From: Leo Yan leo.yan@linaro.org
mainline inclusion from mainline-v5.11-rc1 commit 75eeaddd57f4 category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/I4NGPV CVE: NA
-------------------------------------------------
When outputs strings to the decoding buffer with function snprintf(), SPE decoder needs to detects if any error returns from snprintf() and if so needs to directly bail out. If snprintf() returns success, it needs to update buffer pointer and reduce the buffer length so can continue to output the next string into the consequent memory space.
This complex logics are spreading in the function arm_spe_pkt_desc() so there has many duplicate codes for handling error detecting, increment buffer pointer and decrement buffer size.
To avoid the duplicate code, this patch introduces a new helper function arm_spe_pkt_out_string() which is used to wrap up the complex logics, and it's used by the caller arm_spe_pkt_desc(). This patch moves the variable 'blen' as the function's local variable so allows to remove the unnecessary braces and improve the readability.
This patch simplifies the return value for arm_spe_pkt_desc(): '0' means success and other values mean an error has occurred. To realize this, it relies on arm_spe_pkt_out_string()'s parameter 'err', the 'err' is a cumulative value, returns its final value if printing buffer is called for one time or multiple times. Finally, the error is handled in a central place, rather than directly bailing out in switch-cases, it returns error at the end of arm_spe_pkt_desc().
This patch changes the caller arm_spe_dump() to respect the updated return value semantics of arm_spe_pkt_desc().
Suggested-by: Dave Martin Dave.Martin@arm.com Signed-off-by: Leo Yan leo.yan@linaro.org Reviewed-by: Andre Przywara andre.przywara@arm.com Reviewed-by: Dave Martin Dave.Martin@arm.com Acked-by: Will Deacon will@kernel.org Cc: Alexander Shishkin alexander.shishkin@linux.intel.com Cc: Al Grant Al.Grant@arm.com Cc: Arnaldo Carvalho de Melo acme@kernel.org Cc: Ingo Molnar mingo@redhat.com Cc: James Clark james.clark@arm.com Cc: Jiri Olsa jolsa@redhat.com Cc: John Garry john.garry@huawei.com Cc: Mark Rutland mark.rutland@arm.com Cc: Mathieu Poirier mathieu.poirier@linaro.org Cc: Namhyung Kim namhyung@kernel.org Cc: Peter Zijlstra peterz@infradead.org Cc: Wei Li liwei391@huawei.com Link: https://lore.kernel.org/r/20201119152441.6972-2-leo.yan@linaro.org Signed-off-by: Arnaldo Carvalho de Melo acme@redhat.com Signed-off-by: Wei Li liwei391@huawei.com Reviewed-by: Yang Jihong yangjihong1@huawei.com Signed-off-by: Zheng Zengkai zhengzengkai@huawei.com --- .../arm-spe-decoder/arm-spe-pkt-decoder.c | 302 +++++++++--------- tools/perf/util/arm-spe.c | 2 +- 2 files changed, 151 insertions(+), 153 deletions(-)
diff --git a/tools/perf/util/arm-spe-decoder/arm-spe-pkt-decoder.c b/tools/perf/util/arm-spe-decoder/arm-spe-pkt-decoder.c index 671a4763fb47..fbededc1bcd4 100644 --- a/tools/perf/util/arm-spe-decoder/arm-spe-pkt-decoder.c +++ b/tools/perf/util/arm-spe-decoder/arm-spe-pkt-decoder.c @@ -9,6 +9,7 @@ #include <endian.h> #include <byteswap.h> #include <linux/bitops.h> +#include <stdarg.h>
#include "arm-spe-pkt-decoder.h"
@@ -258,192 +259,189 @@ int arm_spe_get_packet(const unsigned char *buf, size_t len, return ret; }
+static int arm_spe_pkt_out_string(int *err, char **buf_p, size_t *blen, + const char *fmt, ...) +{ + va_list ap; + int ret; + + /* Bail out if any error occurred */ + if (err && *err) + return *err; + + va_start(ap, fmt); + ret = vsnprintf(*buf_p, *blen, fmt, ap); + va_end(ap); + + if (ret < 0) { + if (err && !*err) + *err = ret; + + /* + * A return value of *blen or more means that the output was + * truncated and the buffer is overrun. + */ + } else if ((size_t)ret >= *blen) { + (*buf_p)[*blen - 1] = '\0'; + + /* + * Set *err to 'ret' to avoid overflow if tries to + * fill this buffer sequentially. + */ + if (err && !*err) + *err = ret; + } else { + *buf_p += ret; + *blen -= ret; + } + + return ret; +} + int arm_spe_pkt_desc(const struct arm_spe_pkt *packet, char *buf, size_t buf_len) { - int ret, ns, el, idx = packet->index; + int ns, el, idx = packet->index; unsigned long long payload = packet->payload; const char *name = arm_spe_pkt_name(packet->type); + char *buf_orig = buf; + size_t blen = buf_len; + int err = 0;
switch (packet->type) { case ARM_SPE_BAD: case ARM_SPE_PAD: case ARM_SPE_END: - return snprintf(buf, buf_len, "%s", name); - case ARM_SPE_EVENTS: { - size_t blen = buf_len; - - ret = 0; - ret = snprintf(buf, buf_len, "EV"); - buf += ret; - blen -= ret; - if (payload & 0x1) { - ret = snprintf(buf, buf_len, " EXCEPTION-GEN"); - buf += ret; - blen -= ret; - } - if (payload & 0x2) { - ret = snprintf(buf, buf_len, " RETIRED"); - buf += ret; - blen -= ret; - } - if (payload & 0x4) { - ret = snprintf(buf, buf_len, " L1D-ACCESS"); - buf += ret; - blen -= ret; - } - if (payload & 0x8) { - ret = snprintf(buf, buf_len, " L1D-REFILL"); - buf += ret; - blen -= ret; - } - if (payload & 0x10) { - ret = snprintf(buf, buf_len, " TLB-ACCESS"); - buf += ret; - blen -= ret; - } - if (payload & 0x20) { - ret = snprintf(buf, buf_len, " TLB-REFILL"); - buf += ret; - blen -= ret; - } - if (payload & 0x40) { - ret = snprintf(buf, buf_len, " NOT-TAKEN"); - buf += ret; - blen -= ret; - } - if (payload & 0x80) { - ret = snprintf(buf, buf_len, " MISPRED"); - buf += ret; - blen -= ret; - } + arm_spe_pkt_out_string(&err, &buf, &blen, "%s", name); + break; + case ARM_SPE_EVENTS: + arm_spe_pkt_out_string(&err, &buf, &blen, "EV"); + + if (payload & 0x1) + arm_spe_pkt_out_string(&err, &buf, &blen, " EXCEPTION-GEN"); + if (payload & 0x2) + arm_spe_pkt_out_string(&err, &buf, &blen, " RETIRED"); + if (payload & 0x4) + arm_spe_pkt_out_string(&err, &buf, &blen, " L1D-ACCESS"); + if (payload & 0x8) + arm_spe_pkt_out_string(&err, &buf, &blen, " L1D-REFILL"); + if (payload & 0x10) + arm_spe_pkt_out_string(&err, &buf, &blen, " TLB-ACCESS"); + if (payload & 0x20) + arm_spe_pkt_out_string(&err, &buf, &blen, " TLB-REFILL"); + if (payload & 0x40) + arm_spe_pkt_out_string(&err, &buf, &blen, " NOT-TAKEN"); + if (payload & 0x80) + arm_spe_pkt_out_string(&err, &buf, &blen, " MISPRED"); if (idx > 1) { - if (payload & 0x100) { - ret = snprintf(buf, buf_len, " LLC-ACCESS"); - buf += ret; - blen -= ret; - } - if (payload & 0x200) { - ret = snprintf(buf, buf_len, " LLC-REFILL"); - buf += ret; - blen -= ret; - } - if (payload & 0x400) { - ret = snprintf(buf, buf_len, " REMOTE-ACCESS"); - buf += ret; - blen -= ret; - } + if (payload & 0x100) + arm_spe_pkt_out_string(&err, &buf, &blen, " LLC-ACCESS"); + if (payload & 0x200) + arm_spe_pkt_out_string(&err, &buf, &blen, " LLC-REFILL"); + if (payload & 0x400) + arm_spe_pkt_out_string(&err, &buf, &blen, " REMOTE-ACCESS"); } - if (ret < 0) - return ret; - blen -= ret; - return buf_len - blen; - } + break; case ARM_SPE_OP_TYPE: switch (idx) { - case 0: return snprintf(buf, buf_len, "%s", payload & 0x1 ? - "COND-SELECT" : "INSN-OTHER"); - case 1: { - size_t blen = buf_len; + case 0: + arm_spe_pkt_out_string(&err, &buf, &blen, + payload & 0x1 ? "COND-SELECT" : "INSN-OTHER"); + break; + case 1: + arm_spe_pkt_out_string(&err, &buf, &blen, + payload & 0x1 ? "ST" : "LD");
- if (payload & 0x1) - ret = snprintf(buf, buf_len, "ST"); - else - ret = snprintf(buf, buf_len, "LD"); - buf += ret; - blen -= ret; if (payload & 0x2) { - if (payload & 0x4) { - ret = snprintf(buf, buf_len, " AT"); - buf += ret; - blen -= ret; - } - if (payload & 0x8) { - ret = snprintf(buf, buf_len, " EXCL"); - buf += ret; - blen -= ret; - } - if (payload & 0x10) { - ret = snprintf(buf, buf_len, " AR"); - buf += ret; - blen -= ret; - } + if (payload & 0x4) + arm_spe_pkt_out_string(&err, &buf, &blen, " AT"); + if (payload & 0x8) + arm_spe_pkt_out_string(&err, &buf, &blen, " EXCL"); + if (payload & 0x10) + arm_spe_pkt_out_string(&err, &buf, &blen, " AR"); } else if (payload & 0x4) { - ret = snprintf(buf, buf_len, " SIMD-FP"); - buf += ret; - blen -= ret; - } - if (ret < 0) - return ret; - blen -= ret; - return buf_len - blen; - } - case 2: { - size_t blen = buf_len; - - ret = snprintf(buf, buf_len, "B"); - buf += ret; - blen -= ret; - if (payload & 0x1) { - ret = snprintf(buf, buf_len, " COND"); - buf += ret; - blen -= ret; - } - if (payload & 0x2) { - ret = snprintf(buf, buf_len, " IND"); - buf += ret; - blen -= ret; - } - if (ret < 0) - return ret; - blen -= ret; - return buf_len - blen; + arm_spe_pkt_out_string(&err, &buf, &blen, " SIMD-FP"); } - default: return 0; + break; + case 2: + arm_spe_pkt_out_string(&err, &buf, &blen, "B"); + + if (payload & 0x1) + arm_spe_pkt_out_string(&err, &buf, &blen, " COND"); + if (payload & 0x2) + arm_spe_pkt_out_string(&err, &buf, &blen, " IND"); + + break; + default: + /* Unknown index */ + err = -1; + break; } + break; case ARM_SPE_DATA_SOURCE: case ARM_SPE_TIMESTAMP: - return snprintf(buf, buf_len, "%s %lld", name, payload); + arm_spe_pkt_out_string(&err, &buf, &blen, "%s %lld", name, payload); + break; case ARM_SPE_ADDRESS: switch (idx) { case 0: - case 1: ns = !!(packet->payload & NS_FLAG); + case 1: + ns = !!(packet->payload & NS_FLAG); el = (packet->payload & EL_FLAG) >> 61; payload &= ~(0xffULL << 56); - return snprintf(buf, buf_len, "%s 0x%llx el%d ns=%d", + arm_spe_pkt_out_string(&err, &buf, &blen, + "%s 0x%llx el%d ns=%d", (idx == 1) ? "TGT" : "PC", payload, el, ns); - case 2: return snprintf(buf, buf_len, "VA 0x%llx", payload); - case 3: ns = !!(packet->payload & NS_FLAG); + break; + case 2: + arm_spe_pkt_out_string(&err, &buf, &blen, + "VA 0x%llx", payload); + break; + case 3: + ns = !!(packet->payload & NS_FLAG); payload &= ~(0xffULL << 56); - return snprintf(buf, buf_len, "PA 0x%llx ns=%d", - payload, ns); - default: return 0; + arm_spe_pkt_out_string(&err, &buf, &blen, + "PA 0x%llx ns=%d", payload, ns); + break; + default: + /* Unknown index */ + err = -1; + break; } + break; case ARM_SPE_CONTEXT: - return snprintf(buf, buf_len, "%s 0x%lx el%d", name, - (unsigned long)payload, idx + 1); - case ARM_SPE_COUNTER: { - size_t blen = buf_len; - - ret = snprintf(buf, buf_len, "%s %d ", name, - (unsigned short)payload); - buf += ret; - blen -= ret; + arm_spe_pkt_out_string(&err, &buf, &blen, "%s 0x%lx el%d", + name, (unsigned long)payload, idx + 1); + break; + case ARM_SPE_COUNTER: + arm_spe_pkt_out_string(&err, &buf, &blen, "%s %d ", name, + (unsigned short)payload); switch (idx) { - case 0: ret = snprintf(buf, buf_len, "TOT"); break; - case 1: ret = snprintf(buf, buf_len, "ISSUE"); break; - case 2: ret = snprintf(buf, buf_len, "XLAT"); break; - default: ret = 0; + case 0: + arm_spe_pkt_out_string(&err, &buf, &blen, "TOT"); + break; + case 1: + arm_spe_pkt_out_string(&err, &buf, &blen, "ISSUE"); + break; + case 2: + arm_spe_pkt_out_string(&err, &buf, &blen, "XLAT"); + break; + default: + break; } - if (ret < 0) - return ret; - blen -= ret; - return buf_len - blen; - } + break; default: + /* Unknown packet type */ + err = -1; break; }
- return snprintf(buf, buf_len, "%s 0x%llx (%d)", - name, payload, packet->index); + /* Output raw data if detect any error */ + if (err) { + err = 0; + arm_spe_pkt_out_string(&err, &buf_orig, &buf_len, "%s 0x%llx (%d)", + name, payload, packet->index); + } + + return err; } diff --git a/tools/perf/util/arm-spe.c b/tools/perf/util/arm-spe.c index 3882a5360ada..8901a1656a41 100644 --- a/tools/perf/util/arm-spe.c +++ b/tools/perf/util/arm-spe.c @@ -113,7 +113,7 @@ static void arm_spe_dump(struct arm_spe *spe __maybe_unused, if (ret > 0) { ret = arm_spe_pkt_desc(&packet, desc, ARM_SPE_PKT_DESC_MAX); - if (ret > 0) + if (!ret) color_fprintf(stdout, color, " %s\n", desc); } else { color_fprintf(stdout, color, " Bad packet!\n");