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authorDavid Daney <ddaney@caviumnetworks.com>2010-10-14 11:32:33 -0700
committerRalf Baechle <ralf@linux-mips.org>2010-10-29 19:08:53 +0100
commit949e51bea342da838be5295628e4a7ada8bae833 (patch)
tree8967391768d4da3a99a2adf85e0834e0fa7a2009 /arch/mips/kernel/cpu-probe.c
parent18d693b3598fdebdd5c65a613221793456a7ce45 (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.c13
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)