Messages in this thread Patch in this message | | | From | Marc-Andre Lureau <> | Date | Thu, 15 Feb 2018 10:34:28 +0100 | Subject | Re: [PATCH v14 3/9] fw_cfg: fix sparse warnings in fw_cfg_sel_endianness() |
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On Wed, Feb 14, 2018 at 9:46 PM, Michael S. Tsirkin <mst@redhat.com> wrote: > On Wed, Feb 14, 2018 at 03:18:44PM +0100, Marc-André Lureau wrote: >> The function is used for both LE & BE target type, use __force casting. >> >> Fixes: >> $ make C=1 CF=-D__CHECK_ENDIAN__ drivers/firmware/qemu_fw_cfg.o >> >> drivers/firmware/qemu_fw_cfg.c:55:33: warning: restricted __be16 degrades to integer >> drivers/firmware/qemu_fw_cfg.c:55:52: warning: restricted __le16 degrades to integer >> >> Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> >> --- >> drivers/firmware/qemu_fw_cfg.c | 4 +++- >> 1 file changed, 3 insertions(+), 1 deletion(-) >> >> diff --git a/drivers/firmware/qemu_fw_cfg.c b/drivers/firmware/qemu_fw_cfg.c >> index 90f467232777..85e693287d87 100644 >> --- a/drivers/firmware/qemu_fw_cfg.c >> +++ b/drivers/firmware/qemu_fw_cfg.c >> @@ -52,7 +52,9 @@ static DEFINE_MUTEX(fw_cfg_dev_lock); >> /* pick appropriate endianness for selector key */ >> static inline u16 fw_cfg_sel_endianness(u16 key) >> { >> - return fw_cfg_is_mmio ? cpu_to_be16(key) : cpu_to_le16(key); >> + return fw_cfg_is_mmio ? >> + (u16 __force)cpu_to_be16(key) : >> + (u16 __force)cpu_to_le16(key); >> } >> >> /* read chunk of given fw_cfg blob (caller responsible for sanity-check) */ > > Well the caller does cpu_to_le16 on the result ... > All this makes my head spin. > > IMHO what you want is a wrapper that does iowrite and iowritebe > rather than __force.
iowrite16(key) is the same as iowrite16(cpu_to_le16(key)) ? There is no iowrite16le()...
Is this equivalent, and not introducing regressions?
static inline u16 fw_cfg_sel_endianness(u16 key) +static void fw_cfg_sel_endianness(u16 key) { - return fw_cfg_is_mmio ? cpu_to_be16(key) : cpu_to_le16(key); + if (fw_cfg_is_mmio) + iowrite16be(key, fw_cfg_reg_ctrl); + else + iowrite16(key, fw_cfg_reg_ctrl); }
/* read chunk of given fw_cfg blob (caller responsible for sanity-check) */ @@ -74,7 +77,7 @@ static inline void fw_cfg_read_blob(u16 key, }
mutex_lock(&fw_cfg_dev_lock); - iowrite16(fw_cfg_sel_endianness(key), fw_cfg_reg_ctrl); + fw_cfg_sel_endianness(key);
> > >> -- >> 2.16.1.73.g5832b7e9f2
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