diff options
Diffstat (limited to 'package/busybox/busybox-1.16.2-devmem.patch')
| -rw-r--r-- | package/busybox/busybox-1.16.2-devmem.patch | 76 |
1 files changed, 76 insertions, 0 deletions
diff --git a/package/busybox/busybox-1.16.2-devmem.patch b/package/busybox/busybox-1.16.2-devmem.patch new file mode 100644 index 000000000..f7d1d1df7 --- /dev/null +++ b/package/busybox/busybox-1.16.2-devmem.patch @@ -0,0 +1,76 @@ +From 351ef7188a1a2e2f154bbda6f703c2d3f4af6d79 Mon Sep 17 00:00:00 2001 +From: Denys Vlasenko <vda.linux@googlemail.com> +Date: Wed, 14 Apr 2010 13:37:25 -0700 +Subject: [PATCH] devmem: map two pages only if it is necessary + +function old new delta +devmem_main 463 469 +6 + +Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com> +--- + miscutils/devmem.c | 21 ++++++++++++++------- + 1 files changed, 14 insertions(+), 7 deletions(-) + +diff --git a/miscutils/devmem.c b/miscutils/devmem.c +index e13dedc..39b5808 100644 +--- a/miscutils/devmem.c ++++ b/miscutils/devmem.c +@@ -13,9 +13,9 @@ int devmem_main(int argc UNUSED_PARAM, char **argv) + uint64_t read_result; + uint64_t writeval = writeval; /* for compiler */ + off_t target; +- unsigned page_size = getpagesize(); ++ unsigned page_size, mapped_size, offset_in_page; + int fd; +- int width = 8 * sizeof(int); ++ unsigned width = 8 * sizeof(int); + + /* devmem ADDRESS [WIDTH [VALUE]] */ + // TODO: options? +@@ -50,15 +50,22 @@ int devmem_main(int argc UNUSED_PARAM, char **argv) + if (argv[3]) + writeval = bb_strtoull(argv[3], NULL, 0); + } else { /* argv[2] == NULL */ +- /* make argv[3] to be a valid thing to use */ ++ /* make argv[3] to be a valid thing to fetch */ + argv--; + } + if (errno) +- bb_show_usage(); /* bb_strtouXX failed */ ++ bb_show_usage(); /* one of bb_strtouXX failed */ + + fd = xopen("/dev/mem", argv[3] ? (O_RDWR | O_SYNC) : (O_RDONLY | O_SYNC)); ++ mapped_size = page_size = getpagesize(); ++ offset_in_page = (unsigned)target & (page_size - 1); ++ if (offset_in_page + width > page_size) { ++ /* This access spans pages. ++ * Must map two pages to make it possible: */ ++ mapped_size *= 2; ++ } + map_base = mmap(NULL, +- page_size * 2 /* in case value spans page */, ++ mapped_size, + argv[3] ? (PROT_READ | PROT_WRITE) : PROT_READ, + MAP_SHARED, + fd, +@@ -68,7 +75,7 @@ int devmem_main(int argc UNUSED_PARAM, char **argv) + + // printf("Memory mapped at address %p.\n", map_base); + +- virt_addr = (char*)map_base + (target & (page_size - 1)); ++ virt_addr = (char*)map_base + offset_in_page; + + if (!argv[3]) { + switch (width) { +@@ -119,7 +126,7 @@ int devmem_main(int argc UNUSED_PARAM, char **argv) + } + + if (ENABLE_FEATURE_CLEAN_UP) { +- if (munmap(map_base, page_size * 2) == -1) ++ if (munmap(map_base, mapped_size) == -1) + bb_perror_msg_and_die("munmap"); + close(fd); + } +-- +1.7.1 + |