From 319078dad62eba942d33c8975bdcbb09d1c68ba6 Mon Sep 17 00:00:00 2001 From: Szabolcs Nagy Date: Thu, 2 Jul 2020 17:12:05 +0100 Subject: [PATCH] aarch64: Fix BTI support in libitm sjlj.S did not have the GNU property note markup and the BTI c instructions that are necessary when it is built with branch protection. The notes are only added when libitm is built with branch protection, because old linkers mishandle the note (merge them incorrectly or emit warnings), the BTI instructions are added unconditionally. 2020-07-09 Szabolcs Nagy libitm/ChangeLog: * config/aarch64/sjlj.S: Add BTI marking and related definitions, and add BTI c to function entries. --- libitm/config/aarch64/sjlj.S | 27 +++++++++++++++++++++++++++ 1 file changed, 27 insertions(+) diff --git a/libitm/config/aarch64/sjlj.S b/libitm/config/aarch64/sjlj.S index 5b97b973e27..e2093ca1a97 100644 --- a/libitm/config/aarch64/sjlj.S +++ b/libitm/config/aarch64/sjlj.S @@ -24,6 +24,8 @@ #include "asmcfi.h" +#define BTI_C hint 34 + .text .align 2 .global _ITM_beginTransaction @@ -31,6 +33,7 @@ _ITM_beginTransaction: cfi_startproc + BTI_C mov x1, sp stp x29, x30, [sp, -11*16]! cfi_adjust_cfa_offset(11*16) @@ -70,6 +73,7 @@ GTM_longjmp: /* The first parameter becomes the return value (x0). The third parameter is ignored for now. */ cfi_startproc + BTI_C ldp x19, x20, [x1, 1*16] ldp x21, x22, [x1, 2*16] ldp x23, x24, [x1, 3*16] @@ -87,6 +91,29 @@ GTM_longjmp: cfi_endproc .size GTM_longjmp, . - GTM_longjmp +/* GNU_PROPERTY_AARCH64_* macros from elf.h for use in asm code. */ +#define FEATURE_1_AND 0xc0000000 +#define FEATURE_1_BTI 1 +#define FEATURE_1_PAC 2 + +/* Add a NT_GNU_PROPERTY_TYPE_0 note. */ +#define GNU_PROPERTY(type, value) \ + .section .note.gnu.property, "a"; \ + .p2align 3; \ + .word 4; \ + .word 16; \ + .word 5; \ + .asciz "GNU"; \ + .word type; \ + .word 4; \ + .word value; \ + .word 0; + #if defined(__linux__) || defined(__FreeBSD__) .section .note.GNU-stack, "", %progbits + +/* Add GNU property note if built with branch protection. */ +# ifdef __ARM_FEATURE_BTI_DEFAULT +GNU_PROPERTY (FEATURE_1_AND, FEATURE_1_BTI) +# endif #endif -- 2.30.2