Messages in this thread | | | Subject | Re: [PATCH] MIPS: Always page align TASK_SIZE | From | Harvey Hunt <> | Date | Mon, 8 Feb 2016 13:48:32 -0800 |
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Hi Joshua,
On 02/08/2016 01:35 PM, Joshua Kinard wrote: > On 02/08/2016 13:15, Harvey Hunt wrote: >> Hi David, >> >> On 02/08/2016 10:11 AM, David Daney wrote: >>> On 02/08/2016 10:05 AM, Harvey Hunt wrote: >>>> STACK_TOP_MAX is aligned on a 32k boundary. When __bprm_mm_init() >>>> creates an >>>> initial stack for a process, it does so using STACK_TOP_MAX as the end >>>> of the >>>> vma. A process's arguments and environment information are placed on >>>> the stack >>>> and then the stack is relocated and aligned on a page boundary. When >>>> using a 32 >>>> bit kernel with 64k pages, the relocated stack has the process's args >>>> erroneously stored in the middle of the stack. This means that processes >>>> receive no arguments or environment variables, preventing them from >>>> running >>>> correctly. >>>> >>>> Fix this by aligning TASK_SIZE on a page boundary. >>>> >>>> Signed-off-by: Harvey Hunt <harvey.hunt@imgtec.com> >>>> Cc: David Daney <david.daney@cavium.com> >>>> Cc: Paul Burton <paul.burton@imgtec.com> >>>> Cc: James Hogan <james.hogan@imgtec.com> >>>> Cc: linux-kernel@vger.kernel.org >>>> --- >>>> arch/mips/include/asm/processor.h | 6 +++--- >>>> 1 file changed, 3 insertions(+), 3 deletions(-) >>>> >>>> diff --git a/arch/mips/include/asm/processor.h >>>> b/arch/mips/include/asm/processor.h >>>> index 3f832c3..b618b40 100644 >>>> --- a/arch/mips/include/asm/processor.h >>>> +++ b/arch/mips/include/asm/processor.h >>>> @@ -39,13 +39,13 @@ extern unsigned int vced_count, vcei_count; >>>> #ifdef CONFIG_32BIT >>>> #ifdef CONFIG_KVM_GUEST >>>> /* User space process size is limited to 1GB in KVM Guest Mode */ >>>> -#define TASK_SIZE 0x3fff8000UL >>>> +#define TASK_SIZE (0x40000000UL - PAGE_SIZE) >>>> #else >>>> /* >>>> * User space process size: 2GB. This is hardcoded into a few places, >>>> * so don't change it unless you know what you are doing. >>>> */ >>>> -#define TASK_SIZE 0x7fff8000UL >>>> +#define TASK_SIZE (0x7fff8000UL & PAGE_SIZE) >>> >>> Can you check your math here. This doesn't seem correct. >> >> Thanks for spotting that - it should have been: >> >> (0x7fff8000UL & PAGE_MASK) >> >> I'll do a v2 now. >> > > FYI, TASK_SIZE was recently changed to 0x80000000UL in commit 7f8ca9cb1ed3 on > the linux-mips.org tree.
Thanks, I'll rebase.
> > >>> >>>> #endif >>>> >>>> #define STACK_TOP_MAX TASK_SIZE >>>> @@ -62,7 +62,7 @@ extern unsigned int vced_count, vcei_count; >>>> * support 16TB; the architectural reserve for future expansion is >>>> * 8192EB ... >>>> */ >>>> -#define TASK_SIZE32 0x7fff8000UL >>>> +#define TASK_SIZE32 (0x7fff8000UL & PAGE_SIZE) >>> >>> Same here. >> >> As above. >> >>> >>>> #define TASK_SIZE64 0x10000000000UL >>>> #define TASK_SIZE (test_thread_flag(TIF_32BIT_ADDR) ? TASK_SIZE32 : >>>> TASK_SIZE64) >>>> #define STACK_TOP_MAX TASK_SIZE64 >>>> >>> >> >> Thanks, >> >> Harvey >> >> > >
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