Messages in this thread |  | | Date | Tue, 08 Sep 2020 21:59:28 -0700 (PDT) | Subject | Re: [PATCH 8/8] riscv: remove address space overrides using set_fs() | From | Palmer Dabbelt <> |
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On Sun, 06 Sep 2020 22:58:25 PDT (-0700), Christoph Hellwig wrote: > Stop providing the possibility to override the address space using > set_fs() now that there is no need for that any more. > > Signed-off-by: Christoph Hellwig <hch@lst.de> > --- > arch/riscv/Kconfig | 1 - > arch/riscv/include/asm/thread_info.h | 6 ------ > arch/riscv/include/asm/uaccess.h | 27 +-------------------------- > arch/riscv/kernel/process.c | 1 - > 4 files changed, 1 insertion(+), 34 deletions(-) > > diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig > index 460e3971a80fde..33dde87218ddab 100644 > --- a/arch/riscv/Kconfig > +++ b/arch/riscv/Kconfig > @@ -86,7 +86,6 @@ config RISCV > select SPARSE_IRQ > select SYSCTL_EXCEPTION_TRACE > select THREAD_INFO_IN_TASK > - select SET_FS > select UACCESS_MEMCPY if !MMU > > config ARCH_MMAP_RND_BITS_MIN > diff --git a/arch/riscv/include/asm/thread_info.h b/arch/riscv/include/asm/thread_info.h > index 464a2bbc97ea33..a390711129de64 100644 > --- a/arch/riscv/include/asm/thread_info.h > +++ b/arch/riscv/include/asm/thread_info.h > @@ -24,10 +24,6 @@ > #include <asm/processor.h> > #include <asm/csr.h> > > -typedef struct { > - unsigned long seg; > -} mm_segment_t; > - > /* > * low level task data that entry.S needs immediate access to > * - this struct should fit entirely inside of one cache line > @@ -39,7 +35,6 @@ typedef struct { > struct thread_info { > unsigned long flags; /* low level flags */ > int preempt_count; /* 0=>preemptible, <0=>BUG */ > - mm_segment_t addr_limit; > /* > * These stack pointers are overwritten on every system call or > * exception. SP is also saved to the stack it can be recovered when > @@ -59,7 +54,6 @@ struct thread_info { > { \ > .flags = 0, \ > .preempt_count = INIT_PREEMPT_COUNT, \ > - .addr_limit = KERNEL_DS, \ > } > > #endif /* !__ASSEMBLY__ */ > diff --git a/arch/riscv/include/asm/uaccess.h b/arch/riscv/include/asm/uaccess.h > index 264e52fb62b143..c47e6b35c551f4 100644 > --- a/arch/riscv/include/asm/uaccess.h > +++ b/arch/riscv/include/asm/uaccess.h > @@ -26,29 +26,6 @@ > #define __disable_user_access() \ > __asm__ __volatile__ ("csrc sstatus, %0" : : "r" (SR_SUM) : "memory") > > -/* > - * 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 MAKE_MM_SEG(s) ((mm_segment_t) { (s) }) > - > -#define KERNEL_DS MAKE_MM_SEG(~0UL) > -#define USER_DS MAKE_MM_SEG(TASK_SIZE) > - > -#define get_fs() (current_thread_info()->addr_limit) > - > -static inline void set_fs(mm_segment_t fs) > -{ > - current_thread_info()->addr_limit = fs; > -} > - > -#define uaccess_kernel() (get_fs().seg == KERNEL_DS.seg) > -#define user_addr_max() (get_fs().seg) > - > /** > * access_ok: - Checks if a user space pointer is valid > * @addr: User space pointer to start of block to check > @@ -76,9 +53,7 @@ static inline void set_fs(mm_segment_t fs) > */ > static inline int __access_ok(unsigned long addr, unsigned long size) > { > - const mm_segment_t fs = get_fs(); > - > - return size <= fs.seg && addr <= fs.seg - size; > + return size <= TASK_SIZE && addr <= TASK_SIZE - size; > } > > /* > diff --git a/arch/riscv/kernel/process.c b/arch/riscv/kernel/process.c > index 2b97c493427c9e..19225ec65db62f 100644 > --- a/arch/riscv/kernel/process.c > +++ b/arch/riscv/kernel/process.c > @@ -84,7 +84,6 @@ void start_thread(struct pt_regs *regs, unsigned long pc, > } > regs->epc = pc; > regs->sp = sp; > - set_fs(USER_DS); > } > > void flush_thread(void)
Reviewed-by: Palmer Dabbelt <palmerdabbelt@google.com> Acked-by: Palmer Dabbelt <palmerdabbelt@google.com>
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