From a3f61dc0a5335334958ec3b97d0b1946b4ae5375 Mon Sep 17 00:00:00 2001 From: Benjamin Herrenschmidt Date: Mon, 4 Jun 2007 17:22:48 +1000 Subject: [PATCH] [POWERPC] Merge creation of signal frame 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 Signed-off-by: Paul Mackerras --- 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 | 24 ++------------- 4 files changed, 59 insertions(+), 62 deletions(-) diff --git a/arch/powerpc/kernel/signal.c b/arch/powerpc/kernel/signal.c index a9c148a09361..dee275014e00 100644 --- a/arch/powerpc/kernel/signal.c +++ b/arch/powerpc/kernel/signal.c @@ -11,6 +11,7 @@ #include #include +#include #include #include "signal.h" @@ -28,6 +29,32 @@ 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(oldsp)) + 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 @@ -130,20 +157,12 @@ int do_signal(sigset_t *oldset, struct pt_regs *regs) #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); diff --git a/arch/powerpc/kernel/signal.h b/arch/powerpc/kernel/signal.h index 190d4325f974..c284f75afe77 100644 --- a/arch/powerpc/kernel/signal.h +++ b/arch/powerpc/kernel/signal.h @@ -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, diff --git a/arch/powerpc/kernel/signal_32.c b/arch/powerpc/kernel/signal_32.c index 32481e71d71e..590057e9e987 100644 --- a/arch/powerpc/kernel/signal_32.c +++ b/arch/powerpc/kernel/signal_32.c @@ -282,14 +282,17 @@ long sys_sigaction(int sig, struct old_sigaction __user *act, /* * 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, u32 __old, int r5, */ 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, struct k_sigaction *ka, 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 __user *ctx, * 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, struct k_sigaction *ka, #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, struct k_sigaction *ka, current->thread.fpscr.val = 0; /* turn off all fp exceptions */ + /* create a stack frame for the caller of the handler */ + newsp = ((unsigned long)frame) - __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; diff --git a/arch/powerpc/kernel/signal_64.c b/arch/powerpc/kernel/signal_64.c index c17903cd384a..5004a979ebc0 100644 --- a/arch/powerpc/kernel/signal_64.c +++ b/arch/powerpc/kernel/signal_64.c @@ -195,25 +195,6 @@ static long restore_sigcontext(struct pt_regs *regs, sigset_t *set, int sig, return err; } -/* - * 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 */ @@ -348,8 +329,7 @@ int handle_rt_signal64(int signr, struct k_sigaction *ka, siginfo_t *info, 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); @@ -386,7 +366,7 @@ int handle_rt_signal64(int signr, struct k_sigaction *ka, siginfo_t *info, funct_desc_ptr = (func_descr_t __user *) ka->sa.sa_handler; /* Allocate a dummy caller frame for the signal handler. */ - newsp = (unsigned long)frame - __SIGNAL_FRAMESIZE; + newsp = ((unsigned long)frame) - __SIGNAL_FRAMESIZE; err |= put_user(regs->gpr[1], (unsigned long __user *)newsp); /* Set up "regs" so we "return" to the signal handler. */ -- 2.30.2