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commit 736706bee3298208343a76096370e4f6a5c55915
parent 84c4e1f89fefe70554da0ab33be72c9be7994379
Author: Linus Torvalds <torvalds@linux-foundation.org>
Date:   Mon,  4 Mar 2019 10:39:05 -0800

get rid of legacy 'get_ds()' function

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>

Diffstat:
March/alpha/include/asm/uaccess.h | 1-
March/arm/include/asm/uaccess.h | 1-
March/arm/kernel/process.c | 2+-
March/arm/xen/hypercall.S | 3+--
March/arm64/include/asm/uaccess.h | 1-
March/csky/include/asm/segment.h | 1-
March/h8300/include/asm/segment.h | 6------
March/ia64/include/asm/uaccess.h | 1-
March/m68k/include/asm/segment.h | 7-------
March/microblaze/include/asm/uaccess.h | 1-
March/mips/include/asm/uaccess.h | 1-
March/mips/kernel/ftrace.c | 6+++---
March/mips/kernel/kgdb.c | 4++--
March/mips/kernel/traps.c | 2+-
March/nds32/include/asm/uaccess.h | 1-
March/nds32/kernel/process.c | 2+-
March/nios2/include/asm/uaccess.h | 1-
March/openrisc/include/asm/uaccess.h | 1-
March/parisc/include/asm/uaccess.h | 1-
March/powerpc/include/asm/uaccess.h | 1-
March/riscv/include/asm/uaccess.h | 1-
March/s390/include/asm/uaccess.h | 1-
March/sh/include/asm/segment.h | 1-
March/sparc/include/asm/uaccess_32.h | 1-
March/sparc/include/asm/uaccess_64.h | 1-
March/x86/include/asm/uaccess.h | 1-
March/xtensa/include/asm/asm-uaccess.h | 2--
March/xtensa/include/asm/uaccess.h | 1-
Mdrivers/staging/rtl8723bs/os_dep/osdep_service.c | 4++--
Mfs/read_write.c | 6+++---
Mfs/splice.c | 2+-
Minclude/asm-generic/uaccess.h | 1-
Msecurity/integrity/iint.c | 2+-
33 files changed, 16 insertions(+), 52 deletions(-)

diff --git a/arch/alpha/include/asm/uaccess.h b/arch/alpha/include/asm/uaccess.h @@ -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) diff --git a/arch/arm/include/asm/uaccess.h b/arch/arm/include/asm/uaccess.h @@ -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 diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c @@ -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"; diff --git a/arch/arm/xen/hypercall.S b/arch/arm/xen/hypercall.S @@ -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 diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h @@ -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) diff --git a/arch/csky/include/asm/segment.h b/arch/csky/include/asm/segment.h @@ -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) diff --git a/arch/h8300/include/asm/segment.h b/arch/h8300/include/asm/segment.h @@ -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__ */ diff --git a/arch/ia64/include/asm/uaccess.h b/arch/ia64/include/asm/uaccess.h @@ -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)) diff --git a/arch/m68k/include/asm/segment.h b/arch/m68k/include/asm/segment.h @@ -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 diff --git a/arch/microblaze/include/asm/uaccess.h b/arch/microblaze/include/asm/uaccess.h @@ -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)) diff --git a/arch/mips/include/asm/uaccess.h b/arch/mips/include/asm/uaccess.h @@ -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)) diff --git a/arch/mips/kernel/ftrace.c b/arch/mips/kernel/ftrace.c @@ -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); diff --git a/arch/mips/kernel/kgdb.c b/arch/mips/kernel/kgdb.c @@ -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); diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c @@ -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; diff --git a/arch/nds32/include/asm/uaccess.h b/arch/nds32/include/asm/uaccess.h @@ -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 diff --git a/arch/nds32/kernel/process.c b/arch/nds32/kernel/process.c @@ -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); diff --git a/arch/nios2/include/asm/uaccess.h b/arch/nios2/include/asm/uaccess.h @@ -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)) diff --git a/arch/openrisc/include/asm/uaccess.h b/arch/openrisc/include/asm/uaccess.h @@ -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) diff --git a/arch/parisc/include/asm/uaccess.h b/arch/parisc/include/asm/uaccess.h @@ -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)) diff --git a/arch/powerpc/include/asm/uaccess.h b/arch/powerpc/include/asm/uaccess.h @@ -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) diff --git a/arch/riscv/include/asm/uaccess.h b/arch/riscv/include/asm/uaccess.h @@ -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) diff --git a/arch/s390/include/asm/uaccess.h b/arch/s390/include/asm/uaccess.h @@ -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)) diff --git a/arch/sh/include/asm/segment.h b/arch/sh/include/asm/segment.h @@ -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)) diff --git a/arch/sparc/include/asm/uaccess_32.h b/arch/sparc/include/asm/uaccess_32.h @@ -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)) diff --git a/arch/sparc/include/asm/uaccess_64.h b/arch/sparc/include/asm/uaccess_64.h @@ -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) diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h @@ -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) { diff --git a/arch/xtensa/include/asm/asm-uaccess.h b/arch/xtensa/include/asm/asm-uaccess.h @@ -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: diff --git a/arch/xtensa/include/asm/uaccess.h b/arch/xtensa/include/asm/uaccess.h @@ -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)) diff --git a/drivers/staging/rtl8723bs/os_dep/osdep_service.c b/drivers/staging/rtl8723bs/os_dep/osdep_service.c @@ -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); diff --git a/fs/read_write.c b/fs/read_write.c @@ -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); diff --git a/fs/splice.c b/fs/splice.c @@ -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); diff --git a/include/asm-generic/uaccess.h b/include/asm-generic/uaccess.h @@ -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) diff --git a/security/integrity/iint.c b/security/integrity/iint.c @@ -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);