popl %es 3: popl %fs - POP_GS \pop + addl $(4 + \pop), %esp /* pop the unused "gs" slot */ IRET_FRAME .pushsection .fixup, "ax" 4: movl $0, (%esp) @@ -361,7 +281,6 @@ _ASM_EXTABLE(1b, 4b) _ASM_EXTABLE(2b, 5b) _ASM_EXTABLE(3b, 6b) - POP_GS_EX .endm .macro RESTORE_ALL_NMI cr3_reg:req pop=0 @@ -779,7 +698,7 @@ SYM_CODE_START(__switch_to_asm) #ifdef CONFIG_STACKPROTECTOR movl TASK_stack_canary(%edx), %ebx - movl %ebx, PER_CPU_VAR(stack_canary)+stack_canary_offset + movl %ebx, PER_CPU_VAR(__stack_chk_guard) #endif #ifdef CONFIG_RETPOLINE @@ -976,7 +895,6 @@ SYM_FUNC_START(entry_SYSENTER_32) movl PT_EIP(%esp), %edx /* pt_regs->ip */ movl PT_OLDESP(%esp), %ecx /* pt_regs->sp */ 1: mov PT_FS(%esp), %fs - PTGS_TO_GS popl %ebx /* pt_regs->bx */ addl $2*4, %esp /* skip pt_regs->cx and pt_regs->dx */ @@ -1012,7 +930,6 @@ SYM_FUNC_START(entry_SYSENTER_32) jmp 1b .popsection _ASM_EXTABLE(1b, 2b) - PTGS_TO_GS_EX .Lsysenter_fix_flags: pushl $X86_EFLAGS_FIXED @@ -1154,11 +1071,7 @@ SYM_CODE_START_LOCAL_NOALIGN(handle_exception) SAVE_ALL switch_stacks=1 skip_gs=1 unwind_espfix=1 ENCODE_FRAME_POINTER - /* fixup %gs */ - GS_TO_REG %ecx movl PT_GS(%esp), %edi # get the function address - REG_TO_PTGS %ecx - SET_KERNEL_GS %ecx /* fixup orig %eax */ movl PT_ORIG_EAX(%esp), %edx # get the error code |