* [PATCH v5 1/5] powerpc/signal64: Access function descriptor with user access block
@ 2021-09-17 6:59 ` Christophe Leroy
0 siblings, 0 replies; 10+ messages in thread
From: Christophe Leroy @ 2021-09-17 6:59 UTC (permalink / raw)
To: Benjamin Herrenschmidt, Paul Mackerras, Michael Ellerman, ebiederm, hch
Cc: linuxppc-dev, linux-kernel
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
^ permalink raw reply related [flat|nested] 10+ messages in thread
* [PATCH v5 2/5] powerpc/signal: Include the new stack frame inside the user access block
2021-09-17 6:59 ` Christophe Leroy
@ 2021-09-17 6:59 ` Christophe Leroy
-1 siblings, 0 replies; 10+ messages in thread
From: Christophe Leroy @ 2021-09-17 6:59 UTC (permalink / raw)
To: Benjamin Herrenschmidt, Paul Mackerras, Michael Ellerman, ebiederm, hch
Cc: Christophe Leroy, linux-kernel, linuxppc-dev
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
^ permalink raw reply related [flat|nested] 10+ messages in thread* [PATCH v5 2/5] powerpc/signal: Include the new stack frame inside the user access block
@ 2021-09-17 6:59 ` Christophe Leroy
0 siblings, 0 replies; 10+ messages in thread
From: Christophe Leroy @ 2021-09-17 6:59 UTC (permalink / raw)
To: Benjamin Herrenschmidt, Paul Mackerras, Michael Ellerman, ebiederm, hch
Cc: linuxppc-dev, linux-kernel
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
^ permalink raw reply related [flat|nested] 10+ messages in thread
* [PATCH v5 3/5] signal: Add unsafe_copy_siginfo_to_user()
2021-09-17 6:59 ` Christophe Leroy
@ 2021-09-17 6:59 ` Christophe Leroy
-1 siblings, 0 replies; 10+ messages in thread
From: Christophe Leroy @ 2021-09-17 6:59 UTC (permalink / raw)
To: Benjamin Herrenschmidt, Paul Mackerras, Michael Ellerman, ebiederm, hch
Cc: Christophe Leroy, linux-kernel, linuxppc-dev
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
^ permalink raw reply related [flat|nested] 10+ messages in thread* [PATCH v5 3/5] signal: Add unsafe_copy_siginfo_to_user()
@ 2021-09-17 6:59 ` Christophe Leroy
0 siblings, 0 replies; 10+ messages in thread
From: Christophe Leroy @ 2021-09-17 6:59 UTC (permalink / raw)
To: Benjamin Herrenschmidt, Paul Mackerras, Michael Ellerman, ebiederm, hch
Cc: linuxppc-dev, linux-kernel
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
^ permalink raw reply related [flat|nested] 10+ messages in thread
* [PATCH v5 4/5] powerpc/uaccess: Add unsafe_clear_user()
2021-09-17 6:59 ` Christophe Leroy
@ 2021-09-17 6:59 ` Christophe Leroy
-1 siblings, 0 replies; 10+ messages in thread
From: Christophe Leroy @ 2021-09-17 6:59 UTC (permalink / raw)
To: Benjamin Herrenschmidt, Paul Mackerras, Michael Ellerman, ebiederm, hch
Cc: Christophe Leroy, linux-kernel, linuxppc-dev
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
^ permalink raw reply related [flat|nested] 10+ messages in thread* [PATCH v5 4/5] powerpc/uaccess: Add unsafe_clear_user()
@ 2021-09-17 6:59 ` Christophe Leroy
0 siblings, 0 replies; 10+ messages in thread
From: Christophe Leroy @ 2021-09-17 6:59 UTC (permalink / raw)
To: Benjamin Herrenschmidt, Paul Mackerras, Michael Ellerman, ebiederm, hch
Cc: linuxppc-dev, linux-kernel
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
^ permalink raw reply related [flat|nested] 10+ messages in thread
* [PATCH v5 5/5] powerpc/signal: Use unsafe_copy_siginfo_to_user()
2021-09-17 6:59 ` Christophe Leroy
@ 2021-09-17 6:59 ` Christophe Leroy
-1 siblings, 0 replies; 10+ messages in thread
From: Christophe Leroy @ 2021-09-17 6:59 UTC (permalink / raw)
To: Benjamin Herrenschmidt, Paul Mackerras, Michael Ellerman, ebiederm, hch
Cc: Christophe Leroy, linux-kernel, linuxppc-dev
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>
---
v5: Added missing __user flag when calling unsafe_copy_siginfo_to_user()
v4: Use another approach for compat: drop the unsafe_copy_siginfo_to_user32(), instead directly call copy_siginfo_to_external32() before user_access_begin()
v3: Don't leave compat aside, use the new unsafe_copy_siginfo_to_user32()
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
arch/powerpc/kernel/signal_32.c | 17 ++++++++---------
arch/powerpc/kernel/signal_64.c | 5 +----
2 files changed, 9 insertions(+), 13 deletions(-)
diff --git a/arch/powerpc/kernel/signal_32.c b/arch/powerpc/kernel/signal_32.c
index ff101e2b3bab..0baf3c10b6c0 100644
--- a/arch/powerpc/kernel/signal_32.c
+++ b/arch/powerpc/kernel/signal_32.c
@@ -710,12 +710,6 @@ static long restore_tm_user_regs(struct pt_regs *regs, struct mcontext __user *s
}
#endif
-#ifdef CONFIG_PPC64
-
-#define copy_siginfo_to_user copy_siginfo_to_user32
-
-#endif /* CONFIG_PPC64 */
-
/*
* Set up a signal frame for a "real-time" signal handler
* (one which gets siginfo).
@@ -731,6 +725,7 @@ int handle_rt_signal32(struct ksignal *ksig, sigset_t *oldset,
struct pt_regs *regs = tsk->thread.regs;
/* Save the thread's msr before get_tm_stackpointer() changes it */
unsigned long msr = regs->msr;
+ compat_siginfo_t uinfo;
/* Set up Signal Frame */
frame = get_sigframe(ksig, tsk, sizeof(*frame), 1);
@@ -744,6 +739,9 @@ int handle_rt_signal32(struct ksignal *ksig, sigset_t *oldset,
else
prepare_save_user_regs(1);
+ if (IS_ENABLED(CONFIG_COMPAT))
+ copy_siginfo_to_external32(&uinfo, &ksig->info);
+
if (!user_access_begin(newsp, __SIGNAL_FRAMESIZE + 16 + sizeof(*frame)))
goto badframe;
@@ -779,15 +777,16 @@ 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);
+ if (IS_ENABLED(CONFIG_COMPAT))
+ unsafe_copy_to_user(&frame->info, &uinfo, sizeof(frame->info), failed);
+ else
+ unsafe_copy_siginfo_to_user((void __user *)&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
^ permalink raw reply related [flat|nested] 10+ messages in thread* [PATCH v5 5/5] powerpc/signal: Use unsafe_copy_siginfo_to_user()
@ 2021-09-17 6:59 ` Christophe Leroy
0 siblings, 0 replies; 10+ messages in thread
From: Christophe Leroy @ 2021-09-17 6:59 UTC (permalink / raw)
To: Benjamin Herrenschmidt, Paul Mackerras, Michael Ellerman, ebiederm, hch
Cc: linuxppc-dev, linux-kernel
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>
---
v5: Added missing __user flag when calling unsafe_copy_siginfo_to_user()
v4: Use another approach for compat: drop the unsafe_copy_siginfo_to_user32(), instead directly call copy_siginfo_to_external32() before user_access_begin()
v3: Don't leave compat aside, use the new unsafe_copy_siginfo_to_user32()
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
arch/powerpc/kernel/signal_32.c | 17 ++++++++---------
arch/powerpc/kernel/signal_64.c | 5 +----
2 files changed, 9 insertions(+), 13 deletions(-)
diff --git a/arch/powerpc/kernel/signal_32.c b/arch/powerpc/kernel/signal_32.c
index ff101e2b3bab..0baf3c10b6c0 100644
--- a/arch/powerpc/kernel/signal_32.c
+++ b/arch/powerpc/kernel/signal_32.c
@@ -710,12 +710,6 @@ static long restore_tm_user_regs(struct pt_regs *regs, struct mcontext __user *s
}
#endif
-#ifdef CONFIG_PPC64
-
-#define copy_siginfo_to_user copy_siginfo_to_user32
-
-#endif /* CONFIG_PPC64 */
-
/*
* Set up a signal frame for a "real-time" signal handler
* (one which gets siginfo).
@@ -731,6 +725,7 @@ int handle_rt_signal32(struct ksignal *ksig, sigset_t *oldset,
struct pt_regs *regs = tsk->thread.regs;
/* Save the thread's msr before get_tm_stackpointer() changes it */
unsigned long msr = regs->msr;
+ compat_siginfo_t uinfo;
/* Set up Signal Frame */
frame = get_sigframe(ksig, tsk, sizeof(*frame), 1);
@@ -744,6 +739,9 @@ int handle_rt_signal32(struct ksignal *ksig, sigset_t *oldset,
else
prepare_save_user_regs(1);
+ if (IS_ENABLED(CONFIG_COMPAT))
+ copy_siginfo_to_external32(&uinfo, &ksig->info);
+
if (!user_access_begin(newsp, __SIGNAL_FRAMESIZE + 16 + sizeof(*frame)))
goto badframe;
@@ -779,15 +777,16 @@ 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);
+ if (IS_ENABLED(CONFIG_COMPAT))
+ unsafe_copy_to_user(&frame->info, &uinfo, sizeof(frame->info), failed);
+ else
+ unsafe_copy_siginfo_to_user((void __user *)&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
^ permalink raw reply related [flat|nested] 10+ messages in thread