Atsushi Nemoto writes:

Current ucontext_t does not match with kernel's definition.  Also, on
N32 ABI, we can not use kernel's struct sigcontext since kernel's
sizeof(long) and user's sizeof(long) is differ.

For both data structure, just importing header files from recent glibc
fixes the mismatch.  So here is a patch importing sys/ucontext.h and
bits/sigcontext.t from glibc-2.5.

1 files changed, 80 insertions, 121 deletions

diff --git a/libc/sysdeps/linux/mips/sys/ucontext.h b/libc/sysdeps/linux/mips/sys/ucontext.h
index 90aa09a80..ac496f3d6 100644
--- a/libc/sysdeps/linux/mips/sys/ucontext.h
+++ b/libc/sysdeps/linux/mips/sys/ucontext.h
@@ -1,5 +1,5 @@
-/* Copyright (C) 1998, 1999, 2002, 2003 Free Software Foundation, Inc.
-   This file is part of the GNU C Library.
+/* Copyright (C) 1997, 1998, 2000, 2003, 2004, 2006 Free Software
+   Foundation, Inc.  This file is part of the GNU C Library.
 
    The GNU C Library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
@@ -16,143 +16,102 @@
    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
    02111-1307 USA.  */
 
-/* System V/mips ABI compliant context switching support.  */
-
+/* Don't rely on this, the interface is currently messed up and may need to
+   be broken to be fixed.  */
 #ifndef _SYS_UCONTEXT_H
 #define _SYS_UCONTEXT_H	1
 
 #include <features.h>
+#include <sgidefs.h>
 #include <signal.h>
 
-/* Type for general register.  */
-#if _MIPS_SIM == _MIPS_SIM_ABI32
-typedef __uint32_t greg_t;
-#else
-typedef __uint64_t greg_t;
-#endif
+/* We need the signal context definitions even if they are not used
+   included in <signal.h>.  */
+#include <bits/sigcontext.h>
+
+/* Type for general register.  Even in o32 we assume 64-bit registers,
+   like the kernel.  */
+__extension__ typedef unsigned long long int greg_t;
 
 /* Number of general registers.  */
-#define NGREG	36
+#define NGREG	32
+#define NFPREG	32
 
 /* Container for all general registers.  */
 typedef greg_t gregset_t[NGREG];
 
-/* Number of each register is the `gregset_t' array.  */
-enum
-{
-  CTX_R0 = 0,
-#define CTX_R0	CTX_R0
-  CTX_AT = 1,
-#define CTX_AT	CTX_AT
-  CTX_V0 = 2,
-#define CTX_V0	CTX_V0
-  CTX_V1 = 3,
-#define CTX_V1	CTX_V1
-  CTX_A0 = 4,
-#define CTX_A0	CTX_A0
-  CTX_A1 = 5,
-#define CTX_A1	CTX_A1
-  CTX_A2 = 6,
-#define CTX_A2	CTX_A2
-  CTX_A3 = 7,
-#define CTX_A3	CTX_A3
-  CTX_T0 = 8,
-#define CTX_T0	CTX_T0
-  CTX_T1 = 9,
-#define CTX_T1	CTX_T1
-  CTX_T2 = 10,
-#define CTX_T2	CTX_T2
-  CTX_T3 = 11,
-#define CTX_T3	CTX_T3
-  CTX_T4 = 12,
-#define CTX_T4	CTX_T4
-  CTX_T5 = 13,
-#define CTX_T5	CTX_T5
-  CTX_T6 = 14,
-#define CTX_T6	CTX_T6
-  CTX_T7 = 15,
-#define CTX_T7	CTX_T7
-  CTX_S0 = 16,
-#define CTX_S0	CTX_S0
-  CTX_S1 = 17,
-#define CTX_S1	CTX_S1
-  CTX_S2 = 18,
-#define CTX_S2	CTX_S2
-  CTX_S3 = 19,
-#define CTX_S3	CTX_S3
-  CTX_S4 = 20,
-#define CTX_S4	CTX_S4
-  CTX_S5 = 21,
-#define CTX_S5	CTX_S5
-  CTX_S6 = 22,
-#define CTX_S6	CTX_S6
-  CTX_S7 = 23,
-#define CTX_S7	CTX_S7
-  CTX_T8 = 24,
-#define CTX_T8	CTX_T8
-  CTX_T9 = 25,
-#define CTX_T9	CTX_T9
-  CTX_K0 = 26,
-#define CTX_K0	CTX_K0
-  CTX_K1 = 27,
-#define CTX_K1	CTX_K1
-  CTX_GP = 28,
-#define CTX_GP	CTX_GP
-  CTX_SP = 29,
-#define CTX_SP	CTX_SP
-  CTX_S8 = 30,
-#define CTX_S8	CTX_S8
-  CTX_RA = 31,
-#define CTX_RA	CTX_RA
-  CTX_MDLO = 32,
-#define CTX_MDLO	CTX_MDLO
-  CTX_MDHI = 33,
-#define CTX_MDHI	CTX_MDHI
-  CTX_CAUSE = 34,
-#define CTX_CAUSE	CTX_CAUSE
-  CTX_EPC = 35,
-#define CTX_EPC	CTX_EPC
-};
-
-/* Structure to describe FPU registers.  */
-typedef struct fpregset
-{
-  union
-  {
-#if _MIPS_SIM == _MIPS_SIM_ABI32
-    double fp_dregs[16];
-    float fp_fregs[32];
-    unsigned int fp_regs[32];
-#else
-    double fp_dregs[32];
-    /* float fp_fregs[32]; */
-    __uint64_t fp_regs[32];
-#endif
-  } fp_r;
-  unsigned int fp_csr;
-  unsigned int fp_pad;
+/* Container for all FPU registers.  */
+typedef struct fpregset {
+	union {
+		double	fp_dregs[NFPREG];
+		struct {
+			float		_fp_fregs;
+			unsigned int	_fp_pad;
+		} fp_fregs[NFPREG];
+	} fp_r;
 } fpregset_t;
 
+
 /* Context to describe whole processor state.  */
+#if _MIPS_SIM == _ABIO32
+/* Earlier versions of glibc for mips had an entirely different
+   definition of mcontext_t, that didn't even resemble the
+   corresponding kernel data structure.  Since all legitimate uses of
+   ucontext_t in glibc mustn't have accessed anything beyond
+   uc_mcontext and, even then, taking a pointer to it, casting it to
+   sigcontext_t, and accessing it as such, which is what it has always
+   been, this can still be rectified.  Fortunately, makecontext,
+   [gs]etcontext et all have never been implemented.  */
 typedef struct
-{
-  gregset_t gpregs;
-  fpregset_t fpregs;
-} mcontext_t;
+  {
+    unsigned int regmask;
+    unsigned int status;
+    greg_t pc;
+    gregset_t gregs;
+    fpregset_t fpregs;
+    unsigned int fp_owned;
+    unsigned int fpc_csr;
+    unsigned int fpc_eir;
+    unsigned int used_math;
+    unsigned int dsp;
+    greg_t mdhi;
+    greg_t mdlo;
+    unsigned long hi1;
+    unsigned long lo1;
+    unsigned long hi2;
+    unsigned long lo2;
+    unsigned long hi3;
+    unsigned long lo3;
+  } mcontext_t;
+#else
+typedef struct
+  {
+    gregset_t gregs;
+    fpregset_t fpregs;
+    greg_t mdhi;
+    greg_t hi1;
+    greg_t hi2;
+    greg_t hi3;
+    greg_t mdlo;
+    greg_t lo1;
+    greg_t lo2;
+    greg_t lo3;
+    greg_t pc;
+    unsigned int fpc_csr;
+    unsigned int used_math;
+    unsigned int dsp;
+    unsigned int reserved;
+  } mcontext_t;
+#endif
 
 /* Userlevel context.  */
 typedef struct ucontext
-{
-#if _MIPS_SIM == _MIPS_SIM_ABI32
-  unsigned long int uc_flags;
-#else
-  __uint64_t uc_flags;
-#endif
-  struct ucontext *uc_link;
-  __sigset_t uc_sigmask;
-  stack_t uc_stack;
-  mcontext_t uc_mcontext;
-  int uc_filler[48];
-} ucontext_t;
+  {
+    unsigned long int uc_flags;
+    struct ucontext *uc_link;
+    stack_t uc_stack;
+    mcontext_t uc_mcontext;
+    __sigset_t uc_sigmask;
+  } ucontext_t;
 
 #endif /* sys/ucontext.h */