On Wed, Oct 23, 2024 at 7:02 PM Karthikeyan Ramasubramanian <
krama...@google.com> wrote:
> Add --no-mmap flag to indicate seek and read/write access. This allows
> accessing devices that do not support mapping into memory - eg.
> /dev/nvram, /dev/msr0 etc.
>
> Also currently only WIDTH bytes are mapped into memory even when more
> data is accessed. Fix this by mapping WIDTH * number of data.
>
> Test: ./post_update.sh && m toybox. Push devmem test into DUT and access
> /dev/mem through memory mapped access, /dev/nvram & /dev/msr* through
> non memory-mapped access.
>
> ---
> android/device/generated/flags.h | 8 +++--
> android/device/generated/help.h | 2 +-
> android/device/generated/newtoys.h | 2 +-
> android/linux/generated/flags.h | 8 +++--
> android/linux/generated/help.h | 2 +-
> android/linux/generated/newtoys.h | 2 +-
> android/mac/generated/flags.h | 8 +++--
> android/mac/generated/help.h | 2 +-
> android/mac/generated/newtoys.h | 2 +-
>
(these files only exist in AOSP ... sorry, i should have said to apply your
devmem.c change to a fresh `git clone` of upstream!)
> toys/other/devmem.c | 49 +++++++++++++++++++-----------
> 10 files changed, 53 insertions(+), 32 deletions(-)
>
> diff --git a/android/device/generated/flags.h
> b/android/device/generated/flags.h
> index 9c056073..aa13b2c6 100644
> --- a/android/device/generated/flags.h
> +++ b/android/device/generated/flags.h
> @@ -641,13 +641,14 @@
> #undef FOR_demo_utf8towc
> #endif
>
> -// devmem <1(no-sync)f: <1(no-sync)f:
> +// devmem <1(no-sync)(no-mmap)f: <1(no-sync)(no-mmap)f:
> #undef OPTSTR_devmem
> -#define OPTSTR_devmem "<1(no-sync)f:"
> +#define OPTSTR_devmem "<1(no-sync)(no-mmap)f:"
> #ifdef CLEANUP_devmem
> #undef CLEANUP_devmem
> #undef FOR_devmem
> #undef FLAG_f
> +#undef FLAG_no_mmap
> #undef FLAG_no_sync
> #endif
>
> @@ -4547,7 +4548,8 @@
> #define TT this.devmem
> #endif
> #define FLAG_f (1LL<<0)
> -#define FLAG_no_sync (1LL<<1)
> +#define FLAG_no_mmap (1LL<<1)
> +#define FLAG_no_sync (1LL<<2)
> #endif
>
> #ifdef FOR_df
> diff --git a/android/device/generated/help.h
> b/android/device/generated/help.h
> index 92dd3687..87f92453 100644
> --- a/android/device/generated/help.h
> +++ b/android/device/generated/help.h
> @@ -330,7 +330,7 @@
>
> #define HELP_dos2unix "usage: dos2unix [FILE...]\n\nConvert newline
> format from dos \"\\r\\n\" to unix \"\\n\".\nIf no files listed copy from
> stdin, \"-\" is a synonym for stdin."
>
> -#define HELP_devmem "usage: devmem [-f FILE] ADDR [WIDTH
> [DATA...]]\n\nRead/write physical addresses. WIDTH is 1, 2, 4, or 8 bytes
> (default 4).\nPrefix ADDR with 0x for hexadecimal, output is in same base
> as address.\n\n-f FILE File to operate on (default
> /dev/mem)\n--no-sync Don't open the file with O_SYNC (for cached
> access)"
> +#define HELP_devmem "usage: devmem [-f FILE] ADDR [WIDTH
> [DATA...]]\n\nRead/write physical addresses. WIDTH is 1, 2, 4, or 8 bytes
> (default 4).\nPrefix ADDR with 0x for hexadecimal, output is in same base
> as address.\n\n-f FILE File to operate on (default
> /dev/mem)\n--no-sync Don't open the file with O_SYNC (for cached
> access)\n--no-mmap Don't mmap the file"
>
> #define HELP_count "usage: count [-l]\n\n-l Long output (total bytes,
> human readable, transfer rate, elapsed time)\n\nCopy stdin to stdout,
> displaying simple progress indicator to stderr."
>
> diff --git a/android/device/generated/newtoys.h
> b/android/device/generated/newtoys.h
> index c41eb83f..e99f4f1c 100644
> --- a/android/device/generated/newtoys.h
> +++ b/android/device/generated/newtoys.h
> @@ -60,7 +60,7 @@ USE_DEMO_MANY_OPTIONS(NEWTOY(demo_many_options,
> "ZYXWVUTSRQPONMLKJIHGFEDCBAzyxwv
> USE_DEMO_NUMBER(NEWTOY(demo_number, "D#=3<3M#<0hcdbs", TOYFLAG_BIN))
> USE_DEMO_SCANKEY(NEWTOY(demo_scankey, 0, TOYFLAG_BIN))
> USE_DEMO_UTF8TOWC(NEWTOY(demo_utf8towc, 0, TOYFLAG_USR|TOYFLAG_BIN))
> -USE_DEVMEM(NEWTOY(devmem, "<1(no-sync)f:", TOYFLAG_USR|TOYFLAG_SBIN))
> +USE_DEVMEM(NEWTOY(devmem, "<1(no-sync)(no-mmap)f:",
> TOYFLAG_USR|TOYFLAG_SBIN))
> USE_DF(NEWTOY(df, "HPkhit*a[-HPh]", TOYFLAG_BIN))
> USE_DHCP(NEWTOY(dhcp, "V:H:F:x*r:O*A#<0=20T#<0=3t#<0=3s:p:i:SBRCaovqnbf",
> TOYFLAG_SBIN|TOYFLAG_ROOTONLY))
> USE_DHCP6(NEWTOY(dhcp6, "r:A#<0T#<0t#<0s:p:i:SRvqnbf",
> TOYFLAG_SBIN|TOYFLAG_ROOTONLY))
> diff --git a/android/linux/generated/flags.h
> b/android/linux/generated/flags.h
> index e73e4bf8..27fcd60d 100644
> --- a/android/linux/generated/flags.h
> +++ b/android/linux/generated/flags.h
> @@ -641,13 +641,14 @@
> #undef FOR_demo_utf8towc
> #endif
>
> -// devmem <1(no-sync)f:
> +// devmem <1(no-sync)(no-mmap)f:
> #undef OPTSTR_devmem
> -#define OPTSTR_devmem "<1(no-sync)f:"
> +#define OPTSTR_devmem "<1(no-sync)(no-mmap)f:"
> #ifdef CLEANUP_devmem
> #undef CLEANUP_devmem
> #undef FOR_devmem
> #undef FLAG_f
> +#undef FLAG_no_mmap
> #undef FLAG_no_sync
> #endif
>
> @@ -4547,7 +4548,8 @@
> #define TT this.devmem
> #endif
> #define FLAG_f (FORCED_FLAG<<0)
> -#define FLAG_no_sync (FORCED_FLAG<<1)
> +#define FLAG_no_mmap (FORCED_FLAG<<1)
> +#define FLAG_no_sync (FORCED_FLAG<<2)
> #endif
>
> #ifdef FOR_df
> diff --git a/android/linux/generated/help.h
> b/android/linux/generated/help.h
> index f25a0785..eccc159a 100644
> --- a/android/linux/generated/help.h
> +++ b/android/linux/generated/help.h
> @@ -332,7 +332,7 @@
>
> #define HELP_dos2unix "usage: dos2unix [FILE...]\n\nConvert newline
> format from dos \"\\r\\n\" to unix \"\\n\".\nIf no files listed copy from
> stdin, \"-\" is a synonym for stdin."
>
> -#define HELP_devmem "usage: devmem [-f FILE] ADDR [WIDTH
> [DATA...]]\n\nRead/write physical addresses. WIDTH is 1, 2, 4, or 8 bytes
> (default 4).\nPrefix ADDR with 0x for hexadecimal, output is in same base
> as address.\n\n-f FILE File to operate on (default
> /dev/mem)\n--no-sync Don't open the file with O_SYNC (for cached
> access)"
> +#define HELP_devmem "usage: devmem [-f FILE] ADDR [WIDTH
> [DATA...]]\n\nRead/write physical addresses. WIDTH is 1, 2, 4, or 8 bytes
> (default 4).\nPrefix ADDR with 0x for hexadecimal, output is in same base
> as address.\n\n-f FILE File to operate on (default
> /dev/mem)\n--no-sync Don't open the file with O_SYNC (for cached
> access)\n--no-mmap Don't mmap the file"
>
> #define HELP_count "usage: count [-l]\n\n-l Long output (total bytes,
> human readable, transfer rate, elapsed time)\n\nCopy stdin to stdout,
> displaying simple progress indicator to stderr."
>
> diff --git a/android/linux/generated/newtoys.h
> b/android/linux/generated/newtoys.h
> index c41eb83f..e99f4f1c 100644
> --- a/android/linux/generated/newtoys.h
> +++ b/android/linux/generated/newtoys.h
> @@ -60,7 +60,7 @@ USE_DEMO_MANY_OPTIONS(NEWTOY(demo_many_options,
> "ZYXWVUTSRQPONMLKJIHGFEDCBAzyxwv
> USE_DEMO_NUMBER(NEWTOY(demo_number, "D#=3<3M#<0hcdbs", TOYFLAG_BIN))
> USE_DEMO_SCANKEY(NEWTOY(demo_scankey, 0, TOYFLAG_BIN))
> USE_DEMO_UTF8TOWC(NEWTOY(demo_utf8towc, 0, TOYFLAG_USR|TOYFLAG_BIN))
> -USE_DEVMEM(NEWTOY(devmem, "<1(no-sync)f:", TOYFLAG_USR|TOYFLAG_SBIN))
> +USE_DEVMEM(NEWTOY(devmem, "<1(no-sync)(no-mmap)f:",
> TOYFLAG_USR|TOYFLAG_SBIN))
> USE_DF(NEWTOY(df, "HPkhit*a[-HPh]", TOYFLAG_BIN))
> USE_DHCP(NEWTOY(dhcp, "V:H:F:x*r:O*A#<0=20T#<0=3t#<0=3s:p:i:SBRCaovqnbf",
> TOYFLAG_SBIN|TOYFLAG_ROOTONLY))
> USE_DHCP6(NEWTOY(dhcp6, "r:A#<0T#<0t#<0s:p:i:SRvqnbf",
> TOYFLAG_SBIN|TOYFLAG_ROOTONLY))
> diff --git a/android/mac/generated/flags.h b/android/mac/generated/flags.h
> index 504dd782..59fd25af 100644
> --- a/android/mac/generated/flags.h
> +++ b/android/mac/generated/flags.h
> @@ -641,13 +641,14 @@
> #undef FOR_demo_utf8towc
> #endif
>
> -// devmem <1(no-sync)f:
> +// devmem <1(no-sync)(no-mmap)f:
> #undef OPTSTR_devmem
> -#define OPTSTR_devmem "<1(no-sync)f:"
> +#define OPTSTR_devmem "<1(no-sync)(no-mmap)f:"
> #ifdef CLEANUP_devmem
> #undef CLEANUP_devmem
> #undef FOR_devmem
> #undef FLAG_f
> +#undef FLAG_no_mmap
> #undef FLAG_no_sync
> #endif
>
> @@ -4547,7 +4548,8 @@
> #define TT this.devmem
> #endif
> #define FLAG_f (FORCED_FLAG<<0)
> -#define FLAG_no_sync (FORCED_FLAG<<1)
> +#define FLAG_no_mmap (FORCED_FLAG<<1)
> +#define FLAG_no_sync (FORCED_FLAG<<2)
> #endif
>
> #ifdef FOR_df
> diff --git a/android/mac/generated/help.h b/android/mac/generated/help.h
> index f25a0785..eccc159a 100644
> --- a/android/mac/generated/help.h
> +++ b/android/mac/generated/help.h
> @@ -332,7 +332,7 @@
>
> #define HELP_dos2unix "usage: dos2unix [FILE...]\n\nConvert newline
> format from dos \"\\r\\n\" to unix \"\\n\".\nIf no files listed copy from
> stdin, \"-\" is a synonym for stdin."
>
> -#define HELP_devmem "usage: devmem [-f FILE] ADDR [WIDTH
> [DATA...]]\n\nRead/write physical addresses. WIDTH is 1, 2, 4, or 8 bytes
> (default 4).\nPrefix ADDR with 0x for hexadecimal, output is in same base
> as address.\n\n-f FILE File to operate on (default
> /dev/mem)\n--no-sync Don't open the file with O_SYNC (for cached
> access)"
> +#define HELP_devmem "usage: devmem [-f FILE] ADDR [WIDTH
> [DATA...]]\n\nRead/write physical addresses. WIDTH is 1, 2, 4, or 8 bytes
> (default 4).\nPrefix ADDR with 0x for hexadecimal, output is in same base
> as address.\n\n-f FILE File to operate on (default
> /dev/mem)\n--no-sync Don't open the file with O_SYNC (for cached
> access)\n--no-mmap Don't mmap the file"
>
> #define HELP_count "usage: count [-l]\n\n-l Long output (total bytes,
> human readable, transfer rate, elapsed time)\n\nCopy stdin to stdout,
> displaying simple progress indicator to stderr."
>
> diff --git a/android/mac/generated/newtoys.h
> b/android/mac/generated/newtoys.h
> index c41eb83f..e99f4f1c 100644
> --- a/android/mac/generated/newtoys.h
> +++ b/android/mac/generated/newtoys.h
> @@ -60,7 +60,7 @@ USE_DEMO_MANY_OPTIONS(NEWTOY(demo_many_options,
> "ZYXWVUTSRQPONMLKJIHGFEDCBAzyxwv
> USE_DEMO_NUMBER(NEWTOY(demo_number, "D#=3<3M#<0hcdbs", TOYFLAG_BIN))
> USE_DEMO_SCANKEY(NEWTOY(demo_scankey, 0, TOYFLAG_BIN))
> USE_DEMO_UTF8TOWC(NEWTOY(demo_utf8towc, 0, TOYFLAG_USR|TOYFLAG_BIN))
> -USE_DEVMEM(NEWTOY(devmem, "<1(no-sync)f:", TOYFLAG_USR|TOYFLAG_SBIN))
> +USE_DEVMEM(NEWTOY(devmem, "<1(no-sync)(no-mmap)f:",
> TOYFLAG_USR|TOYFLAG_SBIN))
> USE_DF(NEWTOY(df, "HPkhit*a[-HPh]", TOYFLAG_BIN))
> USE_DHCP(NEWTOY(dhcp, "V:H:F:x*r:O*A#<0=20T#<0=3t#<0=3s:p:i:SBRCaovqnbf",
> TOYFLAG_SBIN|TOYFLAG_ROOTONLY))
> USE_DHCP6(NEWTOY(dhcp6, "r:A#<0T#<0t#<0s:p:i:SRvqnbf",
> TOYFLAG_SBIN|TOYFLAG_ROOTONLY))
> diff --git a/toys/other/devmem.c b/toys/other/devmem.c
> index 9f9a9e03..f37e8ef3 100644
> --- a/toys/other/devmem.c
> +++ b/toys/other/devmem.c
> @@ -2,7 +2,7 @@
> *
> * Copyright 2019 The Android Open Source Project
>
> -USE_DEVMEM(NEWTOY(devmem, "<1(no-sync)f:", TOYFLAG_USR|TOYFLAG_SBIN))
> +USE_DEVMEM(NEWTOY(devmem, "<1(no-sync)(no-mmap)f:",
> TOYFLAG_USR|TOYFLAG_SBIN))
>
> config DEVMEM
> bool "devmem"
> @@ -15,6 +15,7 @@ config DEVMEM
>
> -f FILE File to operate on (default /dev/mem)
> --no-sync Don't open the file with O_SYNC (for cached access)
> + --no-mmap Don't mmap the file
> */
>
> #define FOR_devmem
> @@ -62,32 +63,46 @@ void devmem_main(void)
> flags = writing ? O_RDWR : O_RDONLY;
> if (!FLAG(no_sync)) flags |= O_SYNC;
> fd = xopen(TT.f ?: "/dev/mem", flags);
> - map_off = addr & ~(page_size - 1ULL);
> - map_len = (addr+bytes-map_off);
> - map = xmmap(0, map_len, writing ? PROT_WRITE : PROT_READ, MAP_SHARED,
> fd,
> - map_off);
> - p = map + (addr & (page_size - 1));
> - close(fd);
> + if (FLAG(no_mmap)) xlseek(fd, addr, SEEK_SET);
> + else {
> + map_off = addr & ~(page_size - 1ULL);
> + map_len = addr + (writing ? (toys.optc - 2) * bytes : bytes) -
> map_off;
> + map = xmmap(0, map_len, writing ? PROT_WRITE : PROT_READ,
> MAP_SHARED, fd,
> + map_off);
> + p = map + (addr & (page_size - 1));
> + close(fd);
> + }
> } else p = (void *)addr;
>
> // Not using peek()/poke() because registers care about size of
> read/write.
> if (writing) {
> for (int i = 2; i < toys.optc; i++) {
> data = xatolu(toys.optargs[i], bytes);
> - if (bytes==1) *(char *)p = data;
> - else if (bytes==2) *(unsigned short *)p = data;
> - else if (bytes==4) *(unsigned int *)p = data;
> - else if (sizeof(long)==8 && bytes==8) *(unsigned long *)p = data;
> - p += bytes;
> + if (FLAG(no_mmap)) {
> + xwrite(fd, &data, bytes);
> + xlseek(fd, bytes, SEEK_CUR);
>
is this clearer if you remove the xlseek at the top, and move this xlseek()
before the xwrite()? i know that would mean incrementing addr, but at least
the reasoning is localized (and you don't have (a) "aren't these the wrong
way round?" and (b) "do we actually need a SEEK_CUR? why didn't the write
advance the file offset?").
> + } else {
> + if (bytes==1) *(char *)p = data;
> + else if (bytes==2) *(unsigned short *)p = data;
> + else if (bytes==4) *(unsigned int *)p = data;
> + else if (sizeof(long)==8 && bytes==8) *(unsigned long *)p = data;
> + p += bytes;
> + }
> }
> } else {
> - if (bytes==1) data = *(char *)p;
> - else if (bytes==2) data = *(unsigned short *)p;
> - else if (bytes==4) data = *(unsigned int *)p;
> - else if (sizeof(long)==8 && bytes==8) data = *(unsigned long *)p;
> + if (FLAG(no_mmap)) xread(fd, &data, bytes);
> + else {
> + if (bytes==1) data = *(char *)p;
> + else if (bytes==2) data = *(unsigned short *)p;
> + else if (bytes==4) data = *(unsigned int *)p;
> + else if (sizeof(long)==8 && bytes==8) data = *(unsigned long *)p;
> + }
> printf((!strchr(*toys.optargs, 'x')) ? "%0*ld\n" : "0x%0*lx\n",
> bytes*2, data);
> }
>
> - if (CFG_TOYBOX_FORK) munmap(map, map_len);
> + if (CFG_TOYBOX_FORK) {
> + if (FLAG(no_mmap)) close(fd);
> + else munmap(map, map_len);
> + }
> }
> --
> 2.47.0.105.g07ac214952-goog
>
>
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