ia32: support PIE in asm

In PIE on ia32 function calls should be made using GOT.

JIRA: RTOS-664

arch/ia32/jmp.S

@@ -5,127 +5,149 @@
  *
  * setjmp, longjmp
  *
- * Copyright 2018-2019 Phoenix Systems
- * Author: Jan Sikorski, Andrzej Glowinski
+ * Copyright 2018-2019, 2023 Phoenix Systems
+ * Author: Jan Sikorski, Andrzej Glowinski, Hubert Badocha
  *
  * This file is part of Phoenix-RTOS.
  *
  * %LICENSE%
  */
 
+ /* jmp_buf layout:
+ * esi
+ * ebx
+ * edi
+ * ebp
+ * esp + 4
+ * return address
+ * signal mask indicator (0 - not saved, otherwise saved(GOT addr on PIC))
+ * signal mask (if saved)
+ */
+
 #define __ASSEMBLY__
 
 
 .text
 
-.globl _setjmp
-.type _setjmp, %function
-_setjmp:
+
+.macro SETJMP_SAVE_REGS
 	/* Store registers into jmpbuf */
-	movl 4(%esp),   %edx
-	movl   %ebx,   (%edx)
-	movl   %esi,  4(%edx)
-	movl   %edi,  8(%edx)
-	movl   %ebp, 12(%edx)
+	leal 4(%esp),    %ecx
+	movl  (%ecx),    %edx
+	movl   %esi,    (%edx)
+	movl   %ebx,   4(%edx)
+	movl   %edi,   8(%edx)
+	movl   %ebp,  12(%edx)
 	/* Store stack pointer pointing before return address */
-	leal 4(%esp),   %ecx
-	movl   %ecx, 16(%edx)
-	/* Store jump address */
-	leal  (1f),     %ecx
-	movl   %ecx, 20(%edx)
+	movl   %ecx,  16(%edx)
 	/* Store return address */
-	movl  (%esp),   %ecx
-	movl  %ecx,  24(%edx)
-	/* Store result */
-	movl  $0,       %eax
-	ret
-1:
-	/* Jump point. Push return address to stack */
-	pushl  24(%edx)
+	movl  (%esp),    %ecx
+	movl   %ecx,  20(%edx)
+.endm
+
+
+.globl _setjmp
+.type _setjmp, %function
+.align 4
+_setjmp:
+	SETJMP_SAVE_REGS
+	/* Set no mask indicator */
+	movl   $0,    24(%edx)
+	/* Store result (0) */
+	xorl   %eax,     %eax
 	ret
 .size _setjmp, .-_setjmp
 
 
 .globl setjmp
 .type setjmp, %function
+.align 4
 setjmp:
-        /* Get signal mask */
-	pushl  $0
-	pushl  $0
-	call   signalMask
-	addl   $8,      %esp
-	/* Store registers into jmpbuf */
-	movl 4(%esp),   %edx
-	movl   %ebx,   (%edx)
-	movl   %esi,  4(%edx)
-	movl   %edi,  8(%edx)
-	movl   %ebp, 12(%edx)
-	/* Store stack pointer pointing before return address */
-	leal 4(%esp),   %ecx
-	movl   %ecx, 16(%edx)
-	/* Store jump address */
-	leal  (1f),     %ecx
-	movl   %ecx, 20(%edx)
-	/* Store return address */
-	movl  (%esp),   %ecx
-	movl   %ecx, 24(%edx)
-	/* Store signal mask */
-	movl   %eax, 28(%edx)
-	/* Store result */
-	movl   $0,      %eax
-	ret
-1:
-	/* Jump point. Push return address to stack */
-	pushl 24(%edx)
-	/* Store longjmp return value */
-	pushl    %eax
-	/* Restore signal mask */
-	movl  28(%edx), %ecx
-	pushl    $0xffffffff
-	pushl    %ecx
+	SETJMP_SAVE_REGS
+    /* Get signal mask */
+#if __pic__ == 0
+	pushl    $0
+	pushl    $0
 	call     signalMask
-	addl     $8,    %esp
-	/* Restore longjmp return value */
-	popl     %eax
+	addl     $8,      %esp
+	/* Store signal mask indicator */
+	movl     $1,   24(%edx)
+#else
+	pushl    %ebx
+
+	call     .l1
+.l1:
+	popl     %ebx
+	addl     $_GLOBAL_OFFSET_TABLE_+(.-.l1), %ebx
+
+	pushl    $0
+	pushl    $0
+	call     *signalMask@got(%ebx)
+	addl     $8,      %esp
+	/* Save GOT address as an indicator as it will not be 0 */
+	movl     %ebx, 24(%edx)
+
+	popl     %ebx
+#endif
+	/* Store signal mask */
+	movl     %eax, 28(%edx)
+	/* Store result (0) */
+	xorl     %eax,    %eax
 	ret
 .size setjmp, .-setjmp
 
 
 .globl _longjmp
 .type _longjmp, %function
+.align 4
 _longjmp:
-	movl  4(%esp), %edx
-	movl  8(%esp), %eax
-	test   %eax,  %eax
-	jnz    1f
-	inc    %eax
+	/* Since esi will be restored later it can be used as a scratch register */
+	/* Using it allows to safely call signalMask */
+	movl   4(%esp), %esi
+	/* Check mask indicator */
+	/* Since ebx will be restored later it can be used as a scratch register */
+	/* ebx as the mask indicator is a GOT address in PIC */
+	movl  24(%esi), %ebx
+	test     %ebx,  %ebx
+	jz       1f
+	/* Restore signal mask */
+	pushl    $0xffffffff
+	pushl    28(%esi)
+
+#if __pic__ == 0
+	call     signalMask
+#else
+	call     *signalMask@got(%ebx)
+#endif
+
+	addl     $8,    %esp
 1:
+	/* Get second argument */
+	movl   8(%esp), %eax
+	/* _longjmp shall return 1 if 0 is provided as the second argument */
+	movl     $1,    %ecx
+	test     %eax,  %eax
+	cmove    %ecx,  %eax
 	/* Restore registers from jmpbuf */
-	movl   (%edx), %ebx
-	movl  4(%edx), %esi
-	movl  8(%edx), %edi
-	movl 12(%edx), %ebp
-	movl 16(%edx), %esp
-	/* Restore jump address */
-	movl 20(%edx), %ecx
-	/* Jump */
-	jmp    *%ecx
+	movl   4(%esi), %ebx
+	movl   8(%esi), %edi
+	movl  12(%esi), %ebp
+	movl  16(%esi), %esp
+	/* Jump point. Push return address to stack */
+	pushl 20(%esi)
+	/* At last restore esi */
+	movl    (%esi), %esi
+	ret
 .size _longjmp, .-_longjmp
 
 
 .globl sigsetjmp
 .type sigsetjmp, %function
 sigsetjmp:
-	/* Modify stack frame to skip this function when returning from setjmp */
-	movl  8(%esp), %edx
-	movl  4(%esp), %ecx
-	movl  (%esp),  %eax
-	addl   $8,     %esp
-	pushl  %ecx
-	pushl  %eax
-
+.align 4
+	movl 8(%esp), %edx
 	/* Call proper setjmp */
-	test    %edx,  %edx
-	jne setjmp
-	jmp _setjmp
+	test   %edx,  %edx
+	jz     _setjmp
+	jmp    setjmp
 .size sigsetjmp, .-sigsetjmp

arch/ia32/signal.S

@@ -5,8 +5,8 @@
  *
  * Signal trampoline (ia32)
  *
- * Copyright 2019 Phoenix Systems
- * Author: Jan Sikorski
+ * Copyright 2019, 2023 Phoenix Systems
+ * Author: Jan Sikorski, Hubert Badocha
  *
  * This file is part of Phoenix-RTOS.
  *
@@ -19,14 +19,29 @@
 
 .globl _signal_trampoline
 .type _signal_trampoline, %function
+.align 4
 _signal_trampoline:
 	/* Signal number on stack */
-	call _signal_handler
+#if __pic__ == 0
+	call  _signal_handler
+#else
+	/* ebx will be restored by sigreturn */
+	call  .l1
+.l1:
+	popl  %ebx
+	addl  $_GLOBAL_OFFSET_TABLE_+(.-.l1), %ebx
 
-	addl $4, %esp
+	call  *_signal_handler@got(%ebx)
+#endif
+
+	addl  $4, %esp
 	/* Put old mask on stack */
-	push %eax
+	pushl %eax
 	/* cpu context *, eip, esp on stack */
-	call sigreturn
+#if __pic__ == 0
+	call  sigreturn
+#else
+	call  *sigreturn@got(%ebx)
+#endif
 .size _signal_trampoline, .-_signal_trampoline