[OpenRISC] [PATCH 12/14] sh: remove CONFIG_SET_FS support

Arnd Bergmann
2022-02-14T16:34:50Z

From: Arnd Bergmann <arnd@arndb.de>

sh uses set_fs/get_fs only in one file, to handle address
errors in both user and kernel memory.

It already has an abstraction to differentiate between I/O
and memory, so adding a third class for kernel memory fits
into the same scheme and lets us kill off CONFIG_SET_FS.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
arch/sh/Kconfig | 1 -
arch/sh/include/asm/processor.h | 1 -
arch/sh/include/asm/segment.h | 33 -------------------------------
arch/sh/include/asm/thread_info.h | 2 --
arch/sh/include/asm/uaccess.h | 4 ----
arch/sh/kernel/io_trapped.c | 9 ++-------
arch/sh/kernel/process_32.c | 2 --
arch/sh/kernel/traps_32.c | 30 +++++++++++++++++-----------
8 files changed, 21 insertions(+), 61 deletions(-)
delete mode 100644 arch/sh/include/asm/segment.h

diff --git a/arch/sh/Kconfig b/arch/sh/Kconfig
index 2474a04ceac4..f676e92b7d5b 100644
--- a/arch/sh/Kconfig
+++ b/arch/sh/Kconfig
@@ -65,7 +65,6 @@ config SUPERH
select PERF_EVENTS
select PERF_USE_VMALLOC
select RTC_LIB
- select SET_FS
select SPARSE_IRQ
select TRACE_IRQFLAGS_SUPPORT
help
diff --git a/arch/sh/include/asm/processor.h b/arch/sh/include/asm/processor.h
index 3820d698846e..85a6c1c3c16e 100644
--- a/arch/sh/include/asm/processor.h
+++ b/arch/sh/include/asm/processor.h
@@ -3,7 +3,6 @@
#define __ASM_SH_PROCESSOR_H

#include <asm/cpu-features.h>
-#include <asm/segment.h>
#include <asm/cache.h>

#ifndef __ASSEMBLY__
diff --git a/arch/sh/include/asm/segment.h b/arch/sh/include/asm/segment.h
deleted file mode 100644
index 02e54a3335d6..000000000000
--- a/arch/sh/include/asm/segment.h
+++ /dev/null
@@ -1,33 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-#ifndef __ASM_SH_SEGMENT_H
-#define __ASM_SH_SEGMENT_H
-
-#ifndef __ASSEMBLY__
-
-typedef struct {
- unsigned long seg;
-} mm_segment_t;
-
-#define MAKE_MM_SEG(s) ((mm_segment_t) { (s) })
-
-/*
- * 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.
- */
-#define KERNEL_DS MAKE_MM_SEG(0xFFFFFFFFUL)
-#ifdef CONFIG_MMU
-#define USER_DS MAKE_MM_SEG(PAGE_OFFSET)
-#else
-#define USER_DS KERNEL_DS
-#endif
-
-#define uaccess_kernel() (get_fs().seg == KERNEL_DS.seg)
-
-#define get_fs() (current_thread_info()->addr_limit)
-#define set_fs(x) (current_thread_info()->addr_limit = (x))
-
-#endif /* __ASSEMBLY__ */
-#endif /* __ASM_SH_SEGMENT_H */
diff --git a/arch/sh/include/asm/thread_info.h b/arch/sh/include/asm/thread_info.h
index 598d0184ffea..b119b859a0a3 100644
--- a/arch/sh/include/asm/thread_info.h
+++ b/arch/sh/include/asm/thread_info.h
@@ -30,7 +30,6 @@ struct thread_info {
__u32 status; /* thread synchronous flags */
__u32 cpu;
int preempt_count; /* 0 => preemptable, <0 => BUG */
- mm_segment_t addr_limit; /* thread address space */
unsigned long previous_sp; /* sp of previous stack in case
of nested IRQ stacks */
__u8 supervisor_stack[0];
@@ -58,7 +57,6 @@ struct thread_info {
.status = 0, \
.cpu = 0, \
.preempt_count = INIT_PREEMPT_COUNT, \
- .addr_limit = KERNEL_DS, \
}

/* how to get the current stack pointer from C */
diff --git a/arch/sh/include/asm/uaccess.h b/arch/sh/include/asm/uaccess.h
index ccd219d74851..a79609eb14be 100644
--- a/arch/sh/include/asm/uaccess.h
+++ b/arch/sh/include/asm/uaccess.h
@@ -2,11 +2,7 @@
#ifndef __ASM_SH_UACCESS_H
#define __ASM_SH_UACCESS_H

-#include <asm/segment.h>
#include <asm/extable.h>
-
-#define user_addr_max() (current_thread_info()->addr_limit.seg)
-
#include <asm-generic/access_ok.h>

/*
diff --git a/arch/sh/kernel/io_trapped.c b/arch/sh/kernel/io_trapped.c
index 004ad0130b10..e803b14ef12e 100644
--- a/arch/sh/kernel/io_trapped.c
+++ b/arch/sh/kernel/io_trapped.c
@@ -270,7 +270,6 @@ static struct mem_access trapped_io_access = {

int handle_trapped_io(struct pt_regs *regs, unsigned long address)
{
- mm_segment_t oldfs;
insn_size_t instruction;
int tmp;

@@ -281,16 +280,12 @@ int handle_trapped_io(struct pt_regs *regs, unsigned long address)

WARN_ON(user_mode(regs));

- oldfs = get_fs();
- set_fs(KERNEL_DS);
- if (copy_from_user(&instruction, (void *)(regs->pc),
- sizeof(instruction))) {
- set_fs(oldfs);
+ if (copy_from_kernel_nofault(&instruction, (void *)(regs->pc),
+ sizeof(instruction))) {
return 0;
}

tmp = handle_unaligned_access(instruction, regs,
&trapped_io_access, 1, address);
- set_fs(oldfs);
return tmp == 0;
}
diff --git a/arch/sh/kernel/process_32.c b/arch/sh/kernel/process_32.c
index 1c28e3cddb60..ca01286a0610 100644
--- a/arch/sh/kernel/process_32.c
+++ b/arch/sh/kernel/process_32.c
@@ -123,7 +123,6 @@ int copy_thread(unsigned long clone_flags, unsigned long usp, unsigned long arg,
#if defined(CONFIG_SH_FPU)
childregs->sr |= SR_FD;
#endif
- ti->addr_limit = KERNEL_DS;
ti->status &= ~TS_USEDFPU;
p->thread.fpu_counter = 0;
return 0;
@@ -132,7 +131,6 @@ int copy_thread(unsigned long clone_flags, unsigned long usp, unsigned long arg,

if (usp)
childregs->regs[15] = usp;
- ti->addr_limit = USER_DS;

if (clone_flags & CLONE_SETTLS)
childregs->gbr = tls;
diff --git a/arch/sh/kernel/traps_32.c b/arch/sh/kernel/traps_32.c
index b3c715bc254b..6cdda3a621a1 100644
--- a/arch/sh/kernel/traps_32.c
+++ b/arch/sh/kernel/traps_32.c
@@ -75,6 +75,23 @@ static struct mem_access user_mem_access = {
copy_to_user,
};

+static unsigned long copy_from_kernel_wrapper(void *dst, const void __user *src,
+ unsigned long cnt)
+{
+ return copy_from_kernel_nofault(dst, (const void __force *)src, cnt);
+}
+
+static unsigned long copy_to_kernel_wrapper(void __user *dst, const void *src,
+ unsigned long cnt)
+{
+ return copy_to_kernel_nofault((void __force *)dst, src, cnt);
+}
+
+static struct mem_access kernel_mem_access = {
+ copy_from_kernel_wrapper,
+ copy_to_kernel_wrapper,
+};
+
/*
* handle an instruction that does an unaligned memory access by emulating the
* desired behaviour
@@ -473,7 +490,6 @@ asmlinkage void do_address_error(struct pt_regs *regs,
unsigned long address)
{
unsigned long error_code = 0;
- mm_segment_t oldfs;
insn_size_t instruction;
int tmp;

@@ -489,13 +505,10 @@ asmlinkage void do_address_error(struct pt_regs *regs,
local_irq_enable();
inc_unaligned_user_access();

- oldfs = force_uaccess_begin();
if (copy_from_user(&instruction, (insn_size_t __user *)(regs->pc & ~1),
sizeof(instruction))) {
- force_uaccess_end(oldfs);
goto uspace_segv;
}
- force_uaccess_end(oldfs);

/* shout about userspace fixups */
unaligned_fixups_notify(current, instruction, regs);
@@ -518,11 +531,9 @@ asmlinkage void do_address_error(struct pt_regs *regs,
goto uspace_segv;
}

- oldfs = force_uaccess_begin();
tmp = handle_unaligned_access(instruction, regs,
&user_mem_access, 0,
address);
- force_uaccess_end(oldfs);

if (tmp == 0)
return; /* sorted */
@@ -538,21 +549,18 @@ asmlinkage void do_address_error(struct pt_regs *regs,
if (regs->pc & 1)
die("unaligned program counter", regs, error_code);

- set_fs(KERNEL_DS);
- if (copy_from_user(&instruction, (void __user *)(regs->pc),
+ if (copy_from_kernel_nofault(&instruction, (void *)(regs->pc),
sizeof(instruction))) {
/* Argh. Fault on the instruction itself.
This should never happen non-SMP
*/
- set_fs(oldfs);
die("insn faulting in do_address_error", regs, 0);
}

unaligned_fixups_notify(current, instruction, regs);

- handle_unaligned_access(instruction, regs, &user_mem_access,
+ handle_unaligned_access(instruction, regs, &kernel_mem_access,
0, address);
- set_fs(oldfs);
}
}

--
2.29.2