perf probe: Add sdt probes arguments into the uprobe cmd string (3b1f8311) · Commits · 戴 / test

tools/perf/arch/x86/util/perf_regs.c

+83 −0

Original line number	Diff line number	Diff line
		#include <string.h>

		#include "../../perf.h"
		#include "../../util/util.h"
		#include "../../util/perf_regs.h"

		const struct sample_reg sample_reg_masks[] = {
		@@ -26,3 +29,83 @@ const struct sample_reg sample_reg_masks[] = {
		#endif
		SMPL_REG_END
		};

		struct sdt_name_reg {
		const char *sdt_name;
		const char *uprobe_name;
		};
		#define SDT_NAME_REG(n, m) {.sdt_name = "%" #n, .uprobe_name = "%" #m}
		#define SDT_NAME_REG_END {.sdt_name = NULL, .uprobe_name = NULL}

		static const struct sdt_name_reg sdt_reg_renamings[] = {
		SDT_NAME_REG(eax, ax),
		SDT_NAME_REG(rax, ax),
		SDT_NAME_REG(ebx, bx),
		SDT_NAME_REG(rbx, bx),
		SDT_NAME_REG(ecx, cx),
		SDT_NAME_REG(rcx, cx),
		SDT_NAME_REG(edx, dx),
		SDT_NAME_REG(rdx, dx),
		SDT_NAME_REG(esi, si),
		SDT_NAME_REG(rsi, si),
		SDT_NAME_REG(edi, di),
		SDT_NAME_REG(rdi, di),
		SDT_NAME_REG(ebp, bp),
		SDT_NAME_REG(rbp, bp),
		SDT_NAME_REG_END,
		};

		int sdt_rename_register(char *pdesc, char old_name)
		{
		const struct sdt_name_reg *rnames = sdt_reg_renamings;
		char new_desc, old_desc = *pdesc;
		size_t prefix_len, sdt_len, uprobe_len, old_desc_len, offset;
		int ret = -1;

		while (ret != 0 && rnames->sdt_name != NULL) {
		sdt_len = strlen(rnames->sdt_name);
		ret = strncmp(old_name, rnames->sdt_name, sdt_len);
		rnames += !!ret;
		}

		if (rnames->sdt_name == NULL)
		return 0;

		sdt_len = strlen(rnames->sdt_name);
		uprobe_len = strlen(rnames->uprobe_name);
		old_desc_len = strlen(old_desc) + 1;

		new_desc = zalloc(old_desc_len + uprobe_len - sdt_len);
		if (new_desc == NULL)
		return -1;

		/* Copy the chars before the register name (at least '%') */
		prefix_len = old_name - old_desc;
		memcpy(new_desc, old_desc, prefix_len);

		/* Copy the new register name */
		memcpy(new_desc + prefix_len, rnames->uprobe_name, uprobe_len);

		/* Copy the chars after the register name (if need be) */
		offset = prefix_len + sdt_len;
		if (offset < old_desc_len) {
		/*
		* The orginal register name can be suffixed by 'b',
		* 'w' or 'd' to indicate its size; so, we need to
		* skip this char if we met one.
		*/
		char sfx = old_desc[offset];

		if (sfx == 'b' \|\| sfx == 'w' \|\| sfx == 'd')
		offset++;
		}

		if (offset < old_desc_len)
		memcpy(new_desc + prefix_len + uprobe_len,
		old_desc + offset, old_desc_len - offset);

		free(old_desc);
		*pdesc = new_desc;

		return 0;
		}

tools/perf/util/perf_regs.c

+6 −0

Original line number	Diff line number	Diff line
		@@ -6,6 +6,12 @@ const struct sample_reg __weak sample_reg_masks[] = {
		SMPL_REG_END
		};

		int __weak sdt_rename_register(char **pdesc __maybe_unused,
		char *old_name __maybe_unused)
		{
		return 0;
		}

		#ifdef HAVE_PERF_REGS_SUPPORT
		int perf_reg_value(u64 valp, struct regs_dump regs, int id)
		{

tools/perf/util/perf_regs.h

+6 −0

Original line number	Diff line number	Diff line
		@@ -15,6 +15,12 @@ struct sample_reg {

		extern const struct sample_reg sample_reg_masks[];

		/*
		* The table sdt_reg_renamings is used for adjusting gcc/gas-generated
		* registers before filling the uprobe tracer interface.
		*/
		int sdt_rename_register(char *pdesc, char old_name);

		#ifdef HAVE_PERF_REGS_SUPPORT
		#include <perf_regs.h>

tools/perf/util/probe-file.c

+166 −4

Original line number	Diff line number	Diff line
		@@ -27,6 +27,7 @@
		#include "probe-event.h"
		#include "probe-file.h"
		#include "session.h"
		#include "perf_regs.h"

		/* 4096 - 2 ('\n' + '\0') */
		#define MAX_CMDLEN 4094
		@@ -688,6 +689,166 @@ static unsigned long long sdt_note__get_addr(struct sdt_note *note)
		: (unsigned long long)note->addr.a64[0];
		}

		static const char * const type_to_suffix[] = {
		":s64", "", "", "", ":s32", "", ":s16", ":s8",
		"", ":u8", ":u16", "", ":u32", "", "", "", ":u64"
		};

		static int synthesize_sdt_probe_arg(struct strbuf buf, int i, const char arg)
		{
		char tmp, desc = strdup(arg);
		const char prefix = "", suffix = "";
		int ret = -1;

		if (desc == NULL) {
		pr_debug4("Allocation error\n");
		return ret;
		}

		tmp = strchr(desc, '@');
		if (tmp) {
		long type_idx;
		/*
		* Isolate the string number and convert it into a
		* binary value; this will be an index to get suffix
		* of the uprobe name (defining the type)
		*/
		tmp[0] = '\0';
		type_idx = strtol(desc, NULL, 10);
		/* Check that the conversion went OK */
		if (type_idx == LONG_MIN \|\| type_idx == LONG_MAX) {
		pr_debug4("Failed to parse sdt type\n");
		goto error;
		}
		/* Check that the converted value is OK */
		if (type_idx < -8 \|\| type_idx > 8) {
		pr_debug4("Failed to get a valid sdt type\n");
		goto error;
		}
		suffix = type_to_suffix[type_idx + 8];
		/* Get rid of the sdt prefix which is now useless */
		tmp++;
		memmove(desc, tmp, strlen(tmp) + 1);
		}

		/*
		* The uprobe tracer format does not support all the
		* addressing modes (notably: in x86 the scaled mode); so, we
		* detect ',' characters, if there is just one, there is no
		* use converting the sdt arg into a uprobe one.
		*/
		if (strchr(desc, ',')) {
		pr_debug4("Skipping unsupported SDT argument; %s\n", desc);
		goto out;
		}

		/*
		* If the argument addressing mode is indirect, we must check
		* a few things...
		*/
		tmp = strchr(desc, '(');
		if (tmp) {
		int j;

		/*
		* ...if the addressing mode is indirect with a
		* positive offset (ex.: "1608(%ax)"), we need to add
		* a '+' prefix so as to be compliant with uprobe
		* format.
		*/
		if (desc[0] != '+' && desc[0] != '-')
		prefix = "+";

		/*
		* ...or if the addressing mode is indirect with a symbol
		* as offset, the argument will not be supported by
		* the uprobe tracer format; so, let's skip this one.
		*/
		for (j = 0; j < tmp - desc; j++) {
		if (desc[j] != '+' && desc[j] != '-' &&
		!isdigit(desc[j])) {
		pr_debug4("Skipping unsupported SDT argument; "
		"%s\n", desc);
		goto out;
		}
		}
		}

		/*
		* The uprobe tracer format does not support constants; if we
		* find one in the current argument, let's skip the argument.
		*/
		if (strchr(desc, '$')) {
		pr_debug4("Skipping unsupported SDT argument; %s\n", desc);
		goto out;
		}

		/*
		* The uprobe parser does not support all gas register names;
		* so, we have to replace them (ex. for x86_64: %rax -> %ax);
		* the loop below looks for the register names (starting with
		* a '%' and tries to perform the needed renamings.
		*/
		tmp = strchr(desc, '%');
		while (tmp) {
		size_t offset = tmp - desc;

		ret = sdt_rename_register(&desc, desc + offset);
		if (ret < 0)
		goto error;

		/*
		* The desc pointer might have changed; so, let's not
		* try to reuse tmp for next lookup
		*/
		tmp = strchr(desc + offset + 1, '%');
		}

		if (strbuf_addf(buf, " arg%d=%s%s%s", i + 1, prefix, desc, suffix) < 0)
		goto error;

		out:
		ret = 0;
		error:
		free(desc);
		return ret;
		}

		static char synthesize_sdt_probe_command(struct sdt_note note,
		const char *pathname,
		const char *sdtgrp)
		{
		struct strbuf buf;
		char ret = NULL, *args;
		int i, args_count;

		if (strbuf_init(&buf, 32) < 0)
		return NULL;

		if (strbuf_addf(&buf, "p:%s/%s %s:0x%llx",
		sdtgrp, note->name, pathname,
		sdt_note__get_addr(note)) < 0)
		goto error;

		if (!note->args)
		goto out;

		if (note->args) {
		args = argv_split(note->args, &args_count);

		for (i = 0; i < args_count; ++i) {
		if (synthesize_sdt_probe_arg(&buf, i, args[i]) < 0)
		goto error;
		}
		}

		out:
		ret = strbuf_detach(&buf, NULL);
		error:
		strbuf_release(&buf);
		return ret;
		}

		int probe_cache__scan_sdt(struct probe_cache pcache, const char pathname)
		{
		struct probe_cache_entry *entry = NULL;
		@@ -724,11 +885,12 @@ int probe_cache__scan_sdt(struct probe_cache pcache, const char pathname)
		entry->pev.group = strdup(sdtgrp);
		list_add_tail(&entry->node, &pcache->entries);
		}
		ret = asprintf(&buf, "p:%s/%s %s:0x%llx",
		sdtgrp, note->name, pathname,
		sdt_note__get_addr(note));
		if (ret < 0)
		buf = synthesize_sdt_probe_command(note, pathname, sdtgrp);
		if (!buf) {
		ret = -ENOMEM;
		break;
		}

		strlist__add(entry->tevlist, buf);
		free(buf);
		entry = NULL;

Admin message