diff mbox series

[v3,2/2] powerpc: use probe_user_read()

Message ID afd95fa4747f1c1eb66677025c2c7c9055f43cce.1547652372.git.christophe.leroy@c-s.fr (mailing list archive)
State New, archived
Headers show
Series [v3,1/2] mm: add probe_user_read() | expand

Commit Message

Christophe Leroy Jan. 16, 2019, 4:59 p.m. UTC 
Instead of opencoding, use probe_user_read() to failessly
read a user location.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
---
 v3: No change

 v2: Using probe_user_read() instead of probe_user_address()

 arch/powerpc/kernel/process.c   | 12 +-----------
 arch/powerpc/mm/fault.c         |  6 +-----
 arch/powerpc/perf/callchain.c   | 20 +++-----------------
 arch/powerpc/perf/core-book3s.c |  8 +-------
 arch/powerpc/sysdev/fsl_pci.c   | 10 ++++------
 5 files changed, 10 insertions(+), 46 deletions(-)

Comments

Michael Ellerman Jan. 31, 2019, 4:19 a.m. UTC | #1 
Christophe Leroy <christophe.leroy@c-s.fr> writes:

> Instead of opencoding, use probe_user_read() to failessly
> read a user location.
>
> Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
> ---
>  v3: No change
>
>  v2: Using probe_user_read() instead of probe_user_address()
>
>  arch/powerpc/kernel/process.c   | 12 +-----------
>  arch/powerpc/mm/fault.c         |  6 +-----
>  arch/powerpc/perf/callchain.c   | 20 +++-----------------
>  arch/powerpc/perf/core-book3s.c |  8 +-------
>  arch/powerpc/sysdev/fsl_pci.c   | 10 ++++------
>  5 files changed, 10 insertions(+), 46 deletions(-)

Looks good.

Acked-by: Michael Ellerman <mpe@ellerman.id.au>

cheers

> diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
> index ce393df243aa..6a4b59d574c2 100644
> --- a/arch/powerpc/kernel/process.c
> +++ b/arch/powerpc/kernel/process.c
> @@ -1298,16 +1298,6 @@ void show_user_instructions(struct pt_regs *regs)
>  
>  	pc = regs->nip - (NR_INSN_TO_PRINT * 3 / 4 * sizeof(int));
>  
> -	/*
> -	 * Make sure the NIP points at userspace, not kernel text/data or
> -	 * elsewhere.
> -	 */
> -	if (!__access_ok(pc, NR_INSN_TO_PRINT * sizeof(int), USER_DS)) {
> -		pr_info("%s[%d]: Bad NIP, not dumping instructions.\n",
> -			current->comm, current->pid);
> -		return;
> -	}
> -
>  	seq_buf_init(&s, buf, sizeof(buf));
>  
>  	while (n) {
> @@ -1318,7 +1308,7 @@ void show_user_instructions(struct pt_regs *regs)
>  		for (i = 0; i < 8 && n; i++, n--, pc += sizeof(int)) {
>  			int instr;
>  
> -			if (probe_kernel_address((const void *)pc, instr)) {
> +			if (probe_user_read(&instr, (void __user *)pc, sizeof(instr))) {
>  				seq_buf_printf(&s, "XXXXXXXX ");
>  				continue;
>  			}
> diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c
> index 887f11bcf330..ec74305fa330 100644
> --- a/arch/powerpc/mm/fault.c
> +++ b/arch/powerpc/mm/fault.c
> @@ -276,12 +276,8 @@ static bool bad_stack_expansion(struct pt_regs *regs, unsigned long address,
>  		if ((flags & FAULT_FLAG_WRITE) && (flags & FAULT_FLAG_USER) &&
>  		    access_ok(nip, sizeof(*nip))) {
>  			unsigned int inst;
> -			int res;
>  
> -			pagefault_disable();
> -			res = __get_user_inatomic(inst, nip);
> -			pagefault_enable();
> -			if (!res)
> +			if (!probe_user_read(&inst, nip, sizeof(inst)))
>  				return !store_updates_sp(inst);
>  			*must_retry = true;
>  		}
> diff --git a/arch/powerpc/perf/callchain.c b/arch/powerpc/perf/callchain.c
> index 0af051a1974e..0680efb2237b 100644
> --- a/arch/powerpc/perf/callchain.c
> +++ b/arch/powerpc/perf/callchain.c
> @@ -159,12 +159,8 @@ static int read_user_stack_64(unsigned long __user *ptr, unsigned long *ret)
>  	    ((unsigned long)ptr & 7))
>  		return -EFAULT;
>  
> -	pagefault_disable();
> -	if (!__get_user_inatomic(*ret, ptr)) {
> -		pagefault_enable();
> +	if (!probe_user_read(ret, ptr, sizeof(*ret)))
>  		return 0;
> -	}
> -	pagefault_enable();
>  
>  	return read_user_stack_slow(ptr, ret, 8);
>  }
> @@ -175,12 +171,8 @@ static int read_user_stack_32(unsigned int __user *ptr, unsigned int *ret)
>  	    ((unsigned long)ptr & 3))
>  		return -EFAULT;
>  
> -	pagefault_disable();
> -	if (!__get_user_inatomic(*ret, ptr)) {
> -		pagefault_enable();
> +	if (!probe_user_read(ret, ptr, sizeof(*ret)))
>  		return 0;
> -	}
> -	pagefault_enable();
>  
>  	return read_user_stack_slow(ptr, ret, 4);
>  }
> @@ -307,17 +299,11 @@ static inline int current_is_64bit(void)
>   */
>  static int read_user_stack_32(unsigned int __user *ptr, unsigned int *ret)
>  {
> -	int rc;
> -
>  	if ((unsigned long)ptr > TASK_SIZE - sizeof(unsigned int) ||
>  	    ((unsigned long)ptr & 3))
>  		return -EFAULT;
>  
> -	pagefault_disable();
> -	rc = __get_user_inatomic(*ret, ptr);
> -	pagefault_enable();
> -
> -	return rc;
> +	return probe_user_read(ret, ptr, sizeof(*ret));
>  }
>  
>  static inline void perf_callchain_user_64(struct perf_callchain_entry_ctx *entry,
> diff --git a/arch/powerpc/perf/core-book3s.c b/arch/powerpc/perf/core-book3s.c
> index b0723002a396..4b64ddf0db68 100644
> --- a/arch/powerpc/perf/core-book3s.c
> +++ b/arch/powerpc/perf/core-book3s.c
> @@ -416,7 +416,6 @@ static void power_pmu_sched_task(struct perf_event_context *ctx, bool sched_in)
>  static __u64 power_pmu_bhrb_to(u64 addr)
>  {
>  	unsigned int instr;
> -	int ret;
>  	__u64 target;
>  
>  	if (is_kernel_addr(addr)) {
> @@ -427,13 +426,8 @@ static __u64 power_pmu_bhrb_to(u64 addr)
>  	}
>  
>  	/* Userspace: need copy instruction here then translate it */
> -	pagefault_disable();
> -	ret = __get_user_inatomic(instr, (unsigned int __user *)addr);
> -	if (ret) {
> -		pagefault_enable();
> +	if (probe_user_read(&instr, (unsigned int __user *)addr, sizeof(instr)))
>  		return 0;
> -	}
> -	pagefault_enable();
>  
>  	target = branch_target(&instr);
>  	if ((!target) || (instr & BRANCH_ABSOLUTE))
> diff --git a/arch/powerpc/sysdev/fsl_pci.c b/arch/powerpc/sysdev/fsl_pci.c
> index 918be816b097..c8a1b26489f5 100644
> --- a/arch/powerpc/sysdev/fsl_pci.c
> +++ b/arch/powerpc/sysdev/fsl_pci.c
> @@ -1068,13 +1068,11 @@ int fsl_pci_mcheck_exception(struct pt_regs *regs)
>  	addr += mfspr(SPRN_MCAR);
>  
>  	if (is_in_pci_mem_space(addr)) {
> -		if (user_mode(regs)) {
> -			pagefault_disable();
> -			ret = get_user(inst, (__u32 __user *)regs->nip);
> -			pagefault_enable();
> -		} else {
> +		if (user_mode(regs))
> +			ret = probe_user_read(&inst, (void __user *)regs->nip,
> +					      sizeof(inst));
> +		else
>  			ret = probe_kernel_address((void *)regs->nip, inst);
> -		}
>  
>  		if (!ret && mcheck_handle_load(regs, inst)) {
>  			regs->nip += 4;
> -- 
> 2.13.3
diff mbox series

Patch

diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index ce393df243aa..6a4b59d574c2 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -1298,16 +1298,6 @@  void show_user_instructions(struct pt_regs *regs)
 
 	pc = regs->nip - (NR_INSN_TO_PRINT * 3 / 4 * sizeof(int));
 
-	/*
-	 * Make sure the NIP points at userspace, not kernel text/data or
-	 * elsewhere.
-	 */
-	if (!__access_ok(pc, NR_INSN_TO_PRINT * sizeof(int), USER_DS)) {
-		pr_info("%s[%d]: Bad NIP, not dumping instructions.\n",
-			current->comm, current->pid);
-		return;
-	}
-
 	seq_buf_init(&s, buf, sizeof(buf));
 
 	while (n) {
@@ -1318,7 +1308,7 @@  void show_user_instructions(struct pt_regs *regs)
 		for (i = 0; i < 8 && n; i++, n--, pc += sizeof(int)) {
 			int instr;
 
-			if (probe_kernel_address((const void *)pc, instr)) {
+			if (probe_user_read(&instr, (void __user *)pc, sizeof(instr))) {
 				seq_buf_printf(&s, "XXXXXXXX ");
 				continue;
 			}
diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c
index 887f11bcf330..ec74305fa330 100644
--- a/arch/powerpc/mm/fault.c
+++ b/arch/powerpc/mm/fault.c
@@ -276,12 +276,8 @@  static bool bad_stack_expansion(struct pt_regs *regs, unsigned long address,
 		if ((flags & FAULT_FLAG_WRITE) && (flags & FAULT_FLAG_USER) &&
 		    access_ok(nip, sizeof(*nip))) {
 			unsigned int inst;
-			int res;
 
-			pagefault_disable();
-			res = __get_user_inatomic(inst, nip);
-			pagefault_enable();
-			if (!res)
+			if (!probe_user_read(&inst, nip, sizeof(inst)))
 				return !store_updates_sp(inst);
 			*must_retry = true;
 		}
diff --git a/arch/powerpc/perf/callchain.c b/arch/powerpc/perf/callchain.c
index 0af051a1974e..0680efb2237b 100644
--- a/arch/powerpc/perf/callchain.c
+++ b/arch/powerpc/perf/callchain.c
@@ -159,12 +159,8 @@  static int read_user_stack_64(unsigned long __user *ptr, unsigned long *ret)
 	    ((unsigned long)ptr & 7))
 		return -EFAULT;
 
-	pagefault_disable();
-	if (!__get_user_inatomic(*ret, ptr)) {
-		pagefault_enable();
+	if (!probe_user_read(ret, ptr, sizeof(*ret)))
 		return 0;
-	}
-	pagefault_enable();
 
 	return read_user_stack_slow(ptr, ret, 8);
 }
@@ -175,12 +171,8 @@  static int read_user_stack_32(unsigned int __user *ptr, unsigned int *ret)
 	    ((unsigned long)ptr & 3))
 		return -EFAULT;
 
-	pagefault_disable();
-	if (!__get_user_inatomic(*ret, ptr)) {
-		pagefault_enable();
+	if (!probe_user_read(ret, ptr, sizeof(*ret)))
 		return 0;
-	}
-	pagefault_enable();
 
 	return read_user_stack_slow(ptr, ret, 4);
 }
@@ -307,17 +299,11 @@  static inline int current_is_64bit(void)
  */
 static int read_user_stack_32(unsigned int __user *ptr, unsigned int *ret)
 {
-	int rc;
-
 	if ((unsigned long)ptr > TASK_SIZE - sizeof(unsigned int) ||
 	    ((unsigned long)ptr & 3))
 		return -EFAULT;
 
-	pagefault_disable();
-	rc = __get_user_inatomic(*ret, ptr);
-	pagefault_enable();
-
-	return rc;
+	return probe_user_read(ret, ptr, sizeof(*ret));
 }
 
 static inline void perf_callchain_user_64(struct perf_callchain_entry_ctx *entry,
diff --git a/arch/powerpc/perf/core-book3s.c b/arch/powerpc/perf/core-book3s.c
index b0723002a396..4b64ddf0db68 100644
--- a/arch/powerpc/perf/core-book3s.c
+++ b/arch/powerpc/perf/core-book3s.c
@@ -416,7 +416,6 @@  static void power_pmu_sched_task(struct perf_event_context *ctx, bool sched_in)
 static __u64 power_pmu_bhrb_to(u64 addr)
 {
 	unsigned int instr;
-	int ret;
 	__u64 target;
 
 	if (is_kernel_addr(addr)) {
@@ -427,13 +426,8 @@  static __u64 power_pmu_bhrb_to(u64 addr)
 	}
 
 	/* Userspace: need copy instruction here then translate it */
-	pagefault_disable();
-	ret = __get_user_inatomic(instr, (unsigned int __user *)addr);
-	if (ret) {
-		pagefault_enable();
+	if (probe_user_read(&instr, (unsigned int __user *)addr, sizeof(instr)))
 		return 0;
-	}
-	pagefault_enable();
 
 	target = branch_target(&instr);
 	if ((!target) || (instr & BRANCH_ABSOLUTE))
diff --git a/arch/powerpc/sysdev/fsl_pci.c b/arch/powerpc/sysdev/fsl_pci.c
index 918be816b097..c8a1b26489f5 100644
--- a/arch/powerpc/sysdev/fsl_pci.c
+++ b/arch/powerpc/sysdev/fsl_pci.c
@@ -1068,13 +1068,11 @@  int fsl_pci_mcheck_exception(struct pt_regs *regs)
 	addr += mfspr(SPRN_MCAR);
 
 	if (is_in_pci_mem_space(addr)) {
-		if (user_mode(regs)) {
-			pagefault_disable();
-			ret = get_user(inst, (__u32 __user *)regs->nip);
-			pagefault_enable();
-		} else {
+		if (user_mode(regs))
+			ret = probe_user_read(&inst, (void __user *)regs->nip,
+					      sizeof(inst));
+		else
 			ret = probe_kernel_address((void *)regs->nip, inst);
-		}
 
 		if (!ret && mcheck_handle_load(regs, inst)) {
 			regs->nip += 4;