Commit ebcbd75e authored by Alan Kao's avatar Alan Kao Committed by Palmer Dabbelt

riscv: Fix the bug in memory access fixup code

A piece of fixup code is currently shared by __copy_user and
__clear_user.  It first disables the access to user-space memory
and then returns the "n" argument, which represents #(bytes not processed).
However,__copy_user's "n" is in register a2, while __clear_user's in a1,
and thus it causes errors for programs like setdomainname02 testcase in LTP.

This patch fixes this issue by separating their fixup code and returning
the right value for the kernel to handle a relative fault properly.
Signed-off-by: default avatarAlan Kao <alankao@andestech.com>
Cc: Greentime Hu <greentime@andestech.com>
Cc: Zong Li <zong@andestech.com>
Cc: Vincent Chen <vincentc@andestech.com>
Signed-off-by: default avatarPalmer Dabbelt <palmer@sifive.com>
parent 29dcea88
...@@ -84,7 +84,7 @@ ENTRY(__clear_user) ...@@ -84,7 +84,7 @@ ENTRY(__clear_user)
bgeu t0, t1, 2f bgeu t0, t1, 2f
bltu a0, t0, 4f bltu a0, t0, 4f
1: 1:
fixup REG_S, zero, (a0), 10f fixup REG_S, zero, (a0), 11f
addi a0, a0, SZREG addi a0, a0, SZREG
bltu a0, t1, 1b bltu a0, t1, 1b
2: 2:
...@@ -96,12 +96,12 @@ ENTRY(__clear_user) ...@@ -96,12 +96,12 @@ ENTRY(__clear_user)
li a0, 0 li a0, 0
ret ret
4: /* Edge case: unalignment */ 4: /* Edge case: unalignment */
fixup sb, zero, (a0), 10f fixup sb, zero, (a0), 11f
addi a0, a0, 1 addi a0, a0, 1
bltu a0, t0, 4b bltu a0, t0, 4b
j 1b j 1b
5: /* Edge case: remainder */ 5: /* Edge case: remainder */
fixup sb, zero, (a0), 10f fixup sb, zero, (a0), 11f
addi a0, a0, 1 addi a0, a0, 1
bltu a0, a3, 5b bltu a0, a3, 5b
j 3b j 3b
...@@ -109,9 +109,14 @@ ENDPROC(__clear_user) ...@@ -109,9 +109,14 @@ ENDPROC(__clear_user)
.section .fixup,"ax" .section .fixup,"ax"
.balign 4 .balign 4
/* Fixup code for __copy_user(10) and __clear_user(11) */
10: 10:
/* Disable access to user memory */ /* Disable access to user memory */
csrs sstatus, t6 csrs sstatus, t6
sub a0, a3, a0 mv a0, a2
ret
11:
csrs sstatus, t6
mv a0, a1
ret ret
.previous .previous
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment