sparc64: Fix probe_kernel_{read,write}().

This is based upon a report from Chris Torek and his initial patch.
From Chris's report:

--------------------
This came up in testing kgdb, using the built-in tests -- turn
on CONFIG_KGDB_TESTS, then

    echo V1 > /sys/module/kgdbts/parameters/kgdbts

-- but it would affect using kgdb if you were debugging and looking
at bad pointers.
--------------------

When we get a copy_{from,to}_user() request and the %asi is set to
something other than ASI_AIUS (which is userspace) then we branch off
to a routine called memcpy_user_stub().  It just does a straight
memcpy since we are copying from kernel to kernel in this case.

The logic was that since source and destination are both kernel
pointers we don't need to have exception checks.

But for what probe_kernel_{read,write}() is trying to do, we have to
have the checks, otherwise things like kgdb bad kernel pointer
accesses don't do the right thing.

Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/arch/sparc/lib/GENcopy_from_user.S b/arch/sparc/lib/GENcopy_from_user.S
index 9b0e58f9f970c6f4964913c008020dda19bb8461..b7d0bd6b14063bc1e62cfed3c0e32f0b43799396 100644 (file)
--- a/arch/sparc/lib/GENcopy_from_user.S
+++ b/arch/sparc/lib/GENcopy_from_user.S
@@ -23,7 +23,7 @@
 #define PREAMBLE                                       \
        rd              %asi, %g1;                      \
        cmp             %g1, ASI_AIUS;                  \
-       bne,pn          %icc, memcpy_user_stub;         \
+       bne,pn          %icc, ___copy_in_user;          \
         nop
 #endif
 

diff --git a/arch/sparc/lib/GENcopy_to_user.S b/arch/sparc/lib/GENcopy_to_user.S
index ce79b495c65d0273e6e07f794c6ecf0da4d81276..780550e1afc74fd6efe38ef16f73a07ea021a8f2 100644 (file)
--- a/arch/sparc/lib/GENcopy_to_user.S
+++ b/arch/sparc/lib/GENcopy_to_user.S
@@ -27,7 +27,7 @@
 #define PREAMBLE                                       \
        rd              %asi, %g1;                      \
        cmp             %g1, ASI_AIUS;                  \
-       bne,pn          %icc, memcpy_user_stub;         \
+       bne,pn          %icc, ___copy_in_user;          \
         nop
 #endif
 

diff --git a/arch/sparc/lib/NG2copy_from_user.S b/arch/sparc/lib/NG2copy_from_user.S
index 01ac546a86f4f5d620383f4741bcddbdac86f2d5..119ccb9a54f49e2ac2724650060eb7a1d70e8d9e 100644 (file)
--- a/arch/sparc/lib/NG2copy_from_user.S
+++ b/arch/sparc/lib/NG2copy_from_user.S
@@ -28,7 +28,7 @@
 #define PREAMBLE                                       \
        rd              %asi, %g1;                      \
        cmp             %g1, ASI_AIUS;                  \
-       bne,pn          %icc, memcpy_user_stub;         \
+       bne,pn          %icc, ___copy_in_user;          \
         nop
 #endif
 

diff --git a/arch/sparc/lib/NG2copy_to_user.S b/arch/sparc/lib/NG2copy_to_user.S
index c477e1594a72efc7c70131c46b61baf64ee8a57b..7fe1ccefd9d056a104407c8d1595095c7fc5add8 100644 (file)
--- a/arch/sparc/lib/NG2copy_to_user.S
+++ b/arch/sparc/lib/NG2copy_to_user.S
@@ -37,7 +37,7 @@
 #define PREAMBLE                                       \
        rd              %asi, %g1;                      \
        cmp             %g1, ASI_AIUS;                  \
-       bne,pn          %icc, memcpy_user_stub;         \
+       bne,pn          %icc, ___copy_in_user;          \
         nop
 #endif
 

diff --git a/arch/sparc/lib/NGcopy_from_user.S b/arch/sparc/lib/NGcopy_from_user.S
index 39bb8912c6e7d5d4eeaf4d3de76cc0341202e1fe..5d1e4d1ac21edf09a664663dc005e1fcae805b6a 100644 (file)
--- a/arch/sparc/lib/NGcopy_from_user.S
+++ b/arch/sparc/lib/NGcopy_from_user.S
@@ -25,7 +25,7 @@
 #define PREAMBLE                                       \
        rd              %asi, %g1;                      \
        cmp             %g1, ASI_AIUS;                  \
-       bne,pn          %icc, memcpy_user_stub;         \
+       bne,pn          %icc, ___copy_in_user;          \
         nop
 #endif
 

diff --git a/arch/sparc/lib/NGcopy_to_user.S b/arch/sparc/lib/NGcopy_to_user.S
index bf62fc1a26c72e92e0437272e8edd714bdb51e72..ff630dcb273c9649de6fc9e145fce42e72667787 100644 (file)
--- a/arch/sparc/lib/NGcopy_to_user.S
+++ b/arch/sparc/lib/NGcopy_to_user.S
@@ -28,7 +28,7 @@
 #define PREAMBLE                                       \
        rd              %asi, %g1;                      \
        cmp             %g1, ASI_AIUS;                  \
-       bne,pn          %icc, memcpy_user_stub;         \
+       bne,pn          %icc, ___copy_in_user;          \
         nop
 #endif
 

diff --git a/arch/sparc/lib/U1copy_from_user.S b/arch/sparc/lib/U1copy_from_user.S
index f14efdd6d4a9371b91d18dbeb5f0a8b39fa8cef3..a6ae2ea04bf5dfbffda2884a6a46b051ae2ac2a8 100644 (file)
--- a/arch/sparc/lib/U1copy_from_user.S
+++ b/arch/sparc/lib/U1copy_from_user.S
@@ -23,7 +23,7 @@
 #define PREAMBLE                                       \
        rd              %asi, %g1;                      \
        cmp             %g1, ASI_AIUS;                  \
-       bne,pn          %icc, memcpy_user_stub;         \
+       bne,pn          %icc, ___copy_in_user;          \
         nop;                                           \
 
 #include "U1memcpy.S"

diff --git a/arch/sparc/lib/U1copy_to_user.S b/arch/sparc/lib/U1copy_to_user.S
index 59d531b4a1a5f5104e6b86d37b715ad42ba5a9e7..f4b970eeb485f838ce23dc5507a5bccd6defd348 100644 (file)
--- a/arch/sparc/lib/U1copy_to_user.S
+++ b/arch/sparc/lib/U1copy_to_user.S
@@ -23,7 +23,7 @@
 #define PREAMBLE                                       \
        rd              %asi, %g1;                      \
        cmp             %g1, ASI_AIUS;                  \
-       bne,pn          %icc, memcpy_user_stub;         \
+       bne,pn          %icc, ___copy_in_user;          \
         nop;                                           \
 
 #include "U1memcpy.S"

diff --git a/arch/sparc/lib/U3copy_to_user.S b/arch/sparc/lib/U3copy_to_user.S
index b4cbfe5a97bafdee42c4dc0c9ce6dcde57ab8b04..ef1e493afdfa900a1b32863c2bf2995560cbe0cd 100644 (file)
--- a/arch/sparc/lib/U3copy_to_user.S
+++ b/arch/sparc/lib/U3copy_to_user.S
@@ -23,7 +23,7 @@
 #define PREAMBLE                                       \
        rd              %asi, %g1;                      \
        cmp             %g1, ASI_AIUS;                  \
-       bne,pn          %icc, memcpy_user_stub;         \
+       bne,pn          %icc, ___copy_in_user;          \
         nop;                                           \
 
 #include "U3memcpy.S"

diff --git a/arch/sparc/lib/copy_in_user.S b/arch/sparc/lib/copy_in_user.S
index 884f46499d4e03b6957399dc99397ee698634bef..302c0e60dc2ceb48a3212840ac7891f337419d14 100644 (file)
--- a/arch/sparc/lib/copy_in_user.S
+++ b/arch/sparc/lib/copy_in_user.S
@@ -3,6 +3,7 @@
  * Copyright (C) 1999, 2000, 2004 David S. Miller (davem@redhat.com)
  */
 
+#include <linux/linkage.h>
 #include <asm/asi.h>
 
 #define XCC xcc
@@ -27,18 +28,7 @@
         * to copy register windows around during thread cloning.
         */
 
-       .globl          ___copy_in_user
-       .type           ___copy_in_user,#function
-___copy_in_user:       /* %o0=dst, %o1=src, %o2=len */
-       /* Writing to %asi is _expensive_ so we hardcode it.
-        * Reading %asi to check for KERNEL_DS is comparatively
-        * cheap.
-        */
-       rd              %asi, %g1
-       cmp             %g1, ASI_AIUS
-       bne,pn          %icc, memcpy_user_stub
-        nop
-
+ENTRY(___copy_in_user) /* %o0=dst, %o1=src, %o2=len */
        cmp             %o2, 0
        be,pn           %XCC, 85f
         or             %o0, %o1, %o3
@@ -49,22 +39,24 @@ ___copy_in_user:    /* %o0=dst, %o1=src, %o2=len */
        /* 16 < len <= 64 */
        andcc           %o3, 0x7, %g0
        bne,pn          %XCC, 90f
-        sub            %o0, %o1, %o3
+        nop
 
        andn            %o2, 0x7, %o4
        and             %o2, 0x7, %o2
 1:     subcc           %o4, 0x8, %o4
        EX(ldxa [%o1] %asi, %o5)
-       EX(stxa %o5, [%o1 + %o3] ASI_AIUS)
+       EX(stxa %o5, [%o0] %asi)
+       add             %o1, 0x8, %o1
        bgu,pt          %XCC, 1b
-        add            %o1, 0x8, %o1
+        add            %o0, 0x8, %o0
        andcc           %o2, 0x4, %g0
        be,pt           %XCC, 1f
         nop
        sub             %o2, 0x4, %o2
        EX(lduwa [%o1] %asi, %o5)
-       EX(stwa %o5, [%o1 + %o3] ASI_AIUS)
+       EX(stwa %o5, [%o0] %asi)
        add             %o1, 0x4, %o1
+       add             %o0, 0x4, %o0
 1:     cmp             %o2, 0
        be,pt           %XCC, 85f
         nop
@@ -74,14 +66,15 @@ ___copy_in_user:    /* %o0=dst, %o1=src, %o2=len */
 80:    /* 0 < len <= 16 */
        andcc           %o3, 0x3, %g0
        bne,pn          %XCC, 90f
-        sub            %o0, %o1, %o3
+        nop
 
 82:
        subcc           %o2, 4, %o2
        EX(lduwa [%o1] %asi, %g1)
-       EX(stwa %g1, [%o1 + %o3] ASI_AIUS)
+       EX(stwa %g1, [%o0] %asi)
+       add             %o1, 4, %o1
        bgu,pt          %XCC, 82b
-        add            %o1, 4, %o1
+        add            %o0, 4, %o0
 
 85:    retl
         clr            %o0
@@ -90,26 +83,10 @@ ___copy_in_user:    /* %o0=dst, %o1=src, %o2=len */
 90:
        subcc           %o2, 1, %o2
        EX(lduba [%o1] %asi, %g1)
-       EX(stba %g1, [%o1 + %o3] ASI_AIUS)
+       EX(stba %g1, [%o0] %asi)
+       add             %o1, 1, %o1
        bgu,pt          %XCC, 90b
-        add            %o1, 1, %o1
+        add            %o0, 1, %o0
        retl
         clr            %o0
-
-       .size           ___copy_in_user, .-___copy_in_user
-
-       /* Act like copy_{to,in}_user(), ie. return zero instead
-        * of original destination pointer.  This is invoked when
-        * copy_{to,in}_user() finds that %asi is kernel space.
-        */
-       .globl          memcpy_user_stub
-       .type           memcpy_user_stub,#function
-memcpy_user_stub:
-       save            %sp, -192, %sp
-       mov             %i0, %o0
-       mov             %i1, %o1
-       call            memcpy
-        mov            %i2, %o2
-       ret
-        restore        %g0, %g0, %o0
-       .size           memcpy_user_stub, .-memcpy_user_stub
+ENDPROC(___copy_in_user)