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
-
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This archive was generated by hypermail 2b29 : Thu May 15 2003 - 22:00:30 EST