On Thu, Jan 21, 2021 at 04:23:51PM -0800, Erik Kaneda wrote: > From: Nick Desaulniers <ndesaulniers@xxxxxxxxxx> > > ACPICA commit 4b9135f5774caa796ddf826448811e8e7f08ef2f > > GCC 7.1 gained -Wimplicit-fallthrough to warn on implicit fallthrough, > as well as __attribute__((__fallthrough__)) and comments to explicitly > denote that cases of fallthrough were intentional. Clang also supports > this warning and statement attribute, but not the comment form. > > Robert Moore provides additional context about the lint comments being > removed. They were for "an old version of PC-Lint, which we don't use > anymore." Drop those. > > This will help us enable -Wimplicit-fallthrough throughout the Linux > kernel. > > Suggested-by: Robert Moore <robert.moore@xxxxxxxxx> > Reported-by: Jon Hunter <jonathanh@xxxxxxxxxx> > > Link: https://github.com/acpica/acpica/commit/4b9135f5 > Signed-off-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx> > Signed-off-by: Bob Moore <robert.moore@xxxxxxxxx> > Signed-off-by: Erik Kaneda <erik.kaneda@xxxxxxxxx> With gcc 6.5 (and presumably each gcc version older than 7.1), this patch results in: drivers/acpi/acpica/dscontrol.c: In function ‘acpi_ds_exec_begin_control_op’: drivers/acpi/acpica/dscontrol.c:65:3: error: ‘ACPI_FALLTHROUGH’ undeclared and similar errors for other files. Guenter > --- > drivers/acpi/acpica/dscontrol.c | 2 +- > drivers/acpi/acpica/dswexec.c | 3 +-- > drivers/acpi/acpica/dswload.c | 2 +- > drivers/acpi/acpica/dswload2.c | 2 +- > drivers/acpi/acpica/exfldio.c | 2 +- > drivers/acpi/acpica/exresop.c | 4 ++-- > drivers/acpi/acpica/exstore.c | 4 ++-- > drivers/acpi/acpica/hwgpe.c | 2 +- > drivers/acpi/acpica/utdelete.c | 2 +- > include/acpi/actypes.h | 6 ++++++ > include/acpi/platform/acgcc.h | 15 +++++++++++++++ > 11 files changed, 32 insertions(+), 12 deletions(-) > > -- > 2.29.2 > > diff --git a/drivers/acpi/acpica/dscontrol.c b/drivers/acpi/acpica/dscontrol.c > index 4b5b6e859f62..b58ffc7acdb9 100644 > --- a/drivers/acpi/acpica/dscontrol.c > +++ b/drivers/acpi/acpica/dscontrol.c > @@ -62,7 +62,7 @@ acpi_ds_exec_begin_control_op(struct acpi_walk_state *walk_state, > } > } > > - /*lint -fallthrough */ > + ACPI_FALLTHROUGH; > > case AML_IF_OP: > /* > diff --git a/drivers/acpi/acpica/dswexec.c b/drivers/acpi/acpica/dswexec.c > index 1d4f8c81028c..4a9799246fae 100644 > --- a/drivers/acpi/acpica/dswexec.c > +++ b/drivers/acpi/acpica/dswexec.c > @@ -598,8 +598,7 @@ acpi_status acpi_ds_exec_end_op(struct acpi_walk_state *walk_state) > break; > } > > - /* Fall through */ > - /*lint -fallthrough */ > + ACPI_FALLTHROUGH; > > case AML_INT_EVAL_SUBTREE_OP: > > diff --git a/drivers/acpi/acpica/dswload.c b/drivers/acpi/acpica/dswload.c > index 27069325b6de..dd97c86f8e41 100644 > --- a/drivers/acpi/acpica/dswload.c > +++ b/drivers/acpi/acpica/dswload.c > @@ -224,7 +224,7 @@ acpi_ds_load1_begin_op(struct acpi_walk_state *walk_state, > break; > } > > - /*lint -fallthrough */ > + ACPI_FALLTHROUGH; > > default: > > diff --git a/drivers/acpi/acpica/dswload2.c b/drivers/acpi/acpica/dswload2.c > index edadbe146506..d9a3dfca7555 100644 > --- a/drivers/acpi/acpica/dswload2.c > +++ b/drivers/acpi/acpica/dswload2.c > @@ -214,7 +214,7 @@ acpi_ds_load2_begin_op(struct acpi_walk_state *walk_state, > break; > } > > - /*lint -fallthrough */ > + ACPI_FALLTHROUGH; > > default: > > diff --git a/drivers/acpi/acpica/exfldio.c b/drivers/acpi/acpica/exfldio.c > index ade35ff1c7ba..cde24e0fa6a8 100644 > --- a/drivers/acpi/acpica/exfldio.c > +++ b/drivers/acpi/acpica/exfldio.c > @@ -434,7 +434,7 @@ acpi_ex_field_datum_io(union acpi_operand_object *obj_desc, > * region_field case and write the datum to the Operation Region > */ > > - /*lint -fallthrough */ > + ACPI_FALLTHROUGH; > > case ACPI_TYPE_LOCAL_REGION_FIELD: > /* > diff --git a/drivers/acpi/acpica/exresop.c b/drivers/acpi/acpica/exresop.c > index 4d1b22971d58..4a0f8b8bfe62 100644 > --- a/drivers/acpi/acpica/exresop.c > +++ b/drivers/acpi/acpica/exresop.c > @@ -198,7 +198,7 @@ acpi_ex_resolve_operands(u16 opcode, > > target_op = AML_DEBUG_OP; > > - /*lint -fallthrough */ > + ACPI_FALLTHROUGH; > > case ACPI_REFCLASS_ARG: > case ACPI_REFCLASS_LOCAL: > @@ -264,7 +264,7 @@ acpi_ex_resolve_operands(u16 opcode, > * Else not a string - fall through to the normal Reference > * case below > */ > - /*lint -fallthrough */ > + ACPI_FALLTHROUGH; > > case ARGI_REFERENCE: /* References: */ > case ARGI_INTEGER_REF: > diff --git a/drivers/acpi/acpica/exstore.c b/drivers/acpi/acpica/exstore.c > index 3adc0a29d890..8fe33051275d 100644 > --- a/drivers/acpi/acpica/exstore.c > +++ b/drivers/acpi/acpica/exstore.c > @@ -96,7 +96,7 @@ acpi_ex_store(union acpi_operand_object *source_desc, > return_ACPI_STATUS(AE_OK); > } > > - /*lint -fallthrough */ > + ACPI_FALLTHROUGH; > > default: > > @@ -422,7 +422,7 @@ acpi_ex_store_object_to_node(union acpi_operand_object *source_desc, > break; > } > > - /* Fallthrough */ > + ACPI_FALLTHROUGH; > > case ACPI_TYPE_DEVICE: > case ACPI_TYPE_EVENT: > diff --git a/drivers/acpi/acpica/hwgpe.c b/drivers/acpi/acpica/hwgpe.c > index b13a4ed5bc63..0c84300e915c 100644 > --- a/drivers/acpi/acpica/hwgpe.c > +++ b/drivers/acpi/acpica/hwgpe.c > @@ -167,7 +167,7 @@ acpi_hw_low_set_gpe(struct acpi_gpe_event_info *gpe_event_info, u32 action) > return (AE_BAD_PARAMETER); > } > > - /*lint -fallthrough */ > + ACPI_FALLTHROUGH; > > case ACPI_GPE_ENABLE: > > diff --git a/drivers/acpi/acpica/utdelete.c b/drivers/acpi/acpica/utdelete.c > index 4c0d4e434196..624a26794d55 100644 > --- a/drivers/acpi/acpica/utdelete.c > +++ b/drivers/acpi/acpica/utdelete.c > @@ -112,7 +112,7 @@ static void acpi_ut_delete_internal_obj(union acpi_operand_object *object) > gpe_block); > } > > - /*lint -fallthrough */ > + ACPI_FALLTHROUGH; > > case ACPI_TYPE_PROCESSOR: > case ACPI_TYPE_THERMAL: > diff --git a/include/acpi/actypes.h b/include/acpi/actypes.h > index 647cb11d0a0a..2a32593691bc 100644 > --- a/include/acpi/actypes.h > +++ b/include/acpi/actypes.h > @@ -1286,4 +1286,10 @@ typedef enum { > > #define ACPI_OPT_END -1 > > +/* Definitions for explicit fallthrough */ > + > +#ifndef ACPI_FALLTHROUGH > +#define ACPI_FALLTHROUGH do {} while(0) > +#endif > + > #endif /* __ACTYPES_H__ */ > diff --git a/include/acpi/platform/acgcc.h b/include/acpi/platform/acgcc.h > index 7d63d03cf507..91f7a02c798a 100644 > --- a/include/acpi/platform/acgcc.h > +++ b/include/acpi/platform/acgcc.h > @@ -54,4 +54,19 @@ typedef __builtin_va_list va_list; > > #define ACPI_USE_NATIVE_MATH64 > > +/* GCC did not support __has_attribute until 5.1. */ > + > +#ifndef __has_attribute > +#define __has_attribute(x) 0 > +#endif > + > +/* > + * Explictly mark intentional explicit fallthrough to silence > + * -Wimplicit-fallthrough in GCC 7.1+. > + */ > + > +#if __has_attribute(__fallthrough__) > +#define ACPI_FALLTHROUGH __attribute__((__fallthrough__)) > +#endif > + > #endif /* __ACGCC_H__ */
