tools/perf/util/unwind-libunwind-local.c

Source file repositories/reference/linux-study-clean/tools/perf/util/unwind-libunwind-local.c

File Facts

System
Linux kernel
Corpus path
tools/perf/util/unwind-libunwind-local.c
Extension
.c
Size
19814 bytes
Lines
832
Domain
Support Tooling And Documentation
Bucket
tools
Inferred role
Support Tooling And Documentation: implementation source
Status
source implementation candidate

Why This File Exists

Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.

Dependency Surface

Detected Declarations

Annotated Snippet

struct unwind_info {
	struct perf_sample	*sample;
	struct machine		*machine;
	struct thread		*thread;
	bool			 best_effort;
};

#define dw_read(ptr, type, end) ({	\
	type *__p = (type *) ptr;	\
	type  __v;			\
	if ((__p + 1) > (type *) end)	\
		return -EINVAL;		\
	__v = *__p++;			\
	ptr = (typeof(ptr)) __p;	\
	__v;				\
	})

static int __dw_read_encoded_value(u8 **p, u8 *end, u64 *val,
				   u8 encoding)
{
	u8 *cur = *p;
	*val = 0;

	switch (encoding) {
	case DW_EH_PE_omit:
		*val = 0;
		goto out;
	case DW_EH_PE_ptr:
		*val = dw_read(cur, unsigned long, end);
		goto out;
	default:
		break;
	}

	switch (encoding & DW_EH_PE_APPL_MASK) {
	case DW_EH_PE_absptr:
		break;
	case DW_EH_PE_pcrel:
		*val = (unsigned long) cur;
		break;
	default:
		return -EINVAL;
	}

	if ((encoding & 0x07) == 0x00)
		encoding |= DW_EH_PE_udata4;

	switch (encoding & DW_EH_PE_FORMAT_MASK) {
	case DW_EH_PE_sdata4:
		*val += dw_read(cur, s32, end);
		break;
	case DW_EH_PE_udata4:
		*val += dw_read(cur, u32, end);
		break;
	case DW_EH_PE_sdata8:
		*val += dw_read(cur, s64, end);
		break;
	case DW_EH_PE_udata8:
		*val += dw_read(cur, u64, end);
		break;
	default:
		return -EINVAL;
	}

 out:
	*p = cur;
	return 0;
}

#define dw_read_encoded_value(ptr, end, enc) ({			\
	u64 __v;						\
	if (__dw_read_encoded_value(&ptr, end, &__v, enc)) {	\
		return -EINVAL;                                 \
	}                                                       \
	__v;                                                    \
	})

static int elf_section_address_and_offset(int fd, const char *name, u64 *address, u64 *offset)
{
	Elf *elf;
	GElf_Ehdr ehdr;
	GElf_Shdr shdr;
	int ret = -1;

	elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
	if (elf == NULL)
		return -1;

	if (gelf_getehdr(elf, &ehdr) == NULL)
		goto out_err;

Annotation

Implementation Notes