From 82497fa02d60757c2cfa645cf89a79abb1435273 Mon Sep 17 00:00:00 2001 From: Jean Delvare Date: Fri, 16 Nov 2018 11:18:25 +0100 Subject: [PATCH 02/18] dmidecode: Don't use memcpy on /dev/mem on arm64 On arm64, calling memcpy on /dev/mem will cause a bus error if the start and the end of the buffer are not aligned on a 64-bit boundary. Using option --no-sysfs triggers this. Use a slow manual byte-by-byte copy in that case, to prevent the bus error. This is only a fallback path (at least on Linux) and not performance-critical anyway, as it is a one-time operation and DMI tables are usually not too large. This fixes bug #55026: https://savannah.nongnu.org/bugs/index.php?55026 Signed-off-by: Jean Delvare --- config.h | 5 +++++ util.c | 14 +++++++++++++- 2 files changed, 18 insertions(+), 1 deletion(-) diff --git a/config.h b/config.h index e39091f..4237355 100644 --- a/config.h +++ b/config.h @@ -26,4 +26,9 @@ #define ALIGNMENT_WORKAROUND #endif +/* Avoid unaligned memcpy on /dev/mem */ +#ifdef __aarch64__ +#define USE_SLOW_MEMCPY +#endif + #endif diff --git a/util.c b/util.c index eeffdae..04aaadd 100644 --- a/util.c +++ b/util.c @@ -155,6 +155,18 @@ void *read_file(off_t base, size_t *max_len, const char *filename) return p; } +static void safe_memcpy(void *dest, const void *src, size_t n) +{ +#ifdef USE_SLOW_MEMCPY + size_t i; + + for (i = 0; i < n; i++) + *((u8 *)dest + i) = *((const u8 *)src + i); +#else + memcpy(dest, src, n); +#endif +} + /* * Copy a physical memory chunk into a memory buffer. * This function allocates memory. @@ -214,7 +226,7 @@ void *mem_chunk(off_t base, size_t len, const char *devmem) if (mmp == MAP_FAILED) goto try_read; - memcpy(p, (u8 *)mmp + mmoffset, len); + safe_memcpy(p, (u8 *)mmp + mmoffset, len); if (munmap(mmp, mmoffset + len) == -1) { -- 2.24.0