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Message-Id: <1e1b76f778c28e2e79a7ec303fd36bcd64bf639d.1629732940.git.christophe.leroy@csgroup.eu>
Date: Mon, 23 Aug 2021 15:35:52 +0000 (UTC)
From: Christophe Leroy <christophe.leroy@...roup.eu>
To: Benjamin Herrenschmidt <benh@...nel.crashing.org>,
Paul Mackerras <paulus@...ba.org>,
Michael Ellerman <mpe@...erman.id.au>
Cc: linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org
Subject: [PATCH v2 2/5] powerpc/signal: Include the new stack frame inside the
user access block
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@...roup.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 790c450c2de8..2cca6c8febe1 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;
@@ -952,7 +952,7 @@ 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) {
--
2.25.0
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