diff options
author | David Daney <ddaney@caviumnetworks.com> | 2010-10-14 11:32:33 -0700 |
---|---|---|
committer | Ralf Baechle <ralf@linux-mips.org> | 2010-10-29 19:08:53 +0100 |
commit | 949e51bea342da838be5295628e4a7ada8bae833 (patch) | |
tree | 8967391768d4da3a99a2adf85e0834e0fa7a2009 /arch/mips/kernel/cpu-probe.c | |
parent | 18d693b3598fdebdd5c65a613221793456a7ce45 (diff) |
MIPS: Make TASK_SIZE reflect proper size for both 32 and 64 bit processes.
The TASK_SIZE macro should reflect the size of a user process virtual
address space. Previously for 64-bit kernels, this was not the case.
The immediate cause of pain was in
hugetlbfs/inode.c:hugetlb_get_unmapped_area() where 32-bit processes
trying to mmap a huge page would be served a page with an address
outside of the 32-bit address range. But there are other uses of
TASK_SIZE in the kernel as well that would like an accurate value.
The new definition is nice because it now makes TASK_SIZE and
TASK_SIZE_OF() yield the same value for any given process.
For 32-bit kernels there should be no change, although I did factor
out some code in asm/processor.h that became identical for the 32-bit and
64-bit cases.
__UA_LIMIT is now set to ~((1 << SEGBITS) - 1) for 64-bit kernels.
This should eliminate the possibility of getting a
AddressErrorException in the kernel for addresses that pass the
access_ok() test.
With the patch applied, I can still run o32, n32 and n64 processes,
and have an o32 shell fork/exec both n32 and n64 processes.
Signed-off-by: David Daney <ddaney@caviumnetworks.com>
To: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/1701/
Diffstat (limited to 'arch/mips/kernel/cpu-probe.c')
-rw-r--r-- | arch/mips/kernel/cpu-probe.c | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/arch/mips/kernel/cpu-probe.c b/arch/mips/kernel/cpu-probe.c index f7faa3fb79b2..71620e19827a 100644 --- a/arch/mips/kernel/cpu-probe.c +++ b/arch/mips/kernel/cpu-probe.c @@ -25,6 +25,8 @@ #include <asm/system.h> #include <asm/watch.h> #include <asm/spram.h> +#include <asm/uaccess.h> + /* * Not all of the MIPS CPUs have the "wait" instruction available. Moreover, * the implementation of the "wait" feature differs between CPU families. This @@ -987,6 +989,12 @@ static inline void cpu_probe_ingenic(struct cpuinfo_mips *c, unsigned int cpu) } } +#ifdef CONFIG_64BIT +/* For use by uaccess.h */ +u64 __ua_limit; +EXPORT_SYMBOL(__ua_limit); +#endif + const char *__cpu_name[NR_CPUS]; const char *__elf_platform; @@ -1064,6 +1072,11 @@ __cpuinit void cpu_probe(void) c->srsets = 1; cpu_probe_vmbits(c); + +#ifdef CONFIG_64BIT + if (cpu == 0) + __ua_limit = ~((1ull << cpu_vmbits) - 1); +#endif } __cpuinit void cpu_report(void) |