Commit a6c19dfe authored by Andy Lutomirski's avatar Andy Lutomirski Committed by Linus Torvalds
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arm64,ia64,ppc,s390,sh,tile,um,x86,mm: remove default gate area 



The core mm code will provide a default gate area based on
FIXADDR_USER_START and FIXADDR_USER_END if
!defined(__HAVE_ARCH_GATE_AREA) && defined(AT_SYSINFO_EHDR).

This default is only useful for ia64.  arm64, ppc, s390, sh, tile, 64-bit
UML, and x86_32 have their own code just to disable it.  arm, 32-bit UML,
and x86_64 have gate areas, but they have their own implementations.

This gets rid of the default and moves the code into ia64.

This should save some code on architectures without a gate area: it's now
possible to inline the gate_area functions in the default case.

Signed-off-by: default avatarAndy Lutomirski <luto@amacapital.net>
Acked-by: default avatarNathan Lynch <nathan_lynch@mentor.com>
Acked-by: default avatarH. Peter Anvin <hpa@linux.intel.com>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> [in principle]
Acked-by: Richard Weinberger <richard@nod.at> [for um]
Acked-by: Will Deacon <will.deacon@arm.com> [for arm64]
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Nathan Lynch <Nathan_Lynch@mentor.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent e0d9bf4c

arch/arm64/include/asm/page.h

+0 −3
Original line number Diff line number Diff line
@@ -28,9 +28,6 @@ 
#define PAGE_SIZE		(_AC(1,UL) << PAGE_SHIFT)

#define PAGE_MASK		(~(PAGE_SIZE-1))



/* We do define AT_SYSINFO_EHDR but don't use the gate mechanism */

#define __HAVE_ARCH_GATE_AREA		1



/*

 * The idmap and swapper page tables need some space reserved in the kernel

 * image. Both require pgd, pud (4 levels only) and pmd tables to (section)

arch/arm64/kernel/vdso.c

+0 −19
Original line number Diff line number Diff line
@@ -194,25 +194,6 @@ up_fail: 
	return PTR_ERR(ret);

}



/*

 * We define AT_SYSINFO_EHDR, so we need these function stubs to keep

 * Linux happy.

 */

int in_gate_area_no_mm(unsigned long addr)

{

	return 0;

}



int in_gate_area(struct mm_struct *mm, unsigned long addr)

{

	return 0;

}



struct vm_area_struct *get_gate_vma(struct mm_struct *mm)

{

	return NULL;

}



/*

 * Update the vDSO data page to keep in sync with kernel timekeeping.

 */

arch/ia64/include/asm/page.h

+2 −0
Original line number Diff line number Diff line
@@ -231,4 +231,6 @@ get_order (unsigned long size) 
#define PERCPU_ADDR		(-PERCPU_PAGE_SIZE)

#define LOAD_OFFSET		(KERNEL_START - KERNEL_TR_PAGE_SIZE)



#define __HAVE_ARCH_GATE_AREA	1



#endif /* _ASM_IA64_PAGE_H */

arch/ia64/mm/init.c

+31 −0
Original line number Diff line number Diff line
@@ -278,6 +278,37 @@ setup_gate (void) 
	ia64_patch_gate();

}



static struct vm_area_struct gate_vma;



static int __init gate_vma_init(void)

{

	gate_vma.vm_mm = NULL;

	gate_vma.vm_start = FIXADDR_USER_START;

	gate_vma.vm_end = FIXADDR_USER_END;

	gate_vma.vm_flags = VM_READ | VM_MAYREAD | VM_EXEC | VM_MAYEXEC;

	gate_vma.vm_page_prot = __P101;



	return 0;

}

__initcall(gate_vma_init);



struct vm_area_struct *get_gate_vma(struct mm_struct *mm)

{

	return &gate_vma;

}



int in_gate_area_no_mm(unsigned long addr)

{

	if ((addr >= FIXADDR_USER_START) && (addr < FIXADDR_USER_END))

		return 1;

	return 0;

}



int in_gate_area(struct mm_struct *mm, unsigned long addr)

{

	return in_gate_area_no_mm(addr);

}



void ia64_mmu_init(void *my_cpu_data)

{

	unsigned long pta, impl_va_bits;

arch/powerpc/include/asm/page.h

+0 −3
Original line number Diff line number Diff line
@@ -48,9 +48,6 @@ extern unsigned int HPAGE_SHIFT; 
#define HUGE_MAX_HSTATE		(MMU_PAGE_COUNT-1)

#endif



/* We do define AT_SYSINFO_EHDR but don't use the gate mechanism */

#define __HAVE_ARCH_GATE_AREA		1



/*

 * Subtle: (1 << PAGE_SHIFT) is an int, not an unsigned long. So if we

 * assign PAGE_MASK to a larger type it gets extended the way we want

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