Community source repository for glibc add-on ports branch, master, updated. glibc-2.12-10-g131fafa

[carlos at sourceware dot org]

This is an automated email from the git hooks/post-receive script. It was
generated because a ref change was pushed to the repository containing
the project "Community source repository for glibc add-on ports".

The branch, master has been updated
       via  131fafa7dac6437fd6bb320bac49b0198825b192 (commit)
      from  fdb3ec206ee7671c697544502de6a650186c8cd2 (commit)

Those revisions listed above that are new to this repository have
not appeared on any other notification email; so we list those
revisions in full, below.

- Log -----------------------------------------------------------------
http://sources.redhat.com/git/gitweb.cgi?p=glibc-ports.git;a=commitdiff;h=131fafa7dac6437fd6bb320bac49b0198825b192

commit 131fafa7dac6437fd6bb320bac49b0198825b192
Author: Carlos O'Donell <carlos@systemhalted.org>
Date:   Wed Jun 23 17:03:11 2010 -0400

    [hppa] Fix *context stack usage for varargs
    
    The getcontext, and setcontext functions should
    not adjust the stack, and should load the stack
    pointer from the machine context. Calling makecontext
    should create a frame for spilled incoming arguments,
    and sync uc_stack.ss_sp to the machine context.
    We do not support calling getcontext, modifying ss_sp,
    and calling setcontext directly.

diff --git a/ChangeLog.hppa b/ChangeLog.hppa
index 50a15d7..faad5e9 100644
--- a/ChangeLog.hppa
+++ b/ChangeLog.hppa
@@ -1,3 +1,16 @@
+2010-06-23  Carlos O'Donell  <carlos@codesourcery.com>
+
+	* sysdeps/unix/sysv/linux/hppa/getcontext.S (__getcontext_ret):
+	Document that this function is a non-standard calling ABI.
+	Document register usage.
+	(__getcontext): Use normal %sp without adjustment. Use named
+	resgister %sp. 
+	* sysdeps/unix/sysv/linux/hppa/makecontext.c: Remove FRAME_SIZE.
+	Define FRAME_SIZE_UL, FRAME_SIZE_BYTES, ARGS.
+	(__makecontext): Create and setup a stack frame. 
+	* sysdeps/unix/sysv/linux/hppa/setcontext.S (__setcontext):
+	Use named register %sp. Do not use oSS_SP. 
+
 2010-06-07  Andreas Schwab  <schwab@redhat.com>
 
 	* sysdeps/unix/sysv/linux/hppa/nptl/pthread.h: Update to agree
diff --git a/sysdeps/unix/sysv/linux/hppa/getcontext.S b/sysdeps/unix/sysv/linux/hppa/getcontext.S
index f88fa03..af810b3 100644
--- a/sysdeps/unix/sysv/linux/hppa/getcontext.S
+++ b/sysdeps/unix/sysv/linux/hppa/getcontext.S
@@ -23,17 +23,21 @@
 #include "ucontext_i.h"
 
 
-	/* Trampoline function.  */
+	/* Trampoline function. Non-standard calling ABI.  */
 	/* Can not use ENTRY(__getcontext_ret) here.  */
 	.type	__getcontext_ret, @function
 	.hidden	__getcontext_ret
 __getcontext_ret:
 	.proc
 	.callinfo FRAME=0,NO_CALLS
+	/* r26-r23 contain original r3-r6, but because setcontext
+	   does not reload r3-r6 (it's using them as temporaries)
+	   we must save them elsewhere and swap them back in.  */
 	copy	%r23, %r3
 	copy	%r24, %r4
 	copy	%r25, %r5
 	copy	%r26, %r6
+	/* r20 contains original return pointer.  */
 	bv	0(%r20)
 	copy	%r0, %ret0
 	.procend
@@ -72,13 +76,12 @@ ENTRY(__getcontext)
 	stw	%r27, oR27(%r26)
 	stw	%r28, oR28(%r26)
 	stw	%r29, oR29(%r26)
-	ldo	-64(%sp), %r1	/* Calculate %sp in %r1.  */
-	stw	%r1, oR30(%r26)	/* Save new %sp.  */
+	stw	%sp, oR30(%r26)
 	stw	%r31, oR31(%r26)
 
 	stw	%r0, oUC_FLAGS(%r26)
 	/* stw	%r0, oUC_LINK(%r26) - Do not overwrite.  */
-	stw	%r1, oSS_SP(%r26)
+	stw	%sp, oSS_SP(%r26)
 	stw	%r0, oSS_FLAGS(%r26)
 	stw	%r0, oSS_SIZE(%r26)
 
@@ -127,9 +130,9 @@ ENTRY(__getcontext)
 	fstds	 %fr31, 0(%r1)
 
 	/* Prologue */
-	stwm	%r4, 64(%r30)
+	stwm	%r4, 64(%sp)
 #ifdef PIC
-	stw	%r19, -32(%r30)
+	stw	%r19, -32(%sp)
 #endif
 
 	/* Set up the trampoline registers.
@@ -152,12 +155,12 @@ ENTRY(__getcontext)
 	ldi	SIG_BLOCK, %r26
 
 	/* Epilogue */
-	ldw	-84(%r30), %r2
+	ldw	-84(%sp), %r2
 #ifdef PIC
-	ldw	-96(%r30), %r19
+	ldw	-96(%sp), %r19
 #endif
 	bv	%r0(%r2)
-	ldwm	-64(%r30), %r4
+	ldwm	-64(%sp), %r4
 END(__getcontext)
 
 weak_alias (__getcontext, getcontext)
diff --git a/sysdeps/unix/sysv/linux/hppa/makecontext.c b/sysdeps/unix/sysv/linux/hppa/makecontext.c
index cb036d0..d3e3fb8 100644
--- a/sysdeps/unix/sysv/linux/hppa/makecontext.c
+++ b/sysdeps/unix/sysv/linux/hppa/makecontext.c
@@ -26,26 +26,57 @@
 #include <ucontext.h>
 
 /* POSIX only supports integer arguments.  */
+
+/* Stack must be 64-byte aligned at all times.  */
 #define STACK_ALIGN 64
-#define FRAME_SIZE 8
+/* Size of frame marker in unsigned long words.  */
+#define FRAME_SIZE_UL 8 
+/* Size of frame marker in bytes.  */
+#define FRAME_SIZE_BYTES (8 * sizeof(unsigned long)) 
+/* Size of X arguments in bytes.  */
+#define ARGS(x) (x * sizeof(unsigned long))
 
 void
 __makecontext (ucontext_t *ucp, void (*func) (void), int argc, ...)
 {
-  unsigned long *sp;
+  unsigned long *sp, *osp;
   va_list ap;
   int i;
 
-  /* Get stack pointer (64-byte aligned).  */
-  sp = (unsigned long *)((((unsigned long) ucp->uc_stack.ss_sp) 
-			 + FRAME_SIZE + argc + STACK_ALIGN) 
-		        & ~(STACK_ALIGN - 1));
+  /* Create a 64-byte aligned frame to store args. Use ss_sp if 
+     it is available, otherwise be robust and use the currently
+     saved stack pointer.  */
+  if (ucp->uc_stack.ss_sp && ucp->uc_stack.ss_size)
+    osp = (unsigned long *)ucp->uc_stack.ss_sp;
+  else
+    osp = (unsigned long *)ucp->uc_mcontext.sc_gr[30];
+
+  sp = (unsigned long *)((((unsigned long) osp) 
+			   + FRAME_SIZE_BYTES + ARGS(argc) + STACK_ALIGN) 
+			 & ~(STACK_ALIGN - 1));
+
+  /* Use new frame.  */
+  ucp->uc_mcontext.sc_gr[30] = ((unsigned long) sp);
+
+  /* Finish frame setup.  */
+  if (ucp->uc_link)
+    {
+      /* Returning to the next context and next frame.  */
+      sp[-4/sizeof(unsigned long)] = ucp->uc_link->uc_mcontext.sc_gr[30];
+      sp[-20/sizeof(unsigned long)] = ucp->uc_link->uc_mcontext.sc_gr[2];
+    }
+  else
+    {
+      /* This is the main context. No frame marker, and no return address.  */
+      sp[-4/sizeof(unsigned long)] = 0x0;
+      sp[-20/sizeof(unsigned long)] = 0x0;
+    }
 
   /* Store address to jump to.  */
   ucp->uc_mcontext.sc_gr[2] = (unsigned long) func;
 
+  /* Process arguments.  */
   va_start (ap, argc);
-  /* Handle arguments.  */
   for (i = 0; i < argc; ++i)
     {
       if (i < 4)
@@ -62,13 +93,9 @@ __makecontext (ucontext_t *ucp, void (*func) (void), int argc, ...)
 	} 
 
       /* All other arguments go on the stack.  */
-      sp[-1 * (FRAME_SIZE + 1 + i)] = va_arg (ap, int);
+      sp[-1 * (FRAME_SIZE_UL + 1 + i)] = va_arg (ap, int);
     }
   va_end (ap); 
-
-  /* Adjust the stack pointer to last used argument.  */
-  ucp->uc_mcontext.sc_gr[30] = (unsigned long) sp;
 }
-
-
 weak_alias(__makecontext, makecontext)
+
diff --git a/sysdeps/unix/sysv/linux/hppa/setcontext.S b/sysdeps/unix/sysv/linux/hppa/setcontext.S
index 43ccf24..3353d4e 100644
--- a/sysdeps/unix/sysv/linux/hppa/setcontext.S
+++ b/sysdeps/unix/sysv/linux/hppa/setcontext.S
@@ -25,9 +25,9 @@
 
 ENTRY(__setcontext)
 	/* Prologue */
-	stwm	%r3, 64(%r30)
+	stwm	%r3, 64(%sp)
 #ifdef PIC
-	stw	%r19, -32(%r30)
+	stw	%r19, -32(%sp)
 #endif
 
 	/* Save ucp.  */
@@ -78,7 +78,7 @@ ENTRY(__setcontext)
 	ldw	oR27(%r3), %r27
 	ldw	oR28(%r3), %r28
 	ldw	oR29(%r3), %r29
-	ldw	oR30(%r3), %r30
+	ldw	oR30(%r3), %sp
 	/* ldw	oR31(%r3), %r31 - dyncall scratch register */
 
 	/* Restore floating-point registers.  */
@@ -116,9 +116,13 @@ ENTRY(__setcontext)
 	fldds,mb -8(%r22), %fr1
 	fldds,mb -8(%r22), %fr0
 
-	/* Calculate new stack pointer.  */
-	ldw	oSS_SP(%r3), %sp
-	ldo	64(%sp), %sp
+	/* Do not load oSS_SP into %sp. The value of oSS_SP indicates
+	   the start of the user allocated stack, but not the sp that
+	   should be used by the new context. In fact makecontext 
+	   will create a frame, and adjust sp as required. We do not
+	   support calling getcontext and modifying ss_sp without
+	   a call to makecontext to synchronize ss_sp into the machine
+	   context.  */
 
 	/* Call external function.  */
 	copy	%r2, %r22

-----------------------------------------------------------------------

Summary of changes:
 ChangeLog.hppa                             |   13 +++++++
 sysdeps/unix/sysv/linux/hppa/getcontext.S  |   21 ++++++-----
 sysdeps/unix/sysv/linux/hppa/makecontext.c |   53 +++++++++++++++++++++-------
 sysdeps/unix/sysv/linux/hppa/setcontext.S  |   16 +++++---
 4 files changed, 75 insertions(+), 28 deletions(-)


hooks/post-receive
-- 
Community source repository for glibc add-on ports