diff options
Diffstat (limited to 'coroutine/amd64/Context.S')
| -rw-r--r-- | coroutine/amd64/Context.S | 77 |
1 files changed, 60 insertions, 17 deletions
diff --git a/coroutine/amd64/Context.S b/coroutine/amd64/Context.S index d50732adbc..eebf9bf18e 100644 --- a/coroutine/amd64/Context.S +++ b/coroutine/amd64/Context.S @@ -5,6 +5,10 @@ ## Copyright, 2018, by Samuel Williams. ## +/* Important - do _not_ include <cet.h> in this file; doing so will + * cause an incorrect .note.gnu.property section to be emitted. We have + * one at the bottom of this file */ + #define TOKEN_PASTE(x,y) x##y #define PREFIXED_SYMBOL(prefix,name) TOKEN_PASTE(prefix,name) @@ -13,29 +17,40 @@ .globl PREFIXED_SYMBOL(SYMBOL_PREFIX,coroutine_transfer) PREFIXED_SYMBOL(SYMBOL_PREFIX,coroutine_transfer): - # Save caller state - pushq %rbp - pushq %rbx - pushq %r12 - pushq %r13 - pushq %r14 - pushq %r15 +#if defined(__CET__) && (__CET__ & 0x01) != 0 + /* IBT landing pad */ + endbr64 +#endif + + # Make space on the stack for 6 registers: + subq $48, %rsp - # Save caller stack pointer + # Save caller state: + movq %rbp, 40(%rsp) + movq %rbx, 32(%rsp) + movq %r12, 24(%rsp) + movq %r13, 16(%rsp) + movq %r14, 8(%rsp) + movq %r15, (%rsp) + + # Save caller stack pointer: movq %rsp, (%rdi) - # Restore callee stack pointer + # Restore callee stack pointer: movq (%rsi), %rsp # Restore callee state - popq %r15 - popq %r14 - popq %r13 - popq %r12 - popq %rbx - popq %rbp - - # Put the first argument into the return value + movq 40(%rsp), %rbp + movq 32(%rsp), %rbx + movq 24(%rsp), %r12 + movq 16(%rsp), %r13 + movq 8(%rsp), %r14 + movq (%rsp), %r15 + + # Adjust stack pointer back: + addq $48, %rsp + + # Put the first argument into the return value: movq %rdi, %rax # We pop the return address and jump to it @@ -44,3 +59,31 @@ PREFIXED_SYMBOL(SYMBOL_PREFIX,coroutine_transfer): #if (defined(__linux__) || defined(__FreeBSD__)) && defined(__ELF__) .section .note.GNU-stack,"",%progbits #endif + +#if defined(__ELF__) + +#if defined(__CET__) && (__CET__ & 0x01) != 0 +# define IBT_FLAG 0x01 +#else +# define IBT_FLAG 0x00 +#endif + +/* We do _NOT_ support CET shadow-stack. Do _not_ add the property for + * this to the Context.o object. If you require CET shadow-stack support, + * for now, consider building with --with-coroutine=ucontext */ +#define SHSTK_FLAG 0x00 + +.pushsection .note.gnu.property, "a" +.p2align 3 +.long 0x4 /* Name size ("GNU\0") */ +.long 0x10 /* Descriptor size */ +.long 0x5 /* Type: NT_GNU_PROPERTY_TYPE_0 */ +.asciz "GNU" /* Name */ +# Begin descriptor +.long 0xc0000002 /* Property type: GNU_PROPERTY_X86_FEATURE_1_AND */ +.long 0x4 /* Property size */ +.long (IBT_FLAG | SHSTK_FLAG) +.long 0x0 /* 8-byte alignment padding */ +/* End descriptor */ +.popsection +#endif |