[Cbe-oss-dev] [PATCH 19/21] powerpc: Merge creation of signal frame
Benjamin Herrenschmidt
benh at kernel.crashing.org
Mon Jun 4 15:15:54 EST 2007
The code for creating signal frames was still duplicated and split
in strange ways between 32 and 64 bits, including the SA_ONSTACK
handling being in do_signal on 32 bits but inside handle_rt_signal
on 64 bits etc...
This moves the 64 bits get_sigframe() to the generic signal.c,
cleans it a bit, moves the access_ok() call done by all callers to
it as well, and adapts/cleanups the 3 different signal handling cases
to use that common function.
Signed-off-by: Benjamin Herrenschmidt <benh at kernel.crashing.org>
---
arch/powerpc/kernel/signal.c | 39 ++++++++++++++++++++++--------
arch/powerpc/kernel/signal.h | 6 +++-
arch/powerpc/kernel/signal_32.c | 52 ++++++++++++++++++----------------------
arch/powerpc/kernel/signal_64.c | 22 ----------------
4 files changed, 58 insertions(+), 61 deletions(-)
Index: linux-cell/arch/powerpc/kernel/signal.c
===================================================================
--- linux-cell.orig/arch/powerpc/kernel/signal.c 2007-06-04 14:06:06.000000000 +1000
+++ linux-cell/arch/powerpc/kernel/signal.c 2007-06-04 14:07:25.000000000 +1000
@@ -11,6 +11,7 @@
#include <linux/ptrace.h>
#include <linux/signal.h>
+#include <asm/uaccess.h>
#include "signal.h"
@@ -27,6 +28,32 @@ static inline int is_32bit_task(void)
}
#endif
+/*
+ * Allocate space for the signal frame
+ */
+void __user * get_sigframe(struct k_sigaction *ka, struct pt_regs *regs,
+ size_t frame_size)
+{
+ unsigned long oldsp, newsp;
+
+ /* Default to using normal stack */
+ oldsp = regs->gpr[1];
+
+ /* Check for alt stack */
+ if ((ka->sa.sa_flags & SA_ONSTACK) &&
+ current->sas_ss_size && !on_sig_stack(regs->gpr[1]))
+ oldsp = (current->sas_ss_sp + current->sas_ss_size);
+
+ /* Get aligned frame */
+ newsp = (oldsp - frame_size) & ~0xFUL;
+
+ /* Check access */
+ if (!access_ok(VERIFY_WRITE, (void __user *)newsp, oldsp - newsp))
+ return NULL;
+
+ return (void __user *)newsp;
+}
+
/*
* Restore the user process's signal mask
@@ -129,20 +156,12 @@ int do_signal(sigset_t *oldset, struct p
#endif
if (is32) {
- unsigned int newsp;
-
- if ((ka.sa.sa_flags & SA_ONSTACK) &&
- current->sas_ss_size && !on_sig_stack(regs->gpr[1]))
- newsp = current->sas_ss_sp + current->sas_ss_size;
- else
- newsp = regs->gpr[1];
-
if (ka.sa.sa_flags & SA_SIGINFO)
ret = handle_rt_signal32(signr, &ka, &info, oldset,
- regs, newsp);
+ regs);
else
ret = handle_signal32(signr, &ka, &info, oldset,
- regs, newsp);
+ regs);
#ifdef CONFIG_PPC64
} else {
ret = handle_rt_signal64(signr, &ka, &info, oldset, regs);
Index: linux-cell/arch/powerpc/kernel/signal.h
===================================================================
--- linux-cell.orig/arch/powerpc/kernel/signal.h 2007-06-04 14:06:06.000000000 +1000
+++ linux-cell/arch/powerpc/kernel/signal.h 2007-06-04 14:07:25.000000000 +1000
@@ -12,15 +12,17 @@
#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
+extern void __user * get_sigframe(struct k_sigaction *ka, struct pt_regs *regs,
+ size_t frame_size);
extern void restore_sigmask(sigset_t *set);
extern int handle_signal32(unsigned long sig, struct k_sigaction *ka,
siginfo_t *info, sigset_t *oldset,
- struct pt_regs *regs, unsigned long newsp);
+ struct pt_regs *regs);
extern int handle_rt_signal32(unsigned long sig, struct k_sigaction *ka,
siginfo_t *info, sigset_t *oldset,
- struct pt_regs *regs, unsigned long newsp);
+ struct pt_regs *regs);
extern int handle_rt_signal64(int signr, struct k_sigaction *ka,
siginfo_t *info, sigset_t *set,
Index: linux-cell/arch/powerpc/kernel/signal_32.c
===================================================================
--- linux-cell.orig/arch/powerpc/kernel/signal_32.c 2007-06-04 14:06:06.000000000 +1000
+++ linux-cell/arch/powerpc/kernel/signal_32.c 2007-06-04 14:07:25.000000000 +1000
@@ -282,14 +282,17 @@ long sys_sigaction(int sig, struct old_s
/*
* When we have signals to deliver, we set up on the
* user stack, going down from the original stack pointer:
- * a sigregs struct
+ * an ABI gap of 56 words
+ * an mcontext struct
* a sigcontext struct
* a gap of __SIGNAL_FRAMESIZE bytes
*
- * Each of these things must be a multiple of 16 bytes in size.
+ * Each of these things must be a multiple of 16 bytes in size. The following
+ * structure represent all of this except the __SIGNAL_FRAMESIZE gap
*
*/
-struct sigregs {
+struct sigframe {
+ struct sigcontext sctx; /* the sigcontext */
struct mcontext mctx; /* all the register values */
/*
* Programs using the rs6000/xcoff abi can save up to 19 gp
@@ -698,21 +701,16 @@ int compat_sys_sigaltstack(u32 __new, u3
*/
int handle_rt_signal32(unsigned long sig, struct k_sigaction *ka,
siginfo_t *info, sigset_t *oldset,
- struct pt_regs *regs, unsigned long newsp)
+ struct pt_regs *regs)
{
struct rt_sigframe __user *rt_sf;
struct mcontext __user *frame;
- unsigned long origsp = newsp;
+ unsigned long newsp = 0;
/* Set up Signal Frame */
/* Put a Real Time Context onto stack */
- newsp -= sizeof(*rt_sf);
- rt_sf = (struct rt_sigframe __user *)newsp;
-
- /* create a stack frame for the caller of the handler */
- newsp -= __SIGNAL_FRAMESIZE + 16;
-
- if (!access_ok(VERIFY_WRITE, (void __user *)newsp, origsp - newsp))
+ rt_sf = get_sigframe(ka, regs, sizeof(*rt_sf));
+ if (unlikely(rt_sf == NULL))
goto badframe;
/* Put the siginfo & fill in most of the ucontext */
@@ -742,8 +740,12 @@ int handle_rt_signal32(unsigned long sig
current->thread.fpscr.val = 0; /* turn off all fp exceptions */
+ /* create a stack frame for the caller of the handler */
+ newsp = (unsigned long)rt_sf - __SIGNAL_FRAMESIZE + 16;
if (put_user(regs->gpr[1], (u32 __user *)newsp))
goto badframe;
+
+ /* Fill registers for signal handler */
regs->gpr[1] = newsp;
regs->gpr[3] = sig;
regs->gpr[4] = (unsigned long) &rt_sf->info;
@@ -988,26 +990,17 @@ int sys_debug_setcontext(struct ucontext
* OK, we're invoking a handler
*/
int handle_signal32(unsigned long sig, struct k_sigaction *ka,
- siginfo_t *info, sigset_t *oldset, struct pt_regs *regs,
- unsigned long newsp)
+ siginfo_t *info, sigset_t *oldset, struct pt_regs *regs)
{
struct sigcontext __user *sc;
- struct sigregs __user *frame;
- unsigned long origsp = newsp;
+ struct sigframe __user *frame;
+ unsigned long newsp = 0;
/* Set up Signal Frame */
- newsp -= sizeof(struct sigregs);
- frame = (struct sigregs __user *) newsp;
-
- /* Put a sigcontext on the stack */
- newsp -= sizeof(*sc);
- sc = (struct sigcontext __user *) newsp;
-
- /* create a stack frame for the caller of the handler */
- newsp -= __SIGNAL_FRAMESIZE;
-
- if (!access_ok(VERIFY_WRITE, (void __user *) newsp, origsp - newsp))
+ frame = get_sigframe(ka, regs, sizeof(*frame));
+ if (unlikely(frame == NULL))
goto badframe;
+ sc = (struct sigcontext __user *) &frame->sctx;
#if _NSIG != 64
#error "Please adjust handle_signal()"
@@ -1019,7 +1012,7 @@ int handle_signal32(unsigned long sig, s
#else
|| __put_user(oldset->sig[1], &sc->_unused[3])
#endif
- || __put_user(to_user_ptr(frame), &sc->regs)
+ || __put_user(to_user_ptr(&frame->mctx), &sc->regs)
|| __put_user(sig, &sc->signal))
goto badframe;
@@ -1035,8 +1028,11 @@ int handle_signal32(unsigned long sig, s
current->thread.fpscr.val = 0; /* turn off all fp exceptions */
+ /* create a stack frame for the caller of the handler */
+ newsp -= __SIGNAL_FRAMESIZE;
if (put_user(regs->gpr[1], (u32 __user *)newsp))
goto badframe;
+
regs->gpr[1] = newsp;
regs->gpr[3] = sig;
regs->gpr[4] = (unsigned long) sc;
Index: linux-cell/arch/powerpc/kernel/signal_64.c
===================================================================
--- linux-cell.orig/arch/powerpc/kernel/signal_64.c 2007-06-04 14:06:06.000000000 +1000
+++ linux-cell/arch/powerpc/kernel/signal_64.c 2007-06-04 14:07:25.000000000 +1000
@@ -196,25 +196,6 @@ static long restore_sigcontext(struct pt
}
/*
- * Allocate space for the signal frame
- */
-static inline void __user * get_sigframe(struct k_sigaction *ka, struct pt_regs *regs,
- size_t frame_size)
-{
- unsigned long newsp;
-
- /* Default to using normal stack */
- newsp = regs->gpr[1];
-
- if ((ka->sa.sa_flags & SA_ONSTACK) && current->sas_ss_size) {
- if (! on_sig_stack(regs->gpr[1]))
- newsp = (current->sas_ss_sp + current->sas_ss_size);
- }
-
- return (void __user *)((newsp - frame_size) & -16ul);
-}
-
-/*
* Setup the trampoline code on the stack
*/
static long setup_trampoline(unsigned int syscall, unsigned int __user *tramp)
@@ -348,8 +329,7 @@ int handle_rt_signal64(int signr, struct
long err = 0;
frame = get_sigframe(ka, regs, sizeof(*frame));
-
- if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
+ if (unlikely(frame == NULL))
goto badframe;
err |= __put_user(&frame->info, &frame->pinfo);
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