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MIPS: uaccess: Take EVA into account in [__]clear_user 

__clear_user() (and clear_user() which uses it), always access the user
mode address space, which results in EVA store instructions when EVA is
enabled even if the current user address limit is KERNEL_DS.

Fix this by adding a new symbol __bzero_kernel for the normal kernel
address space bzero in EVA mode, and call that from __clear_user() if
eva_kernel_access().

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Markos Chandras <markos.chandras@imgtec.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Leonid Yegoshin <leonid.yegoshin@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/10844/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This commit is contained in:
James Hogan 2015-08-05 16:41:39 +01:00 committed by Ralf Baechle
parent 6f06a2c45d
commit d6a428fb58
3 changed files with 26 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

32
arch/mips/include/asm/uaccess.h
View File

@ -1235,16 +1235,28 @@ __clear_user(void __user *addr, __kernel_size_t size)
{
__kernel_size_t res;
might_fault();
__asm__ __volatile__(
"move\t$4, %1\n\t"
"move\t$5, $0\n\t"
"move\t$6, %2\n\t"
__MODULE_JAL(__bzero)
"move\t%0, $6"
: "=r" (res)
: "r" (addr), "r" (size)
: "$4", "$5", "$6", __UA_t0, __UA_t1, "$31");
if (eva_kernel_access()) {
__asm__ __volatile__(
"move\t$4, %1\n\t"
"move\t$5, $0\n\t"
"move\t$6, %2\n\t"
__MODULE_JAL(__bzero_kernel)
"move\t%0, $6"
: "=r" (res)
: "r" (addr), "r" (size)
: "$4", "$5", "$6", __UA_t0, __UA_t1, "$31");
} else {
might_fault();
__asm__ __volatile__(
"move\t$4, %1\n\t"
"move\t$5, $0\n\t"
"move\t$6, %2\n\t"
__MODULE_JAL(__bzero)
"move\t%0, $6"
: "=r" (res)
: "r" (addr), "r" (size)
: "$4", "$5", "$6", __UA_t0, __UA_t1, "$31");
}
return res;
}

2
arch/mips/kernel/mips_ksyms.c
View File

@ -17,6 +17,7 @@
#include <asm/fpu.h>
#include <asm/msa.h>
extern void *__bzero_kernel(void *__s, size_t __count);
extern void *__bzero(void *__s, size_t __count);
extern long __strncpy_from_kernel_nocheck_asm(char *__to,
const char *__from, long __len);
@ -64,6 +65,7 @@ EXPORT_SYMBOL(__copy_from_user_eva);
EXPORT_SYMBOL(__copy_in_user_eva);
EXPORT_SYMBOL(__copy_to_user_eva);
EXPORT_SYMBOL(__copy_user_inatomic_eva);
EXPORT_SYMBOL(__bzero_kernel);
#endif
EXPORT_SYMBOL(__bzero);
EXPORT_SYMBOL(__strncpy_from_kernel_nocheck_asm);

2
arch/mips/lib/memset.S
View File

@ -283,6 +283,8 @@ LEAF(memset)
1:
#ifndef CONFIG_EVA
FEXPORT(__bzero)
#else
FEXPORT(__bzero_kernel)
#endif
__BUILD_BZERO LEGACY_MODE