| Message ID | ad4e04090afc7409127ad85f3ce77f0ab67b80bf.1727624528.git.fweimer@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | Teach glibc about possible page sizes and handle gaps in ld.so | expand |
On 9/30/24 4:15 AM, Florian Weimer wrote: > * Maciej W. Rozycki: >> NB other page sizes are architecturally supported by TLB MMU hardware, >> from 1 KiB up to 256 TiB, but not by the MIPS port of Linux, so shouldn't >> this be sysdeps/unix/sysv/linux/mips/bits/pagesize.h instead, so as not to >> apply the limitations of MIPS/Linux to the generic MIPS architecture? > > In theory, any architecture could have future CPUs that support larger > page sizes, so there is no absolute strict upper limit. For > <sys/pagesize.h> to be useful to programmers, the maximum needs to > reflect what they can reasonably expect to matter during the life time > of the file format and application. Power supports page sizes much larger than 64K too, but given your response above... On 9/29/24 11:23 AM, Florian Weimer wrote: > According to arch/powerpc/Kconfig in the Linux kernel sources, > PowerPC supports page sizes up to 256 KiB. However, in practice, > only page sizes up to 64 KiB are used, especially on 64-bit targets. > > If 256 KiB page support is needed, it is probably best to add a > configure check for linker LOAD segment alignment and generate a > <bits/pagesize.h> file that has 256 KiB as the maximum page size. > Regular toolchain defaults only support 64 KiB as the maximum > page size. > --- > sysdeps/powerpc/bits/pagesize.h | 2 ++ > 1 file changed, 2 insertions(+) > create mode 100644 sysdeps/powerpc/bits/pagesize.h > > diff --git a/sysdeps/powerpc/bits/pagesize.h b/sysdeps/powerpc/bits/pagesize.h > new file mode 100644 > index 0000000000..cd688d3fb0 > --- /dev/null > +++ b/sysdeps/powerpc/bits/pagesize.h > @@ -0,0 +1,2 @@ > +#define __GLIBC_PAGE_SHIFT_MIN 12 > +#define __GLIBC_PAGE_SHIFT_MAX 16 LGTM. Reviewed-by: Peter Bergner <bergner@linux.ibm.com> Peter
diff --git a/sysdeps/powerpc/bits/pagesize.h b/sysdeps/powerpc/bits/pagesize.h new file mode 100644 index 0000000000..cd688d3fb0 --- /dev/null +++ b/sysdeps/powerpc/bits/pagesize.h @@ -0,0 +1,2 @@ +#define __GLIBC_PAGE_SHIFT_MIN 12 +#define __GLIBC_PAGE_SHIFT_MAX 16