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/
This commit is contained in:
David Daney 2010-10-14 11:32:33 -07:00 committed by Ralf Baechle
parent 18d693b359
commit 949e51bea3
4 changed files with 37 additions and 24 deletions

View File

@ -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

View File

@ -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

View File

@ -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"

View File

@ -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)