This patch fixes issue of reading and writing V8 sys registers in BE case. It is similar to V7 "ARM: kvm one_reg coproc set and get BE fixes" patch.
It changes reg_from_user and reg_to_user functions to have strong typed 'u64 *val' argument. And it uses endian angnostic way to pick up righ word from '*val' in case when register size is 4 bytes.
Signed-off-by: Victor Kamensky victor.kamensky@linaro.org --- arch/arm64/kvm/sys_regs.c | 39 +++++++++++++++++++++++++++++++++------ 1 file changed, 33 insertions(+), 6 deletions(-)
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c index 02e9d09..e7c3e24 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -701,18 +701,45 @@ static struct sys_reg_desc invariant_sys_regs[] = { NULL, get_ctr_el0 }, };
-static int reg_from_user(void *val, const void __user *uaddr, u64 id) +static int reg_from_user(u64 *val, const void __user *uaddr, u64 id) { - /* This Just Works because we are little endian. */ - if (copy_from_user(val, uaddr, KVM_REG_SIZE(id)) != 0) + unsigned long regsize = KVM_REG_SIZE(id); + union { + u32 word; + u64 dword; + } tmp = {0}; + + if (copy_from_user(&tmp, uaddr, regsize) != 0) return -EFAULT; + switch (regsize) { + case 4: + *val = tmp.word; + break; + case 8: + *val = tmp.dword; + break; + } return 0; }
-static int reg_to_user(void __user *uaddr, const void *val, u64 id) +static int reg_to_user(void __user *uaddr, const u64 *val, u64 id) { - /* This Just Works because we are little endian. */ - if (copy_to_user(uaddr, val, KVM_REG_SIZE(id)) != 0) + unsigned long regsize = KVM_REG_SIZE(id); + union { + u32 word; + u64 dword; + } tmp; + + switch (regsize) { + case 4: + tmp.word = *val; + break; + case 8: + tmp.dword = *val; + break; + } + + if (copy_to_user(uaddr, &tmp, regsize) != 0) return -EFAULT; return 0; }