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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
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/
-rw-r--r--arch/mips/include/asm/pgtable-64.h4
-rw-r--r--arch/mips/include/asm/processor.h40
-rw-r--r--arch/mips/include/asm/uaccess.h4
-rw-r--r--arch/mips/kernel/cpu-probe.c13
4 files changed, 37 insertions, 24 deletions
diff --git a/arch/mips/include/asm/pgtable-64.h b/arch/mips/include/asm/pgtable-64.h
index f00896087dda..55908fd56b1f 100644
--- a/arch/mips/include/asm/pgtable-64.h
+++ b/arch/mips/include/asm/pgtable-64.h
@@ -113,10 +113,10 @@
#endif
#define PTRS_PER_PTE ((PAGE_SIZE << PTE_ORDER) / sizeof(pte_t))
-#if PGDIR_SIZE >= TASK_SIZE
+#if PGDIR_SIZE >= TASK_SIZE64
#define USER_PTRS_PER_PGD (1)
#else
-#define USER_PTRS_PER_PGD (TASK_SIZE / PGDIR_SIZE)
+#define USER_PTRS_PER_PGD (TASK_SIZE64 / PGDIR_SIZE)
#endif
#define FIRST_USER_ADDRESS 0UL
diff --git a/arch/mips/include/asm/processor.h b/arch/mips/include/asm/processor.h
index 0d629bb93cbe..ead6928fa6b8 100644
--- a/arch/mips/include/asm/processor.h
+++ b/arch/mips/include/asm/processor.h
@@ -50,13 +50,10 @@ extern unsigned int vced_count, vcei_count;
* so don't change it unless you know what you are doing.
*/
#define TASK_SIZE 0x7fff8000UL
-#define STACK_TOP ((TASK_SIZE & PAGE_MASK) - SPECIAL_PAGES_SIZE)
-/*
- * This decides where the kernel will search for a free chunk of vm
- * space during mmap's.
- */
-#define TASK_UNMAPPED_BASE ((TASK_SIZE / 3) & ~(PAGE_SIZE))
+#ifdef __KERNEL__
+#define STACK_TOP_MAX TASK_SIZE
+#endif
#define TASK_IS_32BIT_ADDR 1
@@ -71,28 +68,29 @@ extern unsigned int vced_count, vcei_count;
* 8192EB ...
*/
#define TASK_SIZE32 0x7fff8000UL
-#define TASK_SIZE 0x10000000000UL
-#define STACK_TOP \
- (((test_thread_flag(TIF_32BIT_ADDR) ? \
- TASK_SIZE32 : TASK_SIZE) & PAGE_MASK) - SPECIAL_PAGES_SIZE)
+#define TASK_SIZE64 0x10000000000UL
+#define TASK_SIZE (test_thread_flag(TIF_32BIT_ADDR) ? TASK_SIZE32 : TASK_SIZE64)
+
+#ifdef __KERNEL__
+#define STACK_TOP_MAX TASK_SIZE64
+#endif
+
-/*
- * This decides where the kernel will search for a free chunk of vm
- * space during mmap's.
- */
-#define TASK_UNMAPPED_BASE \
- (test_thread_flag(TIF_32BIT_ADDR) ? \
- PAGE_ALIGN(TASK_SIZE32 / 3) : PAGE_ALIGN(TASK_SIZE / 3))
#define TASK_SIZE_OF(tsk) \
- (test_tsk_thread_flag(tsk, TIF_32BIT_ADDR) ? TASK_SIZE32 : TASK_SIZE)
+ (test_tsk_thread_flag(tsk, TIF_32BIT_ADDR) ? TASK_SIZE32 : TASK_SIZE64)
#define TASK_IS_32BIT_ADDR test_thread_flag(TIF_32BIT_ADDR)
#endif
-#ifdef __KERNEL__
-#define STACK_TOP_MAX TASK_SIZE
-#endif
+#define STACK_TOP ((TASK_SIZE & PAGE_MASK) - SPECIAL_PAGES_SIZE)
+
+/*
+ * This decides where the kernel will search for a free chunk of vm
+ * space during mmap's.
+ */
+#define TASK_UNMAPPED_BASE PAGE_ALIGN(TASK_SIZE / 3)
+
#define NUM_FPU_REGS 32
diff --git a/arch/mips/include/asm/uaccess.h b/arch/mips/include/asm/uaccess.h
index c2d53c18fd36..653a412c036c 100644
--- a/arch/mips/include/asm/uaccess.h
+++ b/arch/mips/include/asm/uaccess.h
@@ -35,7 +35,9 @@
#ifdef CONFIG_64BIT
-#define __UA_LIMIT (- TASK_SIZE)
+extern u64 __ua_limit;
+
+#define __UA_LIMIT __ua_limit
#define __UA_ADDR ".dword"
#define __UA_LA "dla"
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)