diff options
Diffstat (limited to 'tools/include/uapi/linux/btf.h')
| -rw-r--r-- | tools/include/uapi/linux/btf.h | 83 |
1 files changed, 80 insertions, 3 deletions
diff --git a/tools/include/uapi/linux/btf.h b/tools/include/uapi/linux/btf.h index 618167cab4e6..11d65871d163 100644 --- a/tools/include/uapi/linux/btf.h +++ b/tools/include/uapi/linux/btf.h @@ -54,8 +54,8 @@ struct btf_type { * decl_tag and type_tag */ __u32 info; - /* "size" is used by INT, ENUM, STRUCT, UNION, DATASEC and ENUM64. - * "size" tells the size of the type it is describing. + /* "size" is used by INT, ENUM, STRUCT, UNION, DATASEC, ENUM64 + * and LOC_PARAM. "size" tells the size of the type it is describing. * * "type" is used by PTR, TYPEDEF, VOLATILE, CONST, RESTRICT, * FUNC, FUNC_PROTO, VAR, DECL_TAG and TYPE_TAG. @@ -92,7 +92,9 @@ enum { BTF_KIND_DECL_TAG = 17, /* Decl Tag */ BTF_KIND_TYPE_TAG = 18, /* Type Tag */ BTF_KIND_ENUM64 = 19, /* Enumeration up to 64-bit values */ - + BTF_KIND_LOC_PARAM = 20, /* Location parameter information */ + BTF_KIND_LOC_PROTO = 21, /* Location prototype for site */ + BTF_KIND_LOCSEC = 22, /* Location section */ NR_BTF_KINDS, BTF_KIND_MAX = NR_BTF_KINDS - 1, }; @@ -212,4 +214,79 @@ struct btf_enum64 { __u32 val_hi32; }; +/* + * BTF_KIND_LOC_PARAM is followed by a single "struct btf_loc_param" + * that contains flags specifying the contents of the vlen-specified + * number of 4-byte values that follow. + */ +struct btf_loc_param { + __u32 flags; + __u32 values[]; +}; + +/* + * The combination of size, vlen and flags gives us the means to interpret + * the following vlen-specified set of 4-byte values: + * + * - a BTF_LOC_PARAM_CONST is a constant value; combination + * of size, vlen and _SIGNED flag determines it. If the value requires + * 64 bits it is stored in {lo,hi} order. + * - a BTF_LOC_PARAM_ADDR|BTF_LOC_PARAM_CONST is an address that should be + * normalized with respect to kernel/module base address. + * - a BTF_LOC_PARAM_REG with vlen 1 is a simple register number; + * with vlen 2 it is a multi-register parameter. Register numbers are + * numbers derived from DW_OP_reg values, i.e. 0 is DW_OP_reg0; since + * DW_OP_fbreg has its own special DW_OP_value and DW_OP_regx can refer + * to an arbitrary register number, we reserve BTF_LOC_PARAM_FBREG for + * the frame base register to avoid collisions. + * - a _REG | OFFSET describes an address without dereferencing it. + * - a _REG | DEREF with vlen 1 dereferences the value in the register + * number specified. + * - a REG | DEREF | OFFSET with vlen > 1 specifies the register number + * in the first 4-byte value and the offset in the remainder. + * In the case of REG and OFFSET combinations, the OFFSET has the width + * of the value words while the type size describes the represented parameter, + * so for example a REG | DEREF | OFFSET with size 8 and vlen 2 would be + * an 8-byte register dereference with signed 4-byte offset, since the vlen 2 + * values consist of a register value and the signed value. + */ +enum btf_loc_param_flags { + BTF_LOC_PARAM_SIGNED = 0x1, + BTF_LOC_PARAM_CONST = 0x2, + BTF_LOC_PARAM_ADDR = 0x4, + BTF_LOC_PARAM_REG = 0x8, + BTF_LOC_PARAM_DEREF = 0x10, + BTF_LOC_PARAM_OFFSET = 0x20, +}; + +enum { + BTF_LOC_PARAM_FBREG = 0xffffffff +}; + +/* + * BTF_KIND_LOC_PROTO specifies location prototypes; i.e. how locations relate + * to parameters; a struct btf_type of BTF_KIND_LOC_PROTO is followed by a + * vlen-specified number of __u32 BTF type ids which specify the associated + * BTF_KIND_LOC_PARAM for each function parameter associated with the + * location. The type should either be 0 (no location info) or point at + * a BTF_KIND_LOC_PARAM. + */ + +/* + * BTF_KIND_LOCSEC consists of vlen-specified number of "struct btf_loc" + * containing location site-specific information for a specific ELF section; + * for example locations in ".text" are in a LOCSEC named "inline.text". + * + * - function (func) + * - location prototype type id (loc_proto) + * - address offset (offset) relative to the runtime base address of the + * ELF section associated with the LOCSEC + */ + +struct btf_loc { + __u32 func; + __u32 loc_proto; + __u32 offset; +}; + #endif /* _UAPI__LINUX_BTF_H__ */ |