Re: PATCH: Use R*_LP, sizeSS, oSS_FLAGS, oSS_SP and oSS_SIZE

["H.J. Lu" <hjl dot tools at gmail dot com>]

On Tue, May 15, 2012 at 4:09 PM, Roland McGrath <roland@hack.frob.com> wrote:
>> --- /dev/null
>> +++ b/sysdeps/unix/sysv/linux/x86_64/sigaltstack.sym
>
> Call it sigaltstack-offsets.sym instead.
>
>> +sizeSS ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? sizeof(stack_t)
>> +oSS_SP ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? sigaltstack(ss_sp)
>> +oSS_SIZE ? ? ? ? ? ? ? ? ? ? sigaltstack(ss_size)
>> +oSS_FLAGS ? ? ? ? ? ? ? ? ? ?sigaltstack(ss_flags)
>
> Space before paren in all cases.
>

Does it look OK?

Thanks.

-- 
H.J.
---
	* sysdeps/unix/sysv/linux/x86_64/Makefile (gen-as-const-headers):
	Add sigaltstack.sym.

	* sysdeps/unix/sysv/linux/x86_64/____longjmp_chk.S: Include
	"sigaltstack.h".
	(CALL_FAIL): Use RSP_LP to operate on stack.  Use RDI_LP on
	longjmp_msg pointer.
	(____longjmp_chk): Use R8_LP and RDX_LP on SP and PC.  Use
	R*_LP, sizeSS, oSS_FLAGS, oSS_SP and oSS_SIZE for alternate
	signal stack.

	* sysdeps/unix/sysv/linux/x86_64/sigaltstack.sym: New.

diff --git a/sysdeps/unix/sysv/linux/x86_64/Makefile
b/sysdeps/unix/sysv/linux/x86_64/Makefile
index 9c9e615..b692212 100644
--- a/sysdeps/unix/sysv/linux/x86_64/Makefile
+++ b/sysdeps/unix/sysv/linux/x86_64/Makefile
@@ -17,6 +17,10 @@ ifeq ($(subdir),csu)
 gen-as-const-headers += ucontext_i.sym
 endif

+ifeq ($(subdir),misc)
+gen-as-const-headers += sigaltstack-offsets.sym
+endif
+
 ifeq ($(subdir),elf)
 sysdep_routines += dl-vdso
 endif
diff --git a/sysdeps/unix/sysv/linux/x86_64/____longjmp_chk.S
b/sysdeps/unix/sysv/linux/x86_64/____longjmp_chk.S
index 1de7e09..9f92cd2 100644
--- a/sysdeps/unix/sysv/linux/x86_64/____longjmp_chk.S
+++ b/sysdeps/unix/sysv/linux/x86_64/____longjmp_chk.S
@@ -19,6 +19,8 @@
 #include <jmpbuf-offsets.h>
 #include <asm-syntax.h>

+#include "sigaltstack-offsets.h"
+
 	.section .rodata.str1.1,"aMS",@progbits,1
 	.type	longjmp_msg,@object
 longjmp_msg:
@@ -29,18 +31,18 @@ longjmp_msg:
 //#define __longjmp ____longjmp_chk

 #ifdef PIC
-# define CALL_FAIL	subq	$8, %rsp;				      \
+# define CALL_FAIL	sub	$8, %RSP_LP;				      \
 			cfi_remember_state;				      \
 			cfi_def_cfa_offset(16);				      \
-			leaq	longjmp_msg(%rip), %rdi;		      \
+			lea	longjmp_msg(%rip), %RDI_LP;		      \
 			call	HIDDEN_JUMPTARGET(__fortify_fail);	      \
 			nop;						      \
 			cfi_restore_state
 #else
-# define CALL_FAIL	subq	$8, %rsp;				      \
+# define CALL_FAIL	sub	$8, %RSP_LP;				      \
 			cfi_remember_state;				      \
 			cfi_def_cfa_offset(16);				      \
-			movq	$longjmp_msg, %rdi;			      \
+			mov	$longjmp_msg, %RDI_LP;			      \
 			call	HIDDEN_JUMPTARGET(__fortify_fail);	      \
 			nop;						      \
 			cfi_restore_state
@@ -52,16 +54,16 @@ longjmp_msg:
 	.text
 ENTRY(____longjmp_chk)
 	/* Restore registers.  */
-	movq	(JB_RSP*8)(%rdi), %r8
+	mov	(JB_RSP*8)(%rdi), %R8_LP
 	movq	(JB_RBP*8)(%rdi), %r9
-	movq	(JB_PC*8)(%rdi), %rdx
+	mov	(JB_PC*8)(%rdi), %RDX_LP
 #ifdef PTR_DEMANGLE
-	PTR_DEMANGLE (%r8)
+	PTR_DEMANGLE (%R8_LP)
 	PTR_DEMANGLE (%r9)
-	PTR_DEMANGLE (%rdx)
+	PTR_DEMANGLE (%RDX_LP)
 #endif

-	cmpq	%r8, %rsp
+	cmp	%R8_LP, %RSP_LP
 	jbe	.Lok

 	/* Save function parameters.  */
@@ -71,19 +73,19 @@ ENTRY(____longjmp_chk)
 	cfi_register (%rsi, %rbx)

 	xorl	%edi, %edi
-	leaq	-24(%rsp), %rsi
+	lea	-sizeSS(%rsp), %RSI_LP
 	movl	$__NR_sigaltstack, %eax
 	syscall
 	/* Without working sigaltstack we cannot perform the test.  */
 	testl	%eax, %eax
 	jne	.Lok2
-	testl	$1, -16(%rsp)
+	testl	$1, (-sizeSS + oSS_FLAGS)(%rsp)
 	jz	.Lfail

-	movq	-24(%rsp), %rax
-	addq	-8(%rsp), %rax
-	subq	%r8, %rax
-	cmpq	-8(%rsp), %rax
+	mov	(-sizeSS + oSS_SP)(%rsp), %RAX_LP
+	add	(-sizeSS + oSS_SIZE)(%rsp), %RAX_LP
+	sub	%R8_LP, %RAX_LP
+	cmp	(-sizeSS + oSS_SIZE)(%rsp), %RAX_LP
 	jae	.Lok2

 .Lfail:	CALL_FAIL
@@ -110,7 +112,7 @@ ENTRY(____longjmp_chk)
 	movq	(JB_R15*8)(%rdi), %r15
 	/* Set return value for setjmp.  */
 	movl	%esi, %eax
-	movq	%r8,%rsp
+	mov	%R8_LP, %RSP_LP
 	movq	%r9,%rbp
 	jmpq	*%rdx
 END (____longjmp_chk)
diff --git a/sysdeps/unix/sysv/linux/x86_64/sigaltstack-offsets.sym
b/sysdeps/unix/sysv/linux/x86_64/sigaltstack-offsets.sym
new file mode 100644
index 0000000..5ff3af4
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/x86_64/sigaltstack-offsets.sym
@@ -0,0 +1,15 @@
+#ifndef _XOPEN_EXTENDED
+# define _XOPEN_EXTENDED
+#endif
+
+#include <stddef.h>
+#include <signal.h>
+
+--
+
+#define sigaltstack(member)	offsetof (stack_t, member)
+
+sizeSS				sizeof (stack_t)
+oSS_SP				sigaltstack (ss_sp)
+oSS_SIZE			sigaltstack (ss_size)
+oSS_FLAGS			sigaltstack (ss_flags)