[PATCH] fs/squashfs: use do_div function for math
From: Sean Nyekjaer sean.nyekjaer.ext@siemensgamesa.com
When compling for x86: ld.bfd: fs/squashfs/sqfs.o: in function `sqfs_read': u-boot/fs/squashfs/sqfs.c:1443: undefined reference to `__udivmoddi4' ld.bfd: u-boot/fs/squashfs/sqfs.c:1521: undefined reference to `__udivmoddi4'
Signed-off-by: Sean Nyekjaer sean.nyekjaer.ext@siemensgamesa.com --- fs/squashfs/sqfs.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/fs/squashfs/sqfs.c b/fs/squashfs/sqfs.c index 5d9c52af80..6405db4ff3 100644 --- a/fs/squashfs/sqfs.c +++ b/fs/squashfs/sqfs.c @@ -8,6 +8,7 @@ */
#include <asm/unaligned.h> +#include <div64.h> #include <errno.h> #include <fs.h> #include <linux/types.h> @@ -1440,7 +1441,7 @@ int sqfs_read(const char *filename, void *buf, loff_t offset, loff_t len, }
for (j = 0; j < datablk_count; j++) { - start = data_offset / ctxt.cur_dev->blksz; + start = do_div(data_offset, ctxt.cur_dev->blksz); table_size = SQFS_BLOCK_SIZE(finfo.blk_sizes[j]); table_offset = data_offset - (start * ctxt.cur_dev->blksz); n_blks = DIV_ROUND_UP(table_size + table_offset, @@ -1516,7 +1517,7 @@ int sqfs_read(const char *filename, void *buf, loff_t offset, loff_t len, goto out; }
- start = frag_entry.start / ctxt.cur_dev->blksz; + start = do_div(frag_entry.start, ctxt.cur_dev->blksz); table_size = SQFS_BLOCK_SIZE(frag_entry.size); table_offset = frag_entry.start - (start * ctxt.cur_dev->blksz); n_blks = DIV_ROUND_UP(table_size + table_offset, ctxt.cur_dev->blksz);
On Thu, May 05, 2022 at 11:26:37AM +0200, Sean Nyekjaer wrote:
From: Sean Nyekjaer sean.nyekjaer.ext@siemensgamesa.com
When compling for x86: ld.bfd: fs/squashfs/sqfs.o: in function `sqfs_read': u-boot/fs/squashfs/sqfs.c:1443: undefined reference to `__udivmoddi4' ld.bfd: u-boot/fs/squashfs/sqfs.c:1521: undefined reference to `__udivmoddi4'
Signed-off-by: Sean Nyekjaer sean.nyekjaer.ext@siemensgamesa.com
fs/squashfs/sqfs.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/fs/squashfs/sqfs.c b/fs/squashfs/sqfs.c index 5d9c52af80..6405db4ff3 100644 --- a/fs/squashfs/sqfs.c +++ b/fs/squashfs/sqfs.c @@ -8,6 +8,7 @@ */
#include <asm/unaligned.h> +#include <div64.h> #include <errno.h> #include <fs.h> #include <linux/types.h> @@ -1440,7 +1441,7 @@ int sqfs_read(const char *filename, void *buf, loff_t offset, loff_t len, }
for (j = 0; j < datablk_count; j++) {
start = data_offset / ctxt.cur_dev->blksz;
start = do_div(data_offset, ctxt.cur_dev->blksz);@@ -1516,7 +1517,7 @@ int sqfs_read(const char *filename, void *buf, loff_t offset, loff_t len, goto out; }
- start = frag_entry.start / ctxt.cur_dev->blksz;
- start = do_div(frag_entry.start, ctxt.cur_dev->blksz); table_size = SQFS_BLOCK_SIZE(frag_entry.size); table_offset = frag_entry.start - (start * ctxt.cur_dev->blksz); n_blks = DIV_ROUND_UP(table_size + table_offset, ctxt.cur_dev->blksz);
Adding maintainers...
Hello,
trini@konsulko.com wrote on Thu, 5 May 2022 09:15:00 -0400:
On Thu, May 05, 2022 at 11:26:37AM +0200, Sean Nyekjaer wrote:
From: Sean Nyekjaer sean.nyekjaer.ext@siemensgamesa.com
When compling for x86: ld.bfd: fs/squashfs/sqfs.o: in function `sqfs_read': u-boot/fs/squashfs/sqfs.c:1443: undefined reference to `__udivmoddi4' ld.bfd: u-boot/fs/squashfs/sqfs.c:1521: undefined reference to `__udivmoddi4'
Signed-off-by: Sean Nyekjaer sean.nyekjaer.ext@siemensgamesa.com
fs/squashfs/sqfs.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/fs/squashfs/sqfs.c b/fs/squashfs/sqfs.c index 5d9c52af80..6405db4ff3 100644 --- a/fs/squashfs/sqfs.c +++ b/fs/squashfs/sqfs.c @@ -8,6 +8,7 @@ */
#include <asm/unaligned.h> +#include <div64.h> #include <errno.h> #include <fs.h> #include <linux/types.h> @@ -1440,7 +1441,7 @@ int sqfs_read(const char *filename, void *buf, loff_t offset, loff_t len, }
for (j = 0; j < datablk_count; j++) {
start = data_offset / ctxt.cur_dev->blksz;
start = do_div(data_offset, ctxt.cur_dev->blksz);@@ -1516,7 +1517,7 @@ int sqfs_read(const char *filename, void *buf, loff_t offset, loff_t len, goto out; }
- start = frag_entry.start / ctxt.cur_dev->blksz;
- start = do_div(frag_entry.start, ctxt.cur_dev->blksz); table_size = SQFS_BLOCK_SIZE(frag_entry.size); table_offset = frag_entry.start - (start * ctxt.cur_dev->blksz); n_blks = DIV_ROUND_UP(table_size + table_offset, ctxt.cur_dev->blksz);
Adding maintainers...
I guess that's a correct fix, so
Reviewed-by: Miquel Raynal miquel.raynal@bootlin.com
Thanks, Miquèl
On Monday 09 May 2022 15:08:15 Miquel Raynal wrote:
Hello,
trini@konsulko.com wrote on Thu, 5 May 2022 09:15:00 -0400:
On Thu, May 05, 2022 at 11:26:37AM +0200, Sean Nyekjaer wrote:
From: Sean Nyekjaer sean.nyekjaer.ext@siemensgamesa.com
When compling for x86: ld.bfd: fs/squashfs/sqfs.o: in function `sqfs_read': u-boot/fs/squashfs/sqfs.c:1443: undefined reference to `__udivmoddi4' ld.bfd: u-boot/fs/squashfs/sqfs.c:1521: undefined reference to `__udivmoddi4'
Signed-off-by: Sean Nyekjaer sean.nyekjaer.ext@siemensgamesa.com
fs/squashfs/sqfs.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/fs/squashfs/sqfs.c b/fs/squashfs/sqfs.c index 5d9c52af80..6405db4ff3 100644 --- a/fs/squashfs/sqfs.c +++ b/fs/squashfs/sqfs.c @@ -8,6 +8,7 @@ */
#include <asm/unaligned.h> +#include <div64.h> #include <errno.h> #include <fs.h> #include <linux/types.h> @@ -1440,7 +1441,7 @@ int sqfs_read(const char *filename, void *buf, loff_t offset, loff_t len, }
for (j = 0; j < datablk_count; j++) {
start = data_offset / ctxt.cur_dev->blksz;
start = do_div(data_offset, ctxt.cur_dev->blksz);@@ -1516,7 +1517,7 @@ int sqfs_read(const char *filename, void *buf, loff_t offset, loff_t len, goto out; }
- start = frag_entry.start / ctxt.cur_dev->blksz;
- start = do_div(frag_entry.start, ctxt.cur_dev->blksz); table_size = SQFS_BLOCK_SIZE(frag_entry.size); table_offset = frag_entry.start - (start * ctxt.cur_dev->blksz); n_blks = DIV_ROUND_UP(table_size + table_offset, ctxt.cur_dev->blksz);
Adding maintainers...
I guess that's a correct fix, so
Reviewed-by: Miquel Raynal miquel.raynal@bootlin.com
Thanks, Miquèl
Hello! do_div() macro modifies its first argument. It is correct? Because previous code did not modify anything.
On Thursday 12 May 2022 12:19:01 Pali Rohár wrote:
On Monday 09 May 2022 15:08:15 Miquel Raynal wrote:
Hello,
trini@konsulko.com wrote on Thu, 5 May 2022 09:15:00 -0400:
On Thu, May 05, 2022 at 11:26:37AM +0200, Sean Nyekjaer wrote:
From: Sean Nyekjaer sean.nyekjaer.ext@siemensgamesa.com
When compling for x86: ld.bfd: fs/squashfs/sqfs.o: in function `sqfs_read': u-boot/fs/squashfs/sqfs.c:1443: undefined reference to `__udivmoddi4' ld.bfd: u-boot/fs/squashfs/sqfs.c:1521: undefined reference to `__udivmoddi4'
Signed-off-by: Sean Nyekjaer sean.nyekjaer.ext@siemensgamesa.com
fs/squashfs/sqfs.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/fs/squashfs/sqfs.c b/fs/squashfs/sqfs.c index 5d9c52af80..6405db4ff3 100644 --- a/fs/squashfs/sqfs.c +++ b/fs/squashfs/sqfs.c @@ -8,6 +8,7 @@ */
#include <asm/unaligned.h> +#include <div64.h> #include <errno.h> #include <fs.h> #include <linux/types.h> @@ -1440,7 +1441,7 @@ int sqfs_read(const char *filename, void *buf, loff_t offset, loff_t len, }
for (j = 0; j < datablk_count; j++) {
start = data_offset / ctxt.cur_dev->blksz;
start = do_div(data_offset, ctxt.cur_dev->blksz);@@ -1516,7 +1517,7 @@ int sqfs_read(const char *filename, void *buf, loff_t offset, loff_t len, goto out; }
- start = frag_entry.start / ctxt.cur_dev->blksz;
- start = do_div(frag_entry.start, ctxt.cur_dev->blksz); table_size = SQFS_BLOCK_SIZE(frag_entry.size); table_offset = frag_entry.start - (start * ctxt.cur_dev->blksz); n_blks = DIV_ROUND_UP(table_size + table_offset, ctxt.cur_dev->blksz);
Adding maintainers...
I guess that's a correct fix, so
Reviewed-by: Miquel Raynal miquel.raynal@bootlin.com
Thanks, Miquèl
Hello! do_div() macro modifies its first argument. It is correct? Because previous code did not modify anything.
* The semantics of do_div() are: * * u32 do_div(u64 *n, u32 base) * { * u32 remainder = *n % base; * *n = *n / base; * return remainder; * }
And this patch replaced:
start = data_offset / ctxt.cur_dev->blksz;
by:
start = do_div(data_offset, ctxt.cur_dev->blksz);
which expands to:
start = data_offset % ctxt.cur_dev->blksz; data_offset = data_offset / ctxt.cur_dev->blksz;
Which is wrong as it calculates something totally different.
So this patch is incorrect.
On Thu, May 12, 2022 at 12:24:01PM +0200, Pali Rohár wrote:
On Thursday 12 May 2022 12:19:01 Pali Rohár wrote:
On Monday 09 May 2022 15:08:15 Miquel Raynal wrote:
Hello,
trini@konsulko.com wrote on Thu, 5 May 2022 09:15:00 -0400:
On Thu, May 05, 2022 at 11:26:37AM +0200, Sean Nyekjaer wrote:
From: Sean Nyekjaer sean.nyekjaer.ext@siemensgamesa.com
When compling for x86: ld.bfd: fs/squashfs/sqfs.o: in function `sqfs_read': u-boot/fs/squashfs/sqfs.c:1443: undefined reference to `__udivmoddi4' ld.bfd: u-boot/fs/squashfs/sqfs.c:1521: undefined reference to `__udivmoddi4'
Signed-off-by: Sean Nyekjaer sean.nyekjaer.ext@siemensgamesa.com
fs/squashfs/sqfs.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/fs/squashfs/sqfs.c b/fs/squashfs/sqfs.c index 5d9c52af80..6405db4ff3 100644 --- a/fs/squashfs/sqfs.c +++ b/fs/squashfs/sqfs.c @@ -8,6 +8,7 @@ */
#include <asm/unaligned.h> +#include <div64.h> #include <errno.h> #include <fs.h> #include <linux/types.h> @@ -1440,7 +1441,7 @@ int sqfs_read(const char *filename, void *buf, loff_t offset, loff_t len, }
for (j = 0; j < datablk_count; j++) {
start = data_offset / ctxt.cur_dev->blksz;
start = do_div(data_offset, ctxt.cur_dev->blksz);@@ -1516,7 +1517,7 @@ int sqfs_read(const char *filename, void *buf, loff_t offset, loff_t len, goto out; }
- start = frag_entry.start / ctxt.cur_dev->blksz;
- start = do_div(frag_entry.start, ctxt.cur_dev->blksz); table_size = SQFS_BLOCK_SIZE(frag_entry.size); table_offset = frag_entry.start - (start * ctxt.cur_dev->blksz); n_blks = DIV_ROUND_UP(table_size + table_offset, ctxt.cur_dev->blksz);
Adding maintainers...
I guess that's a correct fix, so
Reviewed-by: Miquel Raynal miquel.raynal@bootlin.com
Thanks, Miquèl
Hello! do_div() macro modifies its first argument. It is correct? Because previous code did not modify anything.
- The semantics of do_div() are:
- u32 do_div(u64 *n, u32 base)
- {
- u32 remainder = *n % base;
- *n = *n / base;
- return remainder;
- }
And this patch replaced:
start = data_offset / ctxt.cur_dev->blksz;
by:
start = do_div(data_offset, ctxt.cur_dev->blksz);
which expands to:
start = data_offset % ctxt.cur_dev->blksz; data_offset = data_offset / ctxt.cur_dev->blksz;
Which is wrong as it calculates something totally different.
So this patch is incorrect.
Hi Pali,
Yes I agree, I got tricked by some wrong cache from Yocto :/ I have tried lldiv(), and that works on our x86 target.
Do you have an opinion on that? Or do you have another idea to avoid the "undefined reference to `__udivmoddi4'" error?
/Sean
On Thu, May 12, 2022 at 08:02:33PM +0200, Sean Nyekjaer wrote:
On Thu, May 12, 2022 at 12:24:01PM +0200, Pali Rohár wrote:
On Thursday 12 May 2022 12:19:01 Pali Rohár wrote:
On Monday 09 May 2022 15:08:15 Miquel Raynal wrote:
Hello,
trini@konsulko.com wrote on Thu, 5 May 2022 09:15:00 -0400:
On Thu, May 05, 2022 at 11:26:37AM +0200, Sean Nyekjaer wrote:
From: Sean Nyekjaer sean.nyekjaer.ext@siemensgamesa.com
When compling for x86: ld.bfd: fs/squashfs/sqfs.o: in function `sqfs_read': u-boot/fs/squashfs/sqfs.c:1443: undefined reference to `__udivmoddi4' ld.bfd: u-boot/fs/squashfs/sqfs.c:1521: undefined reference to `__udivmoddi4'
Signed-off-by: Sean Nyekjaer sean.nyekjaer.ext@siemensgamesa.com
fs/squashfs/sqfs.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/fs/squashfs/sqfs.c b/fs/squashfs/sqfs.c index 5d9c52af80..6405db4ff3 100644 --- a/fs/squashfs/sqfs.c +++ b/fs/squashfs/sqfs.c @@ -8,6 +8,7 @@ */
#include <asm/unaligned.h> +#include <div64.h> #include <errno.h> #include <fs.h> #include <linux/types.h> @@ -1440,7 +1441,7 @@ int sqfs_read(const char *filename, void *buf, loff_t offset, loff_t len, }
for (j = 0; j < datablk_count; j++) {
start = data_offset / ctxt.cur_dev->blksz;
start = do_div(data_offset, ctxt.cur_dev->blksz);@@ -1516,7 +1517,7 @@ int sqfs_read(const char *filename, void *buf, loff_t offset, loff_t len, goto out; }
- start = frag_entry.start / ctxt.cur_dev->blksz;
- start = do_div(frag_entry.start, ctxt.cur_dev->blksz); table_size = SQFS_BLOCK_SIZE(frag_entry.size); table_offset = frag_entry.start - (start * ctxt.cur_dev->blksz); n_blks = DIV_ROUND_UP(table_size + table_offset, ctxt.cur_dev->blksz);
Adding maintainers...
I guess that's a correct fix, so
Reviewed-by: Miquel Raynal miquel.raynal@bootlin.com
Thanks, Miquèl
Hello! do_div() macro modifies its first argument. It is correct? Because previous code did not modify anything.
- The semantics of do_div() are:
- u32 do_div(u64 *n, u32 base)
- {
- u32 remainder = *n % base;
- *n = *n / base;
- return remainder;
- }
And this patch replaced:
start = data_offset / ctxt.cur_dev->blksz;
by:
start = do_div(data_offset, ctxt.cur_dev->blksz);
which expands to:
start = data_offset % ctxt.cur_dev->blksz; data_offset = data_offset / ctxt.cur_dev->blksz;
Which is wrong as it calculates something totally different.
So this patch is incorrect.
Hi Pali,
Yes I agree, I got tricked by some wrong cache from Yocto :/ I have tried lldiv(), and that works on our x86 target.
Do you have an opinion on that? Or do you have another idea to avoid the "undefined reference to `__udivmoddi4'" error?
Please correct things to use lldiv(), thanks.
On Thursday 12 May 2022 20:02:33 Sean Nyekjaer wrote:
On Thu, May 12, 2022 at 12:24:01PM +0200, Pali Rohár wrote:
On Thursday 12 May 2022 12:19:01 Pali Rohár wrote:
On Monday 09 May 2022 15:08:15 Miquel Raynal wrote:
Hello,
trini@konsulko.com wrote on Thu, 5 May 2022 09:15:00 -0400:
On Thu, May 05, 2022 at 11:26:37AM +0200, Sean Nyekjaer wrote:
From: Sean Nyekjaer sean.nyekjaer.ext@siemensgamesa.com
When compling for x86: ld.bfd: fs/squashfs/sqfs.o: in function `sqfs_read': u-boot/fs/squashfs/sqfs.c:1443: undefined reference to `__udivmoddi4' ld.bfd: u-boot/fs/squashfs/sqfs.c:1521: undefined reference to `__udivmoddi4'
Signed-off-by: Sean Nyekjaer sean.nyekjaer.ext@siemensgamesa.com
fs/squashfs/sqfs.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/fs/squashfs/sqfs.c b/fs/squashfs/sqfs.c index 5d9c52af80..6405db4ff3 100644 --- a/fs/squashfs/sqfs.c +++ b/fs/squashfs/sqfs.c @@ -8,6 +8,7 @@ */
#include <asm/unaligned.h> +#include <div64.h> #include <errno.h> #include <fs.h> #include <linux/types.h> @@ -1440,7 +1441,7 @@ int sqfs_read(const char *filename, void *buf, loff_t offset, loff_t len, }
for (j = 0; j < datablk_count; j++) {
start = data_offset / ctxt.cur_dev->blksz;
start = do_div(data_offset, ctxt.cur_dev->blksz);@@ -1516,7 +1517,7 @@ int sqfs_read(const char *filename, void *buf, loff_t offset, loff_t len, goto out; }
- start = frag_entry.start / ctxt.cur_dev->blksz;
- start = do_div(frag_entry.start, ctxt.cur_dev->blksz); table_size = SQFS_BLOCK_SIZE(frag_entry.size); table_offset = frag_entry.start - (start * ctxt.cur_dev->blksz); n_blks = DIV_ROUND_UP(table_size + table_offset, ctxt.cur_dev->blksz);
Adding maintainers...
I guess that's a correct fix, so
Reviewed-by: Miquel Raynal miquel.raynal@bootlin.com
Thanks, Miquèl
Hello! do_div() macro modifies its first argument. It is correct? Because previous code did not modify anything.
- The semantics of do_div() are:
- u32 do_div(u64 *n, u32 base)
- {
- u32 remainder = *n % base;
- *n = *n / base;
- return remainder;
- }
And this patch replaced:
start = data_offset / ctxt.cur_dev->blksz;
by:
start = do_div(data_offset, ctxt.cur_dev->blksz);
which expands to:
start = data_offset % ctxt.cur_dev->blksz; data_offset = data_offset / ctxt.cur_dev->blksz;
Which is wrong as it calculates something totally different.
So this patch is incorrect.
Hi Pali,
Yes I agree, I got tricked by some wrong cache from Yocto :/ I have tried lldiv(), and that works on our x86 target.
Do you have an opinion on that? Or do you have another idea to avoid the "undefined reference to `__udivmoddi4'" error?
/Sean
Hello! You really should not use C division operator for 64-bit integers as gcc still is not able to generate assembler code for such division on many 32-bit platforms.
You should use some function or macro from linux/math64.h or div64.h header file. For every combination of types, pairs and required operation there is specific function/macro (e.g. u64/u32, u64%u32, u64/u64, etc...).
I think that lldiv() is the correct call here. This function expects u64 as dividend, u32 as divisor and returns u64 result.
On Thu, May 12, 2022 at 08:41:15PM +0200, Pali Rohár wrote:
On Thursday 12 May 2022 20:02:33 Sean Nyekjaer wrote:
On Thu, May 12, 2022 at 12:24:01PM +0200, Pali Rohár wrote:
On Thursday 12 May 2022 12:19:01 Pali Rohár wrote:
On Monday 09 May 2022 15:08:15 Miquel Raynal wrote:
Hello,
trini@konsulko.com wrote on Thu, 5 May 2022 09:15:00 -0400:
On Thu, May 05, 2022 at 11:26:37AM +0200, Sean Nyekjaer wrote:
> From: Sean Nyekjaer sean.nyekjaer.ext@siemensgamesa.com > > When compling for x86: > ld.bfd: fs/squashfs/sqfs.o: in function `sqfs_read': > u-boot/fs/squashfs/sqfs.c:1443: undefined reference to `__udivmoddi4' > ld.bfd: u-boot/fs/squashfs/sqfs.c:1521: undefined reference to `__udivmoddi4' > > Signed-off-by: Sean Nyekjaer sean.nyekjaer.ext@siemensgamesa.com > --- > fs/squashfs/sqfs.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/fs/squashfs/sqfs.c b/fs/squashfs/sqfs.c > index 5d9c52af80..6405db4ff3 100644 > --- a/fs/squashfs/sqfs.c > +++ b/fs/squashfs/sqfs.c > @@ -8,6 +8,7 @@ > */ > > #include <asm/unaligned.h> > +#include <div64.h> > #include <errno.h> > #include <fs.h> > #include <linux/types.h> > @@ -1440,7 +1441,7 @@ int sqfs_read(const char *filename, void *buf, loff_t offset, loff_t len, > } > > for (j = 0; j < datablk_count; j++) { > - start = data_offset / ctxt.cur_dev->blksz; > + start = do_div(data_offset, ctxt.cur_dev->blksz); > table_size = SQFS_BLOCK_SIZE(finfo.blk_sizes[j]); > table_offset = data_offset - (start * ctxt.cur_dev->blksz); > n_blks = DIV_ROUND_UP(table_size + table_offset, > @@ -1516,7 +1517,7 @@ int sqfs_read(const char *filename, void *buf, loff_t offset, loff_t len, > goto out; > } > > - start = frag_entry.start / ctxt.cur_dev->blksz; > + start = do_div(frag_entry.start, ctxt.cur_dev->blksz); > table_size = SQFS_BLOCK_SIZE(frag_entry.size); > table_offset = frag_entry.start - (start * ctxt.cur_dev->blksz); > n_blks = DIV_ROUND_UP(table_size + table_offset, ctxt.cur_dev->blksz);
Adding maintainers...
I guess that's a correct fix, so
Reviewed-by: Miquel Raynal miquel.raynal@bootlin.com
Thanks, Miquèl
Hello! do_div() macro modifies its first argument. It is correct? Because previous code did not modify anything.
- The semantics of do_div() are:
- u32 do_div(u64 *n, u32 base)
- {
- u32 remainder = *n % base;
- *n = *n / base;
- return remainder;
- }
And this patch replaced:
start = data_offset / ctxt.cur_dev->blksz;
by:
start = do_div(data_offset, ctxt.cur_dev->blksz);
which expands to:
start = data_offset % ctxt.cur_dev->blksz; data_offset = data_offset / ctxt.cur_dev->blksz;
Which is wrong as it calculates something totally different.
So this patch is incorrect.
Hi Pali,
Yes I agree, I got tricked by some wrong cache from Yocto :/ I have tried lldiv(), and that works on our x86 target.
Do you have an opinion on that? Or do you have another idea to avoid the "undefined reference to `__udivmoddi4'" error?
/Sean
Hello! You really should not use C division operator for 64-bit integers as gcc still is not able to generate assembler code for such division on many 32-bit platforms.
You should use some function or macro from linux/math64.h or div64.h header file. For every combination of types, pairs and required operation there is specific function/macro (e.g. u64/u32, u64%u32, u64/u64, etc...).
I think that lldiv() is the correct call here. This function expects u64 as dividend, u32 as divisor and returns u64 result.
Thank you for the explanation :) Updated patch should be on the list.
/Sean
Hi
Il gio 12 mag 2022, 20:02 Sean Nyekjaer sean@geanix.com ha scritto:
On Thu, May 12, 2022 at 12:24:01PM +0200, Pali Rohár wrote:
On Thursday 12 May 2022 12:19:01 Pali Rohár wrote:
On Monday 09 May 2022 15:08:15 Miquel Raynal wrote:
Hello,
trini@konsulko.com wrote on Thu, 5 May 2022 09:15:00 -0400:
On Thu, May 05, 2022 at 11:26:37AM +0200, Sean Nyekjaer wrote:
From: Sean Nyekjaer sean.nyekjaer.ext@siemensgamesa.com
When compling for x86: ld.bfd: fs/squashfs/sqfs.o: in function `sqfs_read': u-boot/fs/squashfs/sqfs.c:1443: undefined reference to
`__udivmoddi4'
ld.bfd: u-boot/fs/squashfs/sqfs.c:1521: undefined reference to
`__udivmoddi4'
Signed-off-by: Sean Nyekjaer <
sean.nyekjaer.ext@siemensgamesa.com>
fs/squashfs/sqfs.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/fs/squashfs/sqfs.c b/fs/squashfs/sqfs.c index 5d9c52af80..6405db4ff3 100644 --- a/fs/squashfs/sqfs.c +++ b/fs/squashfs/sqfs.c @@ -8,6 +8,7 @@ */
#include <asm/unaligned.h> +#include <div64.h> #include <errno.h> #include <fs.h> #include <linux/types.h> @@ -1440,7 +1441,7 @@ int sqfs_read(const char *filename, void
*buf, loff_t offset, loff_t len,
} for (j = 0; j < datablk_count; j++) {
start = data_offset / ctxt.cur_dev->blksz;
start = do_div(data_offset, ctxt.cur_dev->blksz); table_size = SQFS_BLOCK_SIZE(finfo.blk_sizes[j]); table_offset = data_offset - (start *ctxt.cur_dev->blksz);
n_blks = DIV_ROUND_UP(table_size + table_offset,@@ -1516,7 +1517,7 @@ int sqfs_read(const char *filename, void
*buf, loff_t offset, loff_t len,
goto out; }
start = frag_entry.start / ctxt.cur_dev->blksz;
start = do_div(frag_entry.start, ctxt.cur_dev->blksz); table_size = SQFS_BLOCK_SIZE(frag_entry.size); table_offset = frag_entry.start - (start *ctxt.cur_dev->blksz);
n_blks = DIV_ROUND_UP(table_size + table_offset,ctxt.cur_dev->blksz);
Adding maintainers...
I guess that's a correct fix, so
Reviewed-by: Miquel Raynal miquel.raynal@bootlin.com
Thanks, Miquèl
Hello! do_div() macro modifies its first argument. It is correct? Because previous code did not modify anything.
- The semantics of do_div() are:
- u32 do_div(u64 *n, u32 base)
- {
- u32 remainder = *n % base;
- *n = *n / base;
- return remainder;
- }
And this patch replaced:
start = data_offset / ctxt.cur_dev->blksz;
by:
start = do_div(data_offset, ctxt.cur_dev->blksz);
which expands to:
start = data_offset % ctxt.cur_dev->blksz; data_offset = data_offset / ctxt.cur_dev->blksz;
Which is wrong as it calculates something totally different.
So this patch is incorrect.
Hi Pali,
Yes I agree, I got tricked by some wrong cache from Yocto :/ I have tried lldiv(), and that works on our x86 target.
start = data_offset; do_div(start, ctxt.cur_dev->blksz);
Something like this?
Michael
Do you have an opinion on that? Or do you have another idea to avoid the "undefined reference to `__udivmoddi4'" error?
/Sean
On Thursday 12 May 2022 20:52:30 Michael Nazzareno Trimarchi wrote:
Hi
Il gio 12 mag 2022, 20:02 Sean Nyekjaer sean@geanix.com ha scritto:
On Thu, May 12, 2022 at 12:24:01PM +0200, Pali Rohár wrote:
On Thursday 12 May 2022 12:19:01 Pali Rohár wrote:
On Monday 09 May 2022 15:08:15 Miquel Raynal wrote:
Hello,
trini@konsulko.com wrote on Thu, 5 May 2022 09:15:00 -0400:
On Thu, May 05, 2022 at 11:26:37AM +0200, Sean Nyekjaer wrote:
> From: Sean Nyekjaer sean.nyekjaer.ext@siemensgamesa.com > > When compling for x86: > ld.bfd: fs/squashfs/sqfs.o: in function `sqfs_read': > u-boot/fs/squashfs/sqfs.c:1443: undefined reference to
`__udivmoddi4'
> ld.bfd: u-boot/fs/squashfs/sqfs.c:1521: undefined reference to
`__udivmoddi4'
> > Signed-off-by: Sean Nyekjaer <
sean.nyekjaer.ext@siemensgamesa.com>
> --- > fs/squashfs/sqfs.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/fs/squashfs/sqfs.c b/fs/squashfs/sqfs.c > index 5d9c52af80..6405db4ff3 100644 > --- a/fs/squashfs/sqfs.c > +++ b/fs/squashfs/sqfs.c > @@ -8,6 +8,7 @@ > */ > > #include <asm/unaligned.h> > +#include <div64.h> > #include <errno.h> > #include <fs.h> > #include <linux/types.h> > @@ -1440,7 +1441,7 @@ int sqfs_read(const char *filename, void
*buf, loff_t offset, loff_t len,
> } > > for (j = 0; j < datablk_count; j++) { > - start = data_offset / ctxt.cur_dev->blksz; > + start = do_div(data_offset, ctxt.cur_dev->blksz); > table_size = SQFS_BLOCK_SIZE(finfo.blk_sizes[j]); > table_offset = data_offset - (start *
ctxt.cur_dev->blksz);
> n_blks = DIV_ROUND_UP(table_size + table_offset, > @@ -1516,7 +1517,7 @@ int sqfs_read(const char *filename, void
*buf, loff_t offset, loff_t len,
> goto out; > } > > - start = frag_entry.start / ctxt.cur_dev->blksz; > + start = do_div(frag_entry.start, ctxt.cur_dev->blksz); > table_size = SQFS_BLOCK_SIZE(frag_entry.size); > table_offset = frag_entry.start - (start *
ctxt.cur_dev->blksz);
> n_blks = DIV_ROUND_UP(table_size + table_offset,
ctxt.cur_dev->blksz);
Adding maintainers...
I guess that's a correct fix, so
Reviewed-by: Miquel Raynal miquel.raynal@bootlin.com
Thanks, Miquèl
Hello! do_div() macro modifies its first argument. It is correct? Because previous code did not modify anything.
- The semantics of do_div() are:
- u32 do_div(u64 *n, u32 base)
- {
- u32 remainder = *n % base;
- *n = *n / base;
- return remainder;
- }
And this patch replaced:
start = data_offset / ctxt.cur_dev->blksz;
by:
start = do_div(data_offset, ctxt.cur_dev->blksz);
which expands to:
start = data_offset % ctxt.cur_dev->blksz; data_offset = data_offset / ctxt.cur_dev->blksz;
Which is wrong as it calculates something totally different.
So this patch is incorrect.
Hi Pali,
Yes I agree, I got tricked by some wrong cache from Yocto :/ I have tried lldiv(), and that works on our x86 target.
start = data_offset; do_div(start, ctxt.cur_dev->blksz);
Something like this?
This is another option and seems that should be OK too.
Michael
Do you have an opinion on that? Or do you have another idea to avoid the "undefined reference to `__udivmoddi4'" error?
/Sean
participants (5)
-
Michael Nazzareno Trimarchi -
Miquel Raynal -
Pali Rohár -
Sean Nyekjaer -
Tom Rini