| Message ID | 20181017163459.20175-3-steve.capper@arm.com (mailing list archive) |
|---|---|
| State | Superseded, archived |
| Headers | show |
| Series | 52-bit userspace VAs | expand |
Hi Steve,
Thank you for the patch! Yet something to improve:
[auto build test ERROR on arm64/for-next/core]
[also build test ERROR on v4.19-rc8]
[cannot apply to next-20181017]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]
url: https://github.com/0day-ci/linux/commits/Steve-Capper/52-bit-userspace-VAs/20181018-061652
base: https://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-next/core
config: arm64-defconfig (attached as .config)
compiler: aarch64-linux-gnu-gcc (Debian 7.2.0-11) 7.2.0
reproduce:
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# save the attached .config to linux build tree
GCC_VERSION=7.2.0 make.cross ARCH=arm64
All error/warnings (new ones prefixed by >>):
In file included from include/linux/cache.h:5:0,
from include/linux/printk.h:9,
from include/linux/kernel.h:14,
from include/asm-generic/bug.h:18,
from arch/arm64/include/asm/bug.h:37,
from include/linux/bug.h:5,
from include/linux/thread_info.h:12,
from fs//hugetlbfs/inode.c:12:
fs//hugetlbfs/inode.c: In function 'hugetlb_get_unmapped_area':
>> arch/arm64/include/asm/processor.h:63:50: error: 'tsk' undeclared (first use in this function)
#define DEFAULT_MAP_WINDOW (test_tsk_thread_flag(tsk, TIF_32BIT) ? \
^
include/uapi/linux/kernel.h:11:41: note: in definition of macro '__ALIGN_KERNEL_MASK'
#define __ALIGN_KERNEL_MASK(x, mask) (((x) + (mask)) & ~(mask))
^
>> include/linux/kernel.h:58:22: note: in expansion of macro '__ALIGN_KERNEL'
#define ALIGN(x, a) __ALIGN_KERNEL((x), (a))
^~~~~~~~~~~~~~
>> include/linux/mm.h:144:26: note: in expansion of macro 'ALIGN'
#define PAGE_ALIGN(addr) ALIGN(addr, PAGE_SIZE)
^~~~~
>> arch/arm64/include/asm/processor.h:70:29: note: in expansion of macro 'PAGE_ALIGN'
#define TASK_UNMAPPED_BASE (PAGE_ALIGN(DEFAULT_MAP_WINDOW / 4))
^~~~~~~~~~
>> arch/arm64/include/asm/processor.h:70:40: note: in expansion of macro 'DEFAULT_MAP_WINDOW'
#define TASK_UNMAPPED_BASE (PAGE_ALIGN(DEFAULT_MAP_WINDOW / 4))
^~~~~~~~~~~~~~~~~~
>> fs//hugetlbfs/inode.c:214:19: note: in expansion of macro 'TASK_UNMAPPED_BASE'
info.low_limit = TASK_UNMAPPED_BASE;
^~~~~~~~~~~~~~~~~~
arch/arm64/include/asm/processor.h:63:50: note: each undeclared identifier is reported only once for each function it appears in
#define DEFAULT_MAP_WINDOW (test_tsk_thread_flag(tsk, TIF_32BIT) ? \
^
include/uapi/linux/kernel.h:11:41: note: in definition of macro '__ALIGN_KERNEL_MASK'
#define __ALIGN_KERNEL_MASK(x, mask) (((x) + (mask)) & ~(mask))
^
>> include/linux/kernel.h:58:22: note: in expansion of macro '__ALIGN_KERNEL'
#define ALIGN(x, a) __ALIGN_KERNEL((x), (a))
^~~~~~~~~~~~~~
>> include/linux/mm.h:144:26: note: in expansion of macro 'ALIGN'
#define PAGE_ALIGN(addr) ALIGN(addr, PAGE_SIZE)
^~~~~
>> arch/arm64/include/asm/processor.h:70:29: note: in expansion of macro 'PAGE_ALIGN'
#define TASK_UNMAPPED_BASE (PAGE_ALIGN(DEFAULT_MAP_WINDOW / 4))
^~~~~~~~~~
>> arch/arm64/include/asm/processor.h:70:40: note: in expansion of macro 'DEFAULT_MAP_WINDOW'
#define TASK_UNMAPPED_BASE (PAGE_ALIGN(DEFAULT_MAP_WINDOW / 4))
^~~~~~~~~~~~~~~~~~
>> fs//hugetlbfs/inode.c:214:19: note: in expansion of macro 'TASK_UNMAPPED_BASE'
info.low_limit = TASK_UNMAPPED_BASE;
^~~~~~~~~~~~~~~~~~
--
In file included from include/linux/cache.h:5:0,
from include/linux/printk.h:9,
from include/linux/kernel.h:14,
from include/asm-generic/bug.h:18,
from arch/arm64/include/asm/bug.h:37,
from include/linux/bug.h:5,
from include/linux/thread_info.h:12,
from fs/hugetlbfs/inode.c:12:
fs/hugetlbfs/inode.c: In function 'hugetlb_get_unmapped_area':
>> arch/arm64/include/asm/processor.h:63:50: error: 'tsk' undeclared (first use in this function)
#define DEFAULT_MAP_WINDOW (test_tsk_thread_flag(tsk, TIF_32BIT) ? \
^
include/uapi/linux/kernel.h:11:41: note: in definition of macro '__ALIGN_KERNEL_MASK'
#define __ALIGN_KERNEL_MASK(x, mask) (((x) + (mask)) & ~(mask))
^
>> include/linux/kernel.h:58:22: note: in expansion of macro '__ALIGN_KERNEL'
#define ALIGN(x, a) __ALIGN_KERNEL((x), (a))
^~~~~~~~~~~~~~
>> include/linux/mm.h:144:26: note: in expansion of macro 'ALIGN'
#define PAGE_ALIGN(addr) ALIGN(addr, PAGE_SIZE)
^~~~~
>> arch/arm64/include/asm/processor.h:70:29: note: in expansion of macro 'PAGE_ALIGN'
#define TASK_UNMAPPED_BASE (PAGE_ALIGN(DEFAULT_MAP_WINDOW / 4))
^~~~~~~~~~
>> arch/arm64/include/asm/processor.h:70:40: note: in expansion of macro 'DEFAULT_MAP_WINDOW'
#define TASK_UNMAPPED_BASE (PAGE_ALIGN(DEFAULT_MAP_WINDOW / 4))
^~~~~~~~~~~~~~~~~~
fs/hugetlbfs/inode.c:214:19: note: in expansion of macro 'TASK_UNMAPPED_BASE'
info.low_limit = TASK_UNMAPPED_BASE;
^~~~~~~~~~~~~~~~~~
arch/arm64/include/asm/processor.h:63:50: note: each undeclared identifier is reported only once for each function it appears in
#define DEFAULT_MAP_WINDOW (test_tsk_thread_flag(tsk, TIF_32BIT) ? \
^
include/uapi/linux/kernel.h:11:41: note: in definition of macro '__ALIGN_KERNEL_MASK'
#define __ALIGN_KERNEL_MASK(x, mask) (((x) + (mask)) & ~(mask))
^
>> include/linux/kernel.h:58:22: note: in expansion of macro '__ALIGN_KERNEL'
#define ALIGN(x, a) __ALIGN_KERNEL((x), (a))
^~~~~~~~~~~~~~
>> include/linux/mm.h:144:26: note: in expansion of macro 'ALIGN'
#define PAGE_ALIGN(addr) ALIGN(addr, PAGE_SIZE)
^~~~~
>> arch/arm64/include/asm/processor.h:70:29: note: in expansion of macro 'PAGE_ALIGN'
#define TASK_UNMAPPED_BASE (PAGE_ALIGN(DEFAULT_MAP_WINDOW / 4))
^~~~~~~~~~
>> arch/arm64/include/asm/processor.h:70:40: note: in expansion of macro 'DEFAULT_MAP_WINDOW'
#define TASK_UNMAPPED_BASE (PAGE_ALIGN(DEFAULT_MAP_WINDOW / 4))
^~~~~~~~~~~~~~~~~~
fs/hugetlbfs/inode.c:214:19: note: in expansion of macro 'TASK_UNMAPPED_BASE'
info.low_limit = TASK_UNMAPPED_BASE;
^~~~~~~~~~~~~~~~~~
vim +/tsk +63 arch/arm64/include/asm/processor.h
52
53 /*
54 * TASK_SIZE - the maximum size of a user space task.
55 * TASK_UNMAPPED_BASE - the lower boundary of the mmap VM area.
56 */
57 #ifdef CONFIG_COMPAT
58 #define TASK_SIZE_32 UL(0x100000000)
59 #define TASK_SIZE (test_thread_flag(TIF_32BIT) ? \
60 TASK_SIZE_32 : TASK_SIZE_64)
61 #define TASK_SIZE_OF(tsk) (test_tsk_thread_flag(tsk, TIF_32BIT) ? \
62 TASK_SIZE_32 : TASK_SIZE_64)
> 63 #define DEFAULT_MAP_WINDOW (test_tsk_thread_flag(tsk, TIF_32BIT) ? \
64 TASK_SIZE_32 : DEFAULT_MAP_WINDOW_64)
65 #else
66 #define TASK_SIZE TASK_SIZE_64
67 #define DEFAULT_MAP_WINDOW DEFAULT_MAP_WINDOW_64
68 #endif /* CONFIG_COMPAT */
69
> 70 #define TASK_UNMAPPED_BASE (PAGE_ALIGN(DEFAULT_MAP_WINDOW / 4))
71 #define STACK_TOP_MAX DEFAULT_MAP_WINDOW_64
72
---
0-DAY kernel test infrastructure Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all Intel Corporation
Hi Steve,
Thank you for the patch! Perhaps something to improve:
[auto build test WARNING on arm64/for-next/core]
[also build test WARNING on v4.19-rc8]
[cannot apply to next-20181017]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]
url: https://github.com/0day-ci/linux/commits/Steve-Capper/52-bit-userspace-VAs/20181018-061652
base: https://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-next/core
config: arm64-defconfig (attached as .config)
compiler: aarch64-linux-gnu-gcc (Debian 7.2.0-11) 7.2.0
reproduce:
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# save the attached .config to linux build tree
GCC_VERSION=7.2.0 make.cross ARCH=arm64
All warnings (new ones prefixed by >>):
In file included from include/linux/cache.h:5:0,
from include/linux/printk.h:9,
from include/linux/kernel.h:14,
from include/asm-generic/bug.h:18,
from arch/arm64/include/asm/bug.h:37,
from include/linux/bug.h:5,
from arch/arm64/include/asm/ptrace.h:90,
from arch/arm64/include/asm/elf.h:24,
from include/linux/elf.h:5,
from arch/arm64/mm/mmap.c:19:
arch/arm64/mm/mmap.c: In function 'arch_pick_mmap_layout':
arch/arm64/include/asm/processor.h:63:50: error: 'tsk' undeclared (first use in this function)
#define DEFAULT_MAP_WINDOW (test_tsk_thread_flag(tsk, TIF_32BIT) ? \
^
include/uapi/linux/kernel.h:11:41: note: in definition of macro '__ALIGN_KERNEL_MASK'
#define __ALIGN_KERNEL_MASK(x, mask) (((x) + (mask)) & ~(mask))
^
include/linux/kernel.h:58:22: note: in expansion of macro '__ALIGN_KERNEL'
#define ALIGN(x, a) __ALIGN_KERNEL((x), (a))
^~~~~~~~~~~~~~
include/linux/mm.h:144:26: note: in expansion of macro 'ALIGN'
#define PAGE_ALIGN(addr) ALIGN(addr, PAGE_SIZE)
^~~~~
arch/arm64/include/asm/processor.h:70:29: note: in expansion of macro 'PAGE_ALIGN'
#define TASK_UNMAPPED_BASE (PAGE_ALIGN(DEFAULT_MAP_WINDOW / 4))
^~~~~~~~~~
arch/arm64/include/asm/processor.h:70:40: note: in expansion of macro 'DEFAULT_MAP_WINDOW'
#define TASK_UNMAPPED_BASE (PAGE_ALIGN(DEFAULT_MAP_WINDOW / 4))
^~~~~~~~~~~~~~~~~~
>> arch/arm64/mm/mmap.c:98:19: note: in expansion of macro 'TASK_UNMAPPED_BASE'
mm->mmap_base = TASK_UNMAPPED_BASE + random_factor;
^~~~~~~~~~~~~~~~~~
arch/arm64/include/asm/processor.h:63:50: note: each undeclared identifier is reported only once for each function it appears in
#define DEFAULT_MAP_WINDOW (test_tsk_thread_flag(tsk, TIF_32BIT) ? \
^
include/uapi/linux/kernel.h:11:41: note: in definition of macro '__ALIGN_KERNEL_MASK'
#define __ALIGN_KERNEL_MASK(x, mask) (((x) + (mask)) & ~(mask))
^
include/linux/kernel.h:58:22: note: in expansion of macro '__ALIGN_KERNEL'
#define ALIGN(x, a) __ALIGN_KERNEL((x), (a))
^~~~~~~~~~~~~~
include/linux/mm.h:144:26: note: in expansion of macro 'ALIGN'
#define PAGE_ALIGN(addr) ALIGN(addr, PAGE_SIZE)
^~~~~
arch/arm64/include/asm/processor.h:70:29: note: in expansion of macro 'PAGE_ALIGN'
#define TASK_UNMAPPED_BASE (PAGE_ALIGN(DEFAULT_MAP_WINDOW / 4))
^~~~~~~~~~
arch/arm64/include/asm/processor.h:70:40: note: in expansion of macro 'DEFAULT_MAP_WINDOW'
#define TASK_UNMAPPED_BASE (PAGE_ALIGN(DEFAULT_MAP_WINDOW / 4))
^~~~~~~~~~~~~~~~~~
>> arch/arm64/mm/mmap.c:98:19: note: in expansion of macro 'TASK_UNMAPPED_BASE'
mm->mmap_base = TASK_UNMAPPED_BASE + random_factor;
^~~~~~~~~~~~~~~~~~
vim +/TASK_UNMAPPED_BASE +98 arch/arm64/mm/mmap.c
1d18c47c Catalin Marinas 2012-03-05 81
1d18c47c Catalin Marinas 2012-03-05 82 /*
1d18c47c Catalin Marinas 2012-03-05 83 * This function, called very early during the creation of a new process VM
1d18c47c Catalin Marinas 2012-03-05 84 * image, sets up which VM layout function to use:
1d18c47c Catalin Marinas 2012-03-05 85 */
8f2af155 Kees Cook 2018-04-10 86 void arch_pick_mmap_layout(struct mm_struct *mm, struct rlimit *rlim_stack)
1d18c47c Catalin Marinas 2012-03-05 87 {
dd04cff1 Kees Cook 2015-04-14 88 unsigned long random_factor = 0UL;
dd04cff1 Kees Cook 2015-04-14 89
dd04cff1 Kees Cook 2015-04-14 90 if (current->flags & PF_RANDOMIZE)
2b68f6ca Kees Cook 2015-04-14 91 random_factor = arch_mmap_rnd();
dd04cff1 Kees Cook 2015-04-14 92
1d18c47c Catalin Marinas 2012-03-05 93 /*
1d18c47c Catalin Marinas 2012-03-05 94 * Fall back to the standard layout if the personality bit is set, or
1d18c47c Catalin Marinas 2012-03-05 95 * if the expected stack growth is unlimited:
1d18c47c Catalin Marinas 2012-03-05 96 */
8f2af155 Kees Cook 2018-04-10 97 if (mmap_is_legacy(rlim_stack)) {
dd04cff1 Kees Cook 2015-04-14 @98 mm->mmap_base = TASK_UNMAPPED_BASE + random_factor;
1d18c47c Catalin Marinas 2012-03-05 99 mm->get_unmapped_area = arch_get_unmapped_area;
1d18c47c Catalin Marinas 2012-03-05 100 } else {
8f2af155 Kees Cook 2018-04-10 101 mm->mmap_base = mmap_base(random_factor, rlim_stack);
1d18c47c Catalin Marinas 2012-03-05 102 mm->get_unmapped_area = arch_get_unmapped_area_topdown;
1d18c47c Catalin Marinas 2012-03-05 103 }
1d18c47c Catalin Marinas 2012-03-05 104 }
1d18c47c Catalin Marinas 2012-03-05 105
:::::: The code at line 98 was first introduced by commit
:::::: dd04cff1dceab18226853b555cf07914648a235f arm64: standardize mmap_rnd() usage
:::::: TO: Kees Cook <keescook@chromium.org>
:::::: CC: Linus Torvalds <torvalds@linux-foundation.org>
---
0-DAY kernel test infrastructure Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all Intel Corporation
On Wed, Oct 17, 2018 at 05:34:57PM +0100, Steve Capper wrote: > We wish to introduce a 52-bit virtual address space for userspace but > maintain compatibility with software that assumes the maximum VA space > size is 48 bit. > > In order to achieve this, on 52-bit VA systems, we make mmap behave as > if it were running on a 48-bit VA system (unless userspace explicitly > requests a VA where addr[51:48] != 0). > > On a system running a 52-bit userspace we need TASK_SIZE to represent > the 52-bit limit as it is used in various places to distinguish between > kernelspace and userspace addresses. > > Thus we need a new limit for mmap, stack, ELF loader and EFI (which uses > TTBR0) to represent the non-extended VA space. > > This patch introduces DEFAULT_MAP_WINDOW and DEFAULT_MAP_WINDOW_64 and > switches the appropriate logic to use that instead of TASK_SIZE. > > Signed-off-by: Steve Capper <steve.capper@arm.com> Whilst testing this series I inadvertantly dropped CONFIG_COMPAT which has led to some kbuild errors with defconfig. I will make the following changes to this patch. [...] > diff --git a/arch/arm64/include/asm/processor.h b/arch/arm64/include/asm/processor.h > index 79657ad91397..46c9d9ff028c 100644 > --- a/arch/arm64/include/asm/processor.h > +++ b/arch/arm64/include/asm/processor.h > @@ -26,6 +26,8 @@ > > #ifndef __ASSEMBLY__ > > +#define DEFAULT_MAP_WINDOW_64 (UL(1) << VA_BITS) > + > /* > * Default implementation of macro that returns current > * instruction pointer ("program counter"). > @@ -58,13 +60,16 @@ > TASK_SIZE_32 : TASK_SIZE_64) > #define TASK_SIZE_OF(tsk) (test_tsk_thread_flag(tsk, TIF_32BIT) ? \ > TASK_SIZE_32 : TASK_SIZE_64) > +#define DEFAULT_MAP_WINDOW (test_tsk_thread_flag(tsk, TIF_32BIT) ? \ > + TASK_SIZE_32 : DEFAULT_MAP_WINDOW_64) Instead of test_tsk_thread_flag I will use test_thread_flag for DEFAULT_MAP_WINDOW. > #else > #define TASK_SIZE TASK_SIZE_64 > +#define DEFAULT_MAP_WINDOW DEFAULT_MAP_WINDOW_64 > #endif /* CONFIG_COMPAT */ > > -#define TASK_UNMAPPED_BASE (PAGE_ALIGN(TASK_SIZE / 4)) > +#define TASK_UNMAPPED_BASE (PAGE_ALIGN(DEFAULT_MAP_WINDOW / 4)) > +#define STACK_TOP_MAX DEFAULT_MAP_WINDOW_64 > > -#define STACK_TOP_MAX TASK_SIZE_64 > #ifdef CONFIG_COMPAT > #define AARCH32_VECTORS_BASE 0xffff0000 > #define STACK_TOP (test_thread_flag(TIF_32BIT) ? \ > diff --git a/drivers/firmware/efi/arm-runtime.c b/drivers/firmware/efi/arm-runtime.c > index 922cfb813109..952cec5b611a 100644 > --- a/drivers/firmware/efi/arm-runtime.c > +++ b/drivers/firmware/efi/arm-runtime.c > @@ -38,7 +38,7 @@ static struct ptdump_info efi_ptdump_info = { > .mm = &efi_mm, > .markers = (struct addr_marker[]){ > { 0, "UEFI runtime start" }, > - { TASK_SIZE_64, "UEFI runtime end" } > + { DEFAULT_MAP_WINDOW_64, "UEFI runtime end" } > }, > .base_addr = 0, > }; [...] Also I will modify arch/arm64/mm/init.c:615 to be: BUILD_BUG_ON(TASK_SIZE_32 > DEFAULT_MAP_WINDOW_64); The above give me a working kernel with defconig. I will perform more tests on COMPAT before sending a revised series out. Cheers,
diff --git a/arch/arm64/include/asm/elf.h b/arch/arm64/include/asm/elf.h index 433b9554c6a1..bc9bd9e77d9d 100644 --- a/arch/arm64/include/asm/elf.h +++ b/arch/arm64/include/asm/elf.h @@ -117,7 +117,7 @@ * 64-bit, this is above 4GB to leave the entire 32-bit address * space open for things that want to use the area for 32-bit pointers. */ -#define ELF_ET_DYN_BASE (2 * TASK_SIZE_64 / 3) +#define ELF_ET_DYN_BASE (2 * DEFAULT_MAP_WINDOW_64 / 3) #ifndef __ASSEMBLY__ diff --git a/arch/arm64/include/asm/processor.h b/arch/arm64/include/asm/processor.h index 79657ad91397..46c9d9ff028c 100644 --- a/arch/arm64/include/asm/processor.h +++ b/arch/arm64/include/asm/processor.h @@ -26,6 +26,8 @@ #ifndef __ASSEMBLY__ +#define DEFAULT_MAP_WINDOW_64 (UL(1) << VA_BITS) + /* * Default implementation of macro that returns current * instruction pointer ("program counter"). @@ -58,13 +60,16 @@ TASK_SIZE_32 : TASK_SIZE_64) #define TASK_SIZE_OF(tsk) (test_tsk_thread_flag(tsk, TIF_32BIT) ? \ TASK_SIZE_32 : TASK_SIZE_64) +#define DEFAULT_MAP_WINDOW (test_tsk_thread_flag(tsk, TIF_32BIT) ? \ + TASK_SIZE_32 : DEFAULT_MAP_WINDOW_64) #else #define TASK_SIZE TASK_SIZE_64 +#define DEFAULT_MAP_WINDOW DEFAULT_MAP_WINDOW_64 #endif /* CONFIG_COMPAT */ -#define TASK_UNMAPPED_BASE (PAGE_ALIGN(TASK_SIZE / 4)) +#define TASK_UNMAPPED_BASE (PAGE_ALIGN(DEFAULT_MAP_WINDOW / 4)) +#define STACK_TOP_MAX DEFAULT_MAP_WINDOW_64 -#define STACK_TOP_MAX TASK_SIZE_64 #ifdef CONFIG_COMPAT #define AARCH32_VECTORS_BASE 0xffff0000 #define STACK_TOP (test_thread_flag(TIF_32BIT) ? \ diff --git a/drivers/firmware/efi/arm-runtime.c b/drivers/firmware/efi/arm-runtime.c index 922cfb813109..952cec5b611a 100644 --- a/drivers/firmware/efi/arm-runtime.c +++ b/drivers/firmware/efi/arm-runtime.c @@ -38,7 +38,7 @@ static struct ptdump_info efi_ptdump_info = { .mm = &efi_mm, .markers = (struct addr_marker[]){ { 0, "UEFI runtime start" }, - { TASK_SIZE_64, "UEFI runtime end" } + { DEFAULT_MAP_WINDOW_64, "UEFI runtime end" } }, .base_addr = 0, }; diff --git a/drivers/firmware/efi/libstub/arm-stub.c b/drivers/firmware/efi/libstub/arm-stub.c index 6920033de6d4..ac297c20ab1e 100644 --- a/drivers/firmware/efi/libstub/arm-stub.c +++ b/drivers/firmware/efi/libstub/arm-stub.c @@ -33,7 +33,7 @@ #define EFI_RT_VIRTUAL_SIZE SZ_512M #ifdef CONFIG_ARM64 -# define EFI_RT_VIRTUAL_LIMIT TASK_SIZE_64 +# define EFI_RT_VIRTUAL_LIMIT DEFAULT_MAP_WINDOW_64 #else # define EFI_RT_VIRTUAL_LIMIT TASK_SIZE #endif
We wish to introduce a 52-bit virtual address space for userspace but maintain compatibility with software that assumes the maximum VA space size is 48 bit. In order to achieve this, on 52-bit VA systems, we make mmap behave as if it were running on a 48-bit VA system (unless userspace explicitly requests a VA where addr[51:48] != 0). On a system running a 52-bit userspace we need TASK_SIZE to represent the 52-bit limit as it is used in various places to distinguish between kernelspace and userspace addresses. Thus we need a new limit for mmap, stack, ELF loader and EFI (which uses TTBR0) to represent the non-extended VA space. This patch introduces DEFAULT_MAP_WINDOW and DEFAULT_MAP_WINDOW_64 and switches the appropriate logic to use that instead of TASK_SIZE. Signed-off-by: Steve Capper <steve.capper@arm.com> --- arch/arm64/include/asm/elf.h | 2 +- arch/arm64/include/asm/processor.h | 9 +++++++-- drivers/firmware/efi/arm-runtime.c | 2 +- drivers/firmware/efi/libstub/arm-stub.c | 2 +- 4 files changed, 10 insertions(+), 5 deletions(-)