5 files changed, 36 insertions, 27 deletions

diff --git a/arch/tile/include/asm/ptrace.h b/arch/tile/include/asm/ptrace.h
index acdae814e016..4a02bb073979 100644
--- a/arch/tile/include/asm/ptrace.h
+++ b/arch/tile/include/asm/ptrace.h
@@ -51,10 +51,7 @@ typedef uint_reg_t pt_reg_t;
 
 /*
  * This struct defines the way the registers are stored on the stack during a
- * system call/exception.  It should be a multiple of 8 bytes to preserve
- * normal stack alignment rules.
- *
- * Must track <sys/ucontext.h> and <sys/procfs.h>
+ * system call or exception.  "struct sigcontext" has the same shape.
  */
 struct pt_regs {
         /* Saved main processor registers; 56..63 are special. */
@@ -80,11 +77,6 @@ struct pt_regs {
 
 #endif /* __ASSEMBLY__ */
 
-/* Flag bits in pt_regs.flags */
-#define PT_FLAGS_DISABLE_IRQ    1  /* on return to kernel, disable irqs */
-#define PT_FLAGS_CALLER_SAVES   2  /* caller-save registers are valid */
-#define PT_FLAGS_RESTORE_REGS   4  /* restore callee-save regs on return */
-
 #define PTRACE_GETREGS          12
 #define PTRACE_SETREGS          13
 #define PTRACE_GETFPREGS        14
@@ -101,6 +93,11 @@ struct pt_regs {
 
 #ifdef __KERNEL__
 
+/* Flag bits in pt_regs.flags */
+#define PT_FLAGS_DISABLE_IRQ    1  /* on return to kernel, disable irqs */
+#define PT_FLAGS_CALLER_SAVES   2  /* caller-save registers are valid */
+#define PT_FLAGS_RESTORE_REGS   4  /* restore callee-save regs on return */
+
 #ifndef __ASSEMBLY__
 
 #define instruction_pointer(regs) ((regs)->pc)
diff --git a/arch/tile/include/asm/sigcontext.h b/arch/tile/include/asm/sigcontext.h
index 7cd7672e3ad4..5e2d03336f53 100644
--- a/arch/tile/include/asm/sigcontext.h
+++ b/arch/tile/include/asm/sigcontext.h
@@ -15,13 +15,21 @@
 #ifndef _ASM_TILE_SIGCONTEXT_H
 #define _ASM_TILE_SIGCONTEXT_H
 
-/* NOTE: we can't include <linux/ptrace.h> due to #include dependencies. */
-#include <asm/ptrace.h>
-
-/* Must track <sys/ucontext.h> */
+#include <arch/abi.h>
 
+/*
+ * struct sigcontext has the same shape as struct pt_regs,
+ * but is simplified since we know the fault is from userspace.
+ */
 struct sigcontext {
-        struct pt_regs regs;
+        uint_reg_t gregs[53];   /* General-purpose registers.  */
+        uint_reg_t tp;          /* Aliases gregs[TREG_TP].  */
+        uint_reg_t sp;          /* Aliases gregs[TREG_SP].  */
+        uint_reg_t lr;          /* Aliases gregs[TREG_LR].  */
+        uint_reg_t pc;          /* Program counter.  */
+        uint_reg_t ics;         /* In Interrupt Critical Section?  */
+        uint_reg_t faultnum;    /* Fault number.  */
+        uint_reg_t pad[5];
 };
 
 #endif /* _ASM_TILE_SIGCONTEXT_H */
diff --git a/arch/tile/include/asm/signal.h b/arch/tile/include/asm/signal.h
index eb0253f32202..c1ee1d61d44c 100644
--- a/arch/tile/include/asm/signal.h
+++ b/arch/tile/include/asm/signal.h
@@ -24,6 +24,7 @@
 #include <asm-generic/signal.h>
 
 #if defined(__KERNEL__) && !defined(__ASSEMBLY__)
+struct pt_regs;
 int restore_sigcontext(struct pt_regs *, struct sigcontext __user *, long *);
 int setup_sigcontext(struct sigcontext __user *, struct pt_regs *);
 void do_signal(struct pt_regs *regs);
diff --git a/arch/tile/kernel/signal.c b/arch/tile/kernel/signal.c
index 45b66a3c991f..ce183aa1492c 100644
--- a/arch/tile/kernel/signal.c
+++ b/arch/tile/kernel/signal.c
@@ -61,13 +61,19 @@ int restore_sigcontext(struct pt_regs *regs,
         /* Always make any pending restarted system calls return -EINTR */
         current_thread_info()->restart_block.fn = do_no_restart_syscall;
 
+        /*
+         * Enforce that sigcontext is like pt_regs, and doesn't mess
+         * up our stack alignment rules.
+         */
+        BUILD_BUG_ON(sizeof(struct sigcontext) != sizeof(struct pt_regs));
+        BUILD_BUG_ON(sizeof(struct sigcontext) % 8 != 0);
+
         for (i = 0; i < sizeof(struct pt_regs)/sizeof(long); ++i)
-                err |= __get_user(((long *)regs)[i],
-                                  &((long __user *)(&sc->regs))[i]);
+                err |= __get_user(regs->regs[i], &sc->gregs[i]);
 
         regs->faultnum = INT_SWINT_1_SIGRETURN;
 
-        err |= __get_user(*pr0, &sc->regs.regs[0]);
+        err |= __get_user(*pr0, &sc->gregs[0]);
         return err;
 }
 
@@ -112,8 +118,7 @@ int setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs)
         int i, err = 0;
 
         for (i = 0; i < sizeof(struct pt_regs)/sizeof(long); ++i)
-                err |= __put_user(((long *)regs)[i],
-                                  &((long __user *)(&sc->regs))[i]);
+                err |= __put_user(regs->regs[i], &sc->gregs[i]);
 
         return err;
 }
@@ -203,19 +208,17 @@ static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
          * Set up registers for signal handler.
          * Registers that we don't modify keep the value they had from
          * user-space at the time we took the signal.
+         * We always pass siginfo and mcontext, regardless of SA_SIGINFO,
+         * since some things rely on this (e.g. glibc's debug/segfault.c).
          */
         regs->pc = (unsigned long) ka->sa.sa_handler;
         regs->ex1 = PL_ICS_EX1(USER_PL, 1); /* set crit sec in handler */
         regs->sp = (unsigned long) frame;
         regs->lr = restorer;
         regs->regs[0] = (unsigned long) usig;
-
-        if (ka->sa.sa_flags & SA_SIGINFO) {
-                /* Need extra arguments, so mark to restore caller-saves. */
-                regs->regs[1] = (unsigned long) &frame->info;
-                regs->regs[2] = (unsigned long) &frame->uc;
-                regs->flags |= PT_FLAGS_CALLER_SAVES;
-        }
+        regs->regs[1] = (unsigned long) &frame->info;
+        regs->regs[2] = (unsigned long) &frame->uc;
+        regs->flags |= PT_FLAGS_CALLER_SAVES;
 
         /*
          * Notify any tracer that was single-stepping it.
diff --git a/arch/tile/kernel/stack.c b/arch/tile/kernel/stack.c
index 38a68b0b4581..ea2e0ce28380 100644
--- a/arch/tile/kernel/stack.c
+++ b/arch/tile/kernel/stack.c
@@ -175,7 +175,7 @@ static struct pt_regs *valid_sigframe(struct KBacktraceIterator* kbt)
                         pr_err("  <received signal %d>\n",
                                frame->info.si_signo);
                 }
-                return &frame->uc.uc_mcontext.regs;
+                return (struct pt_regs *)&frame->uc.uc_mcontext;
         }
         return NULL;
 }