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get rid of legacy 'get_ds()' function

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Every in-kernel use of this function defined it to KERNEL_DS (either as
an actual define, or as an inline function).  It's an entirely
historical artifact, and long long long ago used to actually read the
segment selector valueof '%ds' on x86.

Which in the kernel is always KERNEL_DS.

Inspired by a patch from Jann Horn that just did this for a very small
subset of users (the ones in fs/), along with Al who suggested a script.
I then just took it to the logical extreme and removed all the remaining
gunk.

Roughly scripted with

   git grep -l '(get_ds())' -- :^tools/ | xargs sed -i 's/(get_ds())/(KERNEL_DS)/'
   git grep -lw 'get_ds' -- :^tools/ | xargs sed -i '/^#define get_ds()/d'

plus manual fixups to remove a few unusual usage patterns, the couple of
inline function cases and to fix up a comment that had become stale.

The 'get_ds()' function remains in an x86 kvm selftest, since in user
space it actually does something relevant.

Inspired-by: Jann Horn <jannh@google.com>
Inspired-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Linus Torvalds 2019-03-04 10:39:05 -08:00
parent 84c4e1f89f
commit 736706bee3
33 changed files with 16 additions and 52 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
arch/alpha/include/asm/uaccess.h
View File

@ -18,7 +18,6 @@
#define USER_DS ((mm_segment_t) { -0x40000000000UL })
#define get_fs() (current_thread_info()->addr_limit)
#define get_ds() (KERNEL_DS)
#define set_fs(x) (current_thread_info()->addr_limit = (x))
#define segment_eq(a, b) ((a).seg == (b).seg)

1
arch/arm/include/asm/uaccess.h
View File

@ -59,7 +59,6 @@ extern int __put_user_bad(void);
* Note that this is actually 0x1,0000,0000
*/
#define KERNEL_DS 0x00000000
#define get_ds() (KERNEL_DS)
#ifdef CONFIG_MMU

2
arch/arm/kernel/process.c
View File

@ -150,7 +150,7 @@ void __show_regs(struct pt_regs *regs)
if ((domain & domain_mask(DOMAIN_USER)) ==
domain_val(DOMAIN_USER, DOMAIN_NOACCESS))
segment = "none";
else if (fs == get_ds())
else if (fs == KERNEL_DS)
segment = "kernel";
else
segment = "user";

3
arch/arm/xen/hypercall.S
View File

@ -113,8 +113,7 @@ ENTRY(privcmd_call)
/*
* Disable userspace access from kernel. This is fine to do it
* unconditionally as no set_fs(KERNEL_DS)/set_fs(get_ds()) is
* called before.
* unconditionally as no set_fs(KERNEL_DS) is called before.
*/
uaccess_disable r4

1
arch/arm64/include/asm/uaccess.h
View File

@ -34,7 +34,6 @@
#include <asm/memory.h>
#include <asm/extable.h>
#define get_ds() (KERNEL_DS)
#define get_fs() (current_thread_info()->addr_limit)
static inline void set_fs(mm_segment_t fs)

1
arch/csky/include/asm/segment.h
View File

@ -9,7 +9,6 @@ typedef struct {
} mm_segment_t;
#define KERNEL_DS ((mm_segment_t) { 0xFFFFFFFF })
#define get_ds() KERNEL_DS
#define USER_DS ((mm_segment_t) { 0x80000000UL })
#define get_fs() (current_thread_info()->addr_limit)

6
arch/h8300/include/asm/segment.h
View File

@ -33,12 +33,6 @@ static inline mm_segment_t get_fs(void)
return USER_DS;
}
static inline mm_segment_t get_ds(void)
{
/* return the supervisor data space code */
return KERNEL_DS;
}
#define segment_eq(a, b) ((a).seg == (b).seg)
#endif /* __ASSEMBLY__ */

1
arch/ia64/include/asm/uaccess.h
View File

@ -48,7 +48,6 @@
#define KERNEL_DS ((mm_segment_t) { ~0UL }) /* cf. access_ok() */
#define USER_DS ((mm_segment_t) { TASK_SIZE-1 }) /* cf. access_ok() */
#define get_ds() (KERNEL_DS)
#define get_fs() (current_thread_info()->addr_limit)
#define set_fs(x) (current_thread_info()->addr_limit = (x))

7
arch/m68k/include/asm/segment.h
View File

@ -45,16 +45,9 @@ static inline void set_fs(mm_segment_t val)
: /* no outputs */ : "r" (val.seg) : "memory");
}
static inline mm_segment_t get_ds(void)
{
/* return the supervisor data space code */
return KERNEL_DS;
}
#else
#define USER_DS MAKE_MM_SEG(TASK_SIZE)
#define KERNEL_DS MAKE_MM_SEG(0xFFFFFFFF)
#define get_ds() (KERNEL_DS)
#define get_fs() (current_thread_info()->addr_limit)
#define set_fs(x) (current_thread_info()->addr_limit = (x))
#endif

1
arch/microblaze/include/asm/uaccess.h
View File

@ -42,7 +42,6 @@
# define USER_DS MAKE_MM_SEG(TASK_SIZE - 1)
# endif
# define get_ds() (KERNEL_DS)
# define get_fs() (current_thread_info()->addr_limit)
# define set_fs(val) (current_thread_info()->addr_limit = (val))

1
arch/mips/include/asm/uaccess.h
View File

@ -69,7 +69,6 @@ extern u64 __ua_limit;
#define USER_DS ((mm_segment_t) { __UA_LIMIT })
#endif
#define get_ds() (KERNEL_DS)
#define get_fs() (current_thread_info()->addr_limit)
#define set_fs(x) (current_thread_info()->addr_limit = (x))

6
arch/mips/kernel/ftrace.c
View File

@ -86,7 +86,7 @@ static int ftrace_modify_code(unsigned long ip, unsigned int new_code)
return -EFAULT;
old_fs = get_fs();
set_fs(get_ds());
set_fs(KERNEL_DS);
flush_icache_range(ip, ip + 8);
set_fs(old_fs);
@ -111,7 +111,7 @@ static int ftrace_modify_code_2(unsigned long ip, unsigned int new_code1,
ip -= 4;
old_fs = get_fs();
set_fs(get_ds());
set_fs(KERNEL_DS);
flush_icache_range(ip, ip + 8);
set_fs(old_fs);
@ -135,7 +135,7 @@ static int ftrace_modify_code_2r(unsigned long ip, unsigned int new_code1,
return -EFAULT;
old_fs = get_fs();
set_fs(get_ds());
set_fs(KERNEL_DS);
flush_icache_range(ip, ip + 8);
set_fs(old_fs);

4
arch/mips/kernel/kgdb.c
View File

@ -212,7 +212,7 @@ void kgdb_call_nmi_hook(void *ignored)
mm_segment_t old_fs;
old_fs = get_fs();
set_fs(get_ds());
set_fs(KERNEL_DS);
kgdb_nmicallback(raw_smp_processor_id(), NULL);
@ -318,7 +318,7 @@ static int kgdb_mips_notify(struct notifier_block *self, unsigned long cmd,
/* Kernel mode. Set correct address limit */
old_fs = get_fs();
set_fs(get_ds());
set_fs(KERNEL_DS);
if (atomic_read(&kgdb_active) != -1)
kgdb_nmicallback(smp_processor_id(), regs);

2
arch/mips/kernel/traps.c
View File

@ -1077,7 +1077,7 @@ asmlinkage void do_tr(struct pt_regs *regs)
seg = get_fs();
if (!user_mode(regs))
set_fs(get_ds());
set_fs(KERNEL_DS);
prev_state = exception_enter();
current->thread.trap_nr = (regs->cp0_cause >> 2) & 0x1f;

1
arch/nds32/include/asm/uaccess.h
View File

@ -37,7 +37,6 @@ extern int fixup_exception(struct pt_regs *regs);
#define KERNEL_DS ((mm_segment_t) { ~0UL })
#define USER_DS ((mm_segment_t) {TASK_SIZE - 1})
#define get_ds() (KERNEL_DS)
#define get_fs() (current_thread_info()->addr_limit)
#define user_addr_max get_fs

2
arch/nds32/kernel/process.c
View File

@ -121,7 +121,7 @@ void show_regs(struct pt_regs *regs)
regs->uregs[3], regs->uregs[2], regs->uregs[1], regs->uregs[0]);
pr_info(" IRQs o%s Segment %s\n",
interrupts_enabled(regs) ? "n" : "ff",
segment_eq(get_fs(), get_ds())? "kernel" : "user");
segment_eq(get_fs(), KERNEL_DS)? "kernel" : "user");
}
EXPORT_SYMBOL(show_regs);

1
arch/nios2/include/asm/uaccess.h
View File

@ -26,7 +26,6 @@
#define USER_DS MAKE_MM_SEG(0x80000000UL)
#define KERNEL_DS MAKE_MM_SEG(0)
#define get_ds() (KERNEL_DS)
#define get_fs() (current_thread_info()->addr_limit)
#define set_fs(seg) (current_thread_info()->addr_limit = (seg))

1
arch/openrisc/include/asm/uaccess.h
View File

@ -42,7 +42,6 @@
*/
#define KERNEL_DS (~0UL)
#define get_ds() (KERNEL_DS)
#define USER_DS (TASK_SIZE)
#define get_fs() (current_thread_info()->addr_limit)

1
arch/parisc/include/asm/uaccess.h
View File

@ -16,7 +16,6 @@
#define segment_eq(a, b) ((a).seg == (b).seg)
#define get_ds() (KERNEL_DS)
#define get_fs() (current_thread_info()->addr_limit)
#define set_fs(x) (current_thread_info()->addr_limit = (x))

1
arch/powerpc/include/asm/uaccess.h
View File

@ -28,7 +28,6 @@
#define USER_DS MAKE_MM_SEG(TASK_SIZE - 1)
#endif
#define get_ds() (KERNEL_DS)
#define get_fs() (current->thread.addr_limit)
static inline void set_fs(mm_segment_t fs)

1
arch/riscv/include/asm/uaccess.h
View File

@ -41,7 +41,6 @@
#define KERNEL_DS (~0UL)
#define USER_DS (TASK_SIZE)
#define get_ds() (KERNEL_DS)
#define get_fs() (current_thread_info()->addr_limit)
static inline void set_fs(mm_segment_t fs)

1
arch/s390/include/asm/uaccess.h
View File

@ -31,7 +31,6 @@
#define USER_DS (2)
#define USER_DS_SACF (3)
#define get_ds() (KERNEL_DS)
#define get_fs() (current->thread.mm_segment)
#define segment_eq(a,b) (((a) & 2) == ((b) & 2))

1
arch/sh/include/asm/segment.h
View File

@ -26,7 +26,6 @@ typedef struct {
#define segment_eq(a, b) ((a).seg == (b).seg)
#define get_ds() (KERNEL_DS)
#define get_fs() (current_thread_info()->addr_limit)
#define set_fs(x) (current_thread_info()->addr_limit = (x))

1
arch/sparc/include/asm/uaccess_32.h
View File

@ -25,7 +25,6 @@
#define KERNEL_DS ((mm_segment_t) { 0 })
#define USER_DS ((mm_segment_t) { -1 })
#define get_ds() (KERNEL_DS)
#define get_fs() (current->thread.current_ds)
#define set_fs(val) ((current->thread.current_ds) = (val))

1
arch/sparc/include/asm/uaccess_64.h
View File

@ -31,7 +31,6 @@
#define USER_DS ((mm_segment_t) { ASI_AIUS }) /* har har har */
#define get_fs() ((mm_segment_t){(current_thread_info()->current_ds)})
#define get_ds() (KERNEL_DS)
#define segment_eq(a, b) ((a).seg == (b).seg)

1
arch/x86/include/asm/uaccess.h
View File

@ -25,7 +25,6 @@
#define KERNEL_DS MAKE_MM_SEG(-1UL)
#define USER_DS MAKE_MM_SEG(TASK_SIZE_MAX)
#define get_ds() (KERNEL_DS)
#define get_fs() (current->thread.addr_limit)
static inline void set_fs(mm_segment_t fs)
{

2
arch/xtensa/include/asm/asm-uaccess.h
View File

@ -32,8 +32,6 @@
#define KERNEL_DS 0
#define USER_DS 1
#define get_ds (KERNEL_DS)
/*
* get_fs reads current->thread.current_ds into a register.
* On Entry:

1
arch/xtensa/include/asm/uaccess.h
View File

@ -32,7 +32,6 @@
#define KERNEL_DS ((mm_segment_t) { 0 })
#define USER_DS ((mm_segment_t) { 1 })
#define get_ds() (KERNEL_DS)
#define get_fs() (current->thread.current_ds)
#define set_fs(val) (current->thread.current_ds = (val))

4
drivers/staging/rtl8723bs/os_dep/osdep_service.c
View File

@ -137,7 +137,7 @@ static int isFileReadable(char *path)
ret = PTR_ERR(fp);
}
else {
oldfs = get_fs(); set_fs(get_ds());
oldfs = get_fs(); set_fs(KERNEL_DS);
if (1!=readFile(fp, &buf, 1))
ret = -EINVAL;
@ -165,7 +165,7 @@ static int retriveFromFile(char *path, u8 *buf, u32 sz)
if (0 == (ret =openFile(&fp, path, O_RDONLY, 0))) {
DBG_871X("%s openFile path:%s fp =%p\n", __func__, path , fp);
oldfs = get_fs(); set_fs(get_ds());
oldfs = get_fs(); set_fs(KERNEL_DS);
ret =readFile(fp, buf, sz);
set_fs(oldfs);
closeFile(fp);

6
fs/read_write.c
View File

@ -426,7 +426,7 @@ ssize_t kernel_read(struct file *file, void *buf, size_t count, loff_t *pos)
ssize_t result;
old_fs = get_fs();
set_fs(get_ds());
set_fs(KERNEL_DS);
/* The cast to a user pointer is valid due to the set_fs() */
result = vfs_read(file, (void __user *)buf, count, pos);
set_fs(old_fs);
@ -499,7 +499,7 @@ ssize_t __kernel_write(struct file *file, const void *buf, size_t count, loff_t
return -EINVAL;
old_fs = get_fs();
set_fs(get_ds());
set_fs(KERNEL_DS);
p = (__force const char __user *)buf;
if (count > MAX_RW_COUNT)
count = MAX_RW_COUNT;
@ -521,7 +521,7 @@ ssize_t kernel_write(struct file *file, const void *buf, size_t count,
ssize_t res;
old_fs = get_fs();
set_fs(get_ds());
set_fs(KERNEL_DS);
/* The cast to a user pointer is valid due to the set_fs() */
res = vfs_write(file, (__force const char __user *)buf, count, pos);
set_fs(old_fs);

2
fs/splice.c
View File

@ -357,7 +357,7 @@ static ssize_t kernel_readv(struct file *file, const struct kvec *vec,
ssize_t res;
old_fs = get_fs();
set_fs(get_ds());
set_fs(KERNEL_DS);
/* The cast to a user pointer is valid due to the set_fs() */
res = vfs_readv(file, (const struct iovec __user *)vec, vlen, &pos, 0);
set_fs(old_fs);

1
include/asm-generic/uaccess.h
View File

@ -22,7 +22,6 @@
#endif
#ifndef get_fs
#define get_ds() (KERNEL_DS)
#define get_fs() (current_thread_info()->addr_limit)
static inline void set_fs(mm_segment_t fs)

2
security/integrity/iint.c
View File

@ -200,7 +200,7 @@ int integrity_kernel_read(struct file *file, loff_t offset,
return -EBADF;
old_fs = get_fs();
set_fs(get_ds());
set_fs(KERNEL_DS);
ret = __vfs_read(file, buf, count, &offset);
set_fs(old_fs);