Implement setjmp cookies on x86_64.
Bug: http://b/23942752
Change-Id: Iea8d03de1dd9ca5a128c072c94b10de3a8056348
diff --git a/libc/arch-x86_64/bionic/setjmp.S b/libc/arch-x86_64/bionic/setjmp.S
index 5559f54..09d61f5 100644
--- a/libc/arch-x86_64/bionic/setjmp.S
+++ b/libc/arch-x86_64/bionic/setjmp.S
@@ -50,6 +50,25 @@
#define _JB_SIGMASK 9
#define _JB_SIGMASK_RT 10 // sigprocmask will write here too.
+#define MANGLE_REGISTERS 1
+.macro m_mangle_registers reg
+#if MANGLE_REGISTERS
+ xorq \reg,%rbx
+ xorq \reg,%rbp
+ xorq \reg,%r12
+ xorq \reg,%r13
+ xorq \reg,%r14
+ xorq \reg,%r15
+ xorq \reg,%rsp
+ xorq \reg,%r11
+#endif
+.endm
+
+.macro m_unmangle_registers reg
+ m_mangle_registers \reg
+.endm
+
+
ENTRY(setjmp)
movl $1,%esi
jmp PIC_PLT(sigsetjmp)
@@ -62,11 +81,17 @@
// int sigsetjmp(sigjmp_buf env, int save_signal_mask);
ENTRY(sigsetjmp)
- // Record whether or not we're saving the signal mask.
- movl %esi,(_JB_SIGFLAG * 8)(%rdi)
+ pushq %rdi
+ movq %rsi,%rdi
+ call PIC_PLT(__bionic_setjmp_cookie_get)
+ popq %rdi
+
+ // Record setjmp cookie and whether or not we're saving the signal mask.
+ movq %rax,(_JB_SIGFLAG * 8)(%rdi)
+ pushq %rax
// Do we need to save the signal mask?
- testl %esi,%esi
+ testq $1,%rax
jz 2f
// Save current signal mask.
@@ -79,7 +104,10 @@
2:
// Save the callee-save registers.
+ popq %rax
+ andq $-2,%rax
movq (%rsp),%r11
+ m_mangle_registers %rax
movq %rbx,(_JB_RBX * 8)(%rdi)
movq %rbp,(_JB_RBP * 8)(%rdi)
movq %r12,(_JB_R12 * 8)(%rdi)
@@ -88,6 +116,7 @@
movq %r15,(_JB_R15 * 8)(%rdi)
movq %rsp,(_JB_RSP * 8)(%rdi)
movq %r11,(_JB_PC * 8)(%rdi)
+ m_unmangle_registers %rax
xorl %eax,%eax
ret
@@ -99,7 +128,9 @@
pushq %rsi // Push 'value'.
// Do we need to restore the signal mask?
- cmpl $0,(_JB_SIGFLAG * 8)(%rdi)
+ movq (_JB_SIGFLAG * 8)(%rdi), %rdi
+ pushq %rdi // Push cookie
+ testq $1, %rdi
jz 2f
// Restore the signal mask.
@@ -109,6 +140,10 @@
call PIC_PLT(sigprocmask)
2:
+ // Fetch the setjmp cookie and clear the signal flag bit.
+ popq %rcx
+ andq $-2, %rcx
+
popq %rax // Pop 'value'.
// Restore the callee-save registers.
@@ -120,7 +155,15 @@
movq (_JB_RSP * 8)(%r12),%rsp
movq (_JB_PC * 8)(%r12),%r11
movq (_JB_R12 * 8)(%r12),%r12
+ m_unmangle_registers %rcx
+ // Check the cookie.
+ pushq %rax
+ movq %rcx, %rdi
+ call PIC_PLT(__bionic_setjmp_cookie_check)
+ popq %rax
+
+ // Return 1 if value is 0.
testl %eax,%eax
jnz 1f
incl %eax
