commit d6a428fb583738ad685c91a684748cdee7b2a05f upstream. __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@xxxxxxxxxx> Cc: Markos Chandras <markos.chandras@xxxxxxxxxx> Cc: Paul Burton <paul.burton@xxxxxxxxxx> Cc: Leonid Yegoshin <leonid.yegoshin@xxxxxxxxxx> Cc: linux-mips@xxxxxxxxxxxxxx Patchwork: https://patchwork.linux-mips.org/patch/10844/ Signed-off-by: Ralf Baechle <ralf@xxxxxxxxxxxxxx> [james.hogan@xxxxxxxxxx: backport] Signed-off-by: James Hogan <james.hogan@xxxxxxxxxx> --- arch/mips/include/asm/uaccess.h | 32 ++++++++++++++++++++++---------- arch/mips/kernel/mips_ksyms.c | 2 ++ arch/mips/lib/memset.S | 2 ++ 3 files changed, 26 insertions(+), 10 deletions(-) diff --git a/arch/mips/include/asm/uaccess.h b/arch/mips/include/asm/uaccess.h index d8f7394275af..2d4118499519 100644 --- a/arch/mips/include/asm/uaccess.h +++ b/arch/mips/include/asm/uaccess.h @@ -1207,16 +1207,28 @@ __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 (config_enabled(CONFIG_EVA) && segment_eq(get_fs(), get_ds())) { + __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; } diff --git a/arch/mips/kernel/mips_ksyms.c b/arch/mips/kernel/mips_ksyms.c index 291af0b5c482..e2b6ab74643d 100644 --- a/arch/mips/kernel/mips_ksyms.c +++ b/arch/mips/kernel/mips_ksyms.c @@ -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); diff --git a/arch/mips/lib/memset.S b/arch/mips/lib/memset.S index b8e63fd00375..8f0019a2e5c8 100644 --- a/arch/mips/lib/memset.S +++ b/arch/mips/lib/memset.S @@ -283,6 +283,8 @@ LEAF(memset) 1: #ifndef CONFIG_EVA FEXPORT(__bzero) +#else +FEXPORT(__bzero_kernel) #endif __BUILD_BZERO LEGACY_MODE -- 2.4.10
