[PATCH v3 1/6] powerpc/signal64: Access function descriptor with user access block

[PATCH v3 1/6] powerpc/signal64: Access function descriptor with user access block

[Christophe Leroy]

Access the function descriptor of the handler within a
user access block.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
v3: Flatten the change to avoid nested gotos.
---
 arch/powerpc/kernel/signal_64.c | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/kernel/signal_64.c b/arch/powerpc/kernel/signal_64.c
index 1831bba0582e..7b1cd50bc4fb 100644
--- a/arch/powerpc/kernel/signal_64.c
+++ b/arch/powerpc/kernel/signal_64.c
@@ -936,8 +936,13 @@ int handle_rt_signal64(struct ksignal *ksig, sigset_t *set,
 		func_descr_t __user *funct_desc_ptr =
 			(func_descr_t __user *) ksig->ka.sa.sa_handler;
 
-		err |= get_user(regs->ctr, &funct_desc_ptr->entry);
-		err |= get_user(regs->gpr[2], &funct_desc_ptr->toc);
+		if (!user_read_access_begin(funct_desc_ptr, sizeof(func_descr_t)))
+			goto badfunc;
+
+		unsafe_get_user(regs->ctr, &funct_desc_ptr->entry, badfunc_block);
+		unsafe_get_user(regs->gpr[2], &funct_desc_ptr->toc, badfunc_block);
+
+		user_read_access_end();
 	}
 
 	/* enter the signal handler in native-endian mode */
@@ -962,5 +967,12 @@ int handle_rt_signal64(struct ksignal *ksig, sigset_t *set,
 badframe:
 	signal_fault(current, regs, "handle_rt_signal64", frame);
 
+	return 1;
+
+badfunc_block:
+	user_read_access_end();
+badfunc:
+	signal_fault(current, regs, __func__, (void __user *)ksig->ka.sa.sa_handler);
+
 	return 1;
 }
-- 
2.31.1

[PATCH v3 2/6] powerpc/signal: Include the new stack frame inside the user access block

[Christophe Leroy]

Include the new stack frame inside the user access block and set it up
using unsafe_put_user().

On an mpc 8321 (book3s/32) the improvment is about 4% on a process
sending a signal to itself.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
 arch/powerpc/kernel/signal_32.c | 29 +++++++++++++----------------
 arch/powerpc/kernel/signal_64.c | 14 +++++++-------
 2 files changed, 20 insertions(+), 23 deletions(-)

diff --git a/arch/powerpc/kernel/signal_32.c b/arch/powerpc/kernel/signal_32.c
index 0608581967f0..ff101e2b3bab 100644
--- a/arch/powerpc/kernel/signal_32.c
+++ b/arch/powerpc/kernel/signal_32.c
@@ -726,7 +726,7 @@ int handle_rt_signal32(struct ksignal *ksig, sigset_t *oldset,
 	struct rt_sigframe __user *frame;
 	struct mcontext __user *mctx;
 	struct mcontext __user *tm_mctx = NULL;
-	unsigned long newsp = 0;
+	unsigned long __user *newsp;
 	unsigned long tramp;
 	struct pt_regs *regs = tsk->thread.regs;
 	/* Save the thread's msr before get_tm_stackpointer() changes it */
@@ -734,6 +734,7 @@ int handle_rt_signal32(struct ksignal *ksig, sigset_t *oldset,
 
 	/* Set up Signal Frame */
 	frame = get_sigframe(ksig, tsk, sizeof(*frame), 1);
+	newsp = (unsigned long __user *)((unsigned long)frame - (__SIGNAL_FRAMESIZE + 16));
 	mctx = &frame->uc.uc_mcontext;
 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
 	tm_mctx = &frame->uc_transact.uc_mcontext;
@@ -743,7 +744,7 @@ int handle_rt_signal32(struct ksignal *ksig, sigset_t *oldset,
 	else
 		prepare_save_user_regs(1);
 
-	if (!user_access_begin(frame, sizeof(*frame)))
+	if (!user_access_begin(newsp, __SIGNAL_FRAMESIZE + 16 + sizeof(*frame)))
 		goto badframe;
 
 	/* Put the siginfo & fill in most of the ucontext */
@@ -779,6 +780,9 @@ int handle_rt_signal32(struct ksignal *ksig, sigset_t *oldset,
 	}
 	unsafe_put_sigset_t(&frame->uc.uc_sigmask, oldset, failed);
 
+	/* create a stack frame for the caller of the handler */
+	unsafe_put_user(regs->gpr[1], newsp, failed);
+
 	user_access_end();
 
 	if (copy_siginfo_to_user(&frame->info, &ksig->info))
@@ -790,13 +794,8 @@ int handle_rt_signal32(struct ksignal *ksig, sigset_t *oldset,
 	tsk->thread.fp_state.fpscr = 0;	/* turn off all fp exceptions */
 #endif
 
-	/* create a stack frame for the caller of the handler */
-	newsp = ((unsigned long)frame) - (__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[1] = (unsigned long)newsp;
 	regs->gpr[3] = ksig->sig;
 	regs->gpr[4] = (unsigned long)&frame->info;
 	regs->gpr[5] = (unsigned long)&frame->uc;
@@ -826,7 +825,7 @@ int handle_signal32(struct ksignal *ksig, sigset_t *oldset,
 	struct sigframe __user *frame;
 	struct mcontext __user *mctx;
 	struct mcontext __user *tm_mctx = NULL;
-	unsigned long newsp = 0;
+	unsigned long __user *newsp;
 	unsigned long tramp;
 	struct pt_regs *regs = tsk->thread.regs;
 	/* Save the thread's msr before get_tm_stackpointer() changes it */
@@ -834,6 +833,7 @@ int handle_signal32(struct ksignal *ksig, sigset_t *oldset,
 
 	/* Set up Signal Frame */
 	frame = get_sigframe(ksig, tsk, sizeof(*frame), 1);
+	newsp = (unsigned long __user *)((unsigned long)frame - __SIGNAL_FRAMESIZE);
 	mctx = &frame->mctx;
 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
 	tm_mctx = &frame->mctx_transact;
@@ -843,7 +843,7 @@ int handle_signal32(struct ksignal *ksig, sigset_t *oldset,
 	else
 		prepare_save_user_regs(1);
 
-	if (!user_access_begin(frame, sizeof(*frame)))
+	if (!user_access_begin(newsp, __SIGNAL_FRAMESIZE + sizeof(*frame)))
 		goto badframe;
 	sc = (struct sigcontext __user *) &frame->sctx;
 
@@ -873,6 +873,8 @@ int handle_signal32(struct ksignal *ksig, sigset_t *oldset,
 		unsafe_put_user(PPC_RAW_SC(), &mctx->mc_pad[1], failed);
 		asm("dcbst %y0; sync; icbi %y0; sync" :: "Z" (mctx->mc_pad[0]));
 	}
+	/* create a stack frame for the caller of the handler */
+	unsafe_put_user(regs->gpr[1], newsp, failed);
 	user_access_end();
 
 	regs->link = tramp;
@@ -881,12 +883,7 @@ int handle_signal32(struct ksignal *ksig, sigset_t *oldset,
 	tsk->thread.fp_state.fpscr = 0;	/* turn off all fp exceptions */
 #endif
 
-	/* 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[1] = (unsigned long)newsp;
 	regs->gpr[3] = ksig->sig;
 	regs->gpr[4] = (unsigned long) sc;
 	regs_set_return_ip(regs, (unsigned long) ksig->ka.sa.sa_handler);
diff --git a/arch/powerpc/kernel/signal_64.c b/arch/powerpc/kernel/signal_64.c
index 7b1cd50bc4fb..d80ff83cacb9 100644
--- a/arch/powerpc/kernel/signal_64.c
+++ b/arch/powerpc/kernel/signal_64.c
@@ -847,13 +847,14 @@ int handle_rt_signal64(struct ksignal *ksig, sigset_t *set,
 		struct task_struct *tsk)
 {
 	struct rt_sigframe __user *frame;
-	unsigned long newsp = 0;
+	unsigned long __user *newsp;
 	long err = 0;
 	struct pt_regs *regs = tsk->thread.regs;
 	/* Save the thread's msr before get_tm_stackpointer() changes it */
 	unsigned long msr = regs->msr;
 
 	frame = get_sigframe(ksig, tsk, sizeof(*frame), 0);
+	newsp = (unsigned long __user *)((unsigned long)frame - __SIGNAL_FRAMESIZE);
 
 	/*
 	 * This only applies when calling unsafe_setup_sigcontext() and must be
@@ -862,7 +863,7 @@ int handle_rt_signal64(struct ksignal *ksig, sigset_t *set,
 	if (!MSR_TM_ACTIVE(msr))
 		prepare_setup_sigcontext(tsk);
 
-	if (!user_write_access_begin(frame, sizeof(*frame)))
+	if (!user_write_access_begin(newsp, __SIGNAL_FRAMESIZE + sizeof(*frame)))
 		goto badframe;
 
 	unsafe_put_user(&frame->info, &frame->pinfo, badframe_block);
@@ -900,6 +901,9 @@ int handle_rt_signal64(struct ksignal *ksig, sigset_t *set,
 	}
 
 	unsafe_copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set), badframe_block);
+	/* Allocate a dummy caller frame for the signal handler. */
+	unsafe_put_user(regs->gpr[1], newsp, badframe_block);
+
 	user_write_access_end();
 
 	/* Save the siginfo outside of the unsafe block. */
@@ -919,10 +923,6 @@ int handle_rt_signal64(struct ksignal *ksig, sigset_t *set,
 		regs_set_return_ip(regs, (unsigned long) &frame->tramp[0]);
 	}
 
-	/* Allocate a dummy caller frame for the signal handler. */
-	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. */
 	if (is_elf2_task()) {
 		regs->ctr = (unsigned long) ksig->ka.sa.sa_handler;
@@ -947,7 +947,7 @@ int handle_rt_signal64(struct ksignal *ksig, sigset_t *set,
 
 	/* enter the signal handler in native-endian mode */
 	regs_set_return_msr(regs, (regs->msr & ~MSR_LE) | (MSR_KERNEL & MSR_LE));
-	regs->gpr[1] = newsp;
+	regs->gpr[1] = (unsigned long)newsp;
 	regs->gpr[3] = ksig->sig;
 	regs->result = 0;
 	if (ksig->ka.sa.sa_flags & SA_SIGINFO) {
-- 
2.31.1

[PATCH v3 3/6] signal: Add unsafe_copy_siginfo_to_user()

[Christophe Leroy]

In the same spirit as commit fb05121fd6a2 ("signal: Add
unsafe_get_compat_sigset()"), implement an 'unsafe' version of
copy_siginfo_to_user() in order to use it within user access blocks.

For that, also add an 'unsafe' version of clear_user().

This commit adds the generic fallback for unsafe_clear_user().
Architectures wanting to use unsafe_copy_siginfo_to_user() within a
user_access_begin() section have to make sure they have their
own unsafe_clear_user().

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
v3: Added precision about unsafe_clear_user() in commit message.
---
 include/linux/signal.h  | 15 +++++++++++++++
 include/linux/uaccess.h |  1 +
 kernel/signal.c         |  5 -----
 3 files changed, 16 insertions(+), 5 deletions(-)

diff --git a/include/linux/signal.h b/include/linux/signal.h
index 3f96a6374e4f..70ea7e741427 100644
--- a/include/linux/signal.h
+++ b/include/linux/signal.h
@@ -35,6 +35,21 @@ static inline void copy_siginfo_to_external(siginfo_t *to,
 int copy_siginfo_to_user(siginfo_t __user *to, const kernel_siginfo_t *from);
 int copy_siginfo_from_user(kernel_siginfo_t *to, const siginfo_t __user *from);
 
+static __always_inline char __user *si_expansion(const siginfo_t __user *info)
+{
+	return ((char __user *)info) + sizeof(struct kernel_siginfo);
+}
+
+#define unsafe_copy_siginfo_to_user(to, from, label) do {		\
+	siginfo_t __user *__ucs_to = to;				\
+	const kernel_siginfo_t *__ucs_from = from;			\
+	char __user *__ucs_expansion = si_expansion(__ucs_to);		\
+									\
+	unsafe_copy_to_user(__ucs_to, __ucs_from,			\
+			    sizeof(struct kernel_siginfo), label);	\
+	unsafe_clear_user(__ucs_expansion, SI_EXPANSION_SIZE, label);	\
+} while (0)
+
 enum siginfo_layout {
 	SIL_KILL,
 	SIL_TIMER,
diff --git a/include/linux/uaccess.h b/include/linux/uaccess.h
index c05e903cef02..37073caac474 100644
--- a/include/linux/uaccess.h
+++ b/include/linux/uaccess.h
@@ -398,6 +398,7 @@ long strnlen_user_nofault(const void __user *unsafe_addr, long count);
 #define unsafe_put_user(x,p,e) unsafe_op_wrap(__put_user(x,p),e)
 #define unsafe_copy_to_user(d,s,l,e) unsafe_op_wrap(__copy_to_user(d,s,l),e)
 #define unsafe_copy_from_user(d,s,l,e) unsafe_op_wrap(__copy_from_user(d,s,l),e)
+#define unsafe_clear_user(d, l, e) unsafe_op_wrap(__clear_user(d, l), e)
 static inline unsigned long user_access_save(void) { return 0UL; }
 static inline void user_access_restore(unsigned long flags) { }
 #endif
diff --git a/kernel/signal.c b/kernel/signal.c
index 952741f6d0f9..23f168730b7e 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -3324,11 +3324,6 @@ enum siginfo_layout siginfo_layout(unsigned sig, int si_code)
 	return layout;
 }
 
-static inline char __user *si_expansion(const siginfo_t __user *info)
-{
-	return ((char __user *)info) + sizeof(struct kernel_siginfo);
-}
-
 int copy_siginfo_to_user(siginfo_t __user *to, const kernel_siginfo_t *from)
 {
 	char __user *expansion = si_expansion(to);
-- 
2.31.1

[PATCH v3 4/6] signal: Add unsafe_copy_siginfo_to_user32()

[Christophe Leroy]

In the same spirit as commit fb05121fd6a2 ("signal: Add
unsafe_get_compat_sigset()"), implement an 'unsafe' version of
copy_siginfo_to_user32() in order to use it within user access blocks.

To do so, we need inline version of copy_siginfo_to_external32() as we
don't want any function call inside user access blocks.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
 include/linux/compat.h |  83 +++++++++++++++++++++++++++++-
 include/linux/signal.h |  58 +++++++++++++++++++++
 kernel/signal.c        | 114 +----------------------------------------
 3 files changed, 141 insertions(+), 114 deletions(-)

diff --git a/include/linux/compat.h b/include/linux/compat.h
index 8e0598c7d1d1..68823f4b86ee 100644
--- a/include/linux/compat.h
+++ b/include/linux/compat.h
@@ -412,6 +412,19 @@ int __copy_siginfo_to_user32(struct compat_siginfo __user *to,
 #ifndef copy_siginfo_to_user32
 #define copy_siginfo_to_user32 __copy_siginfo_to_user32
 #endif
+
+#ifdef CONFIG_COMPAT
+#define unsafe_copy_siginfo_to_user32(to, from, label)	do {		\
+	struct compat_siginfo __user *__ucs_to = to;			\
+	const struct kernel_siginfo *__ucs_from = from;			\
+	struct compat_siginfo __ucs_new = {0};				\
+									\
+	__copy_siginfo_to_external32(&__ucs_new, __ucs_from);		\
+	unsafe_copy_to_user(__ucs_to, &__ucs_new,			\
+			    sizeof(struct compat_siginfo), label);	\
+} while (0)
+#endif
+
 int get_compat_sigevent(struct sigevent *event,
 		const struct compat_sigevent __user *u_event);
 
@@ -992,15 +1005,81 @@ static inline bool in_compat_syscall(void) { return false; }
  * appropriately converted them already.
  */
 #ifndef compat_ptr
-static inline void __user *compat_ptr(compat_uptr_t uptr)
+static __always_inline void __user *compat_ptr(compat_uptr_t uptr)
 {
 	return (void __user *)(unsigned long)uptr;
 }
 #endif
 
-static inline compat_uptr_t ptr_to_compat(void __user *uptr)
+static __always_inline compat_uptr_t ptr_to_compat(void __user *uptr)
 {
 	return (u32)(unsigned long)uptr;
 }
 
+static __always_inline void
+__copy_siginfo_to_external32(struct compat_siginfo *to,
+			     const struct kernel_siginfo *from)
+{
+	to->si_signo = from->si_signo;
+	to->si_errno = from->si_errno;
+	to->si_code  = from->si_code;
+	switch(__siginfo_layout(from->si_signo, from->si_code)) {
+	case SIL_KILL:
+		to->si_pid = from->si_pid;
+		to->si_uid = from->si_uid;
+		break;
+	case SIL_TIMER:
+		to->si_tid     = from->si_tid;
+		to->si_overrun = from->si_overrun;
+		to->si_int     = from->si_int;
+		break;
+	case SIL_POLL:
+		to->si_band = from->si_band;
+		to->si_fd   = from->si_fd;
+		break;
+	case SIL_FAULT:
+		to->si_addr = ptr_to_compat(from->si_addr);
+		break;
+	case SIL_FAULT_TRAPNO:
+		to->si_addr = ptr_to_compat(from->si_addr);
+		to->si_trapno = from->si_trapno;
+		break;
+	case SIL_FAULT_MCEERR:
+		to->si_addr = ptr_to_compat(from->si_addr);
+		to->si_addr_lsb = from->si_addr_lsb;
+		break;
+	case SIL_FAULT_BNDERR:
+		to->si_addr = ptr_to_compat(from->si_addr);
+		to->si_lower = ptr_to_compat(from->si_lower);
+		to->si_upper = ptr_to_compat(from->si_upper);
+		break;
+	case SIL_FAULT_PKUERR:
+		to->si_addr = ptr_to_compat(from->si_addr);
+		to->si_pkey = from->si_pkey;
+		break;
+	case SIL_FAULT_PERF_EVENT:
+		to->si_addr = ptr_to_compat(from->si_addr);
+		to->si_perf_data = from->si_perf_data;
+		to->si_perf_type = from->si_perf_type;
+		break;
+	case SIL_CHLD:
+		to->si_pid = from->si_pid;
+		to->si_uid = from->si_uid;
+		to->si_status = from->si_status;
+		to->si_utime = from->si_utime;
+		to->si_stime = from->si_stime;
+		break;
+	case SIL_RT:
+		to->si_pid = from->si_pid;
+		to->si_uid = from->si_uid;
+		to->si_int = from->si_int;
+		break;
+	case SIL_SYS:
+		to->si_call_addr = ptr_to_compat(from->si_call_addr);
+		to->si_syscall   = from->si_syscall;
+		to->si_arch      = from->si_arch;
+		break;
+	}
+}
+
 #endif /* _LINUX_COMPAT_H */
diff --git a/include/linux/signal.h b/include/linux/signal.h
index 70ea7e741427..637260bc193d 100644
--- a/include/linux/signal.h
+++ b/include/linux/signal.h
@@ -65,6 +65,64 @@ enum siginfo_layout {
 	SIL_SYS,
 };
 
+static const struct {
+	unsigned char limit, layout;
+} sig_sicodes[] = {
+	[SIGILL]  = { NSIGILL,  SIL_FAULT },
+	[SIGFPE]  = { NSIGFPE,  SIL_FAULT },
+	[SIGSEGV] = { NSIGSEGV, SIL_FAULT },
+	[SIGBUS]  = { NSIGBUS,  SIL_FAULT },
+	[SIGTRAP] = { NSIGTRAP, SIL_FAULT },
+#if defined(SIGEMT)
+	[SIGEMT]  = { NSIGEMT,  SIL_FAULT },
+#endif
+	[SIGCHLD] = { NSIGCHLD, SIL_CHLD },
+	[SIGPOLL] = { NSIGPOLL, SIL_POLL },
+	[SIGSYS]  = { NSIGSYS,  SIL_SYS },
+};
+
+static __always_inline enum
+siginfo_layout __siginfo_layout(unsigned sig, int si_code)
+{
+	enum siginfo_layout layout = SIL_KILL;
+
+	if ((si_code > SI_USER) && (si_code < SI_KERNEL)) {
+		if ((sig < ARRAY_SIZE(sig_sicodes)) &&
+		    (si_code <= sig_sicodes[sig].limit)) {
+			layout = sig_sicodes[sig].layout;
+			/* Handle the exceptions */
+			if ((sig == SIGBUS) &&
+			    (si_code >= BUS_MCEERR_AR) && (si_code <= BUS_MCEERR_AO))
+				layout = SIL_FAULT_MCEERR;
+			else if ((sig == SIGSEGV) && (si_code == SEGV_BNDERR))
+				layout = SIL_FAULT_BNDERR;
+#ifdef SEGV_PKUERR
+			else if ((sig == SIGSEGV) && (si_code == SEGV_PKUERR))
+				layout = SIL_FAULT_PKUERR;
+#endif
+			else if ((sig == SIGTRAP) && (si_code == TRAP_PERF))
+				layout = SIL_FAULT_PERF_EVENT;
+			else if (IS_ENABLED(CONFIG_SPARC) &&
+				 (sig == SIGILL) && (si_code == ILL_ILLTRP))
+				layout = SIL_FAULT_TRAPNO;
+			else if (IS_ENABLED(CONFIG_ALPHA) &&
+				 ((sig == SIGFPE) ||
+				  ((sig == SIGTRAP) && (si_code == TRAP_UNK))))
+				layout = SIL_FAULT_TRAPNO;
+		}
+		else if (si_code <= NSIGPOLL)
+			layout = SIL_POLL;
+	} else {
+		if (si_code == SI_TIMER)
+			layout = SIL_TIMER;
+		else if (si_code == SI_SIGIO)
+			layout = SIL_POLL;
+		else if (si_code < 0)
+			layout = SIL_RT;
+	}
+	return layout;
+}
+
 enum siginfo_layout siginfo_layout(unsigned sig, int si_code);
 
 /*
diff --git a/kernel/signal.c b/kernel/signal.c
index 23f168730b7e..0d402bdb174e 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -3249,22 +3249,6 @@ COMPAT_SYSCALL_DEFINE2(rt_sigpending, compat_sigset_t __user *, uset,
 }
 #endif
 
-static const struct {
-	unsigned char limit, layout;
-} sig_sicodes[] = {
-	[SIGILL]  = { NSIGILL,  SIL_FAULT },
-	[SIGFPE]  = { NSIGFPE,  SIL_FAULT },
-	[SIGSEGV] = { NSIGSEGV, SIL_FAULT },
-	[SIGBUS]  = { NSIGBUS,  SIL_FAULT },
-	[SIGTRAP] = { NSIGTRAP, SIL_FAULT },
-#if defined(SIGEMT)
-	[SIGEMT]  = { NSIGEMT,  SIL_FAULT },
-#endif
-	[SIGCHLD] = { NSIGCHLD, SIL_CHLD },
-	[SIGPOLL] = { NSIGPOLL, SIL_POLL },
-	[SIGSYS]  = { NSIGSYS,  SIL_SYS },
-};
-
 static bool known_siginfo_layout(unsigned sig, int si_code)
 {
 	if (si_code == SI_KERNEL)
@@ -3286,42 +3270,7 @@ static bool known_siginfo_layout(unsigned sig, int si_code)
 
 enum siginfo_layout siginfo_layout(unsigned sig, int si_code)
 {
-	enum siginfo_layout layout = SIL_KILL;
-	if ((si_code > SI_USER) && (si_code < SI_KERNEL)) {
-		if ((sig < ARRAY_SIZE(sig_sicodes)) &&
-		    (si_code <= sig_sicodes[sig].limit)) {
-			layout = sig_sicodes[sig].layout;
-			/* Handle the exceptions */
-			if ((sig == SIGBUS) &&
-			    (si_code >= BUS_MCEERR_AR) && (si_code <= BUS_MCEERR_AO))
-				layout = SIL_FAULT_MCEERR;
-			else if ((sig == SIGSEGV) && (si_code == SEGV_BNDERR))
-				layout = SIL_FAULT_BNDERR;
-#ifdef SEGV_PKUERR
-			else if ((sig == SIGSEGV) && (si_code == SEGV_PKUERR))
-				layout = SIL_FAULT_PKUERR;
-#endif
-			else if ((sig == SIGTRAP) && (si_code == TRAP_PERF))
-				layout = SIL_FAULT_PERF_EVENT;
-			else if (IS_ENABLED(CONFIG_SPARC) &&
-				 (sig == SIGILL) && (si_code == ILL_ILLTRP))
-				layout = SIL_FAULT_TRAPNO;
-			else if (IS_ENABLED(CONFIG_ALPHA) &&
-				 ((sig == SIGFPE) ||
-				  ((sig == SIGTRAP) && (si_code == TRAP_UNK))))
-				layout = SIL_FAULT_TRAPNO;
-		}
-		else if (si_code <= NSIGPOLL)
-			layout = SIL_POLL;
-	} else {
-		if (si_code == SI_TIMER)
-			layout = SIL_TIMER;
-		else if (si_code == SI_SIGIO)
-			layout = SIL_POLL;
-		else if (si_code < 0)
-			layout = SIL_RT;
-	}
-	return layout;
+	return __siginfo_layout(sig, si_code);
 }
 
 int copy_siginfo_to_user(siginfo_t __user *to, const kernel_siginfo_t *from)
@@ -3389,66 +3338,7 @@ void copy_siginfo_to_external32(struct compat_siginfo *to,
 {
 	memset(to, 0, sizeof(*to));
 
-	to->si_signo = from->si_signo;
-	to->si_errno = from->si_errno;
-	to->si_code  = from->si_code;
-	switch(siginfo_layout(from->si_signo, from->si_code)) {
-	case SIL_KILL:
-		to->si_pid = from->si_pid;
-		to->si_uid = from->si_uid;
-		break;
-	case SIL_TIMER:
-		to->si_tid     = from->si_tid;
-		to->si_overrun = from->si_overrun;
-		to->si_int     = from->si_int;
-		break;
-	case SIL_POLL:
-		to->si_band = from->si_band;
-		to->si_fd   = from->si_fd;
-		break;
-	case SIL_FAULT:
-		to->si_addr = ptr_to_compat(from->si_addr);
-		break;
-	case SIL_FAULT_TRAPNO:
-		to->si_addr = ptr_to_compat(from->si_addr);
-		to->si_trapno = from->si_trapno;
-		break;
-	case SIL_FAULT_MCEERR:
-		to->si_addr = ptr_to_compat(from->si_addr);
-		to->si_addr_lsb = from->si_addr_lsb;
-		break;
-	case SIL_FAULT_BNDERR:
-		to->si_addr = ptr_to_compat(from->si_addr);
-		to->si_lower = ptr_to_compat(from->si_lower);
-		to->si_upper = ptr_to_compat(from->si_upper);
-		break;
-	case SIL_FAULT_PKUERR:
-		to->si_addr = ptr_to_compat(from->si_addr);
-		to->si_pkey = from->si_pkey;
-		break;
-	case SIL_FAULT_PERF_EVENT:
-		to->si_addr = ptr_to_compat(from->si_addr);
-		to->si_perf_data = from->si_perf_data;
-		to->si_perf_type = from->si_perf_type;
-		break;
-	case SIL_CHLD:
-		to->si_pid = from->si_pid;
-		to->si_uid = from->si_uid;
-		to->si_status = from->si_status;
-		to->si_utime = from->si_utime;
-		to->si_stime = from->si_stime;
-		break;
-	case SIL_RT:
-		to->si_pid = from->si_pid;
-		to->si_uid = from->si_uid;
-		to->si_int = from->si_int;
-		break;
-	case SIL_SYS:
-		to->si_call_addr = ptr_to_compat(from->si_call_addr);
-		to->si_syscall   = from->si_syscall;
-		to->si_arch      = from->si_arch;
-		break;
-	}
+	__copy_siginfo_to_external32(to, from);
 }
 
 int __copy_siginfo_to_user32(struct compat_siginfo __user *to,
-- 
2.31.1

[PATCH v3 5/6] powerpc/uaccess: Add unsafe_clear_user()

[Christophe Leroy]

Implement unsafe_clear_user() for powerpc.
It's a copy/paste of unsafe_copy_to_user() with value 0 as source.

It may be improved in a later patch by using 'dcbz' instruction
to zeroize full cache lines at once.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
 arch/powerpc/include/asm/uaccess.h | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/arch/powerpc/include/asm/uaccess.h b/arch/powerpc/include/asm/uaccess.h
index 22c79ab40006..962b675485ff 100644
--- a/arch/powerpc/include/asm/uaccess.h
+++ b/arch/powerpc/include/asm/uaccess.h
@@ -467,6 +467,26 @@ do {									\
 		unsafe_put_user(*(u8*)(_src + _i), (u8 __user *)(_dst + _i), e); \
 } while (0)
 
+#define unsafe_clear_user(d, l, e)					\
+do {									\
+	u8 __user *_dst = (u8 __user *)(d);				\
+	size_t _len = (l);						\
+	int _i;								\
+									\
+	for (_i = 0; _i < (_len & ~(sizeof(u64) - 1)); _i += sizeof(u64)) \
+		unsafe_put_user(0, (u64 __user *)(_dst + _i), e);	\
+	if (_len & 4) {							\
+		unsafe_put_user(0, (u32 __user *)(_dst + _i), e);	\
+		_i += 4;						\
+	}								\
+	if (_len & 2) {							\
+		unsafe_put_user(0, (u16 __user *)(_dst + _i), e);	\
+		_i += 2;						\
+	}								\
+	if (_len & 1)							\
+		unsafe_put_user(0, (u8 __user *)(_dst + _i), e);	\
+} while (0)
+
 #define HAVE_GET_KERNEL_NOFAULT
 
 #define __get_kernel_nofault(dst, src, type, err_label)			\
-- 
2.31.1

[PATCH v3 6/6] powerpc/signal: Use unsafe_copy_siginfo_to_user()

[Christophe Leroy]

Use unsafe_copy_siginfo_to_user() in order to do the copy
within the user access block.

On an mpc 8321 (book3s/32) the improvment is about 5% on a process
sending a signal to itself.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
v3: Don't leave compat aside, use the new unsafe_copy_siginfo_to_user32()
---
 arch/powerpc/kernel/signal_32.c | 8 +++-----
 arch/powerpc/kernel/signal_64.c | 5 +----
 2 files changed, 4 insertions(+), 9 deletions(-)

diff --git a/arch/powerpc/kernel/signal_32.c b/arch/powerpc/kernel/signal_32.c
index ff101e2b3bab..3a2db8af2d65 100644
--- a/arch/powerpc/kernel/signal_32.c
+++ b/arch/powerpc/kernel/signal_32.c
@@ -710,9 +710,9 @@ static long restore_tm_user_regs(struct pt_regs *regs, struct mcontext __user *s
 }
 #endif
 
-#ifdef CONFIG_PPC64
+#ifndef CONFIG_PPC64
 
-#define copy_siginfo_to_user	copy_siginfo_to_user32
+#define unsafe_copy_siginfo_to_user32	unsafe_copy_siginfo_to_user
 
 #endif /* CONFIG_PPC64 */
 
@@ -779,15 +779,13 @@ int handle_rt_signal32(struct ksignal *ksig, sigset_t *oldset,
 		asm("dcbst %y0; sync; icbi %y0; sync" :: "Z" (mctx->mc_pad[0]));
 	}
 	unsafe_put_sigset_t(&frame->uc.uc_sigmask, oldset, failed);
+	unsafe_copy_siginfo_to_user32(&frame->info, &ksig->info, failed);
 
 	/* create a stack frame for the caller of the handler */
 	unsafe_put_user(regs->gpr[1], newsp, failed);
 
 	user_access_end();
 
-	if (copy_siginfo_to_user(&frame->info, &ksig->info))
-		goto badframe;
-
 	regs->link = tramp;
 
 #ifdef CONFIG_PPC_FPU_REGS
diff --git a/arch/powerpc/kernel/signal_64.c b/arch/powerpc/kernel/signal_64.c
index d80ff83cacb9..56c0c74aa28c 100644
--- a/arch/powerpc/kernel/signal_64.c
+++ b/arch/powerpc/kernel/signal_64.c
@@ -901,15 +901,12 @@ int handle_rt_signal64(struct ksignal *ksig, sigset_t *set,
 	}
 
 	unsafe_copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set), badframe_block);
+	unsafe_copy_siginfo_to_user(&frame->info, &ksig->info, badframe_block);
 	/* Allocate a dummy caller frame for the signal handler. */
 	unsafe_put_user(regs->gpr[1], newsp, badframe_block);
 
 	user_write_access_end();
 
-	/* Save the siginfo outside of the unsafe block. */
-	if (copy_siginfo_to_user(&frame->info, &ksig->info))
-		goto badframe;
-
 	/* Make sure signal handler doesn't get spurious FP exceptions */
 	tsk->thread.fp_state.fpscr = 0;
 
-- 
2.31.1