From aeb398768345c74a9e4c01aa3ebf839e858312ec Mon Sep 17 00:00:00 2001 From: "David S. Miller" Date: Sun, 8 Feb 2009 22:32:31 -0800 Subject: 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 --- arch/sparc/lib/GENcopy_from_user.S | 2 +- arch/sparc/lib/GENcopy_to_user.S | 2 +- arch/sparc/lib/NG2copy_from_user.S | 2 +- arch/sparc/lib/NG2copy_to_user.S | 2 +- arch/sparc/lib/NGcopy_from_user.S | 2 +- arch/sparc/lib/NGcopy_to_user.S | 2 +- arch/sparc/lib/U1copy_from_user.S | 2 +- arch/sparc/lib/U1copy_to_user.S | 2 +- arch/sparc/lib/U3copy_to_user.S | 2 +- arch/sparc/lib/copy_in_user.S | 55 +++++++++++--------------------------- 10 files changed, 25 insertions(+), 48 deletions(-) diff --git a/arch/sparc/lib/GENcopy_from_user.S b/arch/sparc/lib/GENcopy_from_user.S index 9b0e58f9f97..b7d0bd6b140 100644 --- 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 ce79b495c65..780550e1afc 100644 --- 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 01ac546a86f..119ccb9a54f 100644 --- 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 c477e1594a7..7fe1ccefd9d 100644 --- 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 39bb8912c6e..5d1e4d1ac21 100644 --- 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 bf62fc1a26c..ff630dcb273 100644 --- 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 f14efdd6d4a..a6ae2ea04bf 100644 --- 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 59d531b4a1a..f4b970eeb48 100644 --- 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 b4cbfe5a97b..ef1e493afdf 100644 --- 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 884f46499d4..302c0e60dc2 100644 --- 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 #include #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) -- cgit v1.2.3