xtensa: fix access to THREAD_RA/THREAD_SP/THREAD_DS

commit 52247123749cc3cbc30168b33ad8c69515c96d23 upstream.

With SMP and a lot of debug options enabled task_struct::thread gets out
of reach of s32i/l32i instructions with base pointing at task_struct,
breaking build with the following messages:

  arch/xtensa/kernel/entry.S: Assembler messages:
  arch/xtensa/kernel/entry.S:1002: Error: operand 3 of 'l32i.n' has invalid value '1048'
  arch/xtensa/kernel/entry.S:1831: Error: operand 3 of 's32i.n' has invalid value '1040'
  arch/xtensa/kernel/entry.S:1832: Error: operand 3 of 's32i.n' has invalid value '1044'

Change base to point to task_struct::thread in such cases.
Don't use a10 in _switch_to to save/restore prev pointer as a2 is not
clobbered.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/xtensa/include/asm/uaccess.h b/arch/xtensa/include/asm/uaccess.h
index fd686dc..c7211e7 100644 (file)
--- a/arch/xtensa/include/asm/uaccess.h
+++ b/arch/xtensa/include/asm/uaccess.h
@@ -52,7 +52,12 @@
  */
        .macro  get_fs  ad, sp
        GET_CURRENT(\ad,\sp)
+#if THREAD_CURRENT_DS > 1020
+       addi    \ad, \ad, TASK_THREAD
+       l32i    \ad, \ad, THREAD_CURRENT_DS - TASK_THREAD
+#else
        l32i    \ad, \ad, THREAD_CURRENT_DS
+#endif
        .endm
 
 /*

diff --git a/arch/xtensa/kernel/entry.S b/arch/xtensa/kernel/entry.S
index ef7f499..db96acb 100644 (file)
--- a/arch/xtensa/kernel/entry.S
+++ b/arch/xtensa/kernel/entry.S
@@ -1820,7 +1820,6 @@ ENTRY(_switch_to)
 
        entry   a1, 16
 
-       mov     a10, a2                 # preserve 'prev' (a2)
        mov     a11, a3                 # and 'next' (a3)
 
        l32i    a4, a2, TASK_THREAD_INFO
@@ -1828,8 +1827,14 @@ ENTRY(_switch_to)
 
        save_xtregs_user a4 a6 a8 a9 a12 a13 THREAD_XTREGS_USER
 
-       s32i    a0, a10, THREAD_RA      # save return address
-       s32i    a1, a10, THREAD_SP      # save stack pointer
+#if THREAD_RA > 1020 || THREAD_SP > 1020
+       addi    a10, a2, TASK_THREAD
+       s32i    a0, a10, THREAD_RA - TASK_THREAD        # save return address
+       s32i    a1, a10, THREAD_SP - TASK_THREAD        # save stack pointer
+#else
+       s32i    a0, a2, THREAD_RA       # save return address
+       s32i    a1, a2, THREAD_SP       # save stack pointer
+#endif
 
        /* Disable ints while we manipulate the stack pointer. */
 
@@ -1870,7 +1875,6 @@ ENTRY(_switch_to)
        load_xtregs_user a5 a6 a8 a9 a12 a13 THREAD_XTREGS_USER
 
        wsr     a14, ps
-       mov     a2, a10                 # return 'prev'
        rsync
 
        retw