| Message ID | 20190730143704.060a2606@canb.auug.org.au (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 7440ea8b2a4430eef5120d0a7faac6c39304ae6d |
| Headers | show |
| Series | drivers/macintosh/smu.c: Mark expected switch fall-through | expand |
| Context | Check | Description |
|---|---|---|
| snowpatch_ozlabs/apply_patch | warning | Failed to apply on branch next (f3365d1a959d5c6527efe3d38276acc9b58e3f3f) |
| snowpatch_ozlabs/apply_patch | fail | Failed to apply to any branch |
Hi all, On Tue, 30 Jul 2019 14:37:04 +1000 Stephen Rothwell <sfr@canb.auug.org.au> wrote: > > Mark switch cases where we are expecting to fall through. > > This patch fixes the following warning (Building: powerpc): > > drivers/macintosh/smu.c: In function 'smu_queue_i2c': > drivers/macintosh/smu.c:854:21: warning: this statement may fall through [-Wimplicit-fallthrough=] > cmd->info.devaddr &= 0xfe; > ~~~~~~~~~~~~~~~~~~^~~~~~~ > drivers/macintosh/smu.c:855:2: note: here > case SMU_I2C_TRANSFER_STDSUB: > ^~~~ > > Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> > Cc: Gustavo A. R. Silva <gustavo@embeddedor.com> > Cc: Kees Cook <keescook@chromium.org> > Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Fixes: 0365ba7fb1fa ("[PATCH] ppc64: SMU driver update & i2c support") Sorry, forgot :-)
Stephen Rothwell <sfr@canb.auug.org.au> writes: > Mark switch cases where we are expecting to fall through. > > This patch fixes the following warning (Building: powerpc): > > drivers/macintosh/smu.c: In function 'smu_queue_i2c': > drivers/macintosh/smu.c:854:21: warning: this statement may fall through [-Wimplicit-fallthrough=] > cmd->info.devaddr &= 0xfe; > ~~~~~~~~~~~~~~~~~~^~~~~~~ > drivers/macintosh/smu.c:855:2: note: here > case SMU_I2C_TRANSFER_STDSUB: > ^~~~ > > Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> > Cc: Gustavo A. R. Silva <gustavo@embeddedor.com> > Cc: Kees Cook <keescook@chromium.org> > Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> > --- > drivers/macintosh/smu.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/drivers/macintosh/smu.c b/drivers/macintosh/smu.c > index 276065c888bc..23f1f41c8602 100644 > --- a/drivers/macintosh/smu.c > +++ b/drivers/macintosh/smu.c > @@ -852,6 +852,7 @@ int smu_queue_i2c(struct smu_i2c_cmd *cmd) > break; > case SMU_I2C_TRANSFER_COMBINED: > cmd->info.devaddr &= 0xfe; > + /* fall through */ > case SMU_I2C_TRANSFER_STDSUB: > if (cmd->info.sublen > 3) > return -EINVAL; Why do we think it's an expected fall through? I can't really convince myself from the surrounding code that it's definitely intentional. cheers
Hi Michael, On Wed, 31 Jul 2019 00:28:55 +1000 Michael Ellerman <mpe@ellerman.id.au> wrote: > > Why do we think it's an expected fall through? I can't really convince > myself from the surrounding code that it's definitely intentional. Its been that way since this code was introduced by commit 0365ba7fb1fa ("[PATCH] ppc64: SMU driver update & i2c support") in 2005 ...
On Wed, Jul 31, 2019 at 12:28:55AM +1000, Michael Ellerman wrote: > Stephen Rothwell <sfr@canb.auug.org.au> writes: > > Mark switch cases where we are expecting to fall through. > > > > This patch fixes the following warning (Building: powerpc): > > > > drivers/macintosh/smu.c: In function 'smu_queue_i2c': > > drivers/macintosh/smu.c:854:21: warning: this statement may fall through [-Wimplicit-fallthrough=] > > cmd->info.devaddr &= 0xfe; > > ~~~~~~~~~~~~~~~~~~^~~~~~~ > > drivers/macintosh/smu.c:855:2: note: here > > case SMU_I2C_TRANSFER_STDSUB: > > ^~~~ > > > > Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> > > Cc: Gustavo A. R. Silva <gustavo@embeddedor.com> > > Cc: Kees Cook <keescook@chromium.org> > > Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> > > --- > > drivers/macintosh/smu.c | 1 + > > 1 file changed, 1 insertion(+) > > > > diff --git a/drivers/macintosh/smu.c b/drivers/macintosh/smu.c > > index 276065c888bc..23f1f41c8602 100644 > > --- a/drivers/macintosh/smu.c > > +++ b/drivers/macintosh/smu.c > > @@ -852,6 +852,7 @@ int smu_queue_i2c(struct smu_i2c_cmd *cmd) > > break; > > case SMU_I2C_TRANSFER_COMBINED: > > cmd->info.devaddr &= 0xfe; > > + /* fall through */ > > case SMU_I2C_TRANSFER_STDSUB: > > if (cmd->info.sublen > 3) > > return -EINVAL; > > Why do we think it's an expected fall through? I can't really convince > myself from the surrounding code that it's definitely intentional. Yeah, good question. Just now when I went looking for who used SMU_I2C_TRANSFER_COMBINED, I found the only caller in arch/powerpc/platforms/powermac/low_i2c.c and it is clearly using a fall-through for building the command for "stdsub" and "combined", so I think that's justification enough: switch(bus->mode) { case pmac_i2c_mode_std: if (subsize != 0) return -EINVAL; cmd->info.type = SMU_I2C_TRANSFER_SIMPLE; break; case pmac_i2c_mode_stdsub: case pmac_i2c_mode_combined: if (subsize > 3 || subsize < 1) return -EINVAL; cmd->info.sublen = subsize; /* that's big-endian only but heh ! */ memcpy(&cmd->info.subaddr, ((char *)&subaddr) + (4 - subsize), subsize); if (bus->mode == pmac_i2c_mode_stdsub) cmd->info.type = SMU_I2C_TRANSFER_STDSUB; else cmd->info.type = SMU_I2C_TRANSFER_COMBINED; Reviewed-by: Kees Cook <keescook@chromium.org>
On Tue, 2019-07-30 at 10:07 -0700, Kees Cook wrote: > > > Why do we think it's an expected fall through? I can't really > > convince > > myself from the surrounding code that it's definitely intentional. > > Yeah, good question. Just now when I went looking for who > used SMU_I2C_TRANSFER_COMBINED, I found the only caller in > arch/powerpc/platforms/powermac/low_i2c.c and it is clearly using a > fall-through for building the command for "stdsub" and "combined", > so I think that's justification enough: Yes, sorry for the delay, the fall through is intentional. Cheers, Ben.
Kees Cook <keescook@chromium.org> writes: > On Wed, Jul 31, 2019 at 12:28:55AM +1000, Michael Ellerman wrote: >> Stephen Rothwell <sfr@canb.auug.org.au> writes: >> > Mark switch cases where we are expecting to fall through. >> > >> > This patch fixes the following warning (Building: powerpc): >> > >> > drivers/macintosh/smu.c: In function 'smu_queue_i2c': >> > drivers/macintosh/smu.c:854:21: warning: this statement may fall through [-Wimplicit-fallthrough=] >> > cmd->info.devaddr &= 0xfe; >> > ~~~~~~~~~~~~~~~~~~^~~~~~~ >> > drivers/macintosh/smu.c:855:2: note: here >> > case SMU_I2C_TRANSFER_STDSUB: >> > ^~~~ >> > >> > Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> >> > Cc: Gustavo A. R. Silva <gustavo@embeddedor.com> >> > Cc: Kees Cook <keescook@chromium.org> >> > Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> >> > --- >> > drivers/macintosh/smu.c | 1 + >> > 1 file changed, 1 insertion(+) >> > >> > diff --git a/drivers/macintosh/smu.c b/drivers/macintosh/smu.c >> > index 276065c888bc..23f1f41c8602 100644 >> > --- a/drivers/macintosh/smu.c >> > +++ b/drivers/macintosh/smu.c >> > @@ -852,6 +852,7 @@ int smu_queue_i2c(struct smu_i2c_cmd *cmd) >> > break; >> > case SMU_I2C_TRANSFER_COMBINED: >> > cmd->info.devaddr &= 0xfe; >> > + /* fall through */ >> > case SMU_I2C_TRANSFER_STDSUB: >> > if (cmd->info.sublen > 3) >> > return -EINVAL; >> >> Why do we think it's an expected fall through? I can't really convince >> myself from the surrounding code that it's definitely intentional. > > Yeah, good question. Just now when I went looking for who > used SMU_I2C_TRANSFER_COMBINED, I found the only caller in > arch/powerpc/platforms/powermac/low_i2c.c and it is clearly using a > fall-through for building the command for "stdsub" and "combined", > so I think that's justification enough: > > switch(bus->mode) { > case pmac_i2c_mode_std: > if (subsize != 0) > return -EINVAL; > cmd->info.type = SMU_I2C_TRANSFER_SIMPLE; > break; > case pmac_i2c_mode_stdsub: > case pmac_i2c_mode_combined: > if (subsize > 3 || subsize < 1) > return -EINVAL; > cmd->info.sublen = subsize; > /* that's big-endian only but heh ! */ > memcpy(&cmd->info.subaddr, ((char *)&subaddr) + (4 - subsize), > subsize); > if (bus->mode == pmac_i2c_mode_stdsub) > cmd->info.type = SMU_I2C_TRANSFER_STDSUB; > else > cmd->info.type = SMU_I2C_TRANSFER_COMBINED; > > > Reviewed-by: Kees Cook <keescook@chromium.org> Thanks. cheers
On Tue, 2019-07-30 at 04:37:04 UTC, Stephen Rothwell wrote: > Mark switch cases where we are expecting to fall through. > > This patch fixes the following warning (Building: powerpc): > > drivers/macintosh/smu.c: In function 'smu_queue_i2c': > drivers/macintosh/smu.c:854:21: warning: this statement may fall through [-= > Wimplicit-fallthrough=3D] > cmd->info.devaddr &=3D 0xfe; > ~~~~~~~~~~~~~~~~~~^~~~~~~ > drivers/macintosh/smu.c:855:2: note: here > case SMU_I2C_TRANSFER_STDSUB: > ^~~~ > > Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> > Cc: Gustavo A. R. Silva <gustavo@embeddedor.com> > Cc: Kees Cook <keescook@chromium.org> > Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Applied to powerpc fixes, thanks. https://git.kernel.org/powerpc/c/7440ea8b2a4430eef5120d0a7faac6c39304ae6d cheers
diff --git a/drivers/macintosh/smu.c b/drivers/macintosh/smu.c index 276065c888bc..23f1f41c8602 100644 --- a/drivers/macintosh/smu.c +++ b/drivers/macintosh/smu.c @@ -852,6 +852,7 @@ int smu_queue_i2c(struct smu_i2c_cmd *cmd) break; case SMU_I2C_TRANSFER_COMBINED: cmd->info.devaddr &= 0xfe; + /* fall through */ case SMU_I2C_TRANSFER_STDSUB: if (cmd->info.sublen > 3) return -EINVAL;
Mark switch cases where we are expecting to fall through. This patch fixes the following warning (Building: powerpc): drivers/macintosh/smu.c: In function 'smu_queue_i2c': drivers/macintosh/smu.c:854:21: warning: this statement may fall through [-Wimplicit-fallthrough=] cmd->info.devaddr &= 0xfe; ~~~~~~~~~~~~~~~~~~^~~~~~~ drivers/macintosh/smu.c:855:2: note: here case SMU_I2C_TRANSFER_STDSUB: ^~~~ Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Gustavo A. R. Silva <gustavo@embeddedor.com> Cc: Kees Cook <keescook@chromium.org> Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> --- drivers/macintosh/smu.c | 1 + 1 file changed, 1 insertion(+)