Messages in this thread |  | | Date | Thu, 8 May 2003 21:31:19 -0700 | From | Andrew Morton <> | Subject | Re: [PATCH] i386 uaccess to fixmap pages |
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Roland McGrath <roland@redhat.com> wrote: > > This patch against 2.5.69 makes uaccess (i.e., access_ok and get/put_user) > to user-accessible fixmap addresses on x86 work.
This doesn't apply against Linus's current tree.
> -#define access_ok(type,addr,size) (__range_ok(addr,size) == 0) > +#define access_ok(type,addr,size) (__range_ok(addr,size) == 0 || \ > + __fixmap_access_ok((unsigned long)(addr), \ > + (size), (type)))
Your patch increases the kernel text by nearly 1%. That's rather a lot for what is a fairly esoteric feature.
text data bss dec hex filename 2805911 592912 732516 4131339 3f0a0b /tmp/vmlinux 2825167 592982 732516 4150665 3f5589 vmlinux
Would it be possible to avoid this by just taking the fault and fixing things up in the exception handler?
> #else > > -#define access_ok(type,addr,size) ( (__range_ok(addr,size) == 0) && \ > +#define access_ok(type,addr,size) ((__range_ok(addr,size) == 0) ? \ > ((type) == VERIFY_READ || boot_cpu_data.wp_works_ok || \ > - __verify_write((void *)(addr),(size)))) > + __verify_write((void *)(addr),(size))) : \ > + __fixmap_access_ok((unsigned long)(addr),size,type))
You'll be wanting to parenthesise `size' and `type' here.
For some reason the patch causes gcc-2.95.3 to choke over the
__put_user(d_off, &lastdirent->d_off);
statement in sys_getdents64().
fs/readdir.c: In function `sys_getdents64': fs/readdir.c:285: internal error--unrecognizable insn: (insn 138 212 147 (set (reg:SI 3 %ebx) (asm_operands/v ("1: movl %%eax,0(%2) 2: movl %%edx,4(%2) 3: .section .fixup,"ax" 4: movl %3,%0 jmp 3b .previous .section __ex_table,"a" .align 4 .long 1b,4b .long 2b,4b .previous") ("=r") 0[ (reg:DI 1 %edx) (reg:SI 0 %eax) (const_int -14 [0xfffffff2]) (reg:SI 3 %ebx) ] [ (asm_input:DI ("A")) (asm_input:SI ("r")) (asm_input:SI ("i")) (asm_input:SI ("0")) ] ("fs/readdir.c") 277)) -1 (insn_list 112 (insn_list 119 (insn_list 137 (nil)))) (nil)) make[1]: *** [fs/readdir.o] Error 1 make[1]: *** Waiting for unfinished jobs.... make: *** [fs] Error 2 - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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