Messages in this thread | | | Subject | Re: [PATCH 10/10] powerpc: remove address space overrides using set_fs() | From | Christophe Leroy <> | Date | Wed, 2 Sep 2020 08:15:12 +0200 |
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Le 27/08/2020 à 17:00, Christoph Hellwig a écrit : > 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/powerpc/Kconfig | 1 - > arch/powerpc/include/asm/processor.h | 7 --- > arch/powerpc/include/asm/thread_info.h | 5 +-- > arch/powerpc/include/asm/uaccess.h | 62 ++++++++------------------ > arch/powerpc/kernel/signal.c | 3 -- > arch/powerpc/lib/sstep.c | 6 +-- > 6 files changed, 22 insertions(+), 62 deletions(-) > > diff --git a/arch/powerpc/include/asm/uaccess.h b/arch/powerpc/include/asm/uaccess.h > index 7fe3531ad36a77..39727537d39701 100644 > --- a/arch/powerpc/include/asm/uaccess.h > +++ b/arch/powerpc/include/asm/uaccess.h > @@ -8,62 +8,36 @@ > #include <asm/extable.h> > #include <asm/kup.h> > > -/* > - * 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. > - * > - * The fs/ds values are now the highest legal address in the "segment". > - * This simplifies the checking in the routines below. > - */ > - > -#define MAKE_MM_SEG(s) ((mm_segment_t) { (s) }) > - > -#define KERNEL_DS MAKE_MM_SEG(~0UL) > #ifdef __powerpc64__ > /* We use TASK_SIZE_USER64 as TASK_SIZE is not constant */ > -#define USER_DS MAKE_MM_SEG(TASK_SIZE_USER64 - 1) > -#else > -#define USER_DS MAKE_MM_SEG(TASK_SIZE - 1) > -#endif > - > -#define get_fs() (current->thread.addr_limit) > +#define TASK_SIZE_MAX TASK_SIZE_USER64 > > -static inline void set_fs(mm_segment_t fs) > +static inline bool __access_ok(unsigned long addr, unsigned long size) > { > - current->thread.addr_limit = fs; > - /* On user-mode return check addr_limit (fs) is correct */ > - set_thread_flag(TIF_FSCHECK); > + if (addr >= TASK_SIZE_MAX) > + return false; > + /* > + * This check is sufficient because there is a large enough gap between > + * user addresses and the kernel addresses. > + */ > + return size <= TASK_SIZE_MAX; > } > - > -#define uaccess_kernel() (get_fs().seg == KERNEL_DS.seg) > -#define user_addr_max() (get_fs().seg) > - > -#ifdef __powerpc64__ > -/* > - * This check is sufficient because there is a large enough > - * gap between user addresses and the kernel addresses > - */ > -#define __access_ok(addr, size, segment) \ > - (((addr) <= (segment).seg) && ((size) <= (segment).seg)) > - > #else > +#define TASK_SIZE_MAX TASK_SIZE > > -static inline int __access_ok(unsigned long addr, unsigned long size, > - mm_segment_t seg) > +static inline bool __access_ok(unsigned long addr, unsigned long size) > { > - if (addr > seg.seg) > - return 0; > - return (size == 0 || size - 1 <= seg.seg - addr); > + if (addr >= TASK_SIZE_MAX) > + return false; > + if (size == 0) > + return false;
__access_ok() was returning true when size == 0 up to now. Any reason to return false now ?
> + return size <= TASK_SIZE_MAX - addr; > } > - > -#endif > +#endif /* __powerpc64__ */ > > #define access_ok(addr, size) \ > (__chk_user_ptr(addr), \ > - __access_ok((__force unsigned long)(addr), (size), get_fs())) > + __access_ok((unsigned long)(addr), (size))) > > /* > * These are the main single-value transfer routines. They automatically
Christophe
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