Author: kevans Date: Wed May 13 18:07:37 2020 New Revision: 361011 URL: https://svnweb.freebsd.org/changeset/base/361011
Log: kernel: provide panicky version of __unreachable __builtin_unreachable doesn't raise any compile-time warnings/errors on its own, so problems with its usage can't be easily detected. While it would be nice for this situation to change and compilers to at least add a warning for trivial cases where local state means the instruction can't be reached, this isn't the case at the moment and likely will not happen. This commit adds an __assert_unreachable, whose intent is incredibly clear: it asserts that this instruction is unreachable. On INVARIANTS builds, it's a panic(), and on non-INVARIANTS it expands to __unreachable(). Existing users of __unreachable() are converted to __assert_unreachable, to improve debuggability if this assumption is violated. Reviewed by: mjg Differential Revision: https://reviews.freebsd.org/D23793 Modified: head/sys/ddb/db_expr.c head/sys/dev/amdtemp/amdtemp.c head/sys/dev/nvdimm/nvdimm.c head/sys/dev/ow/ow.c head/sys/net/mppcc.c head/sys/sys/systm.h head/sys/vm/vm_radix.c Modified: head/sys/ddb/db_expr.c ============================================================================== --- head/sys/ddb/db_expr.c Wed May 13 17:20:51 2020 (r361010) +++ head/sys/ddb/db_expr.c Wed May 13 18:07:37 2020 (r361011) @@ -34,6 +34,7 @@ __FBSDID("$FreeBSD$"); #include <sys/param.h> +#include <sys/systm.h> #include <ddb/ddb.h> #include <ddb/db_lex.h> @@ -229,7 +230,7 @@ db_add_expr(db_expr_t *valuep) lhs |= rhs; break; default: - __unreachable(); + __assert_unreachable(); } t = db_read_token(); } @@ -313,7 +314,7 @@ db_logical_relation_expr( lhs = (lhs <= rhs); break; default: - __unreachable(); + __assert_unreachable(); } t = db_read_token(); } Modified: head/sys/dev/amdtemp/amdtemp.c ============================================================================== --- head/sys/dev/amdtemp/amdtemp.c Wed May 13 17:20:51 2020 (r361010) +++ head/sys/dev/amdtemp/amdtemp.c Wed May 13 18:07:37 2020 (r361011) @@ -666,7 +666,7 @@ amdtemp_gettemp0f(device_t dev, amdsensor_t sensor) temp |= AMDTEMP_TTSR_SELCORE; break; default: - __unreachable(); + __assert_unreachable(); } pci_write_config(dev, AMDTEMP_THERMTP_STAT, temp, 1); @@ -766,7 +766,7 @@ amdtemp_gettemp17h(device_t dev, amdsensor_t sensor) ("sensor %d: not valid", (int)sensor)); return (amdtemp_decode_fam10h_to_17h(sc->sc_offset, val, true)); default: - __unreachable(); + __assert_unreachable(); } } Modified: head/sys/dev/nvdimm/nvdimm.c ============================================================================== --- head/sys/dev/nvdimm/nvdimm.c Wed May 13 17:20:51 2020 (r361010) +++ head/sys/dev/nvdimm/nvdimm.c Wed May 13 18:07:37 2020 (r361011) @@ -35,6 +35,7 @@ __FBSDID("$FreeBSD$"); #include "opt_ddb.h" #include <sys/param.h> +#include <sys/systm.h> #include <sys/bio.h> #include <sys/bitstring.h> #include <sys/bus.h> @@ -236,7 +237,7 @@ read_label(struct nvdimm_dev *nv, int num) return (0); } } - __unreachable(); + __assert_unreachable(); } static int Modified: head/sys/dev/ow/ow.c ============================================================================== --- head/sys/dev/ow/ow.c Wed May 13 17:20:51 2020 (r361010) +++ head/sys/dev/ow/ow.c Wed May 13 18:07:37 2020 (r361011) @@ -507,7 +507,7 @@ again: return (EIO); goto again; default: /* NOTREACHED */ - __unreachable(); + __assert_unreachable(); } if (dir) { OWLL_WRITE_ONE(lldev, &timing_regular); Modified: head/sys/net/mppcc.c ============================================================================== --- head/sys/net/mppcc.c Wed May 13 17:20:51 2020 (r361010) +++ head/sys/net/mppcc.c Wed May 13 18:07:37 2020 (r361011) @@ -232,7 +232,7 @@ int MPPC_Compress(u_char **src, u_char **dst, u_long * } else if (off < 8192) { /* 16-bit offset; 320 <= offset < 8192 */ putbits16(*dst, 0xc000|(off-320), 16, &olen, &l); } else { /* NOTREACHED */ - __unreachable(); + __assert_unreachable(); rtn &= ~MPPC_OK; return (rtn); } Modified: head/sys/sys/systm.h ============================================================================== --- head/sys/sys/systm.h Wed May 13 17:20:51 2020 (r361010) +++ head/sys/sys/systm.h Wed May 13 18:07:37 2020 (r361011) @@ -117,6 +117,9 @@ void kassert_panic(const char *fmt, ...) __printflike VNASSERT(exp, vp, ("condition %s not met at %s:%d (%s)", \ _exp, __FILE__, __LINE__, __func__)); \ } while (0) +#define __assert_unreachable() \ + panic("executing segment marked as unreachable at %s:%d (%s)\n", \ + __FILE__, __LINE__, __func__) #else #define KASSERT(exp,msg) do { \ } while (0) @@ -125,6 +128,7 @@ void kassert_panic(const char *fmt, ...) __printflike } while (0) #define VNPASS(exp, vp) do { \ } while (0) +#define __assert_unreachable() __unreachable() #endif #ifndef CTASSERT /* Allow lint to override */ Modified: head/sys/vm/vm_radix.c ============================================================================== --- head/sys/vm/vm_radix.c Wed May 13 17:20:51 2020 (r361010) +++ head/sys/vm/vm_radix.c Wed May 13 18:07:37 2020 (r361011) @@ -209,7 +209,7 @@ vm_radix_node_load(smrnode_t *p, enum vm_radix_access case SMR: return (smr_entered_load(p, vm_radix_smr)); } - __unreachable(); + __assert_unreachable(); } static __inline void _______________________________________________ svn-src-all@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-all To unsubscribe, send any mail to "svn-src-all-unsubscr...@freebsd.org"
