diff options
Diffstat (limited to 'sysdeps/unix/sysv/linux/i386/makecontext.S')
| -rw-r--r-- | sysdeps/unix/sysv/linux/i386/makecontext.S | 123 |
1 files changed, 0 insertions, 123 deletions
diff --git a/sysdeps/unix/sysv/linux/i386/makecontext.S b/sysdeps/unix/sysv/linux/i386/makecontext.S index 814127d130..7ee56300fa 100644 --- a/sysdeps/unix/sysv/linux/i386/makecontext.S +++ b/sysdeps/unix/sysv/linux/i386/makecontext.S @@ -17,7 +17,6 @@ <https://www.gnu.org/licenses/>. */ #include <sysdep.h> -#include <asm/prctl.h> #include "ucontext_i.h" @@ -68,127 +67,6 @@ ENTRY(__makecontext) jnz 1b 2: -#if SHSTK_ENABLED - /* Check if Shadow Stack is enabled. */ - testl $X86_FEATURE_1_SHSTK, %gs:FEATURE_1_OFFSET - jz L(skip_ssp) - - /* Reload the pointer to ucontext. */ - movl 4(%esp), %eax - - /* Shadow stack is enabled. We need to allocate a new shadow - stack. */ - subl oSS_SP(%eax), %edx - shrl $STACK_SIZE_TO_SHADOW_STACK_SIZE_SHIFT, %edx - - /* Align shadow stack size to 8 bytes. */ - addl $7, %edx - andl $-8, %edx - - /* Store shadow stack size in __ssp[2]. */ - movl %edx, (oSSP + 8)(%eax) - - /* Save ESI in the second scratch register slot. */ - movl %esi, oSCRATCH2(%eax) - /* Save EDI in the third scratch register slot. */ - movl %edi, oSCRATCH3(%eax) - - /* Save the pointer to ucontext. */ - movl %eax, %edi - - /* Get the original shadow stack pointer. */ - rdsspd %esi - - /* Align the saved original shadow stack pointer to the next - 8 byte aligned boundary. */ - andl $-8, %esi - - /* Load the top of the new stack into EDX. */ - movl oESP(%eax), %edx - - /* We need to terminate the FDE here because the unwinder looks - at ra-1 for unwind information. */ - cfi_endproc - - /* Swap the original stack pointer with the top of the new - stack. */ - xchgl %esp, %edx - - /* Add 4 bytes since CALL will push the 4-byte return address - onto stack. */ - addl $4, %esp - - /* Allocate the new shadow stack. Save EBX in the first scratch - register slot. */ - movl %ebx, oSCRATCH1(%eax) - - /* CET syscall takes 64-bit sizes. */ - subl $16, %esp - movl (oSSP + 8)(%eax), %ecx - movl %ecx, (%esp) - movl $0, 4(%esp) - movl %ecx, 8(%esp) - movl $0, 12(%esp) - movl %esp, %ecx - - movl $ARCH_CET_ALLOC_SHSTK, %ebx - movl $__NR_arch_prctl, %eax - ENTER_KERNEL - testl %eax, %eax - jne L(hlt) /* This should never happen. */ - - /* Copy the base address of the new shadow stack to __ssp[1]. */ - movl (%esp), %eax - movl %eax, (oSSP + 4)(%edi) - - addl $16, %esp - - /* Restore EBX from the first scratch register slot. */ - movl oSCRATCH1(%edi), %ebx - - /* Get the size of the new shadow stack. */ - movl (oSSP + 8)(%edi), %ecx - - /* Use the restore stoken to restore the new shadow stack. */ - rstorssp -8(%eax, %ecx) - - /* Save the restore token at the next 8 byte aligned boundary - on the original shadow stack. */ - saveprevssp - - /* Push the address of "jmp exitcode" onto the new stack as - well as the new shadow stack. */ - call 1f - jmp L(exitcode) -1: - - /* Get the new shadow stack pointer. */ - rdsspd %eax - - /* Use the restore stoken to restore the original shadow stack. */ - rstorssp -8(%esi) - - /* Save the restore token on the new shadow stack. */ - saveprevssp - - /* Store the new shadow stack pointer in __ssp[0]. */ - movl %eax, oSSP(%edi) - - /* Restore the original stack. */ - mov %edx, %esp - - cfi_startproc - - /* Restore ESI from the second scratch register slot. */ - movl oSCRATCH2(%edi), %esi - /* Restore EDI from the third scratch register slot. */ - movl oSCRATCH3(%edi), %edi - - ret - -L(skip_ssp): -#endif - /* If the function we call returns we must continue with the context which is given in the uc_link element. To do this set the return address for the function the user provides @@ -244,7 +122,6 @@ L(call_exit): call HIDDEN_JUMPTARGET(exit) /* The 'exit' call should never return. In case it does cause the process to terminate. */ -L(hlt): hlt cfi_startproc END(__makecontext) |