Just began learning this piece of code. Thanks for correcting me.
On 12/22/2014 07:51 PM, Marc Zyngier wrote: > On 22/12/14 11:23, Peng Fan wrote: >> For arm 32 bit architecture, 8 bytes load/store operation in one instruction >> will not be generated by compiler. > > Ever heard of lrdr/strd? > >> And before invoke mmio_read_buf, there is a piece of code: >> " >> len = run->mmio.len; >> if (len > sizeof(unsigned long)) >> return -EINVAL; >> >> data = mmio_read_buf(run->mmio.data, len); >> " >> >> This piece code also tells that len variable does not exceeds 4 bytes. >> So, remove 8 bytes assign in mmio_read_buf and mmio_write_buf. > > NAK. This code is shared between arm and arm64. See commit f42798c. > > M. > >> >> Signed-off-by: Peng Fan <[email protected]> >> CC: Gleb Natapov <[email protected]> >> CC: Paolo Bonzini <[email protected]> >> CC: Christoffer Dall <[email protected]> >> CC: Marc Zyngier <[email protected]> >> CC: Russell King <[email protected]> >> --- >> arch/arm/kvm/mmio.c | 10 ---------- >> 1 file changed, 10 deletions(-) >> >> diff --git a/arch/arm/kvm/mmio.c b/arch/arm/kvm/mmio.c >> index 4cb5a93..953a819 100644 >> --- a/arch/arm/kvm/mmio.c >> +++ b/arch/arm/kvm/mmio.c >> @@ -30,7 +30,6 @@ static void mmio_write_buf(char *buf, unsigned int len, >> unsigned long data) >> u8 byte; >> u16 hword; >> u32 word; >> - u64 dword; >> } tmp; >> >> switch (len) { >> @@ -46,10 +45,6 @@ static void mmio_write_buf(char *buf, unsigned int len, >> unsigned long data) >> tmp.word = data; >> datap = &tmp.word; >> break; >> - case 8: >> - tmp.dword = data; >> - datap = &tmp.dword; >> - break; >> } >> >> memcpy(buf, datap, len); >> @@ -61,7 +56,6 @@ static unsigned long mmio_read_buf(char *buf, unsigned int >> len) >> union { >> u16 hword; >> u32 word; >> - u64 dword; >> } tmp; >> >> switch (len) { >> @@ -76,10 +70,6 @@ static unsigned long mmio_read_buf(char *buf, unsigned >> int len) >> memcpy(&tmp.word, buf, len); >> data = tmp.word; >> break; >> - case 8: >> - memcpy(&tmp.dword, buf, len); >> - data = tmp.dword; >> - break; >> } >> >> return data; >> > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
