* [RFC PATCH 1/3] arc: use BUILD_BUG for invalid sizes in get_user/put_user
2022-02-01 14:55 [RFC PATCH 0/3] arc: remove CONFIG_SET_FS Sergey Matyukevich
@ 2022-02-01 14:55 ` Sergey Matyukevich
2022-02-01 15:08 ` Christoph Hellwig
2022-02-01 14:55 ` [RFC PATCH 2/3] arc: provide __{get,put}_kernel_nofault Sergey Matyukevich
` (2 subsequent siblings)
3 siblings, 1 reply; 10+ messages in thread
From: Sergey Matyukevich @ 2022-02-01 14:55 UTC (permalink / raw)
To: linux-snps-arc
Cc: Vineet Gupta, Vladimir Isaev, Christoph Hellwig,
Sergey Matyukevich, Sergey Matyukevich
From: Sergey Matyukevich <sergey.matyukevich@synopsys.com>
Use BUILD_BUG for compile-time check of invalid sizes passed
to get_user/put_user functions.
Signed-off-by: Sergey Matyukevich <sergey.matyukevich@synopsys.com>
---
arch/arc/include/asm/uaccess.h | 2 ++
1 file changed, 2 insertions(+)
diff --git a/arch/arc/include/asm/uaccess.h b/arch/arc/include/asm/uaccess.h
index 783bfdb3bfa3..9d1205bf90f1 100644
--- a/arch/arc/include/asm/uaccess.h
+++ b/arch/arc/include/asm/uaccess.h
@@ -62,6 +62,7 @@
case 2: __arc_get_user_one(*(k), u, "ldw", __ret); break; \
case 4: __arc_get_user_one(*(k), u, "ld", __ret); break; \
case 8: __arc_get_user_one_64(*(k), u, __ret); break; \
+ default: BUILD_BUG(); \
} \
__ret; \
})
@@ -123,6 +124,7 @@
case 2: __arc_put_user_one(*(k), u, "stw", __ret); break; \
case 4: __arc_put_user_one(*(k), u, "st", __ret); break; \
case 8: __arc_put_user_one_64(*(k), u, __ret); break; \
+ default: BUILD_BUG(); \
} \
__ret; \
})
--
2.35.0
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^ permalink raw reply related [flat|nested] 10+ messages in thread* [RFC PATCH 2/3] arc: provide __{get,put}_kernel_nofault
2022-02-01 14:55 [RFC PATCH 0/3] arc: remove CONFIG_SET_FS Sergey Matyukevich
2022-02-01 14:55 ` [RFC PATCH 1/3] arc: use BUILD_BUG for invalid sizes in get_user/put_user Sergey Matyukevich
@ 2022-02-01 14:55 ` Sergey Matyukevich
2022-02-01 15:10 ` Christoph Hellwig
2022-02-01 14:55 ` [RFC PATCH 3/3] arc: remove set_fs() Sergey Matyukevich
2022-02-02 5:14 ` [RFC PATCH 0/3] arc: remove CONFIG_SET_FS Vineet Gupta
3 siblings, 1 reply; 10+ messages in thread
From: Sergey Matyukevich @ 2022-02-01 14:55 UTC (permalink / raw)
To: linux-snps-arc
Cc: Vineet Gupta, Vladimir Isaev, Christoph Hellwig,
Sergey Matyukevich, Sergey Matyukevich
From: Sergey Matyukevich <sergey.matyukevich@synopsys.com>
Implement the non-faulting kernel access helpers directly
instead of using uaccess routines under set_fs(KERNEL_DS).
Signed-off-by: Sergey Matyukevich <sergey.matyukevich@synopsys.com>
---
arch/arc/include/asm/uaccess.h | 22 ++++++++++++++++++++++
1 file changed, 22 insertions(+)
diff --git a/arch/arc/include/asm/uaccess.h b/arch/arc/include/asm/uaccess.h
index 9d1205bf90f1..c14b692a0a4e 100644
--- a/arch/arc/include/asm/uaccess.h
+++ b/arch/arc/include/asm/uaccess.h
@@ -657,6 +657,28 @@ static inline unsigned long __arc_clear_user(void __user *to, unsigned long n)
return res;
}
+#define HAVE_GET_KERNEL_NOFAULT
+
+#define __get_kernel_nofault(dst, src, type, err_label) \
+ do { \
+ long __err; \
+ \
+ __err = __get_user_fn(sizeof(type), (type *)(src), \
+ (type *)(dst)); \
+ if (unlikely(__err)) \
+ goto err_label; \
+ } while (0)
+
+#define __put_kernel_nofault(dst, src, type, err_label) \
+ do { \
+ long __err; \
+ \
+ __err = __put_user_fn(sizeof(type), (type *)(dst), \
+ (type *)(src)); \
+ if (unlikely(__err)) \
+ goto err_label; \
+ } while (0)
+
#ifndef CONFIG_CC_OPTIMIZE_FOR_SIZE
#define INLINE_COPY_TO_USER
--
2.35.0
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^ permalink raw reply related [flat|nested] 10+ messages in thread* Re: [RFC PATCH 2/3] arc: provide __{get,put}_kernel_nofault
2022-02-01 14:55 ` [RFC PATCH 2/3] arc: provide __{get,put}_kernel_nofault Sergey Matyukevich
@ 2022-02-01 15:10 ` Christoph Hellwig
0 siblings, 0 replies; 10+ messages in thread
From: Christoph Hellwig @ 2022-02-01 15:10 UTC (permalink / raw)
To: Sergey Matyukevich
Cc: linux-snps-arc, Vineet Gupta, Vladimir Isaev, Christoph Hellwig,
Sergey Matyukevich
On Tue, Feb 01, 2022 at 05:55:37PM +0300, Sergey Matyukevich wrote:
> From: Sergey Matyukevich <sergey.matyukevich@synopsys.com>
>
> Implement the non-faulting kernel access helpers directly
> instead of using uaccess routines under set_fs(KERNEL_DS).
>
> Signed-off-by: Sergey Matyukevich <sergey.matyukevich@synopsys.com>
> ---
> arch/arc/include/asm/uaccess.h | 22 ++++++++++++++++++++++
> 1 file changed, 22 insertions(+)
>
> diff --git a/arch/arc/include/asm/uaccess.h b/arch/arc/include/asm/uaccess.h
> index 9d1205bf90f1..c14b692a0a4e 100644
> --- a/arch/arc/include/asm/uaccess.h
> +++ b/arch/arc/include/asm/uaccess.h
> @@ -657,6 +657,28 @@ static inline unsigned long __arc_clear_user(void __user *to, unsigned long n)
> return res;
> }
>
> +#define HAVE_GET_KERNEL_NOFAULT
> +
> +#define __get_kernel_nofault(dst, src, type, err_label) \
> + do { \
Normal kernel style doesn't indent the do { } while inside of
function-like macros.
Otherwise this looks good.
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^ permalink raw reply [flat|nested] 10+ messages in thread
* [RFC PATCH 3/3] arc: remove set_fs()
2022-02-01 14:55 [RFC PATCH 0/3] arc: remove CONFIG_SET_FS Sergey Matyukevich
2022-02-01 14:55 ` [RFC PATCH 1/3] arc: use BUILD_BUG for invalid sizes in get_user/put_user Sergey Matyukevich
2022-02-01 14:55 ` [RFC PATCH 2/3] arc: provide __{get,put}_kernel_nofault Sergey Matyukevich
@ 2022-02-01 14:55 ` Sergey Matyukevich
2022-02-01 15:11 ` Christoph Hellwig
2022-02-02 5:14 ` [RFC PATCH 0/3] arc: remove CONFIG_SET_FS Vineet Gupta
3 siblings, 1 reply; 10+ messages in thread
From: Sergey Matyukevich @ 2022-02-01 14:55 UTC (permalink / raw)
To: linux-snps-arc
Cc: Vineet Gupta, Vladimir Isaev, Christoph Hellwig,
Sergey Matyukevich, Sergey Matyukevich
From: Sergey Matyukevich <sergey.matyukevich@synopsys.com>
Kernel __{get,put}_kernel_nofault operations are implemented for ARC.
There are no other remaining arch/arc specific callers of set_fs().
So just remove it and all the supporting code.
Signed-off-by: Sergey Matyukevich <sergey.matyukevich@synopsys.com>
---
arch/arc/Kconfig | 1 -
arch/arc/include/asm/segment.h | 20 --------------------
arch/arc/include/asm/thread_info.h | 3 ---
arch/arc/include/asm/uaccess.h | 24 ++++++++----------------
4 files changed, 8 insertions(+), 40 deletions(-)
delete mode 100644 arch/arc/include/asm/segment.h
diff --git a/arch/arc/Kconfig b/arch/arc/Kconfig
index 3c2a4753d09b..e0a60a27e14d 100644
--- a/arch/arc/Kconfig
+++ b/arch/arc/Kconfig
@@ -45,7 +45,6 @@ config ARC
select PCI_SYSCALL if PCI
select PERF_USE_VMALLOC if ARC_CACHE_VIPT_ALIASING
select HAVE_ARCH_JUMP_LABEL if ISA_ARCV2 && !CPU_ENDIAN_BE32
- select SET_FS
select TRACE_IRQFLAGS_SUPPORT
config LOCKDEP_SUPPORT
diff --git a/arch/arc/include/asm/segment.h b/arch/arc/include/asm/segment.h
deleted file mode 100644
index 871f8ab11bfd..000000000000
--- a/arch/arc/include/asm/segment.h
+++ /dev/null
@@ -1,20 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0-only */
-/*
- * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
- */
-
-#ifndef __ASMARC_SEGMENT_H
-#define __ASMARC_SEGMENT_H
-
-#ifndef __ASSEMBLY__
-
-typedef unsigned long mm_segment_t;
-
-#define MAKE_MM_SEG(s) ((mm_segment_t) { (s) })
-
-#define KERNEL_DS MAKE_MM_SEG(0)
-#define USER_DS MAKE_MM_SEG(TASK_SIZE)
-#define uaccess_kernel() (get_fs() == KERNEL_DS)
-
-#endif /* __ASSEMBLY__ */
-#endif /* __ASMARC_SEGMENT_H */
diff --git a/arch/arc/include/asm/thread_info.h b/arch/arc/include/asm/thread_info.h
index d36863e34bfc..1e0b2e3914d5 100644
--- a/arch/arc/include/asm/thread_info.h
+++ b/arch/arc/include/asm/thread_info.h
@@ -27,7 +27,6 @@
#ifndef __ASSEMBLY__
#include <linux/thread_info.h>
-#include <asm/segment.h>
/*
* low level task data that entry.S needs immediate access to
@@ -40,7 +39,6 @@ struct thread_info {
unsigned long flags; /* low level flags */
int preempt_count; /* 0 => preemptable, <0 => BUG */
struct task_struct *task; /* main task structure */
- mm_segment_t addr_limit; /* thread address space */
__u32 cpu; /* current CPU */
unsigned long thr_ptr; /* TLS ptr */
};
@@ -56,7 +54,6 @@ struct thread_info {
.flags = 0, \
.cpu = 0, \
.preempt_count = INIT_PREEMPT_COUNT, \
- .addr_limit = KERNEL_DS, \
}
static inline __attribute_const__ struct thread_info *current_thread_info(void)
diff --git a/arch/arc/include/asm/uaccess.h b/arch/arc/include/asm/uaccess.h
index c14b692a0a4e..f07eaf17afaf 100644
--- a/arch/arc/include/asm/uaccess.h
+++ b/arch/arc/include/asm/uaccess.h
@@ -23,14 +23,9 @@
#include <linux/string.h> /* for generic string functions */
-
-#define __kernel_ok (uaccess_kernel())
-
/*
- * Algorithmically, for __user_ok() we want do:
+ * Algorithmically, for __access_ok() we want do:
* (start < TASK_SIZE) && (start+len < TASK_SIZE)
- * where TASK_SIZE could either be retrieved from thread_info->addr_limit or
- * emitted directly in code.
*
* This can however be rewritten as follows:
* (len <= TASK_SIZE) && (start+len < TASK_SIZE)
@@ -41,16 +36,14 @@
* The reason for rewriting being, for majority of cases, @len is generally
* compile time constant, causing first sub-expression to be compile time
* subsumed.
- *
- * The second part would generate weird large LIMMs e.g. (0x6000_0000 - 0x10),
- * so we check for TASK_SIZE using get_fs() since the addr_limit load from mem
- * would already have been done at this call site for __kernel_ok()
- *
*/
-#define __user_ok(addr, sz) (((sz) <= TASK_SIZE) && \
- ((addr) <= (get_fs() - (sz))))
-#define __access_ok(addr, sz) (unlikely(__kernel_ok) || \
- likely(__user_ok((addr), (sz))))
+static inline int __access_ok(unsigned long addr, unsigned long size)
+{
+ __chk_user_ptr(addr);
+ return size <= TASK_SIZE && addr <= TASK_SIZE - size;
+}
+
+#define __access_ok __access_ok
/*********** Single byte/hword/word copies ******************/
@@ -691,7 +684,6 @@ extern unsigned long arc_clear_user_noinline(void __user *to,
#define __clear_user(d, n) arc_clear_user_noinline(d, n)
#endif
-#include <asm/segment.h>
#include <asm-generic/uaccess.h>
#endif
--
2.35.0
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^ permalink raw reply related [flat|nested] 10+ messages in thread* Re: [RFC PATCH 0/3] arc: remove CONFIG_SET_FS
2022-02-01 14:55 [RFC PATCH 0/3] arc: remove CONFIG_SET_FS Sergey Matyukevich
` (2 preceding siblings ...)
2022-02-01 14:55 ` [RFC PATCH 3/3] arc: remove set_fs() Sergey Matyukevich
@ 2022-02-02 5:14 ` Vineet Gupta
2022-02-15 21:04 ` Sergey Matyukevich
3 siblings, 1 reply; 10+ messages in thread
From: Vineet Gupta @ 2022-02-02 5:14 UTC (permalink / raw)
To: Sergey Matyukevich, linux-snps-arc
Cc: Vineet Gupta, Vladimir Isaev, Christoph Hellwig
On 2/1/22 06:55, Sergey Matyukevich wrote:
> Hi all,
>
> This patch series removes SET_FS support for arc.
>
> Sergey Matyukevich (3):
> arc: use BUILD_BUG for invalid sizes in get_user/put_user
> arc: provide __{get,put}_kernel_nofault
> arc: remove set_fs()
>
> arch/arc/Kconfig | 1 -
> arch/arc/include/asm/segment.h | 20 -------------
> arch/arc/include/asm/thread_info.h | 3 --
> arch/arc/include/asm/uaccess.h | 48 ++++++++++++++++++++----------
> 4 files changed, 32 insertions(+), 40 deletions(-)
> delete mode 100644 arch/arc/include/asm/segment.h
Nit - in future please use uppercase "ARC" for prefixing patches.
Added to for-next.
Thx,
-Vineet
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^ permalink raw reply [flat|nested] 10+ messages in thread* Re: [RFC PATCH 0/3] arc: remove CONFIG_SET_FS
2022-02-02 5:14 ` [RFC PATCH 0/3] arc: remove CONFIG_SET_FS Vineet Gupta
@ 2022-02-15 21:04 ` Sergey Matyukevich
2022-02-18 4:03 ` Vineet Gupta
0 siblings, 1 reply; 10+ messages in thread
From: Sergey Matyukevich @ 2022-02-15 21:04 UTC (permalink / raw)
To: Vineet Gupta; +Cc: linux-snps-arc, Vladimir Isaev, Christoph Hellwig
Hi Vineet,
> > Hi all,
> >
> > This patch series removes SET_FS support for arc.
> >
> > Sergey Matyukevich (3):
> > arc: use BUILD_BUG for invalid sizes in get_user/put_user
> > arc: provide __{get,put}_kernel_nofault
> > arc: remove set_fs()
> >
> > arch/arc/Kconfig | 1 -
> > arch/arc/include/asm/segment.h | 20 -------------
> > arch/arc/include/asm/thread_info.h | 3 --
> > arch/arc/include/asm/uaccess.h | 48 ++++++++++++++++++++----------
> > 4 files changed, 32 insertions(+), 40 deletions(-)
> > delete mode 100644 arch/arc/include/asm/segment.h
>
> Nit - in future please use uppercase "ARC" for prefixing patches.
>
> Added to for-next.
IIUC it makes sense to drop this patch series from your for-next branch.
These changes have been superseded by generic approach posted by
Arnd Bergmann, see:
https://lore.kernel.org/linux-arch/CAHk-=whXYWoP6of7js=f4zov62on97mNFRSVRWhY75WoGM6CoQ@mail.gmail.com/T/#t
I tested patches by Arnd on ARC700/ARCHS platforms, so far so good.
Regards,
Sergey
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^ permalink raw reply [flat|nested] 10+ messages in thread