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Re: Proposed change to ppc32 ucontext_t
Ulrich Drepper writes:
> Then symbol versioning is needed.
This patch adds the symbol versioning. I think I have done it
correctly - a review would be appreciated. Older versions of glibc
appear to have setcontext at 2.0 and get/swap/makecontext at 2.1, so
that is what I put in the compat_symbol lines.
For testing, I changed version.h locally to define VERSION as
"2.3.3". The stdlib/tst-setcontext test prints the correct output. I
also tried compiling and linking tst-setcontext against an older
version of glibc and running it against the new libc.so. That gave
the correct output (just "making contexts" and then the program
exits).
Regards,
Paul.
diff -urN cvs/libc/sysdeps/unix/sysv/linux/powerpc/powerpc32/Versions libc/sysdeps/unix/sysv/linux/powerpc/powerpc32/Versions
--- cvs/libc/sysdeps/unix/sysv/linux/powerpc/powerpc32/Versions 2003-08-25 13:15:36.000000000 +1000
+++ libc/sysdeps/unix/sysv/linux/powerpc/powerpc32/Versions 2003-09-23 18:19:41.000000000 +1000
@@ -22,5 +22,6 @@
}
GLIBC_2.3.3 {
posix_fadvise64; posix_fallocate64;
+ setcontext; getcontext; swapcontext; makecontext;
}
}
diff -urN cvs/libc/sysdeps/unix/sysv/linux/powerpc/powerpc32/getcontext.S libc/sysdeps/unix/sysv/linux/powerpc/powerpc32/getcontext.S
--- cvs/libc/sysdeps/unix/sysv/linux/powerpc/powerpc32/getcontext.S 2003-06-18 13:36:23.000000000 +1000
+++ libc/sysdeps/unix/sysv/linux/powerpc/powerpc32/getcontext.S 2003-09-23 19:15:38.000000000 +1000
@@ -18,12 +18,20 @@
02111-1307 USA. */
#include <sysdep.h>
+#include <shlib-compat.h>
#define __ASSEMBLY__
#include <asm/ptrace.h>
#include "ucontext_i.h"
ENTRY(__getcontext)
+ /*
+ * Since we are not attempting to save the altivec registers,
+ * there is no need to get the register storage space
+ * aligned on a 16-byte boundary.
+ */
+ addi r3,r3,_UC_REG_SPACE
+ stw r3,_UC_REGS_PTR - _UC_REG_SPACE(r3)
stw r0,_UC_GREGS+(PT_R0*4)(r3)
stw r1,_UC_GREGS+(PT_R1*4)(r3)
mflr r0
@@ -112,7 +120,7 @@
stfd fp31,_UC_FREGS+(31*8)(r3)
stfd fp0,_UC_FREGS+(32*8)(r3)
- addi r5,r3,_UC_SIGMASK
+ addi r5,r3,_UC_SIGMASK - _UC_REG_SPACE
li r4,0
li r3,SIG_BLOCK
bl JUMPTARGET(sigprocmask)
@@ -123,4 +131,18 @@
blr
PSEUDO_END(__getcontext)
-weak_alias(__getcontext, getcontext)
+versioned_symbol (libc, __getcontext, getcontext, GLIBC_2_3_3)
+
+#if SHLIB_COMPAT (libc, GLIBC_2_1, GLIBC_2_3_3)
+
+#define _ERRNO_H 1
+#include <bits/errno.h>
+
+ENTRY (__getcontext_stub)
+ li r3,ENOSYS
+ b JUMPTARGET(__syscall_error)
+ END (__getcontext_stub)
+
+compat_symbol (libc, __getcontext_stub, getcontext, GLIBC_2_1)
+
+#endif
diff -urN cvs/libc/sysdeps/unix/sysv/linux/powerpc/powerpc32/makecontext.S libc/sysdeps/unix/sysv/linux/powerpc/powerpc32/makecontext.S
--- cvs/libc/sysdeps/unix/sysv/linux/powerpc/powerpc32/makecontext.S 2003-06-18 13:36:38.000000000 +1000
+++ libc/sysdeps/unix/sysv/linux/powerpc/powerpc32/makecontext.S 2003-09-23 19:15:48.000000000 +1000
@@ -18,6 +18,7 @@
02111-1307 USA. */
#include <sysdep.h>
+#include <shlib-compat.h>
#define __ASSEMBLY__
#include <asm/ptrace.h>
@@ -25,22 +26,24 @@
ENTRY(__makecontext)
/* Set up the first 7 args to the function in its registers */
- stw r6,_UC_GREGS+(PT_R3*4)(r3)
- stw r7,_UC_GREGS+(PT_R4*4)(r3)
- stw r8,_UC_GREGS+(PT_R5*4)(r3)
- stw r9,_UC_GREGS+(PT_R6*4)(r3)
- stw r10,_UC_GREGS+(PT_R7*4)(r3)
+ addi r11,r3,_UC_REG_SPACE
+ stw r11,_UC_REGS_PTR(r3)
+ stw r6,_UC_GREGS+(PT_R3*4)(r11)
+ stw r7,_UC_GREGS+(PT_R4*4)(r11)
+ stw r8,_UC_GREGS+(PT_R5*4)(r11)
+ stw r9,_UC_GREGS+(PT_R6*4)(r11)
+ stw r10,_UC_GREGS+(PT_R7*4)(r11)
lwz r8,8(r1)
lwz r9,12(r1)
- stw r8,_UC_GREGS+(PT_R8*4)(r3)
- stw r9,_UC_GREGS+(PT_R9*4)(r3)
+ stw r8,_UC_GREGS+(PT_R8*4)(r11)
+ stw r9,_UC_GREGS+(PT_R9*4)(r11)
/* Set the NIP to the start of the function */
- stw r4,_UC_GREGS+(PT_NIP*4)(r3)
+ stw r4,_UC_GREGS+(PT_NIP*4)(r11)
/* Set the function's r31 to ucp->uc_link for the exitcode below. */
lwz r7,_UC_LINK(r3)
- stw r7,_UC_GREGS+(PT_R31*4)(r3)
+ stw r7,_UC_GREGS+(PT_R31*4)(r11)
/* Set the function's LR to point to the exitcode below. */
#ifdef PIC
@@ -53,7 +56,7 @@
lis r6,L(exitcode)@ha
addi r6,r6,L(exitcode)@l
#endif
- stw r6,_UC_GREGS+(PT_LNK*4)(r3)
+ stw r6,_UC_GREGS+(PT_LNK*4)(r11)
/*
* Set up the stack frame for the function.
@@ -71,7 +74,7 @@
cmpwi r5,8
blt 2f /* less than 8 args is easy */
lwz r10,16(r1)
- stw r10,_UC_GREGS+(PT_R10*4)(r3)
+ stw r10,_UC_GREGS+(PT_R10*4)(r11)
beq 2f /* if exactly 8 args */
subi r9,r5,3
subi r5,r5,8
@@ -83,7 +86,7 @@
3: lwzu r10,4(r6)
stwu r10,4(r8)
bdnz 3b
-2: stw r7,_UC_GREGS+(PT_R1*4)(r3)
+2: stw r7,_UC_GREGS+(PT_R1*4)(r11)
li r6,0
stw r6,0(r7)
@@ -102,4 +105,19 @@
b 4b
END(__makecontext)
-weak_alias(__makecontext, makecontext)
+
+versioned_symbol (libc, __makecontext, makecontext, GLIBC_2_3_3)
+
+#if SHLIB_COMPAT (libc, GLIBC_2_1, GLIBC_2_3_3)
+
+#define _ERRNO_H 1
+#include <bits/errno.h>
+
+ENTRY (__makecontext_stub)
+ li r3,ENOSYS
+ b JUMPTARGET(__syscall_error)
+ END (__makecontext_stub)
+
+compat_symbol (libc, __makecontext_stub, makecontext, GLIBC_2_1)
+
+#endif
diff -urN cvs/libc/sysdeps/unix/sysv/linux/powerpc/powerpc32/setcontext.S libc/sysdeps/unix/sysv/linux/powerpc/powerpc32/setcontext.S
--- cvs/libc/sysdeps/unix/sysv/linux/powerpc/powerpc32/setcontext.S 2003-06-18 13:36:57.000000000 +1000
+++ libc/sysdeps/unix/sysv/linux/powerpc/powerpc32/setcontext.S 2003-09-23 17:01:40.000000000 +1000
@@ -18,6 +18,7 @@
02111-1307 USA. */
#include <sysdep.h>
+#include <shlib-compat.h>
#define __ASSEMBLY__
#include <asm/ptrace.h>
@@ -28,7 +29,7 @@
stwu r1,-16(r1)
stw r0,20(r1)
stw r31,12(r1)
- mr r31,r3
+ lwz r31,_UC_REGS_PTR(r3)
/*
* If this ucontext refers to the point where we were interrupted
@@ -144,6 +145,20 @@
sc
/* NOTREACHED */
-PSEUDO_END(__setcontext)
+PSEUDO_END (__setcontext)
-weak_alias(__setcontext, setcontext)
+versioned_symbol (libc, __setcontext, setcontext, GLIBC_2_3_3)
+
+#if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_3_3)
+
+#define _ERRNO_H 1
+#include <bits/errno.h>
+
+ENTRY (__setcontext_stub)
+ li r3,ENOSYS
+ b JUMPTARGET(__syscall_error)
+ END (__setcontext_stub)
+
+compat_symbol (libc, __setcontext_stub, setcontext, GLIBC_2_0)
+
+#endif
diff -urN cvs/libc/sysdeps/unix/sysv/linux/powerpc/powerpc32/swapcontext.S libc/sysdeps/unix/sysv/linux/powerpc/powerpc32/swapcontext.S
--- cvs/libc/sysdeps/unix/sysv/linux/powerpc/powerpc32/swapcontext.S 2003-06-18 13:37:19.000000000 +1000
+++ libc/sysdeps/unix/sysv/linux/powerpc/powerpc32/swapcontext.S 2003-09-23 19:15:56.000000000 +1000
@@ -18,6 +18,7 @@
02111-1307 USA. */
#include <sysdep.h>
+#include <shlib-compat.h>
#define __ASSEMBLY__
#include <asm/ptrace.h>
@@ -25,6 +26,8 @@
ENTRY(__swapcontext)
/* Save the current context */
+ addi r3,r3,_UC_REG_SPACE
+ stw r3,_UC_REGS_PTR - _UC_REG_SPACE(r3)
stw r0,_UC_GREGS+(PT_R0*4)(r3)
stw r1,_UC_GREGS+(PT_R1*4)(r3)
mflr r0
@@ -115,7 +118,7 @@
stfd fp31,_UC_FREGS+(31*8)(r3)
stfd fp0,_UC_FREGS+(32*8)(r3)
- addi r5,r3,_UC_SIGMASK
+ addi r5,r3,_UC_SIGMASK - _UC_REG_SPACE
addi r4,r4,_UC_SIGMASK
li r3,SIG_SETMASK
bl JUMPTARGET(sigprocmask)
@@ -133,6 +136,8 @@
* r0, xer, ctr. We don't restore r2 since it will be used as
* the TLS pointer.
*/
+ mr r4,r31
+ lwz r31,_UC_REGS_PTR(r31)
lwz r0,_UC_GREGS+(PT_MSR*4)(r31)
cmpwi r0,0
bne L(do_sigret)
@@ -223,11 +228,25 @@
blr
L(do_sigret):
- addi r1,r31,-0xd0
+ addi r1,r4,-0xd0
li r0,SYS_ify(rt_sigreturn)
sc
/* NOTREACHED */
PSEUDO_END(__swapcontext)
-weak_alias(__swapcontext, swapcontext)
+versioned_symbol (libc, __swapcontext, swapcontext, GLIBC_2_3_3)
+
+#if SHLIB_COMPAT (libc, GLIBC_2_1, GLIBC_2_3_3)
+
+#define _ERRNO_H 1
+#include <bits/errno.h>
+
+ENTRY (__swapcontext_stub)
+ li r3,ENOSYS
+ b JUMPTARGET(__syscall_error)
+ END (__swapcontext_stub)
+
+compat_symbol (libc, __swapcontext_stub, swapcontext, GLIBC_2_1)
+
+#endif
diff -urN cvs/libc/sysdeps/unix/sysv/linux/powerpc/powerpc32/ucontext_i.h libc/sysdeps/unix/sysv/linux/powerpc/powerpc32/ucontext_i.h
--- cvs/libc/sysdeps/unix/sysv/linux/powerpc/powerpc32/ucontext_i.h 2003-06-18 13:37:33.000000000 +1000
+++ libc/sysdeps/unix/sysv/linux/powerpc/powerpc32/ucontext_i.h 2003-09-11 16:48:08.000000000 +1000
@@ -24,7 +24,11 @@
#define _UC_LINK 4
#define _UC_STACK_SP 8
#define _UC_STACK_SIZE 16
-#define _UC_SIGMASK 64
-#define _UC_GREGS 192
-#define _UC_FREGS 384
-#define _UC_VREGS 656
+#define _UC_REGS_PTR 48
+#define _UC_SIGMASK 52
+#define _UC_REG_SPACE 180
+
+/* offsets within mcontext_t */
+#define _UC_GREGS 0
+#define _UC_FREGS 192
+#define _UC_VREGS 464
diff -urN cvs/libc/sysdeps/unix/sysv/linux/powerpc/sys/ucontext.h libc/sysdeps/unix/sysv/linux/powerpc/sys/ucontext.h
--- cvs/libc/sysdeps/unix/sysv/linux/powerpc/sys/ucontext.h 2003-07-04 10:12:48.000000000 +1000
+++ libc/sysdeps/unix/sysv/linux/powerpc/sys/ucontext.h 2003-09-11 16:31:52.000000000 +1000
@@ -74,14 +74,40 @@
struct ucontext *uc_link;
stack_t uc_stack;
#if __WORDSIZE == 32
- /* These fields are for backwards compatibility. */
+ /*
+ * These fields are set up this way to maximize source and
+ * binary compatibility with code written for the old
+ * ucontext_t definition, which didn't include space for the
+ * registers.
+ *
+ * Different versions of the kernel have stored the registers on
+ * signal delivery at different offsets from the ucontext struct.
+ * Programs should thus use the uc_mcontext.uc_regs pointer to
+ * find where the registers are actually stored. The registers
+ * will be stored within the ucontext_t struct but not necessarily
+ * at a fixed address. As a side-effect, this lets us achieve
+ * 16-byte alignment for the register storage space if the
+ * Altivec registers are to be saved, without requiring 16-byte
+ * alignment on the whole ucontext_t.
+ *
+ * The uc_mcontext.regs field is included for source compatibility
+ * with programs written against the older ucontext_t definition,
+ * and its name should therefore not change. The uc_pad field
+ * is for binary compatibility with programs compiled against the
+ * old ucontext_t; it ensures that uc_mcontext.regs and uc_sigmask
+ * are at the same offset as previously.
+ */
int uc_pad[7];
- mcontext_t *uc_regs;
- unsigned int uc_oldsigmask[2];
- int uc_pad2;
-#endif
+ union uc_regs_ptr {
+ struct pt_regs *regs;
+ mcontext_t *uc_regs;
+ } uc_mcontext;
+ sigset_t uc_sigmask;
+ char uc_reg_space[sizeof(mcontext_t) + 12]; /* last for extensibility */
+#else /* 64-bit */
sigset_t uc_sigmask;
mcontext_t uc_mcontext; /* last for extensibility */
+#endif
} ucontext_t;
#endif /* sys/ucontext.h */