Re: [PATCH v2 18/18] uaccess: drop maining CONFIG_SET_FS users
On 2/16/22 07:13, Arnd Bergmann wrote: From: Arnd Bergmann There are no remaining callers of set_fs(), so CONFIG_SET_FS can be removed globally, along with the thread_info field and any references to it. This turns access_ok() into a cheaper check against TASK_SIZE_MAX. With CONFIG_SET_FS gone, so drop all remaining references to set_fs()/get_fs(), mm_segment_t and uaccess_kernel(). Signed-off-by: Arnd Bergmann --- arch/Kconfig | 3 - arch/alpha/Kconfig| 1 - arch/alpha/include/asm/processor.h| 4 -- arch/alpha/include/asm/thread_info.h | 2 - arch/alpha/include/asm/uaccess.h | 19 -- 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| 1 - arch/arm/lib/uaccess_with_memcpy.c| 10 arch/csky/Kconfig | 1 - arch/csky/include/asm/processor.h | 2 - arch/csky/include/asm/segment.h | 10 arch/csky/include/asm/thread_info.h | 2 - arch/csky/include/asm/uaccess.h | 3 - arch/csky/kernel/asm-offsets.c| 1 - arch/h8300/Kconfig| 1 - arch/h8300/include/asm/processor.h| 1 - arch/h8300/include/asm/segment.h | 40 - arch/h8300/include/asm/thread_info.h | 3 - arch/h8300/kernel/entry.S | 1 - arch/h8300/kernel/head_ram.S | 1 - arch/h8300/mm/init.c | 6 -- arch/h8300/mm/memory.c| 1 - arch/hexagon/Kconfig | 1 - arch/hexagon/include/asm/thread_info.h| 6 -- arch/hexagon/kernel/process.c | 1 - arch/microblaze/Kconfig | 1 - arch/microblaze/include/asm/thread_info.h | 6 -- arch/microblaze/include/asm/uaccess.h | 24 arch/microblaze/kernel/asm-offsets.c | 1 - arch/microblaze/kernel/process.c | 1 - arch/nds32/Kconfig| 1 - arch/nds32/include/asm/thread_info.h | 4 -- arch/nds32/include/asm/uaccess.h | 15 + arch/nds32/kernel/process.c | 5 +- arch/nds32/mm/alignment.c | 3 - arch/nios2/Kconfig| 1 - arch/nios2/include/asm/thread_info.h | 9 --- arch/nios2/include/asm/uaccess.h | 12 For NIOS2: Acked-by: Dinh Nguyen ___ linux-snps-arc mailing list linux-snps-arc@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-snps-arc
Re: [PATCH v2 18/18] uaccess: drop maining CONFIG_SET_FS users
On Wed, Feb 16, 2022 at 02:13:32PM +0100, Arnd Bergmann wrote:
> From: Arnd Bergmann
>
> There are no remaining callers of set_fs(), so CONFIG_SET_FS
> can be removed globally, along with the thread_info field and
> any references to it.
>
> This turns access_ok() into a cheaper check against TASK_SIZE_MAX.
>
> With CONFIG_SET_FS gone, so drop all remaining references to
> set_fs()/get_fs(), mm_segment_t and uaccess_kernel().
>
> Signed-off-by: Arnd Bergmann
> ---
...
> arch/openrisc/Kconfig | 1 -
> arch/openrisc/include/asm/thread_info.h | 7 ---
> arch/openrisc/include/asm/uaccess.h | 23
...
> fs/exec.c | 6 --
> include/asm-generic/access_ok.h | 10 +---
> include/asm-generic/uaccess.h | 25 +---
> include/linux/syscalls.h | 4 --
> include/linux/uaccess.h | 33 ---
> include/rdma/ib.h | 2 +-
> kernel/events/callchain.c | 4 --
> kernel/events/core.c | 3 -
> kernel/exit.c | 14 -
> kernel/kthread.c | 5 --
> kernel/stacktrace.c | 3 -
> kernel/trace/bpf_trace.c | 4 --
> mm/maccess.c | 11
> mm/memory.c | 8 ---
> net/bpfilter/bpfilter_kern.c | 2 +-
> 72 files changed, 10 insertions(+), 522 deletions(-)
> delete mode 100644 arch/arc/include/asm/segment.h
> delete mode 100644 arch/csky/include/asm/segment.h
> delete mode 100644 arch/h8300/include/asm/segment.h
>
> diff --git a/arch/Kconfig b/arch/Kconfig
> index fa5db36bda67..99349547afed 100644
> --- a/arch/Kconfig
> +++ b/arch/Kconfig
> @@ -24,9 +24,6 @@ config KEXEC_ELF
> config HAVE_IMA_KEXEC
> bool
>
> -config SET_FS
> - bool
> -
> config HOTPLUG_SMT
> bool
>
...
> diff --git a/arch/openrisc/Kconfig b/arch/openrisc/Kconfig
> index f724b3f1aeed..0d68adf6e02b 100644
> --- a/arch/openrisc/Kconfig
> +++ b/arch/openrisc/Kconfig
> @@ -36,7 +36,6 @@ config OPENRISC
> select ARCH_WANT_FRAME_POINTERS
> select GENERIC_IRQ_MULTI_HANDLER
> select MMU_GATHER_NO_RANGE if MMU
> - select SET_FS
> select TRACE_IRQFLAGS_SUPPORT
>
> config CPU_BIG_ENDIAN
> diff --git a/arch/openrisc/include/asm/thread_info.h
> b/arch/openrisc/include/asm/thread_info.h
> index 659834ab87fa..4af3049c34c2 100644
> --- a/arch/openrisc/include/asm/thread_info.h
> +++ b/arch/openrisc/include/asm/thread_info.h
> @@ -40,18 +40,12 @@
> */
> #ifndef __ASSEMBLY__
>
> -typedef unsigned long mm_segment_t;
> -
> struct thread_info {
> struct task_struct *task; /* main task structure */
> unsigned long flags; /* low level flags */
> __u32 cpu;/* current CPU */
> __s32 preempt_count; /* 0 => preemptable, <0 => BUG */
>
> - mm_segment_taddr_limit; /* thread address space:
> -0-0x7FFF for user-thead
> -0-0x for kernel-thread
> - */
> __u8supervisor_stack[0];
>
> /* saved context data */
> @@ -71,7 +65,6 @@ struct thread_info {
> .flags = 0,\
> .cpu= 0,\
> .preempt_count = INIT_PREEMPT_COUNT, \
> - .addr_limit = KERNEL_DS,\
> .ksp= 0,\
> }
>
> diff --git a/arch/openrisc/include/asm/uaccess.h
> b/arch/openrisc/include/asm/uaccess.h
> index 8f049ec99b3e..d6500a374e18 100644
> --- a/arch/openrisc/include/asm/uaccess.h
> +++ b/arch/openrisc/include/asm/uaccess.h
> @@ -22,29 +22,6 @@
> #include
> #include
> #include
> -
> -/*
> - * 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.
> - */
> -
> -/* addr_limit is the maximum accessible address for the task. we misuse
> - * the KERNEL_DS and USER_DS values to both assign and compare the
> - * addr_limit values through the equally misnamed get/set_fs macros.
> - * (see above)
> - */
> -
> -#define KERNEL_DS(~0UL)
> -
> -#define USER_DS (TASK_SIZE)
> -#define get_fs() (current_thread_info()->addr_limit)
> -#define set_fs(x)(current_thread_info()->addr_limit = (x))
> -
> -#define uaccess_kernel() (get_fs() == KERNEL_DS)
> -
> #include
>
> /*
...
> diff --git a/fs/exec.c b/fs/exec.c
> index 79f2c9483302..bc68a0c089ac 100644
> --- a/fs/exec.c
> +++ b/fs/exec.c
> @@ -1303,12 +1303,6 @@ int
Re: [PATCH v2 18/18] uaccess: drop maining CONFIG_SET_FS users
Hi Arnd, > From: Arnd Bergmann > > There are no remaining callers of set_fs(), so CONFIG_SET_FS > can be removed globally, along with the thread_info field and > any references to it. > > This turns access_ok() into a cheaper check against TASK_SIZE_MAX. > > With CONFIG_SET_FS gone, so drop all remaining references to > set_fs()/get_fs(), mm_segment_t and uaccess_kernel(). > > Signed-off-by: Arnd Bergmann Tested-by: Sergey Matyukevich # for arc changes Regards, Sergey ___ linux-snps-arc mailing list linux-snps-arc@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-snps-arc
Re: [PATCH v2 18/18] uaccess: drop maining CONFIG_SET_FS users
On Fri, Feb 18, 2022 at 7:37 AM Christoph Hellwig wrote: > > s/maining/remaining/ ? > > Or maybe rather: > > uaccess: remove CONFIG_SET_FS > > because it is all gone now. > > > With CONFIG_SET_FS gone, so drop all remaining references to > > set_fs()/get_fs(), mm_segment_t and uaccess_kernel(). > > And this sentence does not parse. Both fixed now, thanks! Arnd ___ linux-snps-arc mailing list linux-snps-arc@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-snps-arc
Re: [PATCH v2 18/18] uaccess: drop maining CONFIG_SET_FS users
s/maining/remaining/ ? Or maybe rather: uaccess: remove CONFIG_SET_FS because it is all gone now. > With CONFIG_SET_FS gone, so drop all remaining references to > set_fs()/get_fs(), mm_segment_t and uaccess_kernel(). And this sentence does not parse. ___ linux-snps-arc mailing list linux-snps-arc@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-snps-arc
Re: [PATCH v2 18/18] uaccess: drop maining CONFIG_SET_FS users
Arnd Bergmann writes:
> From: Arnd Bergmann
>
> There are no remaining callers of set_fs(), so CONFIG_SET_FS
> can be removed globally, along with the thread_info field and
> any references to it.
>
> This turns access_ok() into a cheaper check against TASK_SIZE_MAX.
>
> With CONFIG_SET_FS gone, so drop all remaining references to
> set_fs()/get_fs(), mm_segment_t and uaccess_kernel().
For the bits I have looked at recently, and think I understand.
Acked-by: "Eric W. Biederman"
>
> Signed-off-by: Arnd Bergmann
> ---
> fs/exec.c | 6 --
> kernel/exit.c | 14 -
> kernel/kthread.c | 5 --
>
> diff --git a/fs/exec.c b/fs/exec.c
> index 79f2c9483302..bc68a0c089ac 100644
> --- a/fs/exec.c
> +++ b/fs/exec.c
> @@ -1303,12 +1303,6 @@ int begin_new_exec(struct linux_binprm * bprm)
> if (retval)
> goto out_unlock;
>
> - /*
> - * Ensure that the uaccess routines can actually operate on userspace
> - * pointers:
> - */
> - force_uaccess_begin();
> -
> if (me->flags & PF_KTHREAD)
> free_kthread_struct(me);
> me->flags &= ~(PF_RANDOMIZE | PF_FORKNOEXEC | PF_KTHREAD |
> diff --git a/kernel/exit.c b/kernel/exit.c
> index b00a25bb4ab9..0884a75bc2f8 100644
> --- a/kernel/exit.c
> +++ b/kernel/exit.c
> @@ -737,20 +737,6 @@ void __noreturn do_exit(long code)
>
> WARN_ON(blk_needs_flush_plug(tsk));
>
> - /*
> - * If do_dead is called because this processes oopsed, it's possible
> - * that get_fs() was left as KERNEL_DS, so reset it to USER_DS before
> - * continuing. Amongst other possible reasons, this is to prevent
> - * mm_release()->clear_child_tid() from writing to a user-controlled
> - * kernel address.
> - *
> - * On uptodate architectures force_uaccess_begin is a noop. On
> - * architectures that still have set_fs/get_fs in addition to handling
> - * oopses handles kernel threads that run as set_fs(KERNEL_DS) by
> - * default.
> - */
> - force_uaccess_begin();
> -
> kcov_task_exit(tsk);
>
> coredump_task_exit(tsk);
> diff --git a/kernel/kthread.c b/kernel/kthread.c
> index 38c6dd822da8..16c2275d4b50 100644
> --- a/kernel/kthread.c
> +++ b/kernel/kthread.c
> @@ -55,7 +55,6 @@ struct kthread {
> int result;
> int (*threadfn)(void *);
> void *data;
> - mm_segment_t oldfs;
> struct completion parked;
> struct completion exited;
> #ifdef CONFIG_BLK_CGROUP
> @@ -1441,8 +1440,6 @@ void kthread_use_mm(struct mm_struct *mm)
> mmdrop(active_mm);
> else
> smp_mb();
> -
> - to_kthread(tsk)->oldfs = force_uaccess_begin();
> }
> EXPORT_SYMBOL_GPL(kthread_use_mm);
>
> @@ -1457,8 +1454,6 @@ void kthread_unuse_mm(struct mm_struct *mm)
> WARN_ON_ONCE(!(tsk->flags & PF_KTHREAD));
> WARN_ON_ONCE(!tsk->mm);
>
> - force_uaccess_end(to_kthread(tsk)->oldfs);
> -
> task_lock(tsk);
> /*
>* When a kthread stops operating on an address space, the loop
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Re: [PATCH v2 18/18] uaccess: drop maining CONFIG_SET_FS users
On Wed, Feb 16, 2022 at 7:44 PM Sam Ravnborg wrote: > > Hi Arnd, > > Fix spelling in $subject... done > sparc/Kconfig b/arch/sparc/Kconfig > > index 9f6f9bce5292..9276f321b3e3 100644 > > --- a/arch/sparc/Kconfig > > +++ b/arch/sparc/Kconfig > > @@ -46,7 +46,6 @@ config SPARC > > select LOCKDEP_SMALL if LOCKDEP > > select NEED_DMA_MAP_STATE > > select NEED_SG_DMA_LENGTH > > - select SET_FS > > select TRACE_IRQFLAGS_SUPPORT > > > > config SPARC32 > > @@ -101,6 +100,7 @@ config SPARC64 > > select HAVE_SETUP_PER_CPU_AREA > > select NEED_PER_CPU_EMBED_FIRST_CHUNK > > select NEED_PER_CPU_PAGE_FIRST_CHUNK > > + select SET_FS > This looks wrong - looks like some merge went wrong here. Fixed now. > > Other than the above the sparc32 changes looks fine, and with the Kconf > stuff fixed: > Acked-by: Sam Ravnborg # for sparc32 changes Thanks! Arnd ___ linux-snps-arc mailing list linux-snps-arc@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-snps-arc
Re: [PATCH v2 18/18] uaccess: drop maining CONFIG_SET_FS users
Hi Arnd,
Fix spelling in $subject...
sparc/Kconfig b/arch/sparc/Kconfig
> index 9f6f9bce5292..9276f321b3e3 100644
> --- a/arch/sparc/Kconfig
> +++ b/arch/sparc/Kconfig
> @@ -46,7 +46,6 @@ config SPARC
> select LOCKDEP_SMALL if LOCKDEP
> select NEED_DMA_MAP_STATE
> select NEED_SG_DMA_LENGTH
> - select SET_FS
> select TRACE_IRQFLAGS_SUPPORT
>
> config SPARC32
> @@ -101,6 +100,7 @@ config SPARC64
> select HAVE_SETUP_PER_CPU_AREA
> select NEED_PER_CPU_EMBED_FIRST_CHUNK
> select NEED_PER_CPU_PAGE_FIRST_CHUNK
> + select SET_FS
This looks wrong - looks like some merge went wrong here.
>
> config ARCH_PROC_KCORE_TEXT
> def_bool y
> diff --git a/arch/sparc/include/asm/processor_32.h
> b/arch/sparc/include/asm/processor_32.h
> index 647bf0ac7beb..b26c35336b51 100644
> --- a/arch/sparc/include/asm/processor_32.h
> +++ b/arch/sparc/include/asm/processor_32.h
> @@ -32,10 +32,6 @@ struct fpq {
> };
> #endif
>
> -typedef struct {
> - int seg;
> -} mm_segment_t;
> -
> /* The Sparc processor specific thread struct. */
> struct thread_struct {
> struct pt_regs *kregs;
> @@ -50,11 +46,9 @@ struct thread_struct {
> unsigned long fsr;
> unsigned long fpqdepth;
> struct fpq fpqueue[16];
> - mm_segment_t current_ds;
> };
>
> #define INIT_THREAD { \
> - .current_ds = KERNEL_DS, \
> .kregs = (struct pt_regs *)(init_stack+THREAD_SIZE)-1 \
> }
>
> diff --git a/arch/sparc/include/asm/uaccess_32.h
> b/arch/sparc/include/asm/uaccess_32.h
> index 367747116260..9fd6c53644b6 100644
> --- a/arch/sparc/include/asm/uaccess_32.h
> +++ b/arch/sparc/include/asm/uaccess_32.h
> @@ -12,19 +12,6 @@
> #include
>
> #include
> -
> -/* Sparc is not segmented, however we need to be able to fool access_ok()
> - * when doing system calls from kernel mode legitimately.
> - *
> - * "For historical reasons, these macros are grossly misnamed." -Linus
> - */
> -
> -#define KERNEL_DS ((mm_segment_t) { 0 })
> -#define USER_DS ((mm_segment_t) { -1 })
> -
> -#define get_fs() (current->thread.current_ds)
> -#define set_fs(val) ((current->thread.current_ds) = (val))
> -
> #include
>
> /* Uh, these should become the main single-value transfer routines..
> diff --git a/arch/sparc/kernel/process_32.c b/arch/sparc/kernel/process_32.c
> index 2dc0bf9fe62e..88c0c14aaff0 100644
> --- a/arch/sparc/kernel/process_32.c
> +++ b/arch/sparc/kernel/process_32.c
> @@ -300,7 +300,6 @@ int copy_thread(unsigned long clone_flags, unsigned long
> sp, unsigned long arg,
> extern int nwindows;
> unsigned long psr;
> memset(new_stack, 0, STACKFRAME_SZ + TRACEREG_SZ);
> - p->thread.current_ds = KERNEL_DS;
> ti->kpc = (((unsigned long) ret_from_kernel_thread) - 0x8);
> childregs->u_regs[UREG_G1] = sp; /* function */
> childregs->u_regs[UREG_G2] = arg;
> @@ -311,7 +310,6 @@ int copy_thread(unsigned long clone_flags, unsigned long
> sp, unsigned long arg,
> }
> memcpy(new_stack, (char *)regs - STACKFRAME_SZ, STACKFRAME_SZ +
> TRACEREG_SZ);
> childregs->u_regs[UREG_FP] = sp;
> - p->thread.current_ds = USER_DS;
> ti->kpc = (((unsigned long) ret_from_fork) - 0x8);
> ti->kpsr = current->thread.fork_kpsr | PSR_PIL;
> ti->kwim = current->thread.fork_kwim;
Other than the above the sparc32 changes looks fine, and with the Kconf
stuff fixed:
Acked-by: Sam Ravnborg # for sparc32 changes
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[PATCH v2 18/18] uaccess: drop maining CONFIG_SET_FS users
From: Arnd Bergmann There are no remaining callers of set_fs(), so CONFIG_SET_FS can be removed globally, along with the thread_info field and any references to it. This turns access_ok() into a cheaper check against TASK_SIZE_MAX. With CONFIG_SET_FS gone, so drop all remaining references to set_fs()/get_fs(), mm_segment_t and uaccess_kernel(). Signed-off-by: Arnd Bergmann --- arch/Kconfig | 3 - arch/alpha/Kconfig| 1 - arch/alpha/include/asm/processor.h| 4 -- arch/alpha/include/asm/thread_info.h | 2 - arch/alpha/include/asm/uaccess.h | 19 -- 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| 1 - arch/arm/lib/uaccess_with_memcpy.c| 10 arch/csky/Kconfig | 1 - arch/csky/include/asm/processor.h | 2 - arch/csky/include/asm/segment.h | 10 arch/csky/include/asm/thread_info.h | 2 - arch/csky/include/asm/uaccess.h | 3 - arch/csky/kernel/asm-offsets.c| 1 - arch/h8300/Kconfig| 1 - arch/h8300/include/asm/processor.h| 1 - arch/h8300/include/asm/segment.h | 40 - arch/h8300/include/asm/thread_info.h | 3 - arch/h8300/kernel/entry.S | 1 - arch/h8300/kernel/head_ram.S | 1 - arch/h8300/mm/init.c | 6 -- arch/h8300/mm/memory.c| 1 - arch/hexagon/Kconfig | 1 - arch/hexagon/include/asm/thread_info.h| 6 -- arch/hexagon/kernel/process.c | 1 - arch/microblaze/Kconfig | 1 - arch/microblaze/include/asm/thread_info.h | 6 -- arch/microblaze/include/asm/uaccess.h | 24 arch/microblaze/kernel/asm-offsets.c | 1 - arch/microblaze/kernel/process.c | 1 - arch/nds32/Kconfig| 1 - arch/nds32/include/asm/thread_info.h | 4 -- arch/nds32/include/asm/uaccess.h | 15 + arch/nds32/kernel/process.c | 5 +- arch/nds32/mm/alignment.c | 3 - arch/nios2/Kconfig| 1 - arch/nios2/include/asm/thread_info.h | 9 --- arch/nios2/include/asm/uaccess.h | 12 arch/openrisc/Kconfig | 1 - arch/openrisc/include/asm/thread_info.h | 7 --- arch/openrisc/include/asm/uaccess.h | 23 arch/parisc/include/asm/futex.h | 6 -- arch/parisc/lib/memcpy.c | 2 +- arch/sparc/Kconfig| 2 +- arch/sparc/include/asm/processor_32.h | 6 -- arch/sparc/include/asm/uaccess_32.h | 13 - arch/sparc/kernel/process_32.c| 2 - arch/xtensa/Kconfig | 1 - arch/xtensa/include/asm/asm-uaccess.h | 71 --- arch/xtensa/include/asm/processor.h | 7 --- arch/xtensa/include/asm/thread_info.h | 3 - arch/xtensa/include/asm/uaccess.h | 16 - arch/xtensa/kernel/asm-offsets.c | 3 - drivers/hid/uhid.c| 2 +- drivers/scsi/sg.c | 5 -- fs/exec.c | 6 -- include/asm-generic/access_ok.h | 10 +--- include/asm-generic/uaccess.h | 25 +--- include/linux/syscalls.h | 4 -- include/linux/uaccess.h | 33 --- include/rdma/ib.h | 2 +- kernel/events/callchain.c | 4 -- kernel/events/core.c | 3 - kernel/exit.c | 14 - kernel/kthread.c | 5 -- kernel/stacktrace.c | 3 - kernel/trace/bpf_trace.c | 4 -- mm/maccess.c | 11 mm/memory.c | 8 --- net/bpfilter/bpfilter_kern.c | 2 +- 72 files changed, 10 insertions(+), 522 deletions(-) delete mode 100644 arch/arc/include/asm/segment.h delete mode 100644 arch/csky/include/asm/segment.h delete mode 100644 arch/h8300/include/asm/segment.h diff --git a/arch/Kconfig b/arch/Kconfig index fa5db36bda67..99349547afed 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -24,9 +24,6 @@ config KEXEC_ELF config HAVE_IMA_KEXEC bool -config SET_FS - bool - config HOTPLUG_SMT bool diff --git a/arch/alpha/Kconfig b/arch/alpha/Kconfig index 4e87783c90ad..eee8b5b0a58b 100644 --- a/arch/alpha/Kconfig +++ b/arch/alpha/Kconfig @@ -35,7 +35,6 @@ config ALPHA select OLD_SIGSUSPEND select CPU_NO_EFFICIENT_FFS if !ALPHA_EV67 select MMU_GATHER_NO_RANGE - select SET_FS select SPARSEMEM_EXTREME if SPARSEMEM select ZONE_DMA help diff --git
