[PATCH] microblaze: remove CONFIG_SET_FS

Arnd Bergmann
2022-01-17T13:28:12Z

From: Arnd Bergmann <arnd@arndb.de>

I picked microblaze as one of the architectures that still
use set_fs() and converted it not to.

Link: https://lore.kernel.org/lkml/CAK8P3a22ntk5fTuk6xjh1pyS-eVbGo7zDQSVkn2VG1xgp01D9g@mail.gmail.com/
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
This is an old patch I found after Christoph asked about
conversions for the remaining architectures. I have no idea
about the state of this patch, but there is a reasonable
chance that it works.
---
arch/microblaze/Kconfig | 1 -
arch/microblaze/include/asm/thread_info.h | 6 ---
arch/microblaze/include/asm/uaccess.h | 56 ++++++++++-------------
arch/microblaze/kernel/asm-offsets.c | 1 -
4 files changed, 25 insertions(+), 39 deletions(-)

diff --git a/arch/microblaze/Kconfig b/arch/microblaze/Kconfig
index 59798e43cdb0..1fb1cec087b7 100644
--- a/arch/microblaze/Kconfig
+++ b/arch/microblaze/Kconfig
@@ -42,7 +42,6 @@ config MICROBLAZE
select CPU_NO_EFFICIENT_FFS
select MMU_GATHER_NO_RANGE
select SPARSE_IRQ
- select SET_FS
select ZONE_DMA
select TRACE_IRQFLAGS_SUPPORT

diff --git a/arch/microblaze/include/asm/thread_info.h b/arch/microblaze/include/asm/thread_info.h
index 44f5ca331862..a0ddd2a36fb9 100644
--- a/arch/microblaze/include/asm/thread_info.h
+++ b/arch/microblaze/include/asm/thread_info.h
@@ -56,17 +56,12 @@ struct cpu_context {
__u32 fsr;
};

-typedef struct {
- unsigned long seg;
-} mm_segment_t;
-
struct thread_info {
struct task_struct *task; /* main task structure */
unsigned long flags; /* low level flags */
unsigned long status; /* thread-synchronous flags */
__u32 cpu; /* current CPU */
__s32 preempt_count; /* 0 => preemptable,< 0 => BUG*/
- mm_segment_t addr_limit; /* thread address space */

struct cpu_context cpu_context;
};
@@ -80,7 +75,6 @@ struct thread_info {
.flags = 0, \
.cpu = 0, \
.preempt_count = INIT_PREEMPT_COUNT, \
- .addr_limit = KERNEL_DS, \
}

/* how to get the thread information struct from C */
diff --git a/arch/microblaze/include/asm/uaccess.h b/arch/microblaze/include/asm/uaccess.h
index d2a8ef9f8978..346fe4618b27 100644
--- a/arch/microblaze/include/asm/uaccess.h
+++ b/arch/microblaze/include/asm/uaccess.h
@@ -16,45 +16,20 @@
#include <asm/extable.h>
#include <linux/string.h>

-/*
- * On Microblaze the fs value is actually the top of the corresponding
- * address space.
- *
- * The fs value determines whether argument validity checking should be
- * performed or not. If get_fs() == USER_DS, checking is performed, with
- * get_fs() == KERNEL_DS, checking is bypassed.
- *
- * For historical reasons, these macros are grossly misnamed.
- *
- * For non-MMU arch like Microblaze, KERNEL_DS and USER_DS is equal.
- */
-# define MAKE_MM_SEG(s) ((mm_segment_t) { (s) })
-
-# define KERNEL_DS MAKE_MM_SEG(0xFFFFFFFF)
-# define USER_DS MAKE_MM_SEG(TASK_SIZE - 1)
-
-# define get_fs() (current_thread_info()->addr_limit)
-# define set_fs(val) (current_thread_info()->addr_limit = (val))
-# define user_addr_max() get_fs().seg
-
-# define uaccess_kernel() (get_fs().seg == KERNEL_DS.seg)
-
static inline int access_ok(const void __user *addr, unsigned long size)
{
if (!size)
goto ok;

- if ((get_fs().seg < ((unsigned long)addr)) ||
- (get_fs().seg < ((unsigned long)addr + size - 1))) {
- pr_devel("ACCESS fail at 0x%08x (size 0x%x), seg 0x%08x\n",
- (__force u32)addr, (u32)size,
- (u32)get_fs().seg);
+ if ((((unsigned long)addr) > TASK_SIZE) ||
+ (((unsigned long)addr + size - 1) > TASK_SIZE)) {
+ pr_devel("ACCESS fail at 0x%08x (size 0x%x)",
+ (__force u32)addr, (u32)size);
return 0;
}
ok:
- pr_devel("ACCESS OK at 0x%08x (size 0x%x), seg 0x%08x\n",
- (__force u32)addr, (u32)size,
- (u32)get_fs().seg);
+ pr_devel("ACCESS OK at 0x%08x (size 0x%x)\n",
+ (__force u32)addr, (u32)size);
return 1;
}

@@ -280,6 +255,25 @@ extern long __user_bad(void);
__gu_err; \
})

+#define __get_kernel_nofault(dst, src, type, label) \
+{ \
+ type __user *p = (type __force __user *)(src); \
+ type data; \
+ if (__get_user(data, p)) \
+ goto label; \
+ *(type *)dst = data; \
+}
+
+#define __put_kernel_nofault(dst, src, type, label) \
+{ \
+ type __user *p = (type __force __user *)(dst); \
+ type data = *(type *)src; \
+ if (__put_user(data, p)) \
+ goto label; \
+}
+
+#define HAVE_GET_KERNEL_NOFAULT
+
static inline unsigned long
raw_copy_from_user(void *to, const void __user *from, unsigned long n)
{
diff --git a/arch/microblaze/kernel/asm-offsets.c b/arch/microblaze/kernel/asm-offsets.c
index b77dd188dec4..47ee409508b1 100644
--- a/arch/microblaze/kernel/asm-offsets.c
+++ b/arch/microblaze/kernel/asm-offsets.c
@@ -86,7 +86,6 @@ int main(int argc, char *argv[])
/* struct thread_info */
DEFINE(TI_TASK, offsetof(struct thread_info, task));
DEFINE(TI_FLAGS, offsetof(struct thread_info, flags));
- DEFINE(TI_ADDR_LIMIT, offsetof(struct thread_info, addr_limit));
DEFINE(TI_CPU_CONTEXT, offsetof(struct thread_info, cpu_context));
DEFINE(TI_PREEMPT_COUNT, offsetof(struct thread_info, preempt_count));
BLANK();
--
2.29.2