diff options
Diffstat (limited to 'sysdeps/unix/sysv/linux/x86_64/__start_context.S')
| -rw-r--r-- | sysdeps/unix/sysv/linux/x86_64/__start_context.S | 38 |
1 files changed, 7 insertions, 31 deletions
diff --git a/sysdeps/unix/sysv/linux/x86_64/__start_context.S b/sysdeps/unix/sysv/linux/x86_64/__start_context.S index f6436dd6bb..ae04203c90 100644 --- a/sysdeps/unix/sysv/linux/x86_64/__start_context.S +++ b/sysdeps/unix/sysv/linux/x86_64/__start_context.S @@ -24,20 +24,14 @@ /* Use CALL to push __start_context onto the new stack as well as the new shadow stack. RDI points to ucontext: Incoming: - __ssp[0]: The original caller's shadow stack pointer. - __ssp[1]: The size of the new shadow stack. - __ssp[2]: The size of the new shadow stack. - Outgoing: __ssp[0]: The new shadow stack pointer. __ssp[1]: The base address of the new shadow stack. __ssp[2]: The size of the new shadow stack. */ ENTRY(__push___start_context) - /* Save the pointer to ucontext. */ - movq %rdi, %r9 /* Get the original shadow stack pointer. */ - rdsspq %r8 + rdsspq %rcx /* Save the original stack pointer. */ movq %rsp, %rdx /* Load the top of the new stack into RSI. */ @@ -45,24 +39,12 @@ ENTRY(__push___start_context) /* Add 8 bytes to RSI since CALL will push the 8-byte return address onto stack. */ leaq 8(%rsi), %rsp - /* Allocate the new shadow stack. The size of the new shadow - stack is passed in __ssp[1]. */ - lea (oSSP + 8)(%rdi), %RSI_LP - movl $ARCH_CET_ALLOC_SHSTK, %edi - movl $__NR_arch_prctl, %eax - /* The new shadow stack base is returned in __ssp[1]. */ - syscall - testq %rax, %rax - jne L(hlt) /* This should never happen. */ - - /* Get the size of the new shadow stack. */ - movq 8(%rsi), %rdi - - /* Get the base address of the new shadow stack. */ - movq (%rsi), %rsi - + /* The size of the new shadow stack is stored in __ssp[2]. */ + mov (oSSP + 16)(%rdi), %RSI_LP + /* The new shadow stack base is stored in __ssp[1]. */ + mov (oSSP + 8)(%rdi), %RAX_LP /* Use the restore stoken to restore the new shadow stack. */ - rstorssp -8(%rsi, %rdi) + rstorssp -8(%rax, %rsi) /* Save the restore token on the original shadow stack. */ saveprevssp @@ -73,18 +55,12 @@ ENTRY(__push___start_context) jmp __start_context 1: - /* Get the new shadow stack pointer. */ - rdsspq %rdi - /* Use the restore stoken to restore the original shadow stack. */ - rstorssp -8(%r8) + rstorssp -8(%rcx) /* Save the restore token on the new shadow stack. */ saveprevssp - /* Store the new shadow stack pointer in __ssp[0]. */ - movq %rdi, oSSP(%r9) - /* Restore the original stack. */ mov %rdx, %rsp ret |