[Toybox] [PATCH] Support non memory mapped access
enh
enh at google.com
Fri Oct 25 13:21:00 PDT 2024
yeah, with the later xlseek()s removed, the initial one makes sense. but i
told you that having both smelled like a bug, even if i wanted to remove
the wrong one :-)
On Fri, Oct 25, 2024 at 4:20 PM Karthik Ramasubramanian <kramasub at google.com>
wrote:
>
>
> On Thu, Oct 24, 2024 at 7:45 AM enh <enh at google.com> wrote:
>
>>
>>
>> On Wed, Oct 23, 2024 at 7:02 PM Karthikeyan Ramasubramanian <
>> kramasub at 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?").
>>
> xlseek at the top helps to maintain a consistent code structure. Also have
> removed the incorrect xlseek after xwrite. That usage is incorrect on my
> part. I will add test cases to verify in the upcoming patch revision.
>
> Thanks and Regards,
> Karthikeyan.
>
>>
>>
>>> + } 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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